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Devenir des gilets jaunes
No full textInternational audience"Il y a 7 ans surgissait le mouvement des Gilets Jaunes. Si certain·es continuent à vouloir le faire vivre, une très large majorité s'est repliée vers la sphère privée ou engagée dans d'autres luttes. L'étude de leurs trajectoires permet de comprendre à la fois le mouvement et ses conséquences sur des individus en grande partie issus de classes populaires et dépourvus de passé militant. Rédigé par un collectif de recherche pluridisciplinaire, l'ouvrage entend décrire par des portraits sociologiques comment ces femmes et hommes sont devenus des Gilets jaunes. En croisant configurations sociales et territoriales, dispositions acquises et situations vécues dans l'engagement, l'analyse biographique renouvelle le regard sur plusieurs dimensions de ce mouvement social inédit : le rapport au corps, l'engagement en couple, le rapport au savoir, le rapport salarial, les inégalités de genre, l'ancrage territorial et le maintien de l'engagement.
Léon Walras, Economist and Liberal Socialist: Essays
No full textInternational audienceThis book offers an in-depth exploration of the genesis of Léon Walras's work and its impact on the history of economics. Through a thorough examination of both published and unpublished writings, correspondence, and personal notes, the book reveals new insights into Walras's intellectual evolution and his overall conception of economics. It traces the formation of his theoretical framework, the elements of his ``political and social economy,'' and his aspirations for a ``liberal and humanitarian scientific socialism."Traduction de : Jean-Pierre Potier. Léon Walras, économiste et socialiste libéral. Classiques Garnier, 2019, Bibliothèque de l'économiste, 978-2-406-09593-4
Toujours là ?
No full textInternational audienceEtudes issue d'enquêtes collectives sur le mouvement des gilets jaunes qui a débuté en automne 2018 et qui a marqué l'histoire sociale contemporaine de la France par sa durée, son ampleur et ses spécificités. En effet, des collectifs de gilets jaunes se mobilisent encore, contre la réforme des retraites en 2023 notamment, et continuent le renouvellement des pratiques contestataires
Exploration génétique du lupus juvénile : contribution du séquençage de l’exome à la compréhension des formes monogéniques
No full textSystemic lupus erythematosus (SLE) is a chronic, multisystem autoimmune disease with highly heterogeneous clinical manifestations and a complex pathophysiology. The presence of antinuclear antibodies is a key diagnostic biomarker. An increased type I interferon signature is observed in most patients, reflecting its central role in SLE pathogenesis. SLE is considered as a multifactorial disease, resulting from the interplay of genetic and environmental factors. However, rare monogenic forms, caused by pathogenic variants in a single gene, have been described, in particular in patients with early-onset or syndromic presentations. To better characterize the genetic basis of pediatric SLE, we conducted a genetic analysis in a cohort of patients with disease onset before 18 years of age. An initial targeted approach identified a monogenic SLE secondary to a novel DNASE1L3 variant affecting RNA splicing and confirmed using a minigene assay. We then performed exome sequencing in 263 individuals from 172 unrelated families. A molecular diagnosis compatible with the clinical phenotype was found in 17 patients (10% of the cohort). Among these cases, we identified pathogenic or likely pathogenic variants in known monogenic SLE genes, including a novel variant in C1QA. We also detected variants in genes previously associated with SLE-related phenotypes (COPA, ADAR, TLR7, IKZF3, RELA, PTPN11, SERPING1). In addition, we identified variants in genes linked to primary immunodeficiencies (IRAK4, USB1), autoinflammatory disorders (PSTPIP1), and unexpected genes such as ETV6 and MAN1B1, suggesting the involvement of novel pathways in lupus pathogenesis. We also identified candidate variants in genes not previously associated with SLE and contributed to the functional characterization of newly implicated genes involved in monogenic autoimmunity, including SOCS1, PTPN2, and DOCK11. We also initiated studies on somatic SOCS1 variants discovered in the context of hematological malignancies, revealing pathogenic missense mutations that could participate to lymphomagenesis. These findings highlight the heterogenous genetic basis of pediatric lupus and emphasize the importance of genetic testing, particularly in very early-onset or syndromic cases. Notably, nearly one-third of patients in these groups carry a monogenic cause. SLE can be viewed as a clinical syndrome that, particularly in pediatric cases, may represent a shared phenotype resulting from diverse molecular mechanisms. From a clinical perspective, molecular diagnosis enables more accurate classification and the possibility to access to targeted therapies, which may offer greater efficacy and fewer side effects compared to classical immunosuppressive treatments. Finally, studying rare monogenic forms of SLE provides insights into the mechanisms of immune tolerance and contributes to a broader understanding of autoimmunity.Le lupus érythémateux systémique (LES) est une maladie auto-immune systémique chronique caractérisée par une atteinte multiviscérale et une grande hétérogénéité clinique. La présence d’anticorps antinucléaires constitue un marqueur biologique central pour le diagnostic. Un excès d’interféron de type I est également retrouvé chez la majorité des patients et joue un rôle clé dans la physiopathologie de la maladie. Le LES est considéré comme une pathologie multifactorielle, en raison de la contribution combinée de facteurs génétiques et environnementaux. Néanmoins, de rares formes monogéniques ont été rapportées, liées à des variants ponctuels dans un seul gène, notamment chez des patients présentant un début précoce des symptômes. Afin de mieux comprendre les bases génétiques du lupus pédiatrique, nous avons mené une étude sur une cohorte de patients atteints de LES à début pédiatrique (avant 18 ans). Par une approche de Sanger, nous avons tout d’abord identifié un premier cas de lupus monogénique secondaire à un nouveau variant de DNASE1L3. Ce variant, suspecté d’altérer l’épissage, a été fonctionnellement exploré par une approche minigene. Un séquençage de l’exome a ensuite été réalisé chez 263 individus issus de 172 familles distinctes. Au total, un diagnostic moléculaire compatible avec le tableau clinique a pu être établi chez 17 patients, soit environ 10 % de la cohorte. Parmi eux, nous avons mis en évidence des variants pathogènes ou probablement pathogènes dans des gènes déjà connus dans les formes monogéniques de lupus, notamment un nouveau variant de C1QA, ainsi que des variants dans d’autres gènes compatibles avec un phénotype lupique tels que COPA, ADAR, TLR7, IKZF3, RELA, PTPN11 et SERPING1. L’analyse a également révélé des variants dans des gènes associés à des déficits immunitaires (IRAK4, USB1), des maladies auto-inflammatoires (PSTPIP1) ainsi que dans des gènes inattendus comme ETV6 et MAN1B1, suggérant l’implication de voies biologiques jusque-là non reconnues dans la physiopathologie du lupus. Nous avons également identifié des variants dans des gènes candidats et contribué à la caractérisation fonctionnelle de nouveaux gènes impliqués dans des formes monogéniques d’auto-immunité, notamment SOCS1, PTPN2 et DOCK11. Enfin, nous avons également initié des travaux portant sur des variants somatiques du gène SOCS1, identifiés dans un contexte de cancers hématologiques, montrant des variants faux-sens pathogènes. Ces résultats démontrent tout d’abord l’intérêt d’un séquençage pangénomique pour le diagnostic des formes pédiatriques de LES, en particulier pour les formes très précoces ou syndromiques où l’on retrouve une cause génétique dans près d’un tiers des cas. le lupus représente un phénotype autoimmun systémique commun à des altérations moléculaires hétérogènes Pour les patients, la découverte de ces formes monogéniques permet non seulement de préciser le diagnostic, mais ouvre également la voie à des thérapies personnalisées et ciblées, potentiellement plus efficaces et moins toxiques que les immunosuppresseurs classiques. Enfin, l’étude de ces formes rares contribue à une meilleure compréhension des mécanismes de tolérance immunitaire et à l’identification des facteurs moléculaires régulateurs de l’auto-immunité chez l’Homme
Universalité des évènements extrêmes en turbulence
No full textInternational audienceThe universality of small scales, a cornerstone of turbulence, has been nominally confirmed for low-order mean-field statistics, such as the energy spectrum. However, small scales exhibit strong intermittency, exemplified by formation of extreme events which deviate anomalously from a mean-field description. Here, we investigate the universality of small scales by analyzing extreme events of velocity gradients in different turbulent flows, viz., direct numerical simulations of homogeneous isotropic turbulence, inhomogeneous channel flow, and laboratory measurements in a von Kármán mixing tank. We demonstrate that the scaling exponents of velocity gradient moments, as function of Reynolds number ( Re ), are universal, in agreement with previous studies at lower Re , and further show that even proportionality constants are universal when considering one moment order as a function of another. Additionally, by comparing various unconditional and conditional statistics across different flows, we demonstrate that the structure of the velocity gradient tensor is also universal. Overall, our findings provide compelling evidence that even extreme events are universal, with profound implications for turbulence theory and modeling.L'universalité des petites échelles, pierre angulaire de la turbulence, a été nominalement confirmée pour les statistiques de champ moyen d'ordre inférieur, telles que le spectre d'énergie. Cependant, les petites échelles présentent une forte intermittence, illustrée par la formation d'événements extrêmes qui s'écartent de manière anormale d'une description de champ moyen. Nous étudions ici l'universalité des petites échelles en analysant les événements extrêmes des gradients de vitesse dans différents écoulements turbulents, à savoir des simulations numériques directes de turbulence isotrope homogène, des écoulements non homogènes dans des canaux et des mesures en laboratoire dans un réservoir de mélange von Kármán. Nous démontrons que les exposants d'échelle des moments de gradient de vitesse, en fonction du nombre de Reynolds ( Re ), sont universels, en accord avec les études précédentes à Re inférieur, et montrons en outre que même les constantes de proportionnalité sont universelles lorsque l'on considère un ordre de moment comme fonction d'un autre. De plus, en comparant diverses statistiques inconditionnelles et conditionnelles entre différents écoulements, nous démontrons que la structure du tenseur de gradient de vitesse est également universelle
Advancing European high-contrast imaging R&D towards the Habitable Worlds Observatory
No full textInternational audienceAbstract The Habitable Worlds Observatory (HWO) will enable a transformative leap in the direct imaging and characterization of Earth-like exoplanets. For this, NASA is focusing on early investment in technology development prior to mission definition and actively seeking international partnerships earlier than for previous missions. The “R&D for Space-Based HCI in Europe” workshop, held in March 2024 at Paris Observatory, convened leading experts in high-contrast imaging (HCI) to discuss European expertise and explore potential strategies for European contributions to HWO. This paper synthesizes the discussions and outcomes of the workshop, highlighting Europe’s critical contributions to past and current HCI efforts, the synergies between ground- and space-based technologies, and the importance of laboratory testbeds and collaborative funding mechanisms. Key conclusions include the need for Europe to invest in technology development for areas such as deformable mirrors and advanced detectors, and establish or enhance laboratory facilities for system-level testing. Putting emphasis on the urgency of aligning with the timeline of HWO, the participants called on an open affirmation by the European Space Agency (ESA) that a European contribution to HWO is clearly anticipated, to signal national agencies and unlock funding opportunities at the national level. Based on the expertise demonstrated through R&D, Europe is poised to play a pivotal role in advancing global HCI capabilities, contributing to the characterization of temperate exoplanets and fostering innovation across domains
TWIN-WIDTH VII: GROUPS
No full textTwin-width is a recently introduced graph parameter with applications in algorithmics, combinatorics, and finite model theory. For graphs of bounded degree, finiteness of twin-width is preserved by quasiisometry. Thus, through Cayley graphs, it defines a group invariant.We prove that groups which are abelian, hyperbolic, ordered, solvable, or with polynomial growth, have finite twin-width. Twin-width can be characterised by excluding patterns in the self-action by product of the group elements. Based on this characterisation, we propose a strengthening called uniform twin-width, which is stable under constructions such as group extensions, direct products, and direct limits.The existence of finitely generated groups with infinite twin-width is not immediate. We construct one using a result of Osajda on embeddings of graphs into groups. This implies the existence of a class of finite graphs with unbounded twin-width but containing 2 O(n) • n! graphs on vertex set {1, . . . , n}, settling a question asked in a previous work.</div
Answering Related Questions
No full textWe introduce the meta-problem Sidestep(Π, dist, d) for a problem Π, a metric dist over its inputs, and a map d : N → R+ ∪ {∞}. A solution to Sidestep(Π, dist, d) on an input I of Π is a pair (J, Π(J)) such that dist(I, J) ⩽ d(|I|) and Π(J) is a correct answer to Π on input J. This formalizes the notion of answering a related question (or sidestepping the question), for which we give some practical and theoretical motivations, and compare it to the neighboring concepts of smoothed analysis, planted problems, and edition problems. Informally, we call hardness radius the "largest" d such that Sidestep(Π, dist, d) is NP-hard. This framework calls for establishing the hardness radius of problems Π of interest for the relevant distances dist.We exemplify it with graph problems and two distances dist∆ and diste (the edge edit distance) such that dist∆(G, H) (resp. diste(G, H)) is the maximum degree (resp. number of edges) of the symmetric difference of G and H if these graphs are on the same vertex set, and +∞ otherwise. Thus when solving Sidestep(Π, dist∆, d) (resp. Sidestep(Π, diste, d)) on an n-vertex input G, acceptably-close graphs H are obtained by XORing G with a graph of maximum degree at most d(n) (resp. having at most d(n) edges). We show that the decision problems Independent Set, Clique, Vertex Cover, Coloring, Clique Cover have hardness radius n 1 2 -o(1) for dist∆, and n 4 3 -o(1) for diste, that Hamiltonian Cycle (or Hamiltonian Path) has hardness radius 0 for dist∆, and somewhere between n 1 2 -o(1) and n/3 for diste, and that Dominating Set has hardness radius n 1-o(1) for diste. We leave several open questions.Answering Related Questions as challenging as on general inputs. Or, at the very least, D ′ should not contain too many trivial instances. This can in principle be favored by tweaking the distance function between inputs.Second motivation. On the other hand, the magnitude of the hardness radius somehow informs, at least for relevant input metrics, on the degree of difficulty of a problem. For instance, for a chosen distance between inputs of NP-hard graph problems, this draws a hierarchy of increasingly hard problems. We wish to explore how this hierarchy 1 compares with those obtained through the prisms of approximability, parameterized complexity, and smoothed analysis.We will later elaborate on our motivations, and how our new meta-problem and the hardness radius relate to well-established concepts: smoothed analysis, planted problems, and edge modification problems. We now get more formal. Given a problem Π, a distance dist over its inputs, and a non-decreasing function d : N → R + ∪ {∞}, we introduce the following problem.In the above, |I| denotes the size of input I, defined as a natural number. When the main part of I is a graph, |I| denotes its number of vertices. Note that Π can be a decision or a function problem. And in both cases Sidestep(Π, dist, d) is itself a function problem. Thus Π(J) lies in {true, false} if Π is a decision problem, and it is the correct solution to Π on input J, or a special symbol nil indicating the absence of solution, when Π is a function problem. Often, there may be several correct solutions. We denote the set of all correct solutions to Π on J by Sol Π (J), and Π(J) should be thought as any fixed element of Sol Π (J). We make the slight abuse of notation of writing the expression d(n) instead of the function d in the third field of Sidestep.Considered metrics. We will exclusively deal with problems Π whose input is a weightless undirected graph, and optionally an integer threshold, and consider two distances between graphs. Both require that two graphs have the same vertex set for the distance between them to be finite. For every two graphs G, H, dist e (G, Hotherwise, where △ denotes the symmetric difference. For two graphs G, H on the same vertex set, V (G), we may denote by G△H the graph with vertex set V (G) and edge setotherwise, where ∆(•) denotes the maximum degree of its graph argument. If the whole input consists of a graph together with some additional integral, rational, or real parameters (typically serving as thresholds for a graph property), a finite distance between (G, k) and (H, ℓ) implies that k = ℓ. Specifically, for every considered distance dist, dist((G, k), (H, ℓ)) = 1 or these hierarchies since more than one input distance can be considered</div
Every Graph is Essential to Large Treewidth
No full textWe show that for every graph H, there is a hereditary weakly sparse graph class H of unbounded treewidth such that the H-free (i.e., excluding H as an induced subgraph) graphs of H have bounded treewidth. This refutes several conjectures and critically thwarts the quest for the unavoidable induced subgraphs in classes of unbounded treewidth, a wished-for counterpart of the Grid Minor theorem. We actually show a stronger result: For every positive integer t, there is a hereditary graph class t of unbounded treewidth such that for any graph H of treewidth at most t, the H-free graphs of t have bounded treewidth. Our construction is a variant of so-called layered wheels. We also introduce a framework of abstract layered wheels, based on their most salient properties. In particular, we streamline and extend key lemmas previously shown on individual layered wheels. We believe that this should greatly help develop this topic, which appears to be a very strong yet underexploited source of counterexamples
Conflits de valeurs durant la pandémie.Étude de tribunes, appels de collectifs et entretiens dans la presse écrite française(février 2020-janvier 2022)
No full textJean-Claude Guerrini, « Conflitos de valores durante a pandemia: estudo de tribunas, apelos coletivos entrevistas na imprensa escrita francesa (fevereiro 2020- janeiro 2022), Wander Emediato (dir.) Interações controversas e violência verbal sobre temas sociais sensíveis Wander Emediato, Pontes Editores, 2023.The pandemic, which first made its presence felt in France in February 2020, raised a considerable number of questions, as it did around the world, not only about the health situation itself, but also about the various ways of dealing with it. Despite the shock that gripped the majority of the population, there was an immediate need for clarification about what was happening, with government decisions, relayed by the mainstream media, attracting generally critical comments. The crisis situation, which disrupts the comfort of discourse tailored to current behaviours and norms, is by its very nature conducive to the expression of commentators involved in various ways in city life, whether they were keen to provide insights and remedies in line with their aspirations or to seize the opportunity to identify political or social shortcomings or deficiencies that the event had brought to light. This dramatic situation, which suddenly calls into question the most deeply held beliefs and sows discord even within families, seems to us to provide a unique opportunity to examine a specific issue that we consider central to the field of rhetoric and argumentation studies: the forms of value judgements and the role played by values in the formulation of points of view. Argumentation certainly aims to provoke or increase support for theses and proposals for action (Perelman and Olbrechts-Tyteca, 1958: 5). But it also seeks to modify or consolidate the recipient's perception of situations, behaviours, hierarchies and statuses. It strives to modify, in a direction that suits it, the other person's representations, i.e. their images of reality and the often implicit judgements and norms to which they adhere. This is why we felt it would be useful to examine the traces left in the national press by the occasional contributions of individuals and groups wishing to intervene in the public debate through opinion pieces, petitions and appeals, but also through interviews given at the request of journalists keen to hear a particular point of view that had been noticed in the media expressed at length. For an audience eager to break out of its isolation and gain an understanding of the unprecedented situation in which everyone's lives had been turned upside down, these statements by social actors, intellectuals and groups created for the occasion could offer a means of finding one's bearings, recognising common ground and, if necessary, taking a stand.Translated with DeepL.com (free version)La pandémie, qui a fait sentir ses premiers effets en France en février 2020, a suscité, comme partout dans le monde, un nombre considérable d'interrogations portant non seulement sur la situation sanitaire proprement dite, mais aussi sur les diverses manières d'y faire face. En dépit de la sidération qui a gagné la majorité de la population, le besoin de disposer d'un éclairage sur ce qui était en train de se passer s'est immédiatement fait sentir, les décisions gouvernementales, relayées par les grands médias audiovisuels suscitant des commentaires généralement critiques. La situation de crise, qui brise le confort des discours ajustés aux comportements et aux normes courantes, est par nature propice à l'expression de commentateurs impliqués à des titres divers dans la vie de la cité, qu'ils soient désireux d'apporter des éléments d'intelligibilité et des remèdes conformes à leurs aspirations ou qu'ils saisissent cette occasion pour identifier des déficiences ou des carences politiques ou sociales que l'événement viendrait révéler. Cette conjoncture dramatique, remettant brusquement en cause les évidences les mieux ancrées, semant la discorde jusqu'au sein des familles, nous semble procurer une occasion privilégiée pour examiner une question précise, à nos yeux centrale dans le champ des études de rhétorique et d'argumentation, celle des formes du jugement de valeur et du rôle joué par le valeurs dans la formulation des points de vue. L'argumentation vise, certes, à provoquer ou accroître l'adhésion à des thèses, à des propositions d'action (Perelman et Olbrechts-Tyteca, 1958 : 5). Mais elle cherche aussi à modifier ou à consolider la perception que le destinataire peut avoir des situations, des comportements, des hiérarchies et des statuts en vigueur. Elle s'efforce de modifier dans le sens qui lui convient les représentations de l'autre, c'est-à-dire les images qu'il se fait de la réalité, les jugements et les normes le plus souvent implicites auxquels il adhère. C'est pourquoi il nous a paru utile d'examiner les traces laissées dans la presse nationale par la contribution occasionnelle de personnalités et de collectifs désireux d'intervenir dans le débat public dans des tribunes, des pétitions, des appels, mais aussi dans des interviews accordées à la demande de journalistes désireux de voir s'exprimer « en longueur » tel ou tel point de vue remarqué dans les médias. Pour un public désireux de sortir de son isolement, d'accéder à une compréhension de la situation inédite dans laquelle la vie de chacun(e) se trouvait bouleversée, ces prises de position d'acteurs sociaux, d'intellectuels et de collectifs créés pour la circonstance pouvaient offrir un moyen pour se repérer, reconnaître des convergences de vue, et au besoin prendre position