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Portée et limites du modèle Taxipp pour l'analyse redistributive des prélèvements obligatoires
No full textInternational audienceCet article présente le modèle Taxipp, un modèle de microsimulation des prélèvements obligatoires français, qui permet de simuler de façon classique des législations contre factuelles, passées ou présentes, sur un échantillon représentatif de la population française. Le modèle se distingue des approches standards de microsimulation statique en portant un soin particulier à l’imputation de la distribution des hauts revenus et en calant l’ensemble des données sur les informations agrégées de la comptabilité nationale. Le modèle permet ainsi d’offrir des décompositions au niveau micro des mesures de l’ensemble des prélèvements obligatoires en cohérence avec l’approche macroéconomique de la fiscalité présentée par la comptabilité nationale. Il permet par ailleurs de présenter des analyses fines de réformes fiscales au sommet de la distribution des revenus, sur lesquels se concentre souvent le débat public. Un tel exercice a pourtant ses limites. La première est le caractère incontournable des hypothèses d’incidence, en particulier pour les prélèvements réalisés nominalement sur les entreprises ; l’absence de consensus sur l’incidence fiscale de l’impôt sur les bénéfices des sociétés conduit ainsi à des variantes sensiblement différentes. La seconde limite vient des contradictions entre les différentes sources agrégées (comptabilité nationale, sources fiscales) qui sont difficiles à réconcilier. Ces limites ne sont pas dirimantes ; au contraire, elles ouvrent de nombreuses pistes de recherches ultérieures visant à améliorer l’adéquation des approches micro et macro de l’analyse des systèmes socio fiscaux
TEC variations along an East Euro-African chain during 5th april 2010 geomagnetic storm
No full textInternational audienceIn this paper, we analyzed the variations of TEC along a latitudinal East Euro-African chain, during the storm of April 5, 2010. We observed a large asymmetry between the two hemispheres. We detected the presence of a TID in the Northern hemisphere on April 5. The propagation time of the TID from high to low latitudes and the speed of the TID was determined. On April 5, 6 and 7, we observed a decrease of the TEC and changes of the NO+ in the Northern hemisphere. This depletion is caused by the large-scale thermospheric wind disturbances due to Joule heating dissipation in the auroral zone
Spirobifluorene-2,7-dicarbazole-4'-phosphine Oxide as Host for High-Performance Single-Layer Green Phosphorescent OLED Devices
No full textInternational audienceA new host material based on the 2,7,4'-substituted spirobifluorene platform has been designed and used in single-layer phosphorescent OLED with very high efficiency (EQE = 13.2%) and low turn-on voltage (2.4 V). This performance is among the best reported for green single-layer PhOLEDs and may open new avenues in the design of host materials for single-layer devices
Toward a generic representation of random variables for machine learning
No full textThis paper presents a pre-processing and a distance which improve the performance of machine learning algorithms working on independent and identically distributed stochastic processes. We introduce a novel non-parametric approach to represent random variables which splits apart dependency and distribution without losing any information. We also propound an associated metric leveraging this representation and its statistical estimate. Besides experiments on synthetic datasets, the benefits of our contribution is illustrated through the example of clustering financial time series, for instance prices from the credit default swaps market. Results are available on the website www.datagrapple.com and an IPython Notebook tutorial is available at www.datagrapple.com/Tech for reproducible research
Supergravity, complex parameters and the Janis–Newman algorithm
No full textInternational audienceThe Demiański–Janis–Newman (DJN) algorithm is an original solution generating technique. For a long time it has been limited to producing rotating solutions, restricted to the case of a metric and real scalar fields, despite the fact that Demiański extended it to include more parameters such as a NUT charge. Recently two independent prescriptions have been given for extending the algorithm to gauge fields and thus electrically charged configurations. In this paper we aim to end setting up the algorithm by providing a missing but important piece, which is how the transformation is applied to complex scalar fields. We illustrate our proposal through several examples taken from N = 2 supergravity, including the stationary BPS solutions from Behrndt et al and Senʼs axion–dilaton rotating black hole. Moreover we discuss solutions that include pairs of complex parameters, such as the mass and the NUT charge, or the electric and magnetic charges, and we explain how to perform the algorithm in this context (with the example of Kerr–Newman–Taub–NUT and dyonic Kerr–Newman black holes). The final formulation of the DJN algorithm can possibly handle solutions with five of the six Plebański–Demiański parameters along with any type of bosonic fields with spin less than two (exemplified with the stationary Israel–Wilson–Perjes solutions). This provides all the necessary tools for applications to general matter-coupled gravity and to (gauged) supergravity
Microhydration of Protonated Nα-Acetylhistidine: A Theoretical Approach
No full textInternational audienceExtensive exploration of the potential energy surfaces of protonated Nα-acetylhistidine hydrated by 0–3 molecules of water was performed. The methodology combined hierarchical and genealogical (Darwin family tree) approaches using polarizable AMOEBA force field and M06 functional. It is demonstrated that this mixed approach allows recovering a larger number of conformers than the number recovered by using any one of the two methods alone. Hydration enthalpies of protonated Nα-acetylhistidine and of model compounds have been computed using higher theoretical methods, up to the G4MP2 procedure. Excellent agreement with experiment is observed for successive hydration of methylamonium and imidazolium cations using MP2/6-311++G(2d,2p)//M06/6-311++G(d,p) and G4MP2 methods, thereby validating the theory levels used for hydrated protonated Nα-acetylhistidine. It is found that the first hydration enthalpy of protonated Nα-acetylhistidine is ca. 10 kJ mol–1 lower than that of imidazolium, a result explained by the local environment of the positively charged imidazolium moiety
Discrete-valued-pulse optimal control algorithms: Application to spin systems
No full textInternational audienceThis article is aimed at extending the framework of optimal control techniques to the situation where the control field values are restricted to a finite set. We propose generalizations of the standard GRAPE algorithm suited to this constraint. We test the validity and the efficiency of this approach for the inversion of an inhomogeneous ensemble of spin systems with different offset frequencies. It is shown that a remarkable efficiency can be achieved even for a very limited number of discrete values. Some applications in nuclear magnetic resonance are discussed
Inflation physics from the cosmic microwave background and large scale structure
No full textInternational audienceFluctuations in the intensity and polarization of the cosmic microwave background (CMB) and the large-scale distribution of matter in the universe each contain clues about the nature of the earliest moments of time. The next generation of CMB and large-scale structure (LSS) experiments are poised to test the leading paradigm for these earliest moments-the theory of cosmic inflation-and to detect the imprints of the inflationary epoch, thereby dramatically increasing our understanding of fundamental physics and the early universe. A future CMB experiment with sufficient angular resolution and frequency coverage that surveys at least 1% of the sky to a depth of 1 uK-arcmin can deliver a constraint on the tensor-to-scalar ratio that will either result in a 5 σ measurement of the energy scale of inflation or rule out all large-field inflation models, even in the presence of foregrounds and the gravitational lensing B-mode signal. LSS experiments, particularly spectroscopic surveys such as the Dark Energy Spectroscopic Instrument, will complement the CMB effort by improving current constraints on running of the spectral index by up to a factor of four, improving constraints on curvature by a factor of ten, and providing non-Gaussianity constraints that are competitive with the current CMB bounds
Effets de l'introduction de Technologies de l'Information et de la Communication sur les interactions entre citoyens, fournisseurs de services et gouvernants dans des contextes précaires de santé: un regard empirique à travers une expérience pilote de santé mobile en milieu rural au Guatemala
No full textInformation and Communication Technologies (ICTs) have ubiquitous influence on health systems. From smartphone applications and web services to wearable devices and the Internet of Things, innovations are eagerly adopted by patients, clinicians, health centers and governments worldwide. Although their effects on health outcomes, quality and costs have been previously studied, little effort has been made to describe their implications on interactions between individuals. The assessment of their impact is particularly difficult in low-resource health settings, where fundamental dynamics have been disregarded by theoretical studies.This thesis was constructed as an attempt to reduce gaps in the literature about the effects of the introduction of ICTs in low-resource health settings. In the first part, it draws on empirical and theoretical insights from health economics, behavioral science and public administration to consolidate a unified framework. Its formulation allows to derive empirically testable hypotheses regarding health outcomes, co-production of services and actor interactions when mobile technology is introduced. In the second part, it presents the methodology used to generate unique data and to test some of the model's predictions. Principal discussions and conclusions focus on the impact evaluation of a mobile-health pilot experiment that was run in rural Guatemala in the context of newborn and maternal care.The novelty of the thesis lies in the proposed theoretical framework and in the adopted experimental strategy. Results from the pilot experiment highlight the interest of a peculiar organizational setup —virtual communities of indigenous mothers exposed to social support, expert advice and timely medical response via text-message— for precarious health care contexts. Discussions, albeit limited in scope by the exploratory nature of the intervention, shed new light on the impact of ICT-based heath programs in poor contexts. Collaborative governance between citizens, service providers, governments and research entities seems appropriate when sustainable changes in health systems are needed. Analyses are of timely relevance for countries looking to scale-up interventions with potential to induce healthy attitudes in underserved areas.Les Technologies de l'Information et de la Communication (TICs) sont ubiquitaires dans les systèmes de santé. Les innovations récentes, allant des services publics en ligne aux objets connectés, sont adoptées avidement par patients, hôpitaux et gouvernements, partout dans le monde. L'influence des TICs sur la qualité et les coûts des services de santé a été largement étudiée. Pourtant, leurs impacts sur les interactions entre individus restent méconnus, notamment dans les contextes précaires de santé, où peu de recherche théorique a été effectuée.Cette thèse tente d'éclaircir les effets de l'introduction des TICs dans les environnements précaires de santé. Dans ce but, elle décrit, dans la première partie, un cadre d'analyse intégrateur et multidisciplinaire, inspiré de développements en économie de la santé, en sciences comportementales et en administration publique. La formulation de ce cadre de référence permet de suggérer plusieurs hypothèses en relation avec des résultats de santé, la co-production de services, et les interactions entre individus en présence de technologie mobile. Dans la deuxième partie, la méthodologie qui a été menée pour tester le modèle est présentée. Ici, les discussions principales se centrent sur l'étude d'impact d'une expérience pilote de santé mobile qui a été réalisée dans le Guatemala rural.Les contributions principales de ce travail reposent sur le modèle théorique qui a été créé et sur la stratégie expérimentale qui a été déployée pour vérifier sa validité. Les résultats montrent l'intérêt d'un arrangement organisationnel particulier: des communautés virtuelles de mères indigènes exposées à des services de soutien, à des conseils provenant de professionnels de la santé, et à des échanges rapides via message de texte (SMS). La gouvernance de l'information et des services devient collaborative lorsque individus, fournisseurs de service, et décideurs cherchent à résoudre les défaillances du status quo sanitaire
Limits on the Higgs boson lifetime and width from its decay to four charged leptons
No full textsee paper for full list of authorsInternational audienceConstraints on the lifetime and width of the Higgs boson are obtained from H to ZZ to 4 lepton events using data recorded by the CMS experiment during the LHC run 1 with an integrated luminosity of 5.1 and 19.7 inverse femtobarns at a center-of-mass energy of 7 and 8 TeV, respectively. The measurement of the Higgs boson lifetime is derived from its flight distance in the CMS detector with an upper bound of tau[H] 3.5E-9 MeV. The measurement of the width is obtained from an off-shell production technique, generalized to include anomalous couplings of the Higgs boson to two electroweak bosons. From this measurement, a joint constraint is set on the Higgs boson width and a parameter f[LQ] that expresses an anomalous coupling contribution as an on-shell cross-section fraction. The limit on the Higgs boson width is Gamma[H] < 46 MeV with f[LQ] unconstrained and Gamma[H] < 26 MeV for f[LQ] = 0 at the 95% CL. The constraint f[LQ] < 3.8E-3 at the 95% CL is obtained for the expected standard model Higgs boson width