A dedicated state space for power system modeling and frequency and unbalance estimation

International audienceOver the last decades, a great deal of research has been focused on power quality issues in electrical energy transportation. We present a state-space representation to model dynamical power systems like electrical distribution systems. The proposed model is able to take into account all the dynamic behavior of a multiphase power system. It has been applied to model a typical three-phase power system and its unbalance, i.e., an electrical grid which can be perturbed by nonlinear loads and distributed renewable energy generation which is a typical changing system. Associated with an extended Kalman filter, the state-space model is used to iteratively estimate power quality parameters. Indeed, the symmetrical components of the power system, i.e., their amplitude and phase angle values, and the fundamental frequency can be calculated at each iteration without any prior knowledge. The proposed estimation technique is an evolving and adaptive method able to handle the changing power system. Its effectiveness has been evaluated by several tests. Results have been compared to other methods. They show the efficiency and better performance of the proposed method. The fundamental frequency and the symmetrical components are precisely estimated even under disturbed and time-varying conditions. This state-space representation can therefore be used in active power filtering schemes and in load frequency control strategies

Efficient Raman converter in the yellow range with high spatial and spectral brightness

International audienceWe present a Raman converter emitting at 583 nm on the second Stokes order of a line of propan-2-ol pumped by a microlaser at 532 nm in the sub-nanosecond regime. We used a mixture of liquids to adapt the transmission band of a photonic bandgap fiber. The internal conversion efficiency is 67% in photon numbers, and the output power is 1.06 mW, corresponding to a maximum peak power of 338 W. The beam delivered by the converter presents a Gaussian spatial structure and a high spectral brightness, typically more than five times higher than supercontinuum sources in this spectral range

The effect of nocturnal wear of dentures on the sleep quality: A systematic review and meta-analysis

Purpose The effect of nocturnal wear of denture on sleep quality and integrity is still not well understood. Therefore, this systematic review was conducted to provide evidence on this topic. Methods Electronic searches were conducted from 1964 up to September 2015, using MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials. Only publications in English or French, in which sleep quality of edentate adult individuals wearing dentures at night was compared to those not wearing were included in the review. Random effects models were used to pool the effect sizes. Results A total of 10 studies were included in the systematic review and 5 in the meta-analysis. No statistically significant difference between sleeping with denture and without denture was found for the Apnea-Hypopnea Index (AHI; Standard Mean Difference = −0.60, 95 % CI −1.67–0.47; Z = −1.10; p = 0.27). However, there was considerable heterogeneity in the studies included in the meta-analysis (Tau2 = 1.34; Q-value = 59.32, df = 4 (P < 0.0001); I2 = 93.3 %). When results from randomized controlled trials (RCTs) were pooled in subgroup analyses of AHI, there was a tendency towards favoring sleeping without dentures (P = 0.059) and no evidence of heterogeneity between studies (Tau2 = 0.000; Q-value = 0.06, df = 1 (P = 0.80); I2 = 0.000 %). Conclusion The current evidence suggests that there is no difference in the sleep quality and integrity of individuals wearing or not wearing their denture during sleep. However, the results of randomized controlled trials favoring sleeping without dentures and the likely presence of bias in the previous studies indicate the need for further randomized controlled trials for the development of clinical guideline

MexAB-OprM Efflux Pump Interaction with the Peptidoglycan of Escherichia coli and Pseudomonas aeruginosa.

One of the major families of membrane proteins found in prokaryote genome corresponds to the transporters. Among them, the resistance-nodulation-cell division (RND) transporters are highly studied, as being responsible for one of the most problematic mechanisms used by bacteria to resist to antibiotics, i.e., the active efflux of drugs. In Gram-negative bacteria, these proteins are inserted in the inner membrane and form a tripartite assembly with an outer membrane factor and a periplasmic linker in order to cross the two membranes to expulse molecules outside of the cell. A lot of information has been collected to understand the functional mechanism of these pumps, especially with AcrAB-TolC from Escherichia coli, but one missing piece from all the suggested models is the role of peptidoglycan in the assembly. Here, by pull-down experiments with purified peptidoglycans, we precise the MexAB-OprM interaction with the peptidoglycan from Escherichia coli and Pseudomonas aeruginosa, highlighting a role of the peptidoglycan in stabilizing the MexA-OprM complex and also differences between the two Gram-negative bacteria peptidoglycans

Stimulated Raman scattering with large Raman shifts with liquid core Kagome fibers (Orale)

International audienceStimulated Raman scattering in photonic band gap liquid filled fibers is known to be an attractive technique for manufacturing efficient wavelength converters. However the possible frequency shifts are limited by the spectral bandwidth of these fibers. We experimentally demonstrate that Kagome fibers allow to greatly enlarge these shifts

Functional Mechanism of the Efflux Pumps Transcription Regulators From Pseudomonas aeruginosa Based on 3D Structures

Bacterial antibiotic resistance is a worldwide health problem that deserves important research attention in order to develop new therapeutic strategies. Recently, the World Health Organization (WHO) classified Pseudomonas aeruginosa as one of the priority bacteria for which new antibiotics are urgently needed. In this opportunistic pathogen, antibiotics efflux is one of the most prevalent mechanisms where the drug is efficiently expulsed through the cell-wall. This resistance mechanism is highly correlated to the expression level of efflux pumps of the resistance-nodulation-cell division (RND) family, which is finely tuned by gene regulators. Thus, it is worthwhile considering the efflux pump regulators of P. aeruginosa as promising therapeutical targets alternative. Several families of regulators have been identified, including activators and repressors that control the genetic expression of the pumps in response to an extracellular signal, such as the presence of the antibiotic or other environmental modifications. In this review, based on different crystallographic structures solved from archetypal bacteria, we will first focus on the molecular mechanism of the regulator families involved in the RND efflux pump expression in P. aeruginosa, which are TetR, LysR, MarR, AraC, and the two-components system (TCS). Finally, the regulators of known structure from P. aeruginosa will be presented

Optimisation du coût de déploiement de services réseau virtualisés dans le cloud

International audienceLes opérateurs de clouds publics offrent aux particuliers et aux entreprises la possibilité de louer des ressources in-formatiques pour répondreà leurs besoins sans investir dans leur propre matériel. Le concept de Network Functions Virtualisation (NFV) favorise la migration des opérateurs réseau de dispositifs matériels dédiés coûteux et peuévolutifs vers des fonctions réseau logicielles virtualisées. Afin de déployer ces fonctions, les opérateurs réseau peuvent décider de s'abonnerà des offres de clouds publics. Toutefois, leur diversité, tant en termes de capacité de ressources que de prix, fait qu'il est difficile de trouver la combinaison d'offres répondantà tous les besoins au moindre coût. Nous pro-posons de résoudre ce problèmeà l'aide d'un programme linéaire conçu pour aider un opérateur réseauà sélectionner la meilleure combinaison d'offres (en termes de prix) permettant de réserver les machines virtuelles nécessaires pour supporter un ensemble de services réseau. Nous analysons le temps d'exécution de notre solution, et nous estimons leséconomies réalisées par rapportà un schéma traditionnel de miseà disposition de ressources ouà une stratégie de location de ressources sans planification. Enfin, nousévaluons l'opportunité pour un opérateur réseau de construire son propre datacenter alors que des offres de clouds publics sont disponibles

US Cosmic Visions: New Ideas in Dark Matter 2017: Community Report

This white paper summarizes the workshop "U.S. Cosmic Visions: New Ideas in Dark Matter" held at University of Maryland on March 23-25, 2017.Comment: 102 pages + reference