Traitement de données observationnelles et développement d'un code de simulation pour SpIOMM et SITELLE

L’arrivée du spectromètre imageur à transformée de Fourier SITELLE au télescope Canada-France-Hawaï souligne la nécessité d’un calculateur de temps d’exposition permettant aux utilisateurs de l’instrument de planifier leurs observations et leurs demandes de temps de télescope. Une grande partie de mon projet est ainsi le développement d’un code de simulation capable de reproduire les résultats de SITELLE et de son prédecesseur SpIOMM, installé à l’Observatoire du Mont-Mégantic. La précision des simulations est confirmée par une comparaison avec des données SpIOMM et les premières observations de SITELLE. La seconde partie de mon projet consiste en une analyse spectrale de données observationelles. Prenant avantage du grand champ de vue de SpIOMM, les caractéristiques du gaz ionisé (vitesse radiale et intensité) sont étudiées pour l’ensemble de la paire de galaxies en interaction Arp 72. La courbe de rotation dans le visible ainsi que le gradient de métallicité de NGC 5996, la galaxie principale d’Arp 72, sont obtenues ici pour la première fois. La galaxie spirale NGC 7320 est également étudiée à partir d’observations faites à la fois avec SpIOMM et SITELLE.The arrival of the Fourier-transform imaging spectrometer SITELLE at the Canada-France-Hawaii telescope highlights the importance of having an exposure time calculator allowing the instrument’s users to plan ahead their observing proposals. A large part of my project is the development of a simulator able to reproduce the results obtained with SITELLE and its predecessor SpIOMM. The accuracy of the simulations is confirmed through comparison with SpIOMM data and SITELLE’s first observations. The second part of my project is the spectral analysis of observational data. SpIOMM’s large field of view allows us to study the properties (radial velocities and line intensities) of the ionized gas through the entirety of Arp 72, a pair of interacting galaxies. For the first time, the rotation curve in the optical and the metallicity gradient are obtained for NGC 5996, the main galaxy in Arp 72. Both SpIOMM and SITELLE results are also shown for the dwarf spiral galaxy NGC 7320

Strange bedfellows? Attitudes toward minority religious symbols in the public sphere

In this study, we contend that distinguishing individuals who support bans on minority religious symbols from those who want to ban all religious symbols improves our understanding of the roots of opposition to minority religious symbols in the public sphere. We hypothesize that both groups are likely driven by markedly different motivations and that opposition to the presence of minority religious symbols in the public sphere may be the result of an alliance between “strange bedfellows,” clusters of individuals whose political outlooks usually bring them to opposite sides of political debates. Drawing on a survey conducted in the province of Quebec (Canada), we find that while holding liberal values and low religiosity are key characteristics of those who would ban all religious symbols, feelings of cultural threat and generalized prejudice are central characteristics of those who would only restrict minority religious symbols. Negative attitudes specifically toward Muslims, however, also appear to motivate both groups

Ethnic minority belonging in a multilevel political community:The role of exclusionary experiences and welcoming provincial contexts in Canada

Numerous studies demonstrate that immigrant and ethnic minority populations’ sense of belonging to the political communities in which they reside depends in part on the welcoming context: the constellation of policies, discourses, identities and prevailing attitudes relating to ethnocultural diversity in those political communities. However, while these studies typically focus on national belonging, in multilevel political communities belonging may be expressed at the national and subnational levels. Relying on a survey of ethnic minority group members in Canada, this study compares national and subnational belonging in three provinces where subnational and national welcoming contexts are very similar, to one case, Quebec, where the subnational welcoming context is significantly different from the national one. The results show a distinctive set of dynamics in Quebec, where ethnic minorities who feel excluded are more likely than those in other provinces to hold the subnational community responsible for their exclusion.</p

ZNF274 Recruits the Histone Methyltransferase SETDB1 to the 3′ Ends of ZNF Genes

Only a small percentage of human transcription factors (e.g. those associated with a specific differentiation program) are expressed in a given cell type. Thus, cell fate is mainly determined by cell type-specific silencing of transcription factors that drive different cellular lineages. Several histone modifications have been associated with gene silencing, including H3K27me3 and H3K9me3. We have previously shown that genes for the two largest classes of mammalian transcription factors are marked by distinct histone modifications; homeobox genes are marked by H3K27me3 and zinc finger genes are marked by H3K9me3. Several histone methyltransferases (e.g. G9a and SETDB1) may be involved in mediating the H3K9me3 silencing mark. We have used ChIP-chip and ChIP-seq to demonstrate that SETDB1, but not G9a, is associated with regions of the genome enriched for H3K9me3. One current model is that SETDB1 is recruited to specific genomic locations via interaction with the corepressor TRIM28 (KAP1), which is in turn recruited to the genome via interaction with zinc finger transcription factors that contain a Kruppel-associated box (KRAB) domain. However, specific KRAB-ZNFs that recruit TRIM28 (KAP1) and SETDB1 to the genome have not been identified. We now show that ZNF274 (a KRAB-ZNF that contains 5 C2H2 zinc finger domains), can interact with KAP1 both in vivo and in vitro and, using ChIP-seq, we show that ZNF274 binding sites co-localize with SETDB1, KAP1, and H3K9me3 at the 3′ ends of zinc finger genes. Knockdown of ZNF274 with siRNAs reduced the levels of KAP1 and SETDB1 recruitment to the binding sites. These studies provide the first identification of a KRAB domain-containing ZNF that is involved in recruitment of the KAP1 and SETDB1 to specific regions of the human genome

Non-response Error versus Measurement Error: A Dilemma when Using Mail Questionnaires for Election Studies

One strategy used to increase response rates when using mail questionnaires is to prolong the period of data collection. This paper examines the consequences of such a strategy on the Australian Election Studies (1996-2004). The findings suggest that such a strategy has both positive and negative consequences on the overall quality of the survey. On the one hand, prolonging the period of data collection decreases the non-response error by providing a somewhat better representation of hard-to-reach groups of respondents such as the young, full-time employed, and those disinterested in politics. On the other hand, prolonging the period of data collection increases the risk of measurement error. The evidence suggests that post-election events significantly impact on respondents' political opinions. More specifically, the longer respondents wait to return their questionnaire after the elections the more positive their opinions of winning leaders, the more negative their opinions of defeated leaders and the more distant they feel with the policies of defeated parties. Australian investigators thus face a dilemma in deciding when to stop the fieldwork period for their mail election surveys: they must choose between non-response error and measurement error