The CFHTLS Deep Catalog of Interacting Galaxies I. Merger Rate Evolution to z=1.2

We present the rest-frame optical galaxy merger fraction between 0.2<z<1.2, as a function of stellar mass and optical luminosity, as observed by the Canada-France-Hawaii Telescope Legacy Deep Survey (CFHTLS-Deep). We developed a new classification scheme to identify major galaxy-galaxy mergers based on the presence of tidal tails and bridges. These morphological features are signposts of recent and ongoing merger activity. Through the visual classification of all galaxies, down to i_vega<22.2 (~27,000 galaxies) over 2 square degrees, we have compiled the CFHTLS Deep Catalog of Interacting Galaxies, with ~1600 merging galaxies. We find the merger fraction to be 4.3% +/-0.3% at z~0.3 and 19.0% +/-2.5% at z~1, implying evolution of the merger fraction going as (1+z)^m, with m=2.25 +/-0.24. This result is inconsistent with a mild or non-evolving (m4sigma level of confidence. A mild trend, where massive galaxies with M>10^10.7 M_sun are undergoing fewer mergers than less massive systems M~10^10 M_sun), consistent with the expectations of galaxy assembly downsizing is observed. Our results also show that interacting galaxies have on average SFRs double that found in non-interacting field galaxies. We conclude that (1) the optical galaxy merger fraction does evolve with redshift, (2) the merger fraction depends mildly on stellar mass, with lower mass galaxies having higher merger fractions at z<1, and (3) star formation is triggered at all phases of a merger, with larger enhancements at later stages, consistent with N-body simulations.Comment: e.g.: 17 pages, 14 figures, accepted for publication in Ap

Motivation and Technology for Quebec CEGEP ESL Classes

This paper focuses on English as a second language (ESL) learning by students at Quebec Collèges d’Enseignement General et Professionnel (CEGEPs). The research seeks to describe the positive outcome of computer assisted language learning (CALL) practices on the motivational level of students, their efficacy in helping students understand the cultural contexts of a second language, and their role in the achievement of proficiency in oral and written language skills. The main aim of the research is to investigate the role of new constructivist pedagogies and CALL practices in enhancing student motivation for continuous second language learning. Following qualitative case study methodology, the research consisted of a convenience sample of 41 students at a CEGEP in Quebec and used a survey and a focus group to obtain its data. The study found that students were generally motivated to learn English via CALL; however, there were also some shortcomings in this method of instruction. The findings of the research have implications for second language teachers and their students both in Canada and globally. In Canada, the amalgamation of diverse linguistic and migrant communities encourages citizens to be proficient not only in their native tongues, but also in the official languages of the nation—French and English. In the global context, information and communication are the main ingredients of trade, commerce and socialization

Insight into the Cellular Alterations Required for Establishing Opportunistic Pseudomonas aeruginosa Infections

The Gram-negative, opportunistic pathogen Pseudomonas aeruginosa (Pa) is responsible for causing disease of high morbidity and mortality in individuals who are immunocompromised, suffer from damaged epithelial barriers, and who have cystic fibrosis. However, the underlying host cell compromise that allows the establishment of Pa infections remains unknown and is of importance to the development of novel strategies that interrupt Pa infections. The type III secretion system (T3S) allows the direct translocation of bacterial effectors into the host cell cytosol, and in this study was used first, to identify host cell properties involved in the initiation of Pa infections, and then second, to dissect the Pa infectious process. Using the T3S effector ExoS to monitor T3S translocation and the initiation of Pa infections in HT-29 epithelial cells, we identified a relationship between leading edge focal complex adhesion properties involved in cell migration and sensitivity to Pa-T3S. Highly migratory T24 epithelial cells were used to further explore the role of host cell migration in Pa infections, using manipulations of ExoS GTPase activating (GAP) and ADP-ribosyltransferase (ADPRT) activities to manipulate T3S. These studies allowed dissection of the Pa infectious process, and found that Pa expressing wild type ExoS preferentially bound to the leading edge of T24 cells, where ExoS GAP activity interfered with Pa internalization, and ExoS ADPRT activity interrupted actin-plasma membrane associations required for T3S translocation. Interestingly, both toxic events limited the Pa infectious process. Further studies of MTC, MTLn3, and MDCK epithelial cells identified a reciprocal relationship between Rac1 and Rho activation at the leading edge and Pa internalization and T3S translocation efficiency. Together, the studies in this dissertation highlight the role of actin-plasma membrane associations and Rho-GTPases in directing T3S translocation and the Pa infectious process, and the ability of Pa to hijack these factors during cell migration. Our studies in turn are consistent with cell migration properties induced in response to tissue damage being the cellular compromise that leads to the initiation of Pa infections, and that effectors such as ExoS are able to interrupt these same properties to limit the infectious process and maintain the opportunistic nature of Pa infections

Temporal HeartNet: Towards Human-Level Automatic Analysis of Fetal Cardiac Screening Video

We present an automatic method to describe clinically useful information about scanning, and to guide image interpretation in ultrasound (US) videos of the fetal heart. Our method is able to jointly predict the visibility, viewing plane, location and orientation of the fetal heart at the frame level. The contributions of the paper are three-fold: (i) a convolutional neural network architecture is developed for a multi-task prediction, which is computed by sliding a 3x3 window spatially through convolutional maps. (ii) an anchor mechanism and Intersection over Union (IoU) loss are applied for improving localization accuracy. (iii) a recurrent architecture is designed to recursively compute regional convolutional features temporally over sequential frames, allowing each prediction to be conditioned on the whole video. This results in a spatial-temporal model that precisely describes detailed heart parameters in challenging US videos. We report results on a real-world clinical dataset, where our method achieves performance on par with expert annotations.Comment: To appear in MICCAI, 201

Gender, class and space in the field of parenthood comparing middle-class fractions in Amsterdam and London

This paper argues that becoming a parent/carer can be seen as a new field of social relations and suggests how gender is the key mechanism in the reconfiguration of class relations in this field. By conceptualising parenthood as a field, that is a social world with specific stakes and rules, this study suggests that residential decisions and strategies developed by different middle-class households do not solely depend on their class habitus, but also on gendered positions and dispositions in respect to division of labour, child care and school choice. Drawing on interview data from London and Amsterdam, this study re-addresses the issue of middle–class time-space trajectories at a specific period in the life course. We contend that the middle classes are not just differentiated by various orientations of capital (economic versus cultural) but that interaction of class and gender is also key for understanding practices of the middle classes as they enter the field of parenthood. These practices are strongly influenced by labour market and welfare regimes (as the Netherlands/England comparison makes clear). In the new field of parenthood the work of realigning class habitus (through social reproduction) is highly gendered, but to different degrees that are made evident in the different neighbourhood settings. In terms of urban space this points to the significance of the particular neighbourhood structure and opportunities of the city as a whole as well as a more active idea of the role of space in the particular working out of class and gender in specific neighbourhood contexts. Urban space is a situating framework and an active process in trajectories of social reproduction

Zeeman Slowers for Strontium based on Permanent Magnets

We present the design, construction, and characterisation of longitudinal- and transverse-field Zeeman slowers, based on arrays of permanent magnets, for slowing thermal beams of atomic Sr. The slowers are optimised for operation with deceleration related to the local laser intensity (by the parameter $\epsilon$), which uses more effectively the available laser power, in contrast to the usual constant deceleration mode. Slowing efficiencies of up to $\approx$ $18$ $$ are realised and compared to those predicted by modelling. We highlight the transverse-field slower, which is compact, highly tunable, light-weight, and requires no electrical power, as a simple solution to slowing Sr, well-suited to spaceborne application. For $^{88}$Sr we achieve a slow-atom flux of around $6\times 10^9$ atoms$\,$s$^{-1}$ at $30$ ms$^{-1}$, loading approximately $5\times 10^8$ atoms in to a magneto-optical-trap (MOT), and capture all isotopes in approximate relative natural abundances

Solar wind data from the MIT plasma experiments on Pioneer 6 and Pioneer 7

Hourly averages are presented of solar wind proton parameters obtained from experiments on the Pioneer 6 and Pioneer 7 spacecraft during the period December 16, 1965 to August 1971. The number of data points available on a given day depends upon the spacecraft-earth distance, the telemetry bit rate, and the ground tracking time allotted to each spacecraft. Thus, the data obtained earlier in the life of each spacecraft are more complete. The solar wind parameters are given in the form of plots and listings. Trajectory information is also given along with a detailed description of the analysis procedures used to extract plasma parameters from the measured data

An exploration of the portrayal of the UK soft drinks industry levy in UK national newspapers.

OBJECTIVE: News media play a role in politics through the portrayal of policies, influencing public and policymaker perceptions of appropriate solutions. This study explored the portrayal of sugar and sugar-sweetened beverage (SSB) taxes in UK national newspapers. Findings aid understanding of the role newspapers play in shaping understanding and acceptance of policies such as the UK Soft Drink Industry Levy (SDIL). DESIGN: Articles discussing sugar or SSB taxes published in six UK national newspapers between 1 April 2016 and 1 May 2019 were retrieved from the LexisNexis database. Articles were thematically analysed to reveal policy portrayal. SETTING/PARTICIPANTS: Analysis of UK newspaper articles. RESULTS: Two hundred and eighty-six articles were assessed. Sugar and SSB taxes were discussed across the sample period but publication peaked at SDIL announcement and introduction. Themes were split according to support for or opposition to taxation. Supportive messaging consistently highlighted the negative impacts of sugar on health and the need for complex actions to reduce sugar consumption. Opposing messages emphasised individual responsibility for health and the unfairness of taxation both for organisations and the public. CONCLUSIONS: Sugar and SSB taxes received considerable media attention between 2016 and 2019. All newspapers covered arguments in support of and opposition to taxation. Health impacts of excess sugar and the role of the soft drink industry in reducing sugar consumption were prevalent themes, suggesting a joined-up health advocacy approach. Industry arguments were more varied, suggesting a less collaborative argument. Further research should investigate how other media channels portray taxes such as the SDIL