title: Generation of non-Gaussian statistics and coherent structures in ideal magnetohydrodynamics

authors: Wan, Minping

subjects: mathematics

abstract: Spectral method simulations of ideal magnetohydrodynamics are used to investigate production of coherent small scale structures, a feature of fluid models that is usually associated with inertial range signatures of nonuniform dissipation, and the associated emergence of non-Gaussian statistics. The near-identical growth of non-Gaussianity in ideal and nonideal cases suggests that generation of coherent structures and breaking of self-similarity are essentially ideal processes. This has important implications for understanding the origin of intermittency in turbulence.

text: Generation of non-Gaussian statistics and coherent structures in ideal magnetohydrodynamics Spectral method simulations of ideal magnetohydrodynamics are used to investigate production of coherent small scale structures, a feature of fluid models that is usually associated with inertial range signatures of nonuniform dissipation, and the associated emergence of non-Gaussian statistics. The near-identical growth of non-Gaussianity in ideal and nonideal cases suggests that generation of coherent structures and breaking of self-similarity are essentially ideal processes. This has important implications for understanding the origin of intermittency in turbulence.

year: 2009

title: Temporal and spatial variations in phytoplankton productivity in surface waters of a warm-temperate, monomictic lake in New Zealand

authors: von Westernhagen, Nina

subjects: Eutrophication

abstract: Surface phytoplankton productivity measurements were carried out in morphologically complex Lake Rotoiti with the objective of defining variations between sites and seasons, and the dominant environmental drivers of these variations. Measurements were carried out monthly at two depths at each of three morphologically diverse stations for 1 year throughout the lake. Productivity at the surface of the shallow embayment was significantly higher in most months of the year compared with the surface of the other two stations but there were no significant differences from September to December 2004. There were no relationships between measured environmental variables and primary productivity or specific production. Inorganic nutrient concentrations at the surface of the shallow station were low throughout the whole year but at the other two stations they showed a typical pattern for monomictic lakes of higher levels during winter mixing and declining concentrations during thermal stratification. The high variability between sites found in this study indicates that it is important to account for local differences in productivity in morphologically diverse lakes, and that whole lake productivity estimates may vary greatly depending on the location and depth of productivity measurements.

text: Temporal and spatial variations in phytoplankton productivity in surface waters of a warm-temperate, monomictic lake in New Zealand Surface phytoplankton productivity measurements were carried out in morphologically complex Lake Rotoiti with the objective of defining variations between sites and seasons, and the dominant environmental drivers of these variations. Measurements were carried out monthly at two depths at each of three morphologically diverse stations for 1 year throughout the lake. Productivity at the surface of the shallow embayment was significantly higher in most months of the year compared with the surface of the other two stations but there were no significant differences from September to December 2004. There were no relationships between measured environmental variables and primary productivity or specific production. Inorganic nutrient concentrations at the surface of the shallow station were low throughout the whole year but at the other two stations they showed a typical pattern for monomictic lakes of higher levels during winter mixing and declining concentrations during thermal stratification. The high variability between sites found in this study indicates that it is important to account for local differences in productivity in morphologically diverse lakes, and that whole lake productivity estimates may vary greatly depending on the location and depth of productivity measurements.

year: 2010

title: Enabling conditions for professional development of te reo Māori teachers

authors: Franken, Margaret

subjects: Māori language teachers

abstract: The paper outlines a professional development programme for secondary school teachers of te reo Māori (under the auspices of Te Hiringa i te Mahara) conducted by a language teacher educator and an expert in Māori bilingualism and biliteracy. While the principles underpinning the programme reflect a strong task-based
orientation, the programme approached development needs for the teachers from the point of view of understanding “enabling conditions” (Franken, Rau, Ngata & Parata, n.d.) for effective language learning and teaching (see also Ellis, 2005),
rather than understanding task based learning and teaching per se. The programme drew on the current practices of the teachers and made use of epistemology of Māori language and Māori language learning. The paper presents observations from monitoring data collected during the programme supporting the claim that such an approach to the professional development of language teachers promotes a strong knowledge base and pedagogical reasoning skills (Richards, 1998), and in particular for te reo Māori teachers, fosters a sense of their own professional identity.

text: Enabling conditions for professional development of te reo Māori teachers The paper outlines a professional development programme for secondary school teachers of te reo Māori (under the auspices of Te Hiringa i te Mahara) conducted by a language teacher educator and an expert in Māori bilingualism and biliteracy. While the principles underpinning the programme reflect a strong task-based
orientation, the programme approached development needs for the teachers from the point of view of understanding “enabling conditions” (Franken, Rau, Ngata & Parata, n.d.) for effective language learning and teaching (see also Ellis, 2005),
rather than understanding task based learning and teaching per se. The programme drew on the current practices of the teachers and made use of epistemology of Māori language and Māori language learning. The paper presents observations from monitoring data collected during the programme supporting the claim that such an approach to the professional development of language teachers promotes a strong knowledge base and pedagogical reasoning skills (Richards, 1998), and in particular for te reo Māori teachers, fosters a sense of their own professional identity.

year: 2009