From laser cooling to aging: a unified Levy flight description

Intriguing phenomena such as subrecoil laser cooling of atoms, or aging phenomenon in glasses, have in common that the systems considered do not reach a steady-state during the experiments, although the experimental time scales are very large compared to the microscopic ones. We revisit some standard models describing these phenomena, and reformulate them in a unified framework in terms of lifetimes of the microscopic states of the system. A universal dynamical mechanism emerges, leading to a generic time-dependent distribution of lifetimes, independently of the physical situation considered.Comment: 8 pages, 2 figures; accepted for publication in American Journal of Physic

Temporal sampling helps unravel the genetic structure of naturally occurring populations of a phytoparasitic nematode. 2. Separating the relative effects of gene flow and genetic drift

International audienceStudying wild pathogen populations in natural ecosystems offers the opportunity to better understand the evolutionary dynamics of biotic diseases in crops and to enhance pest control strategies. We used simulations and genetic markers to investigate the spatial and temporal population genetic structure of wild populations of the beet cyst nematode Heterodera schachtii on a wild host plant species, the sea beet (Beta vulgaris spp. maritima), the wild ancestor of cultivated beets. Our analysis of the variation of eight microsatellite loci across four study sites showed that (i) wild H. schachtii populations displayed fine-scaled genetic structure with no evidence of substantial levels of gene flow beyond the scale of the host plant, and comparisons with simulations indicated that (ii) genetic drift substantially affected the residual signals of isolation-by-distance processes, leading to departures from migration–drift equilibrium. In contrast to what can be suspected for (crop) field populations, this showed that wild cyst nematodes have very low dispersal capabilities and are strongly disconnected from each other. Our results provide some key elements for designing pest control strategies , such as decreasing passive dispersal events to limit the spread of virulence among field nematode populations

Technological developments as an answer to bridge management challenges

IABSE Symposium 2019, Towards a Resilient Built Environment - Risk and Asset Management, GUIMARAES, PORTUGAL, 27-/03/2019 - 29/03/2019Bridge management is a challenge as owners have to deal with limited financial resources to maintain the functionalities and safety of ageing structures. Demands on transportation networks change, due to regulatory developments, society's evolution and shifts with high expectations on the operational performance of roadway bridges with reduced congestion, delay, and accidents. To minimize intrusion in the transport flow, inspection and monitoring methods should be non?destructive, minimally invasive. They should be capable of yielding rapid and accurate inspection results allowing an adequate response from the asset manager. Research aims at including autonomously operating equipment (e.g. robotics), non?intrusive (remote or proximity) observation techniques, or other methods that ensure quality and performance control of the roadway bridges in time, more safely, more quickly and/or to a higher degree of accuracy and precision.The innovation subgroup in COST action TU1406 investigates novel condition monitoring and sensing technologies for the assessment of structural serviceability and safety. Advanced, integrated, cost-effective and reliable instrumentation solutions, techniques and concepts are looked at with the aim to provide data, that will be used to compute innovative performance indicators. In this context, this paper briefly reminds some significant challenges associated with bridge management and presents three examples of innovation in bridge monitoring and NDT investigation techniques

Adaptive optics telemetry standard: Design and specification of a novel data exchange format

Context. The amount of adaptive optics (AO) telemetry generated by visible/near-infrared ground-based observatories is ever greater, leading to a growing need for a standardised data exchange format to support performance analysis, AO research, and development activities that involve large-scale telemetry mining, processing, and curation.Aims. This paper introduces the Adaptive Optics Telemetry (AOT) data exchange format as a standard for sharing AO telemetry from visible/infrared ground-based observatories. AOT is based on the flexible image transport system (FITS) and aims to provide unambiguous and consistent data access across various systems and configurations, including natural and single- or multiple-laser guide-star AO systems.Methods. We designed AOT with a focus on two key use cases: atmospheric turbulence parameter estimation and point-spread function reconstruction. We prototyped and tested the design using existing AO telemetry datasets from multiple systems: single conjugate with natural and laser guide stars, tomographic systems with multi-channel wavefront sensors, and single- and multi-wavefront correctors in systems featuring either a Shack-Hartmann or Pyramid as the main wavefront sensor.Results. The AOT file structure has been thoroughly defined, with specified data fields, descriptions, data types, units, and expected dimensions. To support this format, we have developed a Python package that enables the data conversion, reading, writing, and exploration of AOT files; it has been made publicly available and is compatible with a general-purpose Python package manager. We have demonstrated the flexibility of the AOT format by packaging data from five different instruments, installed on different telescopes

VarGoats project : a dataset of 1159 whole-genome sequences to dissect Capra hircus global diversity

Since their domestication 10,500 years ago, goat populations with distinctive genetic backgrounds have adapted to a broad variety of environments and breeding conditions. The VarGoats project is an international 1000-genome resequencing program designed to understand the consequences of domestication and breeding on the genetic diversity of domestic goats and to elucidate how speciation and hybridization have modeled the genomes of a set of species representative of the genus Capra. A dataset comprising 652 sequenced goats and 507 public goat sequences, including 35 animals representing eight wild species, has been collected worldwide. We identified 74,274,427 single nucleotide polymorphisms (SNPs) and 13,607,850 insertion-deletions (InDels) by aligning these sequences to the latest version of the goat reference genome (ARS1). A Neighbor-joining tree based on Reynolds genetic distances showed that goats from Africa, Asia and Europe tend to group into independent clusters. Because goat breeds from Oceania and Caribbean (Creole) all derive from imported animals, they are distributed along the tree according to their ancestral geographic origin. We report on an unprecedented international effort to characterize the genome-wide diversity of domestic goats. This large range of sequenced individuals represents a unique opportunity to ascertain how the demographic and selection processes associated with post-domestication history have shaped the diversity of this species. Data generated for the project will also be extremely useful to identify deleterious mutations and polymorphisms with causal effects on complex traits, and thus will contribute to new knowledge that could be used in genomic prediction and genome-wide association studies

Foamy Macrophages from Tuberculous Patients' Granulomas Constitute a Nutrient-Rich Reservoir for M. tuberculosis Persistence

Tuberculosis (TB) is characterized by a tight interplay between Mycobacterium tuberculosis and host cells within granulomas. These cellular aggregates restrict bacterial spreading, but do not kill all the bacilli, which can persist for years. In-depth investigation of M. tuberculosis interactions with granuloma-specific cell populations are needed to gain insight into mycobacterial persistence, and to better understand the physiopathology of the disease. We have analyzed the formation of foamy macrophages (FMs), a granuloma-specific cell population characterized by its high lipid content, and studied their interaction with the tubercle bacillus. Within our in vitro human granuloma model, M. tuberculosis long chain fatty acids, namely oxygenated mycolic acids (MA), triggered the differentiation of human monocyte-derived macrophages into FMs. In these cells, mycobacteria no longer replicated and switched to a dormant non-replicative state. Electron microscopy observation of M. tuberculosis–infected FMs showed that the mycobacteria-containing phagosomes migrate towards host cell lipid bodies (LB), a process which culminates with the engulfment of the bacillus into the lipid droplets and with the accumulation of lipids within the microbe. Altogether, our results suggest that oxygenated mycolic acids from M. tuberculosis play a crucial role in the differentiation of macrophages into FMs. These cells might constitute a reservoir used by the tubercle bacillus for long-term persistence within its human host, and could provide a relevant model for the screening of new antimicrobials against non-replicating persistent mycobacteria

Refroidissement laser sub-recul par résonances noires:-exp. avec des atomes d'hélium métastables,-approches Monte-Carlo quantique et vols de Lévy

This thesis presents new experimental and theoretical approaches of laser cooling by dark resonances. The recoil energy is the kinetic energy communicated to an atom initially at rest by the absorption or by the emission of a single photon. This important milestone in laser cooling has been overcome for the first time in 1988 by the method of velocity selective dark resonances. This work deals with extensions of this method to the long interaction time regime and to several dimensions. The new experimental setup is based on the development of a laser trap of ultracold metastable helium atoms. The atoms are released in free fall and their small velocities allow the interaction time to be increased by 2 orders of magnitude. Stray magnetic fields are compensated to one milligauss by mechanical Hanle effect experiments. The first experiments with this new setup reached one fortieth of the recoil energy (100 nanokelvins) in one dimension. The recoil limit has been passed for the first time in two dimensions, reaching one twentieth of the recoil energy, i e. 200 nanokelvins. Theoretically, a new type of quantum Monte-Carlo simulations much more efficient than the resolution of optical Bloch equations. The long interaction time behaviour has been explored. These simulations suggested another new approach, based on the Lévy statistics recently introduced to study anomalous diffusion. With this approach, we proved a conjecture predicting a decrease of the temperature as the inverse of the interaction time. We also give new analytical results, for example about the proportion of cooled atoms or about the role of dimensionality.Ce mémoire présente de nouvelles approches expérimentales et théoriques du refroidissement laser sub-recul par résonances noires. L'énergie de recul est l'énergie cinétique communiquée à un atome initialement immobile par l'absorption ou l'émission d'un seul photon. C'est une échelle importante dans le refroidissement d'atomes par laser, franchie pour la première fois en 1988, sur un jet d'hélium métastable, grâce à la méthode des résonances noires sélectives en vitesse. Ce travail porte sur les développements de cette méthode, d'une part dans le régime des temps longs, d'autre part à plusieurs dimensions. Le nouveau schéma expérimental repose sur la réalisation d'un piège laser d'atomes d'hélium métastables ultrafroids, à partir duquel on lâche en chute libre le nuage d'atomes piégés, dont les vitesses autorisent des temps d'interaction accrus par deux ordres de grandeur. Les champs magnétiques ont été compensés à un milligauss près par des expériences d'effet Hanle mécanique. Les premières expériences effectuées avec le nouveau dispositif ont permis d'atteindre un quarantième de l'énergie de recul (100 nanokelvins) à une dimension. La limite du recul à deux dimensions a pu être franchie pour la première fois (un vingtième de l'énergie du recul, soit 200 nanokelvins) Sur le plan théorique, on a développé un nouveau type de simulations Monte-Carlo quantiques beaucoup plus efficaces que la résolution des équations de Bloch optiques On a pu explorer ainsi le régime des temps longs. Ces simulations ont suggéré une approche statistique complètement nouvelle du problème, basée sur les statistiques de Lévy récemment introduites pour étudier la diffusion anormale. Cette approche a permis de confirmer une conjecture prédisant une décroissance de la température atteinte comme l'inverse du temps d'interaction. Elle fournit également des résultats analytiques nouveaux, par exemple sur la proportion d'atomes refroidis ou sur le rôle de la dimensionnalité

Accueil des adolescents dans un service de psychiatrie adulte de secteur :intérêts et limites (études sur 8 ans)

LE KREMLIN-B.- PARIS 11-BU Méd (940432101) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF