Search results for "Polarization"
showing 10 items of 1884 documents
Frontières des communautés polarisées : application à l'étude des théories complotistes autour des vaccins
2021
Les données des réseaux sociaux sont de plus en plus utilisées pour en extraire de la valeur, dans des domaines tels que le marketing, la politique ou la sociologie. Celles-ci peuvent être représentées sous forme de graphes, en modélisant précisément les interactions à travers des liens dirigés et pondérés. Dans l'analyse des données des réseaux sociaux, l'étude des communautés est une étape essentielle. Toutefois, pour une interprétation fine des phénomènes, il est également nécessaire d'étudier leurs interactions et de pouvoir détecter des traces de polarisation. Nous proposons une méthode qui permet d'évaluer l'antagonisme des communautés et d'identifier leurs frontières dans des réseaux…
Mutations urbaines et logiques de localisation des emplois: le cas de la Communauté de l'agglomération dijonnaise (1990, 1999).
2004
The aim of this paper is to analyze the spatial changes in the Dijon urban area (COMADI) by studying in particular the new tendencies of localization of the high order producer services. Our results display a multicentric structure of the COMADI which exhibits several employment poles. Not only the economic composition of these poles differs between the central pole and the peripheral ones but this composition changes over the study period (1990-1999). New localization logics appear for the high order services : if the historical center remains specialized in financial activities, insurance and real estate (FIRE), the other producer services are more likely to be localized in the periphery.…
Single π0 production off neutrons bound in deuteron with linearly polarized photons
2021
The quasifree γ→d→π0n(p) photon beam asymmetry, Σ, has been measured at photon energies, Eγ, from 390 to 610 MeV, corresponding to center of mass energy from 1.271 to 1.424 GeV, for the first time. The data were collected in the A2 hall of the MAMI electron beam facility with the Crystal Ball and TAPS calorimeters covering pion center-of-mass angles from 49∘ to 148∘. In this kinematic region, polarization observables are sensitive to contributions from the Δ(1232) and N(1440) resonances. The extracted values of Σ have been compared to predictions based on partial-wave analyses (PWAs) of the existing pion photoproduction database. Our comparison includes the SAID, MAID and Bonn–Gatchina anal…
Predictors of credibility of online media in the spanish polarized media system
2019
Credibility of online news media is facing important challenges: the levelling effect of the digital environment, the changing habits of consumption, polarization of discourses… This scenario makes it relevant to address what features of news brands and news content shape the credibility of contemporary journalism. This article tests a set of items, including journalistic standards, reputation and citizen participation, in order to build predictors involved in credibility judgments. The authors carried on a quantitative survey (n=416), representative of the Spanish online population. Results identified currency of information, inclusion of analysis and context, citation of sources and inclu…
Study of Σ(1385) and Ξ(1321) hyperon and antihyperon production in deep inelastic muon scattering
2013
Large samples of \Lambda, \Sigma(1385) and \Xi(1321) hyperons produced in deep-inelastic muon scattering off a ^6LiD target were collected with the COMPASS experimental setup at CERN. The relative yields of \Sigma(1385)^+, \Sigma(1385)^-, \bar{\Sigma}(1385)^-, \bar{\Sigma}(1385)^+, \Xi(1321)^-, and \bar{\Xi}(1321)^+ hyperons decaying into \Lambda(\bar{\Lambda})\pi were measured. The heavy hyperon to \Lambda and heavy antihyperon to \bar{\Lambda} yield ratios were found to be in the range 3.8% to 5.6% with a relative uncertainty of about 10%. They were used to tune the parameters relevant for strange particle production of the LEPTO Monte Carlo generator.
Dynamics of Strongly Coupled Modes between Surface Plasmon Polaritons and Photoactive Molecules: The Effect of the Stokes Shift
2017
We have investigated the dynamics of strongly coupled modes of surface plasmon polaritons (SPPs) and fluorescent molecules by analyzing their scattered emission polarization. While the scattered emission of SPPs is purely transverse magnetic (TM) polarized, the strong coupling with molecules induces transverse electric (TE) polarized emission via the partial molecular nature of the formed SPP–molecule polariton mode. We observe that the TM/TE ratio of the polariton emission follows the contribution of the molecular excited states in this hybrid mode. By using several types of molecules, we observe that, in addition to the coupling strength, which determines the contribution of the molecular…
Ionic currents ofdrosophila embryonic neurons derived from selectively cultured CNS midline precursors
2000
In order to investigate the electrogenesis of defined cell populations, we applied an in vitro system that allows the selective culturing of individual Drosophila CNS precursors under different conditions. CNS midline (ML) precursors prepared from gastrula stage embryos gave rise to progeny cells with neuronal and glial morphology that expressed specific markers. Using whole-cell patch-clamp recordings, a detailed description of ionic currents present in this defined cell population is provided. Most ionic currents of cultured ML neurons were similar to other cultured Drosophila neurons, even though their embryonic origin is different. They displayed at least two voltage-gated potassium cur…
Manipulation of antiferromagnetic domain distribution in Mn2 Au by ultrahigh magnetic fields and by strain
2017
Evidence for a spin reorientation in antiferromagnetic (AFM) Mn2Au thin films induced by high magnetic fields as well as by the application of in-plane mechanical stress is provided. The AFM domain population in the samples was investigated by resonant X-ray Magnetic Linear Dichroism (XMLD) measurements at the L3 edge of Mn using a variable linear polarization of the incident photon beam. As grown samples show no XMLD signal due to averaging over a random AFM domain distribution. After the exposure to a 70 T in-plane magnetic field a clear XMLD signal indicating the generation of a preferential AFM domain orientation is obtained. The same type of XMLD signal is observed when the thin films …
Disparités géographiques et convergence des régions européennes : une approche par l'économétrie spatiale
2002
The aim of this dissertation is to analyze the convergence process between European regions by taking into account spatial patterns of economic activities. First, with the help of literature reviews on theoretical and empirical analyses of growth and convergence and on economic geography models, we show in chapter 1 why geographic disparities should be introduced in the study of convergence between economies. Next, the spatial statistic and econometric tools allowing to reach this goal are detailed in chapter 2. Finally, three empirical studies of the convergence process in presence of geographic disparities are carried out. They are based on a sample for per capita GDP of 138 regions, belo…
Measurement of the SMC muon beam polarisation using the asymmetry in the elastic scattering off polarised electrons
2000
A muon beam polarimeter was built for the SMC experiment at the CERN SPS, for beam energies of 100 and 190 GeV. The beam polarisation is determined from the asymmetry in the elastic scattering off the polarised electrons of a ferromagnetic target whose magnetisation is periodically reversed. At muon energies of 100 and 190 GeV the measured polarisation is P-mu = -0.80 +/- 0.03 (stat.) +/- 0.02 (syst.) and P-mu = - 0.797 +/- 0.011 (stat.) +/- 0.012 (syst.), respectively. These results agree with measurements of the beam polarisation using a shape analysis of the decay positron energy spectrum. (C) 2000 Elsevier Science B.V. All rights reserved.