Temporal Aperture Modulation

The two types of modulation techniques useful to X-ray imaging are reviewed. The use of optimum coded temporal aperature modulation is shown, in certain cases, to offer an advantage over a spatial aperture modulator. Example applications of a diffuse anisotropic X-ray background experiment and a wide field of view hard X-ray imager are discussed

Pre-enriched, not primordial ellipticals

We follow the chemical evolution of a galaxy through star formation and its feedback into the inter-stellar medium, starting from primordial gas and allowing for gas to inflow into the region being modelled. We attempt to reproduce observed spectral line-strengths for early-type galaxies to constrain their star formation histories. The efficiencies and times of star formation are varied as well as the amount and duration of inflow. We evaluate the chemical enrichment and the mass of stars made with time. Single stellar population (SSP) data are then used to predict line-strengths for composite stellar populations. The results are compared with observed line-strengths in ten ellipticals, including some features which help to break the problem of age-metallicity degeneracy in old stellar populations. We find that the elliptical galaxies modelled require high metallicity SSPs (>3 x solar) at later times. In addition the strong lines observed cannot be produced by an initial starburst in primordial gas, even if a large amount of inflow is allowed for during the first few x 10E+8 years. This is because some pre-enrichment is required for lines in the bulk of the stars to approach the observed line-strengths in ellipticals.Comment: 18 pages, 8 figures, Latex, accepted for publication in MNRA

On the relation between viscoelastic and magnetohydrodynamic flows and their instabilities

We demonstrate a close analogy between a viscoelastic medium and an electrically conducting fluid containing a magnetic field. Specifically, the dynamics of the Oldroyd-B fluid in the limit of large Deborah number corresponds to that of a magnetohydrodynamic (MHD) fluid in the limit of large magnetic Reynolds number. As a definite example of this analogy, we compare the stability properties of differentially rotating viscoelastic and MHD flows. We show that there is an instability of the Oldroyd-B fluid that is physically distinct from both the inertial and elastic instabilities described previously in the literature, but is directly equivalent to the magnetorotational instability in MHD. It occurs even when the specific angular momentum increases outwards, provided that the angular velocity decreases outwards; it derives from the kinetic energy of the shear flow and does not depend on the curvature of the streamlines. However, we argue that the elastic instability of viscoelastic Couette flow has no direct equivalent in MHD.Comment: 21 pages, 3 figures, to be published in J. Fluid Mec

Auditing the TPACK confidence of Australian pre-service teachers: the TPACK confidence survey (TCS)

This chapter describes the construction and validation of an instrument to measure teachers’ Technological Pedagogical Content Knowledge (TPACK). The TPACK Confidence Survey (TCS) contains scales that measure teachers’ attitudes toward using ICT; confidence to use ICT for teaching and learning tasks (TPACK); competency with ICT; Technology Knowledge (TK); and TPACK Vocational Self-efficacy. The scale measuring TPACK confidence uses the Learning With ICTs: Measuring ICT Use in the Curriculum instrument that has been evaluated and reported previously. This paper proposes that the TCS provides a valid and reliable instrument with which to audit teachers’ TPACK confidence

The Early Promise of TBRI Implementation in Schools

The program known as Trust Based Relational Intervention® (TBRI®) began as an exploration into the detrimental behaviors of foster and adopted children placed in homes with unsuspecting caregivers who assumed their living environment would result in positive results rather than fear based emotions and behaviors. The researchers at the Karyn Purvis Institute of Child Development (KPICD) at Texas Christian University held summer camps for adopted children and through that work developed an intervention to meet the needs of children who had experienced trauma. KPICD identifies these young people as “children from hard places” (Purvis & Cross, 2005). Copeland et al (2007) reported that an estimated 68% of children in the United States have experienced some sort of trauma. This astounding statistic holds great meaning for teachers and administrators, because these children from hard places routinely manifest aggressive and undesired behaviors due to an altering of their physiology. The literature on TBRI® at this point mostly has chronicled success with families, group homes and summer camps (McKenzie, Purvis, & Cross, 2014; Howard, Parris, Neilson, Lusk, Bush, Purvis & Cross, 2014; Purvis & Cross, 2006). TBRI® has only recently been implemented in school settings. This report provides an overview of the impacts of trauma, trauma related work in schools, and the four articles published to this point related to the use of TBRI® in schools

A self-sustaining nonlinear dynamo process in Keplerian shear flows

A three-dimensional nonlinear dynamo process is identified in rotating plane Couette flow in the Keplerian regime. It is analogous to the hydrodynamic self-sustaining process in non-rotating shear flows and relies on the magneto-rotational instability of a toroidal magnetic field. Steady nonlinear solutions are computed numerically for a wide range of magnetic Reynolds numbers but are restricted to low Reynolds numbers. This process may be important to explain the sustenance of coherent fields and turbulent motions in Keplerian accretion disks, where all its basic ingredients are present.Comment: 4 pages, 7 figures, accepted for publication in Physical Review Letter

Healthy Green Schools: Investigating how schools can nurture healthier and more environmentally aware young people

With complex problems relating to climate change and human health shaping society in the twenty-first century, the ability of schools to foster awareness and proactive behaviours around these issues is of pressing concern to public health practitioners, educators, and policymakers. This exploratory and iterative thesis maps what is known about the extent and range of integrated health and sustainability approaches undertaken in schools globally. It explores why schools have acted around these issues and how. A mixed-methods research approach makes use of current evidence to inform effective and responsive further inquiries. The thesis consists of three empirical research studies that were designed and undertaken sequentially, as follows: 1. Systematic scoping review of global evidence (Chapter 3) 2. Thematic synthesis of global evidence (Chapter 4) 3. In-depth qualitative case study of New Zealand Enviroschools (Chapters 5 and 6) The systematic scoping review of global evidence collated 87 sources. The four main areas in which integrated approaches were implemented were: teaching and learning (n= 27), physical environment adaptations (n= 23), ecologically focused policy development (n= 13) and whole-school holistic approaches (n= 12). Evidence has increased in the last two decades and is heterogeneous in nature, with few sustained attempts to explain the potential role of theory in design, implementation, and evaluation of healthy green approaches. The thematic synthesis generated four key drivers of integrated approaches: an awareness of the urgency of issues related to the environment and human health; a need for systemic solutions to wicked problems; increased levels of reflective curiosity; and a focus on transformative actions. Across the evidence, integrated approaches were thought to foster connected systems (between upstream and downstream school influences) and connected thinking (through action-oriented, place-based experiences). The evidence suggests that holistic approaches that seek to reorient whole-school culture through action and policy are deemed most likely to reflect the urgency and systemic nature of the climate emergency. Across disciplines, three theories resonate with integrated school-based action and policy: (eco)sociological theories (education), transformation theories (social science), and salutogenesis (public health). The in-depth qualitative case study of New Zealand ‘Enviroschools’ reveals the importance of quality relationships with others, environments, and oneself in the design, implementation, and sustainability of an approach that aims to foster healthier and more environmentally aware young people within the mainstream school context. Implementation strategies such as planning using a sustainability lens, co-ordination between regional and national networks, and providing those involved with feedback in context, were associated with building and nurturing quality relationships across the school community by encouraging connections and a shift in mindset around change. The findings generated in this thesis outline why a mainstream movement towards an integrated conceptual ‘third space’ may be necessary at the intersection between health, environment, and education. This ‘third space’ refers to an integration of health (first space) and environment (second space) into a socioecological (third space) that is united in its complexity rather than divided into separate complex problems. A movement towards an integrated conceptual ‘third space’ may connect previously disaggregated systems and thinking to reveal transformative and pragmatic ways in which schools can develop, implement, and sustain action and policy which nurtures healthier and more environmentally aware young people