2,539 research outputs found

    Surface roughness prediction in milling based on tool displacements

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    In this paper, an experimental device using non-contact displacement sensors for the investigation of milling tool behaviour is presented. It enables the recording of high frequency tool vibrations during milling operations. The aim of this study is related to the surface topography prediction using tool displacements and based on tool center point methodology. From the recorded signals and the machining parameters, the tool deformation is modeled. Then, from the calculated deflection, the surface topography in 3D can be predicted. In recent studies, displacements in XY plane have been measured to predict the surface topography in flank milling. In this article, the angular deflection of the tool is also considered. This leads to the prediction of surfaces obtained in flank milling as well as in end milling operations. Validation tests were carried out: the predicted profiles were compared to the measured profile. The results show that the prediction corresponds well in shape and amplitude with the measurement

    Spatial Mobility and Returns to Education:Some Evidence from a Sample of French Youth

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    The purpose of this article is to reevaluate the returns to geographic mobility and to the levelof education, taking into account the interaction between these two variables. We have at ourdisposal an original French database that permits precise calculation of the distance betweenthe place of education and the location of first employment. We thus capture mobility withouta priori regarding the geographical areas selected, and we use kilometric thresholds toestimate the returns to spatial mobility. Our results suggest decreasing returns to spatialmobility as the distance covered rises and increasing returns to mobility with higher levels ofeducation. In addition, for all levels of education, including the lowest, returns to geographicmobility prove to be positive, for one threshold at least and several distances.spatial mobility; returns to schooling; earnings function

    Strong anisotropic influence of local-field effects on the dielectric response of {\alpha}-MoO3

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    Dielectric properties of {\alpha}-MoO3 are investigated by a combination of valence electron-energy loss spectroscopy and ab initio calculation at the random phase approximation level with the inclusion of local-field effects (LFE). A meticulous comparison between experimental and calculated spectra is performed in order to interpret calculated dielectric properties. The dielectric function of MoO3 has been obtained along the three axes and the importance of LFE has been shown. In particular, taking into account LFE is shown to be essential to describe properly the intensity and position of the Mo-N2,3 edges as well as the low energy part of the spectrum. A detailed study of the energy-loss function in connection with the dielectric response function also shows that the strong anisotropy of the energy-loss function of {\alpha}-MoO3 is driven by an anisotropic influence of LFE. These LFE significantly dampen a large peak in {\epsilon}2, but only along the [010] direction. Thanks to a detailed analysis at specific k-points of the orbitals involved in this transition, the origin of this peak has not only been evidenced but a connection between the inhomogeneity of the electron density and the anisotropic influence of local-field effects has also been established. More specifically, this anisotropy is governed by a strongly inhomogeneous spatial distribution of the empty states. This depletion of the empty states is localized around the terminal oxygens and accentuates the electron inhomogeneity.Comment: Supplemental Material include

    MRD in multiple myeloma: more questions than answers?

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    The growing interest in minimal residual disease (MRD)assessment in multiple myeloma (MM) is related to thehigh quality of responses achieved with novel agents andto the development of reliable techniques to evaluateMRD both within the bone marrow using next-generationsequencing (NGS) or next-generationflow cytometry(NGF), and outside the bone marrow using imagingtechniques, such as positron emission tomography-computed tomography (PET-CT)1. A consensus paperby the International Myeloma Working Group (IMWG),published in 2016, represents the reference document onMRD in MM2

    Surface roughness prediction in milling based on tool displacements

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    In this paper, an experimental device using non-contact displacement sensors for the investigation of milling tool behaviour is presented. It enables the recording of high frequency tool vibrations during milling operations. The aim of this study is related to the surface topography prediction using tool displacements and based on tool center point methodology. From the recorded signals and the machining parameters, the tool deformation is modeled. Then, from the calculated deflection, the surface topography in 3D can be predicted. In recent studies, displacements in XY plane have been measured to predict the surface topography in flank milling. In this article, the angular deflection of the tool is also considered. This leads to the prediction of surfaces obtained in flank milling as well as in end milling operations. Validation tests were carried out: the predicted profiles were compared to the measured profile. The results show that the prediction corresponds well in shape and amplitude with the measurement

    A pseudo-R2 measure for selecting genomic markers with crossing hazards functions

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    <p>Abstract</p> <p>Background</p> <p>In genomic medical studies, one of the major objectives is to identify genomic factors with a prognostic impact on time-to-event outcomes so as to provide new insights into the disease process. Selection usually relies on statistical univariate indices based on the Cox model. Such model assumes proportional hazards (PH) which is unlikely to hold for each genomic marker.</p> <p>Methods</p> <p>In this paper, we introduce a novel pseudo-R<sup>2 </sup>measure derived from a crossing hazards model and designed for the selection of markers with crossing effects. The proposed index is related to the score statistic and quantifies the extent of a genomic factor to separate patients according to their survival times and marker measurements. We also show the importance of considering genomic markers with crossing effects as they potentially reflect the complex interplay between markers belonging to the same pathway.</p> <p>Results</p> <p>Simulations show that our index is not affected by the censoring and the sample size of the study. It also performs better than classical indices under the crossing hazards assumption. The practical use of our index is illustrated in a lung cancer study. The use of the proposed pseudo-R<sup>2 </sup>allows the identification of cell-cycle dependent genes not identified when relying on the PH assumption.</p> <p>Conclusions</p> <p>The proposed index is a novel and promising tool for selecting markers with crossing hazards effects.</p

    Catulle et l'inceste. Approches psychanalytique et anthropologique

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    Trente ans aprĂšs H. D. Rankin, « Catullus and Incest », Eranos, 74, 1976, l’auteur rĂ©examine le traitement du thĂšme de l’inceste par Catulle : conception thĂ©orique dans un poĂšme mythologique, le c. 64, imputations d’inceste lancĂ©es contre des contemporains. Il envisage les textes du point de vue des catĂ©gories de la sociĂ©tĂ© romaine (types de parenté : cognatio, filiation ou collatĂ©ralitĂ©, adfinitas ; fas ; degrĂ© de gravitĂ©), et passe en revue les interprĂ©tations antĂ©rieures : approche psychanalytique (c. 72), « gender studies » (c. 63), et propose une analyse anthropologique du c. 88, inspirĂ©e des thĂ©ories de F. HĂ©ritier sur l’« inceste du deuxiĂšme type ».Thirty years after H. D. Rankin’s “Catullus and Incest”, Eranos, 74, 1976, the author investigates afresh how Catullus dealt with incest: through a theoretical view in a mythological poem, c. 64, and by charges of incest brought against coeval characters. This paper examines these texts with regard to Roman categories (kinship types: cognatio, descent or collateral lines, adfinitas; fas; importance attached to the matter) and reviews previous interpretations: the psychoanalytical approach (c. 72) and gender studies (c. 63). He finally offers a new anthropological explanation of c. 88, based on F. HĂ©ritier’s theory of “second type incest”

    Wolf FEUERHAHN (dir.), La Politique des chaires au CollĂšge de France

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    « RĂ©pondant Ă  l’actualitĂ© migratoire, le CollĂšge de France a dĂ©cidĂ© de crĂ©er une chaire ‟Migrations et SociĂ©tĂ©s”, qu’il confie Ă  François HĂ©ran ». C’est ainsi que le quotidien français LibĂ©ration a rendu compte en avril 2018 d’une Ă©lection dans cette prestigieuse institution. Sans trop forcer le trait, on pourrait dire que les trois caractĂ©ristiques gĂ©nĂ©ralement associĂ©es Ă  cet Ă©tablissement sont rappelĂ©es avec une belle concision : le souci de suivre au plus prĂšs l’évolution des phĂ©nomĂšnes e..
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