Advanced Laser Vibrometry in Pulsed Mode using Poly-Pulse Waveforms and Time-frequency Processing

International audienceVibration sensing by laser radar with a pulsed emission is a promising technique for long range target recognition and identification. However, compared to its continuous-wave counterpart, it is impaired by its greater sensitivity to speckle noise and its lack of robustness to multiple independent vibrations of the target surface. Using poly-pulse waveforms for greater velocity resolution, we developed a new estimator to take into account signal statistics, and time frequency representations that can achieve better performance than classical processing methods. Simulations show a 5dB improvement in Signal-to- Noise Ratio (SNR) when speckle noise is dominant, and 4dB improvement when signal is weak in regard to detection noise

Visibilité et présence de l’image dans l’espace ecclésial

Cet ouvrage met au cœur de son propos une interrogation simple : dans l’organisation complexe de l’espace de l’église médiévale, les emplacements choisis pour les images qui ornent les murs et les objets n’offrent pas toujours la possibilité de voir celles-ci, d’en déchiffrer le contenu. Certaines semblent réservées à des groupes de l’assemblée stationnant dans des espaces spécifiques, d’autres ne sont pas visibles depuis les principales zones affectées aux fidèles ou aux clercs, d’autres encore sont situées trop haut. Le rapport, a priori évident, entre représentation et visibilité se trouve donc souvent démenti, appelant alors une nouvelle notion, celle de présence. Analyser la tension existant entre ces trois catégories – figuration, visibilité et présence – implique une étude croisée des œuvres figurées, des monuments et des sources écrites. Les notions de mobilité et de fixité permettent également de prendre en compte les multiples jeux d’échelles à l’œuvre dans ce lieu rituel qu’est l’église, impliquant des objets, des manuscrits, des dispositifs liturgiques, des gestes, des déplacements physiques, dialoguant avec un décor appliqué au corps même du monument, épousant l’immobilité de l’architecture. Les cinq chapitres thématiques qui organisent ce volume mettent en regard différents cas issus de l’Occident médiéval et de l’Orient byzantin, selon une chronologie longue (de l’Antiquité tardive à la fin du Moyen Âge), dans une volonté de décloisonner les disciplines et les aires géographiques afin de tirer tous les enseignements d’une approche transversale de l’image médiévale

Overexpression of S100A4 in human cancer cell lines resistant to methotrexate

Methotrexate is a chemotherapeutic drug that is used in therapy of a wide variety of cancers. The efficiency of treatment with this drug is compromised by the appearance of resistance. Combination treatments of MTX with other drugs that could modulate the expression of genes involved in MTX resistance would be an adequate strategy to prevent the development of this resistance. Methods: The differential expression pattern between sensitive and MTX-resistant cells was determined by whole human genome microarrays and analyzed with the GeneSpring GX software package. A global comparison of all the studied cell lines was performed in order to find out differentially expressed genes in the majority of the MTX-resistant cells. S100A4 mRNA and protein levels were determined by RT-Real-Time PCR and Western blot, respectively. Functional validations of S100A4 were performed either by transfection of an expression vector for S100A4 or a siRNA against S100A4. Transfection of an expression vector encoding for β-catenin was used to inquire for the possible transcriptional regulation of S100A4 through the Wnt pathway. Results: S100A4 is overexpressed in five out of the seven MTX-resistant cell lines studied. Ectopic overexpression of this gene in HT29 sensitive cells augmented both the intracellular and extracellular S100A4 protein levels and caused desensitization toward MTX. siRNA against S100A4 decreased the levels of this protein and caused a chemosensitization in combined treatments with MTX. β-catenin overexpression experiments support a possible involvement of the Wnt signaling pathway in S100A4 transcriptional regulation in HT29 cells. Conclusions: S100A4 is overexpressed in many MTX-resistant cells. S100A4 overexpression decreases the sensitivity of HT29 colon cancer human cells to MTX, whereas its knockdown causes chemosensitization toward MTX. Both approaches highlight a role for S100A4 in MTX resistanc

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

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

Les souffrances sociales à la Martinique et leurs modes de gestion

À la Martinique, département d outre-mer fondé sur une organisation socio-raciale inégalitaire héritée du système colonial esclavagiste, les tensions et les inégalités entre les milieux sociaux pèsent encore lourdement. D une part, la domination sociale et économique des anciens colons, les békés, perdure dans le temps et, d autre part, le passé esclavagiste non assumé par une frange de la population martiniquaise descendante d esclaves africains génère encore des frustrations, de la souffrance et un besoin de reconnaissance identitaire. À cette souffrance historique s imbrique une autre souffrance dite sociale, en raison du contexte socio-économique dans lequel les inégalités sociales et les écarts entre les classes ne cessent de se creuser. Partant de ce constat, cette thèse se propose d analyser à partir de l ethnographie d un quartier populaire de Fort-de-France, la dialectique entre les souffrances sociales et les modes de gestion des malheurs qui traversent la vie de certains Martiniquais parmi les plus dominés. Par ailleurs, nous menons une réflexion sur la gestion collective de la souffrance à la suite d une catastrophe aérienne qui a causé la mort de 152 Martiniquais. Celle-ci souligne l importance de la tentative de reconstruction identitaire lors d une situation exceptionnelle venant perturber violemment l ordre établi.In Martinique, french overseas department established on an unegalitarian socio-racial organization inherited from the slave colonial system, the tensions and the disparities between the social environments weigh still heavily. On one hand, the social and economic domination of the ancient colonists, the békés, continues in the time and, on the other hand, the slave past not assumed by a part of the inhabitant of Martinique, descendants of African slaves, still generates frustrations, suffering and a need of gratitude. With this historic suffering another suffering known as social is imbricated, because of the socioeconomic context in which the social inequalities and the distance between the classes do not cease growing hollow. Leaving of this report, on one hand, this thesis suggests analyzing from the thnography of a popular district of Fort-de-France, the dialectic between the social suffreings and the modes of management of the misfortunes, which cross the life of certain inhabitants of Martinique among the most dominated. On the other hand, we lead a reflection on the collective management of the suffering following an air crash, which caused the death of 152 inhabitants of Martinique. This one underline the importance of the attempt of identical reconstrcution during an exceptional position coming to perturb violently the established order.PARIS-Médiathèque MQB (751132304) / SudocPARIS-Fondation MSH (751062301) / SudocSudocFranceF

Etude théorique et expérimentale de la vibrométrie laser à longue distance par lidar cohérent

La mesure sans contact et à grande distance de vibrations de faible amplitude (de l'ordre du micromètre) est un besoin grandissant dans le monde industriel, tant dans le domaine civil pour étudier l'intégrité de structures, que dans le domaine militaire afin de réaliser l identification de cibles. Les lidars à détection cohérente hétérodyne (ou lidars cohérents) permettent la mesure de vitesse de vibration jusqu à quelques micromètres par seconde, à plusieurs kilomètres, voire plusieurs dizaines de kilomètres de distance. Leur principe est de mesurer le décalage fréquentiel de l onde laser dû à l effet Doppler subi lors de la rétrodiffusion sur une cible vibrante. La problématique scientifique des travaux exposés dans ce mémoire est la conception d'un vibromètre laser capable de mesurer ces faibles vitesses de vibration à grande distance sur des cibles non coopératives. Une étude théorique et expérimentale est menée, concernant, en particulier, les bruits affectant la mesure de vibration par lidar, ainsi que le couplage entre la tache laser et la répartition des modes de vibration sur la surface de la cible. Un simulateur de la mesure, validé en comparant les mesures expérimentales sur une maquette d'avion avec les mesures simulées, permet de déterminer les performances du système. Puis la capacité de mesure des lidars cohérents est démontrée expérimentalement, à partir d'une architecture lidar fibrée à 1,5 micromètre, sur des cibles en vol à 2,5 km, ainsi que par des mesures très basses fréquences sur bâtiments. Enfin, la possibilité de compensation des vibrations propres de la plateforme en vue d'embarquer le vibromètre laser sur un porteur mobile est étudiée.Remote sensing of very low amplitude (few micrometers) vibration at long range is a growing need in the industry, both in the civilian sector to study the integrity of structure, and in the military sector to achieve target identification. Coherent lidars allow the measure of vibration speed around some micrometers per second at a range of several kilometers or even dozens of kilometres. They are based on the measure of the frequency shift due to Doppler effect suffered when backscattering on a moving target occurs. The scientific issue of the work reported in this thesis is to design a laser vibrometer measuring these low vibration speeds of non-cooperative targets at long range. A theoretical and experimental study is conducted, more particularly about the noise affecting the measure, and the coupling between the laser spot and the vibration patterns on the surface of the target. A simulator of the measure, validated by comparing experimental measurements on a model airplane with simulated measurements, is built to determine the system performance. Then the experimental demonstration of the ability of coherent lidar to perform long range and high sensitivity measurements is made on flying targets at 2.5 km, and by very low frequency measures on buildings, using a 1.55 micron all fibered lidar. Finally, the compensation of own platform vibration is studied in order to board the laser vibrometer on a moving carrier.ORSAY-PARIS 11-BU Sciences (914712101) / SudocSudocFranceF