3,528 research outputs found

    Discipline-based educational development: examples from four Canadian universities

    Get PDF
    Discipline-based educational development , integrating the principles of teaching and learning with specific content knowledge of a discipline, is emerging as a complement to more traditional, centralized models of teaching support, bringing with it its own advantages and challenges. Partly, it is a question of belonging: it helps to be part of a team of people - possibly with a variety of specialties in areas like curriculum, pedagogy, educational technology - and operating from a centre offers this important support, but coming from a single unit across campus may make it harder to connect with those teaching in departments. Conversely, working in a department creates many opportunities to connect with faculty and students, but can be isolating as there is unlikely to be a team of any size at the department level doing similar work. This panel discussion will explore four examples of discipline-based educational development at Canadian universities, highlighting successful initiatives and challenges faced by educators in implementing this approach. In one case, teaching is transforming via graduate student projects within specific courses, and the others have variations on teaching centre models with different levels of connections to departments - in one case with staff members embedded in departments. We will also be interested to learn of other models from those who attend the discussion. Overall, this panel discussion aims to raise awareness of the value of discipline-based education development in STEM education and to provide a platform for dialogue and collaboration among educators and educational developers in Canadian post-secondary institutions

    The return of the merging galaxy subclusters of El Gordo?

    Full text link
    Merging galaxy clusters with radio relics provide rare insights to the merger dynamics as the relics are created by the violent merger process. We demonstrate one of the first uses of the properties of the radio relic to reduce the uncertainties of the dynamical variables and determine the 3D configuration of a cluster merger, ACT-CL J0102-4915, nicknamed El Gordo. From the double radio relic observation and the X-ray observation of a comet-like gas morphology induced by motion of the cool core, it is widely believed that El Gordo is observed shortly after the first core-passage of the subclusters. We employ a Monte Carlo simulation to investigate the three-dimensional (3D) configuration and dynamics of El Gordo. Using the polarization fraction of the radio relic, we constrain the estimate of the angle between the plane of the sky and the merger axis to be α=21 degree±119\alpha = 21~{\rm degree} \pm^9_{11}. We find the relative 3D merger speed of El Gordo to be 2400±200400 km s12400\pm^{400}_{200}~{\rm km}~{\rm s}^{-1} at pericenter. The two possible estimates of the time-since-pericenter are 0.46±0.160.090.46\pm^{0.09}_{0.16} Gyr and 0.91±0.390.220.91\pm^{0.22}_{0.39} Gyr for the outgoing and returning scenario respectively. We put our estimates of the time-since-pericenter into context by showing that if the time-averaged shock velocity is approximately equal to or smaller than the pericenter velocity of the corresponding subcluster in the center of mass frame, the two subclusters are more likely to be moving towards, rather than away, from each other, post apocenter. We compare and contrast the merger scenario of El Gordo with that of the Bullet Cluster, and show that this late-stage merging scenario explains why the southeast dark matter lensing peak of El Gordo is closer to the merger center than the southeast cool core.Comment: Figure 1 explains the configuration of the different components of El Gordo. Figure 9 explains the merger scenario. 20 pages, 23 figures. Accepted by MNRA

    Associated Higgs production with top quarks at the Large Hadron Collider: NLO QCD corrections

    Full text link
    We present in detail the calculation of the O(alpha_s^3) inclusive total cross section for the process pp -> t-tbar-h, in the Standard Model, at the CERN Large Hadron Collider with center-of-mass energy sqrt(s_H)=14 TeV. The calculation is based on the complete set of virtual and real O(alpha_s) corrections to the parton level processes q-qbar -> t-tbar-h and gg -> t-tbar-h, as well as the tree level processes (q,qbar)g -> t-tbar-h-(q,qbar). The virtual corrections involve the computation of pentagon diagrams with several internal and external massive particles, first encountered in this process. The real corrections are computed using both the single and the two cutoff phase space slicing method. The next-to-leading order QCD corrections significantly reduce the renormalization and factorization scale dependence of the Born cross section and moderately increase the Born cross section for values of the renormalization and factorization scales above m_t.Comment: 70 pages, 12 figures, RevTeX4: one word changed in the abstract, one sentence reworded in the introduction. To appear in Phys. Rev.

    Trilinear gauge boson couplings and bilepton production in the SU(3)_C X SU(3)_L X U(1)_N models

    Full text link
    The trilinear gauge boson couplings in the SU(3)_C X SU(3)_L X U(1)_N (3 - 3 - 1) models are presented. We find that new Z2Z_2 does not interact with the usual (in the standard model) gauge bosons Z,W±Z, W^\pm. Based on these results, production of new heavy gauge bosons at high energy colliders such as e^+ e^- is calculated. We show that the cross sections obtained in the 3 - 3 - 1 model with right-handed neutrinos can be one order bigger than the same in the minimal 3 - 3 - 1 model.Comment: 20 pages, 4 figure, late

    MC2:galaxy imaging and redshift analysis of the merging cluster CIZA J2242.8+5301

    Get PDF
    X-ray and radio observations of CIZA J2242.8+5301 suggest that it is a major cluster merger. Despite being well studied in the X-ray and radio, little has been presented on the cluster structure and dynamics inferred from its galaxy population. We carried out a deep (i<25i\lt 25) broadband imaging survey of the system with Subaru SuprimeCam (g and i bands) and the Canada–France–Hawaii Telescope (r band), as well as a comprehensive spectroscopic survey of the cluster area (505 redshifts) using Keck DEep Imaging Multi-Object Spectrograph. We use these data to perform a comprehensive galaxy/redshift analysis of the system, which is the first step to a proper understanding of the geometry and dynamics of the merger, as well as using the merger to constrain self-interacting dark matter. We find that the system is dominated by two subclusters of comparable richness with a projected separation of 6\buildrel{\,\prime}\over{.} 9_{-0.5}^{+0.7} (1.30.10+0.13  Mpc_{-0.10}^{+0.13}\;{\rm Mpc}). We find that the north and south subclusters have similar redshifts of z0.188z\approx 0.188 with a relative line-of-sight (LOS) velocity difference of 69 ± 190 km  s1{\rm km}\;{{{\rm s}}^{-1}}. We also find that north and south subclusters have velocity dispersions of 116090+1001160_{-90}^{+100} and 108070+100  km  s11080_{-70}^{+100}\;{\rm km}\;{{{\rm s}}^{-1}}, respectively. These correspond to masses of 16.13.3+4.6×101416.1_{-3.3}^{+4.6}\times {{10}^{14}} and 13.02.5+4.0×101413.0_{-2.5}^{+4.0}\times {{10}^{14}} M{{M}_{\odot }}, respectively. While velocity dispersion measurements of merging clusters can be biased, we believe the bias in this system to be minor due to the large projected separation and nearly plane-of-sky merger configuration. We also find that the cDs of the north and south subclusters are very near their subcluster centers, in both projection (55 and 85 kpc, respectively) and normalized LOS velocity (Δv/σv=0.43±0.13|{\Delta }v|/{{\sigma }_{v}}=0.43\pm 0.13 and 0.21 ± 0.12 for the north and south, respectively). CIZA J2242.8+5301 is a relatively clean dissociative cluster merger with near 1:1 mass ratio, which makes it an ideal merger for studying merger-associated physical phenomena

    Age and trust as moderators in the relation between procedural justice and turnover: a large-scale longitudinal study

    Get PDF
    Item does not contain fulltextThe current study investigated the moderating roles of age and trust in the relation of procedural justice with turnover. It was expected that the relation between procedural justice and turnover was weaker for older workers and those with high prior trust in their leader. Older workers are better at regulating their emotions, and focus more on positive aspects of their relationships with others, and therefore react less intensely to unfair treatment. Moreover, people with high trust are more likely to attribute unfair treatment to circumstances instead of deliberate intention than people with low trust. Finally, we expected a three-way interaction between age, trust, and procedural justice in relation to turnover, where older workers with high trust would have less strong reactions than younger workers and older workers with low trust. Results from a three-wave longitudinal survey among 1,597 Dutch employees indeed revealed significant interactions between trust and procedural justice in relation to turnover. Furthermore, the three-way interaction was significant, with negative relations for younger workers, but a non-significant relation was found for older workers with low trust. Contrary to expectations, negative relations were found between procedural justice and turnover for older workers with high trust
    corecore