La mention de la méthodologie des sondages électoraux dans les quotidiens québécois de 1979 à 1997

Faute de réglementation gouvernementale, la capacité autorégulatrice des médias et un marché concurrentiel permettent-ils d’améliorer la présentation de la méthodologie des sondages électoraux? L’analyse de 390 comptes rendus de sondages électoraux publiés de 1979 à 1997 révèle que le nombre d’informations méthodologiques transmises est demeuré stable après une légère hausse entre 1979 et 1984. L’identité du commanditaire, la nationalité du sondeur, l’intervention d’experts dans le travail journalistique et l’unité territoriale sur laquelle porte le sondage influencent la présentation de la méthodologie. En conclusion, l’autorégulation et la concurrence n’améliorent pas la qualité de la présentation de la méthodologie en raison des intérêts et des contraintes des entreprises de presse, des journalistes et des firmes de sondage.Can the media self-regulation ability and a competitive market improve the publication quality of methodological data about electoral polls, without a governmental regulation? An analysis of 390 reports on electoral polls published from 1979 to 1997 shows the stability of the number of methodological data included, after a small increase between 1979 and 1984. The sponsor's identity, the pollster's nationality, the interacting between journalists and experts, in addition to the territorial unit on which the results are applicable influence the presentation of methodology. In conclusion, the author states that the self-regulation and the competition do not improve the publication quality of methodological data owing to the interests and constraints of press companies, journalists and pollsters

Entre la peur et la confiance : l'histoire, le contenu et l'auditoire des émissions d'information politique et d'infodivertissement à la télévision francophone au Québec

Thèse numérisée par la Division de la gestion de documents et des archives de l'Université de Montréal

« La question qui tue » : l’interrogation politique et l’infodivertissement

La littérature sur les interviews politiques dans les émissions télévisées combinant information et divertissement questionne régulièrement la qualité de l’information que les citoyens peuvent y trouver, notamment la rigueur des interrogations conduites par leurs animateurs. En comparant des entrevues menées avec des chefs de partis politiques dans une émission d’information (Le Téléjournal) et un talk show d’infodivertissement (Tout le monde en parle) de la télévision publique canadienne, à l’occasion de deux campagnes électorales, nous examinons l’occurrence de deux modalités précises de l’interrogation politique : les questions d’appui et celles d’objection. Bien que ces genres de questions soient prescrits dans les manuels de journalisme, notre analyse indique qu’elles ne sont pas plus récurrentes dans les émissions d’information que d’infodivertissement. Nous concluons que, lorsque les animateurs de talk shows interrogent des personnalités politiques, ils pratiquent un mimétisme qui les approche des entrevues journalistiques et réduit la spécificité de ces dernières.The literature about political interviews on tv talk shows combining information and entertainment often fuels debates about the quality of information that people can find in, including the rigor of the host's interrogations. We compare interviews with political parties’ leaders on a tv news program (Le Téléjournal) and on an infotainment talk show (Tout le monde en parle) on a Canadian tv public channel during two election campaigns. We examine the occurrence of two specific forms of the political interrogation: follow-up questions and challenging questions.  Although journalism textbooks prescribe these sorts of questions our analysis indicates that they are not more recurrent on tv news programs than on the infotainment ones. We conclude that when talk show hosts interrogate politics they practice a sort of mimicry what brings them closer of journalistic interviews and decreases its specificities

Multi-Scale Analysis of Magnetic Fields in Filamentary Molecular Clouds in Orion A

New visible and K-band polarization measurements on stars surrounding molecular clouds in Orion A and stars in the BN vicinity are presented. Our results confirm that magnetic fields located inside the Orion A molecular clouds and in their close neighborhood are spatially connected. On and around the BN object, we measured the angular offsets between the K-band polarization data and available submm data. We find high values of the polarization degree, P_{K}, and of the optical depth, \tau_{K}, close to an angular offset position of 90^{\circ} whereas lower values of P_{K} and \tau_{K} are observed for smaller angular offsets. We interpret these results as evidence for the presence of various magnetic field components toward lines of sight in the vicinity of BN. On a larger scale, we measured the distribution of angular offsets between available H-band polarization data and the same submm data set. Here we find an increase of with angular offset which we interpret as a rotation of the magnetic field by \lesssim 60^{\circ}. This trend generalizes previous results on small scale toward and around lines of sight to BN and is consistent with a twist of the magnetic field on a larger scale towards OMC-1. A comparison of our results with several other studies suggests that a two-component magnetic field, maybe helical, could be wrapping the OMC-1 filament.Comment: 53 pages, 21 figures, 7 tables, Accepted in the Astrophysical Journa

Empirical modelling of the BLASTPol achromatic half-wave plate for precision submillimetre polarimetry

A cryogenic achromatic half-wave plate (HWP) for submillimetre astronomical polarimetry has been designed, manufactured, tested and deployed in the Balloon-borne Large-Aperture Submillimeter Telescope for Polarimetry (BLASTPol). The design is based on the five-slab Pancharatnam recipe and itworks in thewavelength range 200–600 μm, making it the broadestband HWP built to date at (sub)millimetre wavelengths. The frequency behaviour of the HWP has been fully characterized at room and cryogenic temperatures with incoherent radiation from a polarizing Fourier transform spectrometer. We develop a novel empirical model, complementary to the physical and analytical ones available in the literature, that allows us to recover the HWP Mueller matrix and phase shift as a function of frequency and extrapolated to 4 K. We show that most of the HWP non-idealities can be modelled by quantifying one wavelength-dependent parameter, the position of the HWP equivalent axes, which is then readily implemented in a map-making algorithm. We derive this parameter for a range of spectral signatures of input astronomical sources relevant to BLASTPol, and provide a benchmark example of how our method can yield improved accuracy on measurements of the polarization angle on the sky at submillimetre wavelengths

The JCMT BISTRO Survey: Studying the Complex Magnetic Field of L43

We present observations of polarized dust emission at 850 μm from the L43 molecular cloud, which sits in the Ophiuchus cloud complex. The data were taken using SCUBA-2/POL-2 on the James Clerk Maxwell Telescope as a part of the BISTRO large program. L43 is a dense (NH 10 22 2 ~ –1023 cm−2) complex molecular cloud with a submillimeter-bright starless core and two protostellar sources. There appears to be an evolutionary gradient along the isolated filament that L43 is embedded within, with the most evolved source closest to the Sco OB2 association. One of the protostars drives a CO outflow that has created a cavity to the southeast. We see a magnetic field that appears to be aligned with the cavity walls of the outflow, suggesting interaction with the outflow. We also find a magnetic field strength of up to ∼160 ± 30 μG in the main starless core and up to ∼90 ± 40 μG in the more diffuse, extended region. These field strengths give magnetically super- and subcritical values, respectively, and both are found to be roughly trans-Alfvénic. We also present a new method of data reduction for these denser but fainter objects like starless cores

Filamentary Network and Magnetic Field Structures Revealed with BISTRO in the High-Mass Star-Forming Region NGC2264 : Global Properties and Local Magnetogravitational Configurations

We report 850 $\mu$m continuum polarization observations toward the filamentary high-mass star-forming region NGC 2264, taken as part of the B-fields In STar forming Regions Observations (BISTRO) large program on the James Clerk Maxwell Telescope (JCMT). These data reveal a well-structured non-uniform magnetic field in the NGC 2264C and 2264D regions with a prevailing orientation around 30 deg from north to east. Field strengths estimates and a virial analysis for the major clumps indicate that NGC 2264C is globally dominated by gravity while in 2264D magnetic, gravitational, and kinetic energies are roughly balanced. We present an analysis scheme that utilizes the locally resolved magnetic field structures, together with the locally measured gravitational vector field and the extracted filamentary network. From this, we infer statistical trends showing that this network consists of two main groups of filaments oriented approximately perpendicular to one another. Additionally, gravity shows one dominating converging direction that is roughly perpendicular to one of the filament orientations, which is suggestive of mass accretion along this direction. Beyond these statistical trends, we identify two types of filaments. The type-I filament is perpendicular to the magnetic field with local gravity transitioning from parallel to perpendicular to the magnetic field from the outside to the filament ridge. The type-II filament is parallel to the magnetic field and local gravity. We interpret these two types of filaments as originating from the competition between radial collapsing, driven by filament self-gravity, and the longitudinal collapsing, driven by the region's global gravity.Comment: Accepted for publication in the Astrophysical Journal. 43 pages, 32 figures, and 4 tables (including Appendix