Beyond the 2nd Fermi Pulsar Catalog

Over thirteen times more gamma-ray pulsars have now been studied with the Large Area Telescope on NASA's Fermi satellite than the ten seen with the Compton Gamma-Ray Observatory in the nineteen-nineties. The large sample is diverse, allowing better understanding both of the pulsars themselves and of their roles in various cosmic processes. Here we explore the prospects for even more gamma-ray pulsars as Fermi enters the 2nd half of its nominal ten-year mission. New pulsars will naturally tend to be fainter than the first ones discovered. Some of them will have unusual characteristics compared to the current population, which may help discriminate between models. We illustrate a vision of the future with a sample of six pulsars discovered after the 2nd Fermi Pulsar Catalog was written.Comment: 6 pages, to appear in the proceedings of "The Fast and the Furious: Energetic Phenomena in Isolated Neutron Stars, Pulsar Wind Nebulae and Supernova Remnants",ESAC, Madrid, Spain, 22 - 24 May 2013 http://xmm.esac.esa.int/external/xmm_science/workshops/2013_science/, to be published as a regular issue of the Astronomische Nachrichten / Astronomical Notes (AN

Les enjeux d'une restructuration de la sous-traitance sur les conditions de travail chez un donneur d'ordre

International audienceLa communication présente un cas de restructuration des rapports entre un donneur d'ordre et ses sous-traitant

L’Action de l’État en Mer, le point de vue d’un officier de marine

L’Action de l’État en Mer (AEM) est une organisation administrative et opérationnelle visant à garantir les intérêts de l’État en mer tout en optimisant ses moyens. Chaque administration est responsable de l’exécution de ses activités propres mais participe aux autres, si nécessaire, et à la demande du Préfet maritime. La Marine nationale a réparti des moyens navals et aériens dans chacune des zones maritimes afin de permettre à l’État, en complémentarité avec les autres administrations, de surveiller nos espaces sous juridiction et d’intervenir si nécessaire. La Marine est plus spécialisée dans les missions de Haute mer ou nécessitant un niveau élevé d’engagement militaire ou de sophistication des moyens. L’organisation maritime française est un modèle envié. Son principal défi réside aujourd’hui dans les moyens d’intervention que l’État pourra mettre en œuvre pour remplir ses missions régaliennes en mer.Law enforcement at sea (AEM) is an administrative and operational organization to guarantee French state interests at sea while optimizing its capabilities. Each administration is responsible for its mission but it also ensures other missions on request of the « Préfet maritime ». The French Navy has dispatched naval and aerial capabilities in each of the maritime areas in order to enable the State, together with other governments, to monitor areas under our jurisdiction and to intervene if necessary. The Navy is more specialized in missions in the High Sea or requiring a high level of military involvement or sophistication of the capabilities. The French maritime organization is a model that is looked after. Its main challenge now lies in the intervention capabilities the State would implement to carry out its sovereign functions at sea

Combining Reinforcement Learning and Constraint Programming for Combinatorial Optimization

Combinatorial optimization has found applications in numerous fields, from aerospace to transportation planning and economics. The goal is to find an optimal solution among a finite set of possibilities. The well-known challenge one faces with combinatorial optimization is the state-space explosion problem: the number of possibilities grows exponentially with the problem size, which makes solving intractable for large problems. In the last years, deep reinforcement learning (DRL) has shown its promise for designing good heuristics dedicated to solve NP-hard combinatorial optimization problems. However, current approaches have two shortcomings: (1) they mainly focus on the standard travelling salesman problem and they cannot be easily extended to other problems, and (2) they only provide an approximate solution with no systematic ways to improve it or to prove optimality. In another context, constraint programming (CP) is a generic tool to solve combinatorial optimization problems. Based on a complete search procedure, it will always find the optimal solution if we allow an execution time large enough. A critical design choice, that makes CP non-trivial to use in practice, is the branching decision, directing how the search space is explored. In this work, we propose a general and hybrid approach, based on DRL and CP, for solving combinatorial optimization problems. The core of our approach is based on a dynamic programming formulation, that acts as a bridge between both techniques. We experimentally show that our solver is efficient to solve two challenging problems: the traveling salesman problem with time windows, and the 4-moments portfolio optimization problem. Results obtained show that the framework introduced outperforms the stand-alone RL and CP solutions, while being competitive with industrial solvers

Quality of life in patients with locked-in syndrome: Evolution over a 6-year period

International audienceBackground: Improved knowledge of the quality of life (QoL) of locked-in syndrome (LIS) patients have implications for managing their care, and assists clinicians in choosing the most appropriate interventions. We performed a survey of a population of LIS patients to describe the course of the QoL of LIS patients over a 6-year period and to determine the potential predictive factors of QoL changes over time. Method: This is a study performed over a 6-year period in patients with a LIS diagnosis. Questionnaires were sent in 2007 and 2013. The following data were recorded: i) sociodemographic data; ii) clinical data related to LIS, physical/handicap status, psychological status; iii) self-reported QoL: Anamnestic Comparative Self-Assessment (ACSA); iv) Integration in life: French Reintegration to Normal Living Index (RNLI). Results: Among the 67 patients included in 2007, 39 (58 %) patients returned their questionnaire in 2013. The LIS etiology was stroke in 51 individuals. The QoL of the patients was relatively satisfactory compared to populations in other severe conditions. Twenty-one (70 %) individuals reported a stable/improved QoL between 2007 and 2013. The physical/handicap statuses in 2007 and 2013 were not related to the QoL 6 years later, with the exception of one communication parameter: the individuals who used yes-no code reported significantly lower QoL levels than those who did not in 2013. Discussion: In opposition to a widespread opinion, LIS persons report a relatively satisfactory QoL level that stays stable over time, suggesting that life with LIS is worth living. Preservation of autonomy and communication may help them to live as normal life as possible

Comparison of fixed size and variable size packet models in an optical ring network: Algorithms and performances

Colloque avec actes et comité de lecture. internationale.International audienceIn this paper, we compare the use of two packets models in slotted optical ring networks: a model where each message has to be routed in consecutive slots, and a model where the slots can be routed independently. We first focus on the algorithmic complexity of the related problems. Then, we give the results we obtain with an OMNET simulator in terms of messages delay and jitter and of communication resources really used at each step

Coupling 3D groundwater modeling with CFC-based age dating to classify local groundwater circulation in an unconfined crystalline aquifer

International audienceNitrogen pollution of freshwater and estuarine environments is one of the most urgent environmental crises. Shallow aquifers with predominantly local flow circulation are particularly vulnerable to agricultural contaminants. Water transit time and flow path are key controls on catchment nitrogen retention and removal capacity, but the relative importance of hydrogeological and topographical factors in determining these parameters is still uncertain. We used groundwater dating and numerical modeling techniques to assess transit time and flow path in an unconfined aquifer in Brittany, France. The 35.5 km2 study catchment has a crystalline basement underneath a ∼60 m thick weathered and fractured layer, and is separated into a distinct upland and lowland area by an 80 m-high butte. We used groundwater discharge and groundwater ages derived from chlorofluorocarbon (CFC) concentration to calibrate a free-surface flow model simulating groundwater flow circulation. We found that groundwater flow was highly local (mean travel distance = 350 m), substantially smaller than the typical distance between neighboring streams (∼1 km), while CFC-based ages were quite old (mean = 40 years). Sensitivity analysis revealed that groundwater travel distances were not sensitive to geological parameters (i.e. arrangement of geological layers and permeability profile) within the constraints of the CFC age data. However, circulation was sensitive to topography in the lowland area where the water table was near the land surface, and to recharge rate in the upland area where water input modulated the free surface of the aquifer. We quantified these differences with a local groundwater ratio (rGW-LOCAL), defined as the mean groundwater travel distance divided by the mean of the reference surface distances (the distance water would have to travel across the surface of the digital elevation model). Lowland, rGW-LOCAL was near 1, indicating primarily topographical controls. Upland, rGW-LOCAL was 1.6, meaning the groundwater recharge area is almost twice as large as the topographically-defined catchment for any given point. The ratio rGW-LOCAL is sensitive to recharge conditions as well as topography and it could be used to compare controls on groundwater circulation within or between catchments

Physics of fully-loaded laser-plasma accelerators

International audienceWhile large efforts have been devoted to improving the quality of electron beams from laser plasma accelerators, often to the detriment of the charge, many applications do not require very high quality but high-charge beams. Despite this need, the acceleration of largely charged beams has been barely studied.Here we explore both experimentally and numerically the physics of highly loaded wakefield acceleration. We find that the shape of the electron spectra is strikingly independent of the laser energy, due to the emergence of a saturation effect induced by beamloading. A transition from quasi-Maxwellian spectra at high plasma densities to flatter spectra at lower densities is also found, which is shown to be produced by the wakefield driven by the electron bunch itself after the laser depletion

A doubly responsive probe for the detection of Cys4-tagged proteins

International audienceRecombinant proteins bearing a tag are crucial tools for assessing protein location or function. Small tags such as Cys4 tag (tetracysteine; Cys–Cys–X–X–Cys–Cys) are less likely disrupt protein function in the living cell than green fluorescent protein. Herein we report the first example of the design and synthesis of a dual fluorescence and hyperpolarized 129Xe NMR-based sensor of Cys4-tagged proteins. This sensor becomes fluorescent when bound to such Cys4-tagged peptides, and the 129Xe NMR spectrum exhibits a specific signal, characteristic of the biosensor-peptide association