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MIRS/MMX: an imaging spectrometer to observe the Martian aerosols
No full textInternational audienceMIRS (MMX InfraRed Spectrometer) is the imaging spectrometer (0.9-3.6 µm) [1] of the JAXA MMX (Martian Moons eXploration) mission [2]. The mission will be launched in 2026 to the Martian system, with an arrival planned in 2027. The mission's main objective is to study the two Martian moons, Phobos and Deimos, to collect samples of Phobos and bring them back to Earth in 2031. Another major aim of the mission [3] and the MIRS instrument [1] is to answer key science questions regarding the transport processes of dust and water in the Martian atmosphere [3], such as: how do local and regional dust storms form, grow and evolve? What is the diurnal behaviour of water ice clouds (formation, transport, dynamics)? The MMX probe will be injected into a quasi-circular equatorial orbit around Mars at an altitude of about 6000 km. From this particular orbit, four different observation modes of MIRS are expected for Mars observations (see Figure 1): the so-called nominal mode that maximises the longitudinal overlap, global mapping mode that covers all the illuminated Martian disk up to medium-high latitudes (+/- 60°), region of interest mode that provides temporal resolution (down to 15 minutes) above a limited area, and the limb mode. Each mode will be useful to study the spatial and temporal variations of aerosols (atmospheric dust, water and CO2 ices), and their fine diurnal variations. Indeed, the particular orbit of MMX (the second probe after Hope to be in equatorial orbit) will get us access to observations at very different local times with high spatial resolution, which will certainly provide some answers to the question addressed above.Figure 1: Illustration of the four observation modes of MIRS. The red swath represents the MIRS angle of view. The blue swath corresponds to the observation footprints acquired during a sequence of each observation mode, thanks to MIRS scanning capability (scanner mirror) and spacecraft maneuvers. Credits: CNES. To prepare for future MIRS observations, we use the DISORT (DIScrete-Ordinate-method Radiative Transfer) code [4, 5] through the pyRT_DISORT Python module [6] to simulate the expected radiance of the Martian atmosphere that MIRS will measure. The idea is to produce a look-up table (simulated spectra bank) to retrieve the aerosol properties in the flight data, which allows a faster retrieval as soon as the data are downlinked. First, we will present the parameter space exploration of the radiative transfer model done to quantify the impact of each physical parameter (e.g., observation angles, surface albedo) on the generated spectra. Then, we will discuss the look-up table parameter ranges and steps, which impact the size, as well as the computation time to create the look-up table and the time to search in it. Finally, we will show MIRS images simulated with DISORT in real conditions of the MMX probe arrival, for different atmospheric conditions (dust storms, ice clouds, clear atmosphere) and considering a simulated representative instrument transfer function [7]
Climate change : impacts and adaptation at local scale
No full textConférencier invité à l'Alliance Française de Reykjavik (Islande
Ιnterrοger les espaces alternatifs et οppοsitiοnnels des mοuvances anarchistes et libertaires à Caen et à Athènes. : Une apprοche filmique et une analyse marxiste et décοlοniale des rappοrts de pοuvοir, de prοductiοn et d'οrganisatiοn de l'espace.
No full textThis thesis combines a theoretical framework with a documentary film, allowing both to interact in a complementary way. Grounded in a situated and committed positionality, this dissertation draws on the tools of dialectical materialism, decolonial epistemologies, and radical geography to question the power relations embedded in the production, configuration, and appropriation of space. It investigates, on the one hand, how the social structure of the capitalist mode of production produces and shapes urban space; on the other hand, it explores the collective strategies of resistance and subversion carried out by anarchist and libertarian movements in Caen (France) and Athens (Greece), as well as the alternative and oppositional spaces that emerge from them. Through a transversal and dialectical analysis of the contradictions and conflicts—both internal and external—of capitalist and oppositional spatial formations, this research critically assesses the potential and limitations of these counter-hegemonic spaces to align with a logic of “revolutionary discontinuity” and to contribute to transforming the social relations of domination along the lines of class, gender, and race.Cette thèse se compose d’une analyse théorique et d’un film documentaire, articulés de manière complémentaire. Inscrite dans une position située et engagée, elle mobilise les outils du matérialisme dialectique, des épistémologies décoloniales et de la géographie radicale pour explorer les rapports de pouvoir à l’œuvre dans les processus de production, d’organisation et d’appropriation de l’espace. Elle interroge, d’un côté, la manière dont la structure sociale du mode de production capitaliste produit et façonne l’espace urbain ; de l’autre, les stratégies collectives de résistance et de subversion portées par les mouvances anarchistes et libertaires à Caen (France) et à Athènes (Grèce), ainsi que les espaces alternatifs et oppositionnels qui en émergent. À travers une analyse transversale et dialectique des contradictions et des conflictualités, à la fois internes et externes, des spatialités capitaliste et oppositionnelle, cette recherche s’attache à rendre compte des potentialités et des limites de ces espaces de rupture à s’inscrire dans une logique du « discontinuisme révolutionnaire » et à infléchir les rapports sociaux de domination de classe, de genre et de race
A comparative analysis of Phase I dose-finding designs incorporating pharmacokinetics information
No full textInternational audienceIn early clinical trials, incorporating biological mechanisms of drug action in model-baseddrug development may improve Phase I success rates compared to approaches neglecting establishedmechanisms. Our goal is to investigate how pharmacokinetics (PK) knowledge isintroduced in dose-finding methods and assess the performance of Bayesian designs incorporatingPK data to estimate toxicity and robustness to misspecifications. Following a literaturereview, three approaches to integrate PK data into toxicity estimation were selected. The firstapproach assumes a normal distribution for the Area Under the Curve (AUC). The secondmethod estimates a population PK model from longitudinal concentration data to computethe AUC for each patient. The third considers latent PK profiles to measure drug exposure.Different scenarios were implemented reflecting assumptions about the maximum tolerateddose (MTD) position and misspecifications in PK exposure measures or the PK model. Dosefindingmethods were compared using the probability of correct MTD selection and the estimatedprobability of toxicity at each dose. PK dose-finding designs performed well in termsof accurate MTD selection and were at least as effective as a method without PK. They wererobust to underlying PK model misspecification and incorrect exposure measure. Additionally,these methods can assess the dose-toxicity curve
Time to integrate measurement uncertainty in method comparison and interpretation of hemostasis laboratory assays
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Évolution des répercussions psychologiques de l’épidémie de Covid-19 sur les patients hémodialysés et leurs soignants entre avril 2020 et avril 2022
No full textNational audienceINTRODUCTION: The health crisis linked to the COVID-19 pandemic and the changes in practices it imposed in dialysis centers were accompanied by observable psychological repercussions for both patients and caregivers. Our aim was to assess the evolution of these repercussions in these two populations, to identify the coping strategies used, and to study the association between psychological symptoms and coping strategies. METHODS: This multi-center, French, non-interventional study was conducted in two phases (T1 : April 2020 and T2 : April 2022) in 13 volunteer dialysis facilities. Pseudonymized questionnaires were used to collect sociodemographic data, self-reported psychological history, and, at both study times, stress levels (simple numerical stress scales), anxiety and depressive symptomatology (Hospital Anxiety and Depression Scale), and coping strategies (Brief COPE). Factors associated with anxiety and depression were studied with a multivariable logistic regression model. RESULTS: 177 patients and 99 caregivers participated in both phases of the study. In each population, stress and anxiety scores decreased significantly between T1 and T2 (p<0.001), while depression scores remained stable. The most frequently used coping strategy was the use of positive thoughts and was associated with lower anxiety and depression symptoms. By contrast, the avoidance strategy was associated with more anxiety-depressive symptoms. CONCLUSION: By April 2022, in France, hemodialysis caregivers’ and patients’ health crisis-related stress and anxiety levels had decreased compared with April 2020. Positive thinking coping strategies should be promoted among patients and caregivers because they have been shown to protect mood.IntroductionLa crise sanitaire liée à l’épidémie de Covid-19 et les changements de pratiques imposés dans les centres de dialyse se sont accompagnés de répercussions psychologiques aussi bien chez les patients que chez les soignants. Notre objectif était d’évaluer l’évolution de ces répercussions dans ces deux populations, d’identifier les stratégies de coping mobilisées et d’étudier le lien entre symptômes psychologiques et stratégies de coping.MéthodesCette étude multicentrique, française, non interventionnelle a été menée en deux temps (T1 : avril 2020 et T2 : avril 2022) au sein de 13 structures de dialyse. Grâce à des questionnaires pseudonymisés, nous avons comparé les niveaux de stress entre T1 et T2 (échelles numériques simples de stress), la symptomatologie anxieuse et dépressive (Hospital Anxiety and Depression Scale) et les stratégies de coping (BRIEF-COPE). Les facteurs associés aux symptômes anxiodépressifs ont été étudiés grâce à un modèle de régression logistique multiple.Résultats177 patients et 99 soignants ont participé aux deux temps de l’étude. Dans chaque population, les scores de stress et d’anxiété ont significativement diminué entre T1 et T2 (p < 0,01) alors que les scores de dépression sont restés stables. La stratégie de coping la plus utilisée était le recours aux pensées positives et était associée à des symptômes d’anxiété et de dépression moins importants. Au contraire, la stratégie d’évitement était associée à davantage de symptômes anxiodépressifs.ConclusionEn avril 2022, en France, les niveaux de stress et d’anxiété des soignants et patients en hémodialyse liés à la crise sanitaire avaient diminué par rapport à avril 2020. Les stratégies d’adaptation fondées sur des pensées positives sont à encourager chez les patients et soignants, car elles s’avèrent protectrices sur l’humeur
Large responses to antidepressants or methodological artifacts? A secondary analysis of STAR*D, a single-arm, open-label, non-industry antidepressant trial
No full textInternational audienceOBJECTIVES: To replicate Stone et al.’s (2022) [1] finding that the distribution of response in clinical antidepressant trials is trimodal with large, medium-effect, and small subgroups. METHODS: To apply finite mixture modeling to pre-post Hamilton Depression Rating Scale (HDRS) differences (n = 2184) of STAR*D study’s level 1, a single-arm, open-label study. For a successful replication, the best fitting model had to be trimodal, with comparable components as in Stone et al. Secondary/sensitivity analyses repeated the analysis for different baseline levels of depression severity, imputed values, and patient-reported depression symptoms. RESULTS: The best fitting models were either bimodal or trimodal but the trimodal solution did not meet criteria for replication. The bimodal model had one component with HDRS mean change of M = -13.0, SD = 6.7 and included 65.3% of patients, and another component with M = -1.8, SD = 5.1, 34.7%, respectively. For the trimodal model, the component with the largest change (M = -14.3, SD = 6.4) applied to 52% of patients, which differed substantially from the large effect component in Stone et al. (M = -18.8, SD = 5.1) which applied to 7.2%. Secondary/sensitivity analyses arrived at similar conclusions and for patient-reported depression symptoms the best fitting models were unimodal or bimodal. CONCLUSIONS: This analysis failed to identify the trimodal distribution of response reported in Stone et al. In addition to being difficult to operationalize for regulatory purposes, results from mixture modeling are not sufficiently reliable to replace the more robust approach of comparing mean differences in depression rating scale scores between treatment arms
Territorial and gender-linked risk factors for Buruli ulcer in Southern Benin: A case-control study using geographic and behavioral surveying
No full textInternational audienceObjectives The manuscript examines the risk factors associated with Buruli ulcer in endemic regions of Benin, focusing on community practices, agricultural activities, and age and gender disparities. Methods The study, conducted from November 2021 to June 2024, used a prospective case-control approach combined with a geographic health survey. The study involved home interviews followed by guided tours of areas frequented by participants, allowing the precise identification of practices at risk of Buruli ulcer. Univariate analysis and stepwise backward stepwise logistic regression were carried out. Results Overall, 117 patients and 234 controls were included. Multivariate analysis showed that activities such as bathing (OR = 3.2, p = .04), farming in flooded areas (OR = 3.8, p = .02), and frequenting irrigation canals (OR = 5.0, p = .003) were independent risk factors for Buruli ulcer. The originality of this study was that these risks were not distributed in the same way across territory and depended on age and gender. Conclusion The findings suggest that public health interventions need to consider gender, age, territorial features, and local agricultural practices. Furthermore, integrating geographical and spatial data into epidemiological studies offers valuable insights helping to prevent the spread of this neglected tropical disease
Distribution reappraisal of peripheral T‐ and NK‐cell lymphoma entities through the French Lymphopath network database
No full textInternational audienceNo abstract availabl
Resolving structural variations missed by short-read sequencing uncovers their pathogenicity
No full textInternational audienceBackground: Short-read genome sequencing (sr-GS) affords efficient and accurate characterisation of apparently balanced chromosomal rearrangement (ABCR) breakpoints except in 9%-11% of cases that remain undetectable.Methods: Among 117 ABCR that we studied in patients with abnormal phenotype, 14 (11.9%) could not be detected by our current strategy including sr-GS, alignment against the GRCh38 reference genome and structural variant (SV) detection using Breakdancer V.1.4.5. These were all reciprocal translocations, 10 of which implicated constitutive heterochromatin, acrocentric short arms or pericentromeric regions. We re-aligned the sequencing data against the T2T-CHM13 V.2.0 reference genome and re-analysed them using five other SV callers (DELLY, GRIDSS, LUMPY, Manta and SvABA). In addition, 11 ABCRs were further characterised using FISH, linked-read sequencing, long-read sequencing or optical genome mapping, either isolated or combined.Results: We were able to characterise the breakpoints at the bp level for 12 translocations and identify specific breakpoint patterns using Integrative Genome Viewer (IGV). In each translocation, at least one breakpoint involved highly repetitive elements such as alpha-satellites, segmental duplications, satellite repeats or other poorly mapped regions. For six out of 12 patients, one of the breakpoints could explain the phenotype either by gene disruption (CAMTA1, DYRK1A, NLGN4X) or position effect (BMP2, DIAPH2, SIX3).Conclusion: Failure of sr-GS is due to highly repetitive genomic regions at SV breakpoints, either absent from the reference genome or not attributed to a unique position. The resolution of ABCRs is essential to patients' care since it allowed us to conclude to a pathogenic variant in 50% of patients