[alpha/Fe] in the thin and the thick disk towards an automatic parametrization of stellar spectra

We test an automatic procedure to measure [Fe/H] and [alpha/Fe] on high resolution spectra. The test sample is the intersection of the ELODIE library and a catalogue of 830 stars having well determined abundances.Comment: Three-dimensional Universe with Gaia, 4-7 October 2004, Observatoire de Paris-Meudon, France (ESA SP-576), eds M. Perryman & C. Turo

Towards a better understanding of clogged steam generators: a sensitivity analysis of dynamic themohydraulic model output

Communication available online at http://hans.wackernagel.free.fr/article_ICONE_final_140311.pdfInternational audienceTube support plate clogging of steam generators affects their operating and requires frequent maintenance operations. A diagnosis method based on dynamic behaviour analysis is under development at EDF to provide means of optimisation of maintenance strategies. Previous work showed that the dynamic response to a power transient of the wide range level measurement contains informations about the clogging state of steam generators. The diagnosis method consists of comparisons of the measured dynamic response with simulations on a mono-dimensional dynamic steam generator model for various input clogging configurations. In order to assess the potential of this method, a sensitivity analysis has been conducted through a quasi-Monte Carlo scheme to compute sensitivity indices for each half tube support plate's clogging ratio. Sensitivity indices are usually defined for scalar model outputs. Principal component analysis has been used to determine a small subset of variables that condense the information about the shape of the response curves. Finally, estimation variability was assessed by construction of bootstrap confidence intervals. The results showed that half of the preselected input variables have negligible influence and allowed to rank the most important ones. Interactions of input variables have been estimated to exert only a small influence on the output. The effects of clogging on the steam generator dynamics has been characterised qualitatively and quantitatively

A novel approach for electric load curve holistic modelling and simulation

International audienceThis paper presents a novel approach of an electric load curve simulator using a set of grey box models that results to an efficient trade-off between complete and complex physical models and fast simplified statistical models. The input parameters are macroscopic data coming from large databases such as national census, DSO’s client information and meteorological data such as temperature or irradiation data. The problem of matching between the different databases is investigated to assess comparable load curves. Validation is performed using load measurements at the medium voltage level. Once the model is calibrated it can be turned into a good prediction tool useful for planning studies since it permits easily to incorporate the evolution of usages, the characteristics of consumption devices, as well as the evolution of the building’s characteristics

3-D magnetotelluric inversion with coast effect modeling to assess the geothermal potential of Anses d'Arlet (Martinique, Lesser Antilles)

2pWithin the framework of a global French program towards development of renewable energies, Martinique Island (Lesser Antilles, France) has been extensively investigated (from 2012 to 2013) through an integrated multi-disciplinary approach, with the aim to identify precisely the potential geothermal resources previously highlighted (Gadalia et al., 2014). Among the investigation methods deployed (geological, geochemical and hydrogeological), we carried out three magnetotelluric (MT) surve ys at three of the four most promising areas of Martinique, namely the Anses d'Arlet, the Montagne Pelée and the Pitons du Carbet prospects. A total of 32 MT tensors were collected in the Anses d'Arlet area in the frequency range 1000 Hz to 10-2-10-3Hz togetherwith TEM soundings for potential static shift correction. A 3-D MT inversion of the full tensor was carried out including the coast effect. The 3-D resistivity model reveals a major resistive body elongated in the NNO -SSE direction, corresponding to the main structural volcanic axis of the area, and interpreted as a deep intrusion almost reaching the surface. Based on geological observations -an alteration zone located between Anses d'Arlet and Petite Anse-the shallow conductive layer identified eastward is interpreted as the remaining of an old cap-rock partly eroded that becomes thicker southwards. The latter could be related with the altered core of the Morne Larcher. Other studies allowed the reconstructing of the geothermal system evolution to its present and moderate apparent activi ty mainly located south of the resistive anomaly. This intrusion could act as heat source for the geothermal system. This sector is identified as the most interesting for further exploration wells. In order to better understand structures highlighted by the real data distribution and test the strategy to integrate correction coefficients for the coast effect (modeled separately) during the inversion, we designed a forward model using the s ame bathymetry, topography and MT sounding distribution of the survey. Impedance tensors were calculated for the 32 sites. The geometry of the 3-D structure has been designed quasi-independently of the data distribution to assess the impact of un-appropriate acquisition grid. The 3-D inversion was run with these synthetic data (Hautot et al, 2000, 2007). The results indicate that the general structure is recovered for the first 1000 m. Deeper, and southward, the absence of MT soundings surrounding the resistive body prevented a good lateral constraint, causing its disappearance. To the north, the conductive body "pseudo caprock" is well defined, especially on layer 5 (Figure 2), were the apex of a supposed geothermal reservoir could be identified (sites 3 and 6). Deeper the eastern border remains very well constrained by the eastern MT synthetic soundings

SPHERE IRDIS and IFS astrometric strategy and calibration

We present the current results of the astrometric characterization of the VLT planet finder SPHERE over 2 years of on-sky operations. We first describe the criteria for the selection of the astrometric fields used for calibrating the science data: binaries, multiple systems, and stellar clusters. The analysis includes measurements of the pixel scale and the position angle with respect to the North for both near-infrared subsystems, the camera IRDIS and the integral field spectrometer IFS, as well as the distortion for the IRDIS camera. The IRDIS distortion is shown to be dominated by an anamorphism of 0.60+/-0.02% between the horizontal and vertical directions of the detector, i.e. 6 mas at 1". The anamorphism is produced by the cylindrical mirrors in the common path structure hence common to all three SPHERE science subsystems (IRDIS, IFS, and ZIMPOL), except for the relative orientation of their field of view. The current estimates of the pixel scale and North angle for IRDIS are 12.255+/-0.009 milliarcseconds/pixel for H2 coronagraphic images and -1.75+/-0.08 deg. Analyses of the IFS data indicate a pixel scale of 7.46+/-0.02 milliarcseconds/pixel and a North angle of -102.18+/-0.13 deg. We finally discuss plans for providing astrometric calibration to the SPHERE users outside the instrument consortium.Comment: 12 pages, 6 figures, 3 table

3-D Magnetotelluric Investigations for geothermal exploration in Martinique (Lesser Antilles). Characteristic Deep Resistivity Structures, and Shallow Resistivity Distribution Matching Heliborne TEM Results

Within the framework of a global French program oriented towards the development of renewable energies, Martinique Island (Lesser Antilles, France) has been extensively investigated (from 2012 to 2013) through an integrated multi-methods approach, with the aim to define precisely the potential geothermal ressources, previously highlighted (Sanjuan et al., 2003). Amongst the common investigation methods deployed, we carried out three magnetotelluric (MT) surveys located above three of the most promising geothermal fields of Martinique, namely the Anses d'Arlet, the Montagne Pel{\'e}e and the Pitons du Carbet prospects. A total of about 100 MT stations were acquired showing single or multi-dimensional behaviors and static shift effects. After processing data with remote reference, 3-D MT inversions of the four complex elements of MT impedance tensor without pre-static-shift correction, have been performed for each sector, providing three 3-D resistivity models down to about 12 to 30 km depth. The sea coast effect has been taken into account in the 3-D inversion through generation of a 3-D resistivity model including the bathymetry around Martinique from the coast up to a distance of 200 km. The forward response of the model is used to calculate coast effect coefficients that are applied to the calculated MT response during the 3-D inversion process for comparison with the observed data. 3-D resistivity models of each sector, which are inherited from different geological history, show 3-D resistivity distribution and specificities related to its volcanological history. In particular, the geothermal field related to the Montagne Pel{\'e}e strato-volcano, is characterized by a quasi ubiquitous conductive layer and quite monotonic typical resistivity distribution making interpretation difficult in terms of geothermal targets. At the opposite, the resistivity distribution of Anse d'Arlet area is radically different and geothermal target is thought to be connected to a not so deep resistive intrusion elongated along a main structural axis. Beside these interesting deep structures, we demonstrate, after analyzing the results of the recent heliborne TEM survey covering the whole Martinique, that surface resistivity distribution obtained from 3-D inversion reproduce faithfully the resistivity distribution observed by TEM. In spite of a very different sampling scale, this comparison illustrates the ability of 3-D MT inversion to take into account and reproduce static shift effects in the sub-surface resistivity distribution.Comment: Wordl Geothermal Congress 2015, Apr 2015, Melbourne, Australi

Evaluation of the Housing First program in patients with severe mental disorders in France: study protocol for a randomized controlled trial.

International audienceBACKGROUND: Recent studies in North American contexts have suggested that the Housing First model is a promising strategy for providing effective services to homeless people with mental illness. In the context of the highly generous French national health and social care system, which is easily accessible and does not require out-of-pocket payment, the French Health Ministry insists on rigorous techniques, including randomized protocols, to evaluate the impact of Housing First approaches in France.Method and design: A prospective randomized trial was designed to assess the impact of a Housing First intervention on health outcomes and costs over a period of 24 months on homeless people with severe mental illness, compared to Treatment-As-Usual. The study is being conducted in four cities in France: Lille, Marseille, Paris and Toulouse. The inclusion criteria are as follows: over 18 years of age, absolutely homeless or in precarious housing, and possessing a 'high' level of need: diagnosis of schizophrenia or bipolar disorder and moderate to severe disability according to the Multnomah Community Ability Scale (score <= 62) and at least one of the following three criteria: 1) having been hospitalized for mental illness two or more times in any one year during the preceding five years; 2) co-morbid alcohol or substance use; and 3) having been recently arrested or incarcerated. Participants will be randomized to receiving the Housing First intervention or Treatment-As-Usual. The Housing First intervention provides immediate access to independent housing and community care. The primary outcome criterion is the use of high-cost health services (that is,, number of hospital admissions and number of emergency department visits) during the 24-month follow-up period. Secondary outcome measures include health outcomes, social functioning, housing stability and contact with police services. An evaluation of the cost-effectiveness and cost-utility of Housing First will also be conducted. A total of 300 individuals per group will be included. DISCUSSION: This is the first study to examine the impact of a Housing First intervention compared to Treatment-As-Usual in France. It should provide key information to policymakers concerning the cost-effectiveness and health outcomes of the Housing First model in the French context.Trial registration: The current clinical trial number is NCT01570712

Elemental abundances as a function of kinematics in the Milky Way's disk

We present the results of our investigation of three samples kinematically representative of the thin and thick disks and the Hercules stream using the catalogue of Soubiran & Girard (2005). We have observed abundance trends and age distribution of each component. Our results show that the two disks are chemically well separated, they overlap greatly in metallicity and both show parallel decreasing trends of alpha elements with increasing metallicity, in the interval -0.80 < [Fe/H] < -0.30. The thick disk is clearly older than the thin disk with a tentative evidence of an Age-Metallicity Relation over 2-3 Gyr and a hiatus in star formation before the formation of the thin disk. In order to improve the statistics on the disk's abundance trends, we have developed an automatic code, TGMET{\Large\alpha}; to determine (Teff, logg, [Fe/H], [\alpha/Fe]) for thousands of stellar spectra available in spectroscopic archives. We have assessed the performances of the algorithm for 350 spectra of stars being part of the abundance catalogue