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Search Results: 1 - 10 of 16283 matches for " Mireille Le Guen "
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Effectiveness of Family Planning Policies: The Abortion Paradox
Nathalie Bajos, Mireille Le Guen, Aline Bohet, Henri Panjo, Caroline Moreau, the FECOND group
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0091539
Abstract: Objective The relation between levels of contraceptive use and the incidence of induced abortion remains a topic of heated debate. Many of the contradictions are likely due to the fact that abortion is the end point of a process that starts with sexual activity, contraceptive use (or non-use), followed by unwanted pregnancy, a decision to terminate, and access to abortion. Trends in abortion rates reflect changes in each step of this process, and opposing trends may cancel each other out. This paper aims to investigate the roles played by the dissemination of contraception and the evolving norms of motherhood on changes in abortion rates. Methods Drawing data from six national probability surveys that explored contraception and pregnancy wantedness in France from 1978 through 2010, we used multivariate linear regression to explore the associations between trends in contraceptive rates and trends in (i) abortion rates, (ii) unwanted pregnancy rates, (iii) and unwanted birth rates, and to determine which of these 3 associations was strongest. Findings The association between contraceptive rates and abortion rates over time was weaker than that between contraception rates and unwanted pregnancy rates (p = 0.003). Similarly, the association between contraceptive rates and unwanted birth rates over time was weaker than that between contraceptive rates and unwanted pregnancy rates (p = 0.000).
Carto-humeur, carto-humour: France, ta Bretagne f… le camp
Yves LE GUEN
Mappemonde , 1987,
Abstract:
Stratified Static Analysis Based on Variable Dependencies
David Monniaux,Julien Le Guen
Computer Science , 2011,
Abstract: In static analysis by abstract interpretation, one often uses widening operators in order to enforce convergence within finite time to an inductive invariant. Certain widening operators, including the classical one over finite polyhedra, exhibit an unintuitive behavior: analyzing the program over a subset of its variables may lead a more precise result than analyzing the original program! In this article, we present simple workarounds for such behavior.
Oscillating dipole model for the X-ray standing wave enhanced fluorescence in periodic multilayers
Jean-Michel André,Karine Le Guen,Philippe Jonnard
Physics , 2013, DOI: 10.1016/j.sab.2013.03.012
Abstract: Periodic multilayers give rise to enhanced X-ray fluorescence when a regime of standing waves occurs within the structure. This regime may concern the primary radiation used to induce the fluorescence, the secondary radiation of fluorescence or both of them. Until now, existing models only dealt with standing wave regime of primary radiation. We present a theoretical approach based on the oscillating dipole model and the coupled-wave theory that can treat efficiently any standing wave regime. We compare our simulations to experimental data available in the literature.
Feasibility considerations of a soft-x-ray distributed feedback laser pumped by an x-ray free electron laser
Jean-Michel André,Karine Le Guen,Philippe Jonnard
Physics , 2014, DOI: 10.1088/1054-660X/24/8/085001
Abstract: We discuss the feasibility of a soft-x-ray distributed feedback laser (DFL) pumped by an x-ray free electron laser (X-FEL). The DFL under consideration is a Mg/SiC bi-layered Bragg reflector pumped by a single X-FEL bunch at 57.4 eV, stimulating the Mg L2,3 emission at 49 eV corresponding to the 3s-3d -> 2p1/2,3/2 transition. Based on a model developed by Yariv and Yeh and an extended coupled-wave theory, we show that it would be possible to obtain a threshold gain compatible with the pumping provided by available X-FEL facilities.
Kossel diffraction and photonic modes in one-dimensional photonic crystal
J. -M André,Philippe Jonnard,K. Le Guen,F. Bridou
Physics , 2015, DOI: 10.1088/0031-8949/90/8/085503
Abstract: Kossel diffraction under standing-wave excitation in a one-dimensional photonic crystal is investigated. It is shown that by combining the reciprocity theorem, the Fermi golden rule and the concept of density of photonic modes, it is possible to predict the behaviour of the Kossel diffraction in such a system.
High-resolution x-ray analysis with multilayer gratings
Philippe Jonnard,Karine Le Guen,Jean-Michel André
Physics , 2013, DOI: 10.1002/xrs.1128
Abstract: Periodic multilayers are nowadays widely used to perform x-ray analysis in the soft x-ray range (photon energy lower than 1 keV). However, they do not permit to obtain high-resolution spectra like natural or synthetic crystals. Thus, multilayers cannot resolve interferences between close x-ray lines. It has been shown and demonstrated experimentally that patterning a grating profile within a multilayer structure leads to a diffractive optics with improved resolving power. We illustrate the use of a Mo/B4C multilayer grating in the Fe L and C K spectral ranges, around 700 eV and 280 eV respectively. First, in the Fe L range, the improved spectral resolution enables us to distinguish the Fe L\alpha and L\beta emissions (separated by 13 eV). In addition, using a sample made of a mix of LiF and an iron ore, we show that it is possible to easily resolve the F K and Fe L emissions. These examples demonstrate that an improved x-ray analysis can be obtained with multilayer gratings when there is the need to study samples having elements giving rise to close emission lines. Second, in the C K range, by comparing C K\alpha spectra from B4C and cellulose, we show that the shape of the emission band is sensitive to the chemical state of the carbon atom.
Characterization of Al and Mg Alloys from Their X-Ray Emission Bands
Philippe Jonnard,Karine Le Guen,R. Gauvin,Jean-Fran?ois Le Berre
Physics , 2013, DOI: 10.1017/S1431927609090060
Abstract: The valence states of Mg-Al alloys are compared to those of reference materials (pure Mg and Al metals, and intermetallics). Two methods based on X-ray emission spectroscopy are proposed to determine the phases and their proportion: first, by analyzing the Al valence spectra of the Mg-rich alloys and the Mg valence spectra of the Al-rich alloys; second, by fitting with a linear combination of the reference spectra the Al spectra of the Al-rich alloys and the Mg spectra of the Mg-rich alloys. This enables us to determine that Al and Al3Mg2 are present in the 0-43.9 wt% Al composition range and Mg and Al12Mg17 are present in the 62.5-100 wt% Al composition range. In the 43.9-62.5% Al range, the alloy is single phase and an underestimation of the Al content of the alloy can be estimated from the comparison of the bandwidth of the alloy spectrum to the bandwidths of the reference spectra.
Plasma Spraying and Characterization of Tungsten Carbide-Cobalt Coatings by the Water-Stabilized System WSP
Pavel Ctibor,Micheala Ka parová,Jeremy Bellin,Emmanuel Le Guen,Franti ek Zahálka
Advances in Materials Science and Engineering , 2009, DOI: 10.1155/2009/254848
Abstract: Tungsten carbide-cobalt powders (WC-17wt% Co) were plasma sprayed by a water-stabilized system WSP. Experiments with variable feeding distances and spray distances were carried out. Thinner coatings were deposited on carbon steel substrates and thicker coatings on stainless steel substrates to compare different cooling conditions. Basic characterization of coatings was done by XRD, SEM, and light microscopy plus image analysis. Microhardness was measured on polished cross-sections. The main focus of investigation was resistance against wear in dry as well as wet conditions. The appropriate tests were performed with set-ups based on ASTM G65 and G75, respectively. The influence of spray parameters onto coating wear performance was observed. The results of mechanical tests were discussed in connection with changes of phase composition and with the quality of the coating's microstructure. The results show that for obtaining the best possible WC-17Co coating with WSP process, from the viewpoint of wear resistance, the desired parameters combination is long feeding distance combined with short spray distance.
Chest computed tomography with multiplanar reformatted images for diagnosing traumatic bronchial rupture: a case report
Morgan Le Guen, Catherine Beigelman, Belaid Bouhemad, Yang Wenj?e, Frederic Marmion, Jean-Jacques Rouby
Critical Care , 2007, DOI: 10.1186/cc6109
Abstract: Three-dimensional reconstruction of the airways using a workstation connected to a multidetector chest computed tomography (CT) scanner may change the diagnostic strategy in patients with blunt chest trauma with clinical signs evocative of bronchial rupture.In this case report of a young motor biker, a complete disruption of the intermediary trunk was first misdiagnosed using standard chest helical CT and bronchoscopy. Postprocessing procedures including three-dimensional extraction of the tracheobronchial tree were determinants for establishing the diagnosis, and emergent surgical repair was successfully performed. Follow-up using CT with three-dimensional reconstructions evidenced a bronchial stenosis located at the site of the rupture.The present study demonstrates the potential interest of performing three-dimensional reconstructions by extraction of the tracheal–bronchial tree in patients with severe blunt chest trauma suspected of bronchial rupture.Tracheobronchial injuries, although rarely observed following blunt chest trauma [1-3], are associated with a mortality ranging between 9% and 30% [3-5]. Traumatic injury of the airways is suspected in the presence of subcutaneous cervical emphysema expanding with mechanical ventilation, pneumomediastinum and recurrent pneumothorax due to a persisting air leak [6]. To date, tracheobronchoscopy remains the reference diagnostic tool [1,6-11]. The procedure, however, is accurate only when performed by trained thoracic or trauma surgeons and pneumologists [7,12]. Moreover, the tracheobronchial injury may be very difficult to diagnose even by an experienced practitioner. As a consequence, tracheobronchial injury may go unnoticed during the early stage of resuscitation and can lead to increased mortality [5] and morbidity through recurrent pneumonia, mediastinitis and atelectasis delaying the mechanical ventilation withdrawal [8,13].Chest computed tomography (CT) is considered the more relevant diagnostic tool in hemodyna
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