title: Oblique and rippled heliosphere structures from the Interstellar Boundary Explorer.

authors: Zirnstein, Eric J.

subjects: Astrophysical plasmas

abstract: Past analysis has shown that the heliosphere structure can be deduced from correlations between long-scale solar wind pressure evolution and energetic neutral atom emissions. However, this required spatial and temporal averaging that smoothed out small or dynamic features of the heliosphere. In late 2014, the solar wind dynamic pressure increased by roughly 50% over a period of 6 months, causing a time and directional-dependent rise in around 2-6 keV energetic neutral atom fluxes from the heliosphere observed by the Interstellar Boundary Explorer. Here, we use the 2014 pressure enhancement to provide a simultaneous derivation of the three-dimensional heliospheric termination shock (HTS) and heliopause (HP) distances at high resolution from Interstellar Boundary Explorer measurements. The analysis reveals rippled HTS and HP surfaces that are oblique with respect to the local interstellar medium upwind direction, with significant asymmetries in the heliosphere structure compared to steady-state heliosphere models. We estimate that the heliosphere boundaries contain roughly ten astronomical unit-sized spatial variations, with slightly larger variations on the HTS surface than the HP and a large-scale, southwards-directed obliquity of the surfaces in the meridional plane. Comparisons of the derived HTS and HP distances with Voyager observations indicate substantial differences in the heliosphere boundaries in the northern versus southern hemispheres and their motion over time.

text: Oblique and rippled heliosphere structures from the Interstellar Boundary Explorer. Past analysis has shown that the heliosphere structure can be deduced from correlations between long-scale solar wind pressure evolution and energetic neutral atom emissions. However, this required spatial and temporal averaging that smoothed out small or dynamic features of the heliosphere. In late 2014, the solar wind dynamic pressure increased by roughly 50% over a period of 6 months, causing a time and directional-dependent rise in around 2-6 keV energetic neutral atom fluxes from the heliosphere observed by the Interstellar Boundary Explorer. Here, we use the 2014 pressure enhancement to provide a simultaneous derivation of the three-dimensional heliospheric termination shock (HTS) and heliopause (HP) distances at high resolution from Interstellar Boundary Explorer measurements. The analysis reveals rippled HTS and HP surfaces that are oblique with respect to the local interstellar medium upwind direction, with significant asymmetries in the heliosphere structure compared to steady-state heliosphere models. We estimate that the heliosphere boundaries contain roughly ten astronomical unit-sized spatial variations, with slightly larger variations on the HTS surface than the HP and a large-scale, southwards-directed obliquity of the surfaces in the meridional plane. Comparisons of the derived HTS and HP distances with Voyager observations indicate substantial differences in the heliosphere boundaries in the northern versus southern hemispheres and their motion over time.

year: 2022

title: Biotic interactions are an unexpected yet critical control on the complexity of an abiotically driven polar ecosystem.

authors: Lee, Charles Kai-Wu

abstract: Abiotic and biotic factors control ecosystem biodiversity, but their relative contributions remain unclear. The ultraoligotrophic ecosystem of the Antarctic Dry Valleys, a simple yet highly heterogeneous ecosystem, is a natural laboratory well-suited for resolving the abiotic and biotic controls of community structure. We undertook a multidisciplinary investigation to capture ecologically relevant biotic and abiotic attributes of more than 500 sites in the Dry Valleys, encompassing observed landscape heterogeneities across more than 200 km². Using richness of autotrophic and heterotrophic taxa as a proxy for functional complexity, we linked measured variables in a parsimonious yet comprehensive structural equation model that explained significant variations in biological complexity and identified landscape-scale and fine-scale abiotic factors as the primary drivers of diversity. However, the inclusion of linkages among functional groups was essential for constructing the best-fitting model. Our findings support the notion that biotic interactions make crucial contributions even in an extremely simple ecosystem.

text: Biotic interactions are an unexpected yet critical control on the complexity of an abiotically driven polar ecosystem. Abiotic and biotic factors control ecosystem biodiversity, but their relative contributions remain unclear. The ultraoligotrophic ecosystem of the Antarctic Dry Valleys, a simple yet highly heterogeneous ecosystem, is a natural laboratory well-suited for resolving the abiotic and biotic controls of community structure. We undertook a multidisciplinary investigation to capture ecologically relevant biotic and abiotic attributes of more than 500 sites in the Dry Valleys, encompassing observed landscape heterogeneities across more than 200 km². Using richness of autotrophic and heterotrophic taxa as a proxy for functional complexity, we linked measured variables in a parsimonious yet comprehensive structural equation model that explained significant variations in biological complexity and identified landscape-scale and fine-scale abiotic factors as the primary drivers of diversity. However, the inclusion of linkages among functional groups was essential for constructing the best-fitting model. Our findings support the notion that biotic interactions make crucial contributions even in an extremely simple ecosystem.

year: 2019

title: What (actually) matters in literacy education: Contributions from community psychology

authors: Furness, Jane Amanda

subjects: Family literacy

abstract: This paper describes the critical role community psychology theories played in reframing literacy research involving mainly Māori and Pacific peoples’ extended families and communities. Within a critical social constructionist paradigm, ecological systems theory and holistic, integrative theories of wellbeing brought much-needed new thinking to how family-focused adult literacy education might be theorised and practiced. This reframing marks a challenge to and movement away from still-dominant Western individualistic, behavioural orientated, skills-based and formal economy-focused ways of thinking about people’s literacy abilities. It highlights the important role of community psychology in developing theory, informing policy and enhancing practices in culturally diverse education settings to achieve both educational and quality of life aims. Improving quality of life is not possible through literacy education in and of itself, but rather through the inculcation in programme design and delivery of those things which are fundamental and critical to the participants’ overall wellbeing and welfare.

text: What (actually) matters in literacy education: Contributions from community psychology This paper describes the critical role community psychology theories played in reframing literacy research involving mainly Māori and Pacific peoples’ extended families and communities. Within a critical social constructionist paradigm, ecological systems theory and holistic, integrative theories of wellbeing brought much-needed new thinking to how family-focused adult literacy education might be theorised and practiced. This reframing marks a challenge to and movement away from still-dominant Western individualistic, behavioural orientated, skills-based and formal economy-focused ways of thinking about people’s literacy abilities. It highlights the important role of community psychology in developing theory, informing policy and enhancing practices in culturally diverse education settings to achieve both educational and quality of life aims. Improving quality of life is not possible through literacy education in and of itself, but rather through the inculcation in programme design and delivery of those things which are fundamental and critical to the participants’ overall wellbeing and welfare.

year: 2013