title: Phenomenology for the decay of energy-containing eddies in homogeneous MHD turbulence

authors: Hossain, Murshed

subjects: magnetohydrodynamics (MHD)

abstract: We evaluate a number of simple, one‐point phenomenological models for the decay of energy‐containing eddies in magnetohydrodynamic(MHD) and hydrodynamicturbulence. The MHDmodels include effects of cross helicity and Alfvénic couplings associated with a constant mean magnetic field, based on physical effects well‐described in the literature. The analytic structure of three separate MHDmodels is discussed. The single hydrodynamic model and several MHDmodels are compared against results from spectral‐method simulations. The hydrodynamic model phenomenology has been previously verified against experiments in wind tunnels, and certain experimentally determined parameters in the model are satisfactorily reproduced by the present simulation. This agreement supports the suitability of our numerical calculations for examining MHDturbulence, where practical difficulties make it more difficult to study physical examples. When the triple‐decorrelation time and effects of spectral anisotropy are properly taken into account, particular MHDmodels give decay rates that remain correct to within a factor of 2 for several energy‐halving times. A simple model of this type is likely to be useful in a number of applications in space physics, astrophysics, and laboratory plasma physics where the approximate effects of turbulence need to be included.

text: Phenomenology for the decay of energy-containing eddies in homogeneous MHD turbulence We evaluate a number of simple, one‐point phenomenological models for the decay of energy‐containing eddies in magnetohydrodynamic(MHD) and hydrodynamicturbulence. The MHDmodels include effects of cross helicity and Alfvénic couplings associated with a constant mean magnetic field, based on physical effects well‐described in the literature. The analytic structure of three separate MHDmodels is discussed. The single hydrodynamic model and several MHDmodels are compared against results from spectral‐method simulations. The hydrodynamic model phenomenology has been previously verified against experiments in wind tunnels, and certain experimentally determined parameters in the model are satisfactorily reproduced by the present simulation. This agreement supports the suitability of our numerical calculations for examining MHDturbulence, where practical difficulties make it more difficult to study physical examples. When the triple‐decorrelation time and effects of spectral anisotropy are properly taken into account, particular MHDmodels give decay rates that remain correct to within a factor of 2 for several energy‐halving times. A simple model of this type is likely to be useful in a number of applications in space physics, astrophysics, and laboratory plasma physics where the approximate effects of turbulence need to be included.

year: 1995

title: From the drawing board into schools: An analysis of the development and implementation of a new physics curriculum in New Zealand secondary schools

authors: Fernandez, Teresa Sushama

subjects: Educational Change

abstract: This thesis explored the introduction of a new physics curriculum in New Zealand secondary schools. It was part of a nationwide overhaul of the whole school curriculum from primary to secondary schools, initiated in the early 1990s. The study of curriculum change is inextricably woven with teacher change, as the teacher is seen as central to any real change in curricula in the classroom. Some theories of teacher change are reviewed here and synthesised into a list of criteria relevant to bringing about effective change in teachers and their practices. A sociocultural perspective emerged as being a useful theoretical approach in analysing and explaining these processes of curriculum change and teacher change because it takes a holistic approach that deals with 'people, places and things' and the discourses involved therein. In particular, Wenger's sociocultural theory was used to study the introduction of a new senior physics curriculum. His terms 'reification' and 'participation' were seen to apply to this research: the curriculum document was taken to be a reified communication artifact, and 'participation' is involved in every stage of its development and implementation. In the context of this theorising, data was procured from in-depth interviews with the three curriculum writers and ten physics teachers in and around a provincial city in New Zealand. The teachers were interviewed three times over a period of three years: before, during and after the first year of implementation; namely 1996 to 1998. The interviews showed that most of these ten physics teachers did not undergo any significant change in their teaching because of the introduction of 'Physics in the New Zealand Curriculum'. The reasons or barriers identified, such as lack of guidelines and clarity, and contentment with their own existing practice, were aligned with factors that have been identified by other researchers as important influences on teachers undergoing change, such as clarity of change and need for change. Three key elements were identified from these issues emerging from the data as necessary conditions or resources for teacher change: knowledge, support and time. In the present study, there was very limited knowledge held by the teachers about 'what', 'how' and 'why' changes were being implemented. Secondly, there was little social and system support for the curriculum change. Finally, teachers had little time to focus on and reflect on the change. A model of curriculum change, incorporating Wenger's notions of 'reification' and 'participation', but extended to include 'dereification' emerged from the data. 'Dereification' highlighted an important stage whereby the curriculum document as an artifact, needed to be incorporated into the plane of lived experiences of teachers. The introduction of the term 'dereification' supported the development of this model of curriculum change incorporating teacher change whereby the model outlined processes of reification and dereification involved in a mandated curriculum change. The model of curriculum change developed here also contained a screen that symbolises the lack of intersubjective linkage between teachers and the designers of the new curriculum. There was no follow-up teachers' guide, not enough explanation of the curriculum document, no direct communication between the writers and the teachers, and insufficient professional development for the teachers using it. The research findings led to three propositions: the curriculum document as a key artifact was not sufficient to effect a curriculum change; the lack of transparency of the curriculum document development was a constraint on teachers' commitment to the curriculum change; and the lack of support for teachers in their dereification of the curriculum document impacted negatively on curriculum change. The key elements of knowledge, support and time identified as crucial for teachers to effect any real change in their practice are critical at different points in the model of curriculum change. It is suggested that using such an interplay between the factors underlying teacher change and the sociocultural analysis of curriculum change, might enable more pro-active intervention at the various stages of the process of a curriculum change to effect a real change.

text: From the drawing board into schools: An analysis of the development and implementation of a new physics curriculum in New Zealand secondary schools This thesis explored the introduction of a new physics curriculum in New Zealand secondary schools. It was part of a nationwide overhaul of the whole school curriculum from primary to secondary schools, initiated in the early 1990s. The study of curriculum change is inextricably woven with teacher change, as the teacher is seen as central to any real change in curricula in the classroom. Some theories of teacher change are reviewed here and synthesised into a list of criteria relevant to bringing about effective change in teachers and their practices. A sociocultural perspective emerged as being a useful theoretical approach in analysing and explaining these processes of curriculum change and teacher change because it takes a holistic approach that deals with 'people, places and things' and the discourses involved therein. In particular, Wenger's sociocultural theory was used to study the introduction of a new senior physics curriculum. His terms 'reification' and 'participation' were seen to apply to this research: the curriculum document was taken to be a reified communication artifact, and 'participation' is involved in every stage of its development and implementation. In the context of this theorising, data was procured from in-depth interviews with the three curriculum writers and ten physics teachers in and around a provincial city in New Zealand. The teachers were interviewed three times over a period of three years: before, during and after the first year of implementation; namely 1996 to 1998. The interviews showed that most of these ten physics teachers did not undergo any significant change in their teaching because of the introduction of 'Physics in the New Zealand Curriculum'. The reasons or barriers identified, such as lack of guidelines and clarity, and contentment with their own existing practice, were aligned with factors that have been identified by other researchers as important influences on teachers undergoing change, such as clarity of change and need for change. Three key elements were identified from these issues emerging from the data as necessary conditions or resources for teacher change: knowledge, support and time. In the present study, there was very limited knowledge held by the teachers about 'what', 'how' and 'why' changes were being implemented. Secondly, there was little social and system support for the curriculum change. Finally, teachers had little time to focus on and reflect on the change. A model of curriculum change, incorporating Wenger's notions of 'reification' and 'participation', but extended to include 'dereification' emerged from the data. 'Dereification' highlighted an important stage whereby the curriculum document as an artifact, needed to be incorporated into the plane of lived experiences of teachers. The introduction of the term 'dereification' supported the development of this model of curriculum change incorporating teacher change whereby the model outlined processes of reification and dereification involved in a mandated curriculum change. The model of curriculum change developed here also contained a screen that symbolises the lack of intersubjective linkage between teachers and the designers of the new curriculum. There was no follow-up teachers' guide, not enough explanation of the curriculum document, no direct communication between the writers and the teachers, and insufficient professional development for the teachers using it. The research findings led to three propositions: the curriculum document as a key artifact was not sufficient to effect a curriculum change; the lack of transparency of the curriculum document development was a constraint on teachers' commitment to the curriculum change; and the lack of support for teachers in their dereification of the curriculum document impacted negatively on curriculum change. The key elements of knowledge, support and time identified as crucial for teachers to effect any real change in their practice are critical at different points in the model of curriculum change. It is suggested that using such an interplay between the factors underlying teacher change and the sociocultural analysis of curriculum change, might enable more pro-active intervention at the various stages of the process of a curriculum change to effect a real change.

year: 2007

title: Ngā whakaaro o ngā ākonga: perspectives and experiences of Māori students in outdoor education in Aotearoa New Zealand

authors: Washbourn, Phil

subjects: Outdoor education

abstract: This study aims to develop an understanding of the perspectives and experiences of Māori students in a secondary school outdoor education programme in Aotearoa New Zealand. Lynch (2012) indicated that “there is a clear need, and wide scope, for research into: cultural elements of outdoor education programmes; cultural effects on participants; culturally appropriate research approaches and programme effects on, and experiences of, people who identify as Māori” (p.49). Outdoor education in Aotearoa New Zealand has been heavily influenced by ‘Eurocentric’ values and practices that contrast with those of Te Ao Māori. In line with a number of calls to re-envision the field, the perspectives and experiences of Māori and the incorporation of Te Ao Māori pedagogies are vital to the reconstruction of an integrated and inclusive Aotearoa New Zealand expression of Outdoor Education for the 21st century.
This study, guided by culturally responsive research methodology, used focus groups to investigate the opinions, thoughts and expectations of Māori students of outdoor education. Thematic analysis was used to analyse the focus group data, and four major themes were identified: the importance of shared experience and relationships to positive experiences of outdoor education; the distinctive practices of outdoor education make learning enjoyable and engaging; the importance to students of making connections with Te Ao Māori through experience, stories of places and history; and the complexity of engaging Māori in participation in outdoor education, including factors such as affordability, the influence of friends and whānau and prioritising educational pathways. A range of practices and approaches from Te Ao Māori are considered and presented, based on the contribution of the student participants, including pedagogical principles from Te Ao Māori such as wānanga, whanaungatanga and tauira. Suggestions for practice include developing connections within the community and experiencing Te Ao Māori learning contexts such as waka ama, noho marae and mahinga kai.

text: Ngā whakaaro o ngā ākonga: perspectives and experiences of Māori students in outdoor education in Aotearoa New Zealand This study aims to develop an understanding of the perspectives and experiences of Māori students in a secondary school outdoor education programme in Aotearoa New Zealand. Lynch (2012) indicated that “there is a clear need, and wide scope, for research into: cultural elements of outdoor education programmes; cultural effects on participants; culturally appropriate research approaches and programme effects on, and experiences of, people who identify as Māori” (p.49). Outdoor education in Aotearoa New Zealand has been heavily influenced by ‘Eurocentric’ values and practices that contrast with those of Te Ao Māori. In line with a number of calls to re-envision the field, the perspectives and experiences of Māori and the incorporation of Te Ao Māori pedagogies are vital to the reconstruction of an integrated and inclusive Aotearoa New Zealand expression of Outdoor Education for the 21st century.
This study, guided by culturally responsive research methodology, used focus groups to investigate the opinions, thoughts and expectations of Māori students of outdoor education. Thematic analysis was used to analyse the focus group data, and four major themes were identified: the importance of shared experience and relationships to positive experiences of outdoor education; the distinctive practices of outdoor education make learning enjoyable and engaging; the importance to students of making connections with Te Ao Māori through experience, stories of places and history; and the complexity of engaging Māori in participation in outdoor education, including factors such as affordability, the influence of friends and whānau and prioritising educational pathways. A range of practices and approaches from Te Ao Māori are considered and presented, based on the contribution of the student participants, including pedagogical principles from Te Ao Māori such as wānanga, whanaungatanga and tauira. Suggestions for practice include developing connections within the community and experiencing Te Ao Māori learning contexts such as waka ama, noho marae and mahinga kai.

year: 2018