Rapid response to the M_w 4.9 earthquake of November 11, 2019 in Le Teil, Lower Rhône Valley, France

On November 11, 2019, a Mw 4.9 earthquake hit the region close to Montelimar (lower Rhône Valley, France), on the eastern margin of the Massif Central close to the external part of the Alps. Occuring in a moderate seismicity area, this earthquake is remarkable for its very shallow focal depth (between 1 and 3 km), its magnitude, and the moderate to large damages it produced in several villages. InSAR interferograms indicated a shallow rupture about 4 km long reaching the surface and the reactivation of the ancient NE-SW La Rouviere normal fault in reverse faulting in agreement with the present-day E-W compressional tectonics. The peculiarity of this earthquake together with a poor coverage of the epicentral region by permanent seismological and geodetic stations triggered the mobilisation of the French post-seismic unit and the broad French scientific community from various institutions, with the deployment of geophysical instruments (seismological and geodesic stations), geological field surveys, and field evaluation of the intensity of the earthquake. Within 7 days after the mainshock, 47 seismological stations were deployed in the epicentral area to improve the Le Teil aftershocks locations relative to the French permanent seismological network (RESIF), monitor the temporal and spatial evolution of microearthquakes close to the fault plane and temporal evolution of the seismic response of 3 damaged historical buildings, and to study suspected site effects and their influence in the distribution of seismic damage. This seismological dataset, completed by data owned by different institutions, was integrated in a homogeneous archive and distributed through FDSN web services by the RESIF data center. This dataset, together with observations of surface rupture evidences, geologic, geodetic and satellite data, will help to unravel the causes and rupture mechanism of this earthquake, and contribute to account in seismic hazard assessment for earthquakes along the major regional Cévenne fault system in a context of present-day compressional tectonics

Jeunes chercheurs en lettres, spécialité “cultures médiatiques”

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Littérature et cultures médiatiques : positionnement, pratiques et dynamiques de la jeune recherche

International audienceÀ partir de nos expériences de doctorants spécialisés dans l’étude des cultures médiatiques nous interrogeons la place de cet objet d’étude à l’université à travers nos positionnements et nos pratiques. Alors que ce domaine de recherche génère un vif engouement scientifique et qu’il apporte des réponses aux questions posées par les diverses productions et pratiques culturelles contemporaines, sa reconnaissance institutionnelle demeure problématique pour les jeunes chercheurs qui envisagent une carrière universitaire. Nous faisons l’hypothèse que cette reconnaissance difficile est due à la nature interdisciplinaire des recherches en cultures médiatiques qui empêche leur inscription dans une discipline donnée et conséquemment leur représentation dans les sections disciplinaires définies par le Conseil National des Universités. L’absence d’encadrement disciplinaire spécifique aux cultures médiatiques implique des prises de position théoriques, méthodologiques et stratégiques de la part des jeunes chercheurs qui travaillent sur des objets au croisement des disciplines. Étant issus de parcours littéraires nous pensons les cultures médiatiques dans le prolongement des acquis théoriques de cette discipline tout en intégrant les approches relatives à l’étude du cinéma, du jeu vidéo, du récit graphique… Ce dialogue interdisciplinaire n’est pas que métaphorique puisque les chercheurs travaillant sur les mêmes objets mais provenant de disciplines différentes se rassemblent autour de communautés dans le but commun de faire progresser la recherche

Physical and mechanical properties of clay–sand mixes to assess the performance of earth construction materials

International audienceThe reduction of CO2 emissions has become an important parameter in the choice of construction materials. Earth guarantees a low environment impact due to the reduced need of energy for its processing and transportation and also provides natural hygrothermal comfort. To facilitate the design of earthen constructions, the development of models is necessary. This paper aims to provide a database of experimental results that could be easily used for developing models based on the competition between positive effect of capillary pressure on material cohesion and negative effect induced by matrix shrinkage restrained by aggregates. Mechanical and thermal tests were carried out on three reconstituted soils composed of pure kaolinite and three contents of fine sand (0, 30 and 60%), as well as different water content configurations (fabrication water content and after drying at 50% RH). The thermal properties analyzed included thermal conductivity and specific heat capacity. The mechanical properties studied encompassed the tensile (three-point bending test) and compressive strengths, Young's modulus and Poisson's ratio (using video correlation). Moreover, an original test was developed for measuring sample shrinkage during drying. Specifically, the results clearly showed that while shrinkage is divided by 5 for the maximal sand content, tensile strength is reduced by half. Therefore, these results allow to assess the balance between benefices and disadvantages of capillary pressure induced by clay drying on earth construction materials, which is of first interest to assess cracking risk in a structure

Homogenization with non‐homogeneous plastic flow

International audienceAbstract This paper provides the solution of a homogenization model that simultaneously considers the plastic and elastic strain fields in a single analytical formulation. In addition, the authors aim to decouple plastic flows triggered in the inclusions, in the matrix at the interfaces with the inclusions, and in the matrix at a large distance from the inclusions. The authors propose an admissible displacement field containing elastic and anelastic contributions in series. This field provides a new strain homogenization formula in which the plastic deformations in the inclusions, at the interface between the matrix and the inclusions, and in the matrix far from the inclusions appear explicitly. Applications allow to evaluate the pertinence of the approximation provided by this field, and show that this new formulation is able to create macroscopic work hardening while all the elementary phases have elastic‐perfectly plastic behaviour without resorting to expensive numerical simulations (such as mesoscopic finite element modelling). This is the consequence of the simultaneous presence of elasticity and plasticity on the one hand and, on the other, the possibility of triggering plastic flows independently on the surface of each type of inclusion and in the matrix at a large distance from the inclusions

SWITCH1 (SWI1): a novel protein required for the establishment of sister chromatid cohesion and for bivalent formation at meiosis

We have characterized a new gene, SWI1, involved in sister chromatid cohesion during both male and female meiosis in Arabidopsis thaliana. A first allele, swi1.1, was obtained as a T-DNA tagged mutant and was described previously as abnormal exclusively in female meiosis. We have isolated a new allele, swi1.2, which is defective for both male and female meiosis. In swi1.2 male meiosis, the classical steps of prophase were not observed, especially because homologs do not synapse. Chromatid arms and centromeres lost their cohesion in a stepwise manner before metaphase I, and 20 chromatids instead of five bivalents were seen at the metaphase plate, which was followed by an aberrant segregation. In contrast, swi1.2 female meiocytes performed a mitotic-like division instead of meiosis, indicating a distinct role for SWI1 or a different effect of the loss of SWI1 function in both processes. The SWI1 gene was cloned; the putative SWI1 protein did not show strong similarity to any known protein. Plants transformed with a SWI1–GFP fusion indicated that SWI1 protein is present in meiocyte nuclei, before meiosis and at a very early stage of prophase. Thus, SWI1 appears to be a novel protein involved in chromatid cohesion establishment and in chromosome structure during meiosis, but with clear differences between male and female meiosis

A tandem array of CBF/DREB1 genes is located in a major freezing tolerance QTL region on Medicago truncatula chromosome 6.

Freezing provokes severe yield losses to different fall-sown annual legumes. Understanding the molecular bases of freezing tolerance is of great interest for breeding programs. Medicago truncatula Gaertn. is an annual temperate forage legume that has been chosen as a model species for agronomically and economically important legume crops. The present study aimed to identify positional candidate genes for a major freezing tolerance quantitative trait locus that was previously mapped to M. truncatula chromosome 6 (Mt-FTQTL6) using the LR3 population derived from a cross between the freezing-tolerant accession F83005-5 and the freezing-sensitive accession DZA045-5. The confidence interval of Mt-FTQTL6 was narrowed down to the region comprised between markers MTIC153 and NT6054 using recombinant F7 and F8 lines. A bacterial-artificial chromosome (BAC) clone contig map was constructed in an attempt to close the residual assembly gap existing therein. Twenty positional candidate genes including twelve C-repeat binding factor (CBF)/dehydration-responsive element binding factor 1 (DREB1) genes were identified from BAC-derived sequences and whole-genome shotgun sequences (WGS). CBF/DREB1 genes are organized in a tandem array within an approximately 296-Kb region. Eleven CBF/DREB1 genes were isolated and sequenced from F83005-5 and DZA045-5 which revealed high polymorphism among these accessions. Unique features characterizing CBF/DREB1 genes from M. truncatula, such as alternative splicing and large tandem duplication, are elucidated for the first time. Overall, twenty genes were identified as potential candidates to explain Mt-FTQTL6 effect. Their future functional characterization will uncover the gene(s) involved in freezing tolerance difference observed between F83005-5 and DZA045-5. Knowledge transfer for breeding improvement of crop legumes is expected. Furthermore, CBF/DREB1 related data will certainly have a large impact on research studies targeting this group of transcriptional activators in M. truncatula and other legume species

Basic Notions and Analytic Terminology in Archaeo-Anthropology: A First Attempt, and a Reappraisal of Jean Leclerc’s Seminal Work

L’archéologie francophone est souvent perçue comme rigoureuse dans le choix des termes, descriptifs et interprétatifs, concernant les restes mortuaires. Toutefois, si chacun utilise un vocabulaire qu’il pense précis, un rapide tour d’horizon de la bibliographie révèle une terminologiepeu fixée, parfois foisonnante, rarement traduisible en anglais, avec un manque de consensus sur le sens ou l’emploi des mots et avec une absence généralisée de référence à leur définition initiale. Certes, ce foisonnement peut être vu comme une source d’innovation qui correspond à des besoins nouveaux et aux mutations de l’archéologie funéraire mais il doit ensuite être discuté, évalué, élagué. Partant d’un article princeps mais méconnu de Jean Leclerc (1975), notre groupe de réflexion s’est donné pour tâche de réfléchir à des concepts de base de l’archéo-anthropologie, pour la plupart déjà proposés dans ce travail pionnier, restreint alors aux seules sépultures collectives (cadre que nous avons élargi). Nos premières propositions portent sur deux lieux communs de l’archéologie (et de l’archéologie de la mort, en particulier) : les types de connexion anatomique et l’effet de paroi. Selon les contextes (sépulture individuelle, plurielle, amas osseux, etc.), les premiers renvoient à des rapports anatomiques différents, parfois paradoxaux, ce que ne résout pas l’apposition d’adjectifs et qui rend délicat l’emploi de la terminologie proposée en 1975 (connexions strictes, lâches, à distance, absence de connexion). Le second a suscité un tel engouement qu’il a généré quantité de dérivés qui montrent que la recherche absolue de la précision est souvent synonyme de confusion. Le vocabulaire analytique n’est qu’un outil pour structurer et partager l’observation et pour progresser vers l’interprétation (évolution taphonomique, reconstitution de l’appareil et de la structure funéraire, réinterventions, etc.). Il doit être simple, le plus universel et le plus clair possible

Angiogenesis Inhibition by a Short 13 Amino Acid Peptide Sequence of Tetrastatin, the α4(IV) NC1 Domain of Collagen IV

International audienceAngiogenesis is defined as the formation of new capillaries by sprouting from the pre-existing microvasculature. It occurs in physiological and pathological processes particularly in tumor growth and metastasis. α1, α2, α3, and α6 NC1 domains from type IV collagen were reported to inhibit tumor angiogenesis. We previously demonstrated that the α4 NC1 domain from type IV collagen, named Tetrastatin, inhibited tumor growth in a mouse melanoma model. The inhibitory activity was located in a 13 amino acid sequence named QS-13. In the present paper, we demonstrate that QS-13 decreases VEGF-induced-angiogenesis in vivo using the Matrigel plug model. Fluorescence molecular tomography allows the measurement of a 65% decrease in Matrigel plug angiogenesis following QS-13 administration. The results are confirmed by CD31 microvessel density analysis on Matrigel plug slices. QS-13 peptide decreases Human Umbilical Vein Endothelial Cells (HUVEC) migration and pseudotube formation in vitro. Relevant QS-13 conformations were obtained from molecular dynamics simulations and docking. A putative interaction of QS-13 with α 5 β 1 integrin was investigated. The interaction was confirmed by affinity chromatography, solid phase assay, and surface plasmon resonance. QS-13 binding site on α 5 β 1 integrin is located in close vicinity to the RGD binding site, as demonstrated by competition assays. Collectively, our results suggest that QS-13 exhibits a mighty anti-angiogenic activity that could be used in cancer treatment and other pathologies with excessive angiogenesis such as hemangioma, psoriasis or diabetes