title: Macroclimate and topography interact to influence the abundance of divaricate plants in New Zealand

authors: Lusk, Christopher H.

subjects: Science & Technology

abstract: The abundance of the divaricate growth form in New Zealand has been interpreted as either (a) the response of an isolated flora to cool, dry, Plio-Pleistocene climates; or (b) a defense against large browsing birds (moa) that were hunted to extinction shortly after human arrival during the last millennium. We used patterns of divaricate plant abundance across present-day landscapes to test a novel synthetic hypothesis: that the divaricate form is of most value to plants on fertile soils that attract herbivores, on sites where climatic constraints prevent plants from quickly growing out of the browse zone. This hypothesis predicts that divaricate species should be most abundant on terraces (landforms that are both fertile and frost-prone) in regions that are cold and dry, and should be scarce across all topographic positions in the warmest (largely frost-free) regions. To address our hypothesis, we first tested the influence of topography on frost regimes and nutrient levels by measuring temperatures and soil total C, N, and P at four standard topographic positions at five localities differing widely in macroclimate. We then extracted a dataset of 236 surveys comprising 9,877 relevé plots from the New Zealand National Vegetation Survey databank. We calculated the proportion of arborescent species with a divaricate growth form and the proportion of total arborescentcover contributed by divaricates on each plot; we then fitted linear mixed-effect models predicting these response variables as functions of topographic position and climate. The number of frosts recorded averaged <1 yr–1 at the warmest of the five sites studied, to >60 yr–1 on all topographic positions at the coldest site. Terraces were subject to more frequent and harder frosts than any other topographic position. Topography had no significant influence on total N or C:N, but total P was higher on terraces and in gullies than on faces or ridges. Frost-free period was the dominant influence on both species representation and cover of divaricate plants throughout the country. The effect of topography was also significant, but weaker. The effect of frost-free period was stronger on sites with water deficits than on sites where precipitation exceeded evapotranspiration. Divaricates made their largest contributions on terraces in cold, dry regions; as predicted, they were scarce on all topographic positions on sites with frost-free periods >300 days. Our hypothesis was generally supported, although the effect of topography on divaricate abundance was not as strong as some previous studies led us to expect. Divaricates made their largest contributions to arborescent species richness and cover on sites where climatic restrictions on growth coincide with relatively high nutrient availability. The contemporary distribution of the divaricate form across New Zealand landscapes thus appears to be reasonably well explained by the hypothesized interaction of climate and fertility-mediated browsing, although experiments may provide more conclusive tests of this hypothesis.

text: Macroclimate and topography interact to influence the abundance of divaricate plants in New Zealand The abundance of the divaricate growth form in New Zealand has been interpreted as either (a) the response of an isolated flora to cool, dry, Plio-Pleistocene climates; or (b) a defense against large browsing birds (moa) that were hunted to extinction shortly after human arrival during the last millennium. We used patterns of divaricate plant abundance across present-day landscapes to test a novel synthetic hypothesis: that the divaricate form is of most value to plants on fertile soils that attract herbivores, on sites where climatic constraints prevent plants from quickly growing out of the browse zone. This hypothesis predicts that divaricate species should be most abundant on terraces (landforms that are both fertile and frost-prone) in regions that are cold and dry, and should be scarce across all topographic positions in the warmest (largely frost-free) regions. To address our hypothesis, we first tested the influence of topography on frost regimes and nutrient levels by measuring temperatures and soil total C, N, and P at four standard topographic positions at five localities differing widely in macroclimate. We then extracted a dataset of 236 surveys comprising 9,877 relevé plots from the New Zealand National Vegetation Survey databank. We calculated the proportion of arborescent species with a divaricate growth form and the proportion of total arborescentcover contributed by divaricates on each plot; we then fitted linear mixed-effect models predicting these response variables as functions of topographic position and climate. The number of frosts recorded averaged <1 yr–1 at the warmest of the five sites studied, to >60 yr–1 on all topographic positions at the coldest site. Terraces were subject to more frequent and harder frosts than any other topographic position. Topography had no significant influence on total N or C:N, but total P was higher on terraces and in gullies than on faces or ridges. Frost-free period was the dominant influence on both species representation and cover of divaricate plants throughout the country. The effect of topography was also significant, but weaker. The effect of frost-free period was stronger on sites with water deficits than on sites where precipitation exceeded evapotranspiration. Divaricates made their largest contributions on terraces in cold, dry regions; as predicted, they were scarce on all topographic positions on sites with frost-free periods >300 days. Our hypothesis was generally supported, although the effect of topography on divaricate abundance was not as strong as some previous studies led us to expect. Divaricates made their largest contributions to arborescent species richness and cover on sites where climatic restrictions on growth coincide with relatively high nutrient availability. The contemporary distribution of the divaricate form across New Zealand landscapes thus appears to be reasonably well explained by the hypothesized interaction of climate and fertility-mediated browsing, although experiments may provide more conclusive tests of this hypothesis.

year: 2020

title: Plasticization of Bloodmeal-based Thermoplastics

authors: Verbeek, Casparus Johan R.

abstract: Water is the most common plasticizer for proteinbased thermoplastics, lowering the softening point to a allow processing without excessive degradation. The biggest drawback of using water a plasticizer is that water easily evaporates from the material during use or storage. This leads to embrittlement and loss of functionality over time. In this study a series of high molecular mass plasticizers were evaluated for their efficiency in plasticizing bloodmeal-based thermoplastics. It was found that propylene glycol, di and tri-ethylene glycol were most efficient in increasing the material’s ductility, as measured by elongation at break. Using 10 parts plasticizer per hundred bloodmeal (pphBM) in combination with 10 pphBM urea gave optimal results in terms of Young’s modulus, tensile strength and processability. The mechanical properties of plasticized samples showed a stronger dependency on moisture content, compared to unplasticized samples and reached higher equilibrium moisture content in a shorter time. Using 10 pphBM TEG as plasticizer in resulted in a plastic material with a Young’s modulus of 869 MPa, tensile strength of 14.7 MPa and an elongation at break of 46%.

text: Plasticization of Bloodmeal-based Thermoplastics Water is the most common plasticizer for proteinbased thermoplastics, lowering the softening point to a allow processing without excessive degradation. The biggest drawback of using water a plasticizer is that water easily evaporates from the material during use or storage. This leads to embrittlement and loss of functionality over time. In this study a series of high molecular mass plasticizers were evaluated for their efficiency in plasticizing bloodmeal-based thermoplastics. It was found that propylene glycol, di and tri-ethylene glycol were most efficient in increasing the material’s ductility, as measured by elongation at break. Using 10 parts plasticizer per hundred bloodmeal (pphBM) in combination with 10 pphBM urea gave optimal results in terms of Young’s modulus, tensile strength and processability. The mechanical properties of plasticized samples showed a stronger dependency on moisture content, compared to unplasticized samples and reached higher equilibrium moisture content in a shorter time. Using 10 pphBM TEG as plasticizer in resulted in a plastic material with a Young’s modulus of 869 MPa, tensile strength of 14.7 MPa and an elongation at break of 46%.

year: 2013

title: Systemic racism in clinical psychology: Symposia

authors: Wairoa-Harrison, Sophia

subjects: Racial oppression

abstract: This study constitutes a part of the Working to End Racial Oppression (WERO) project on Systemic Racism in Health Education, Training, and Practice. The focus is on the three dimensions of racism in psychology in Aotearoa New Zealand: its costs, systems and the potential responses that exist. Content: To set the scene, the session will begin with a 30-minute presentation that outlines evidence from three WERO studies on different levels of racism affecting indigenous Māori and minoritised groups. First study presents findings from a desktop analysis of papers across university psychology departments. The findings will be compared with previous studies (Levy, 2007; Levy & Waitoki, 2015) to identify the changes in inclusion of Māori and culturally focused paper at different timepoints. The second study involves semi-structured interviews with Māori students enrolled in clinical psychology training programmes (n = 19) to understand the extent of cultural responsiveness, support, disparities, and representation within programmes. The third study draws on preliminary survey findings with directors of training programmes to depict the progress towards including taha Māori and cultural competency in the psychology curriculum since the studies by Abbott and Durie (1987) and Nathan (1999). The rest of the session will be conducted as a wānanga or a forum that includes a panel discussion amongst WERO research team while allowing for a reciprocal exchange of knowledge with the attendees. Opportunities will be provided for attendees to ask questions, provide feedback to the research analyses and findings, and share their experiences of witnessing or encountering racism in psychology. The session will be opened with a karakia (prayer) and attendees to be offered manaakitanga (hospitality) and tikanga (custom) to ensure cultural safety. Goals: In this session, the research team will bring the evidence derived from robust analyses on existence and ramifications of racism in psychology to the fore. These findings will be integrated with the Waitangi Tribunal claim (Levy, 2018) to shed light on the manifestations of racism across systems and agents responsible for the regulation, training and employment of psychologists. Findings will be used to inform ways for all in psychology to embark on Te Tiriti-focused, culturally-competent and equitable approaches in the quest of indigenising the psychology discipline and advancing it to be relevant to the multicultural nature of Aotearoa populations.

text: Systemic racism in clinical psychology: Symposia This study constitutes a part of the Working to End Racial Oppression (WERO) project on Systemic Racism in Health Education, Training, and Practice. The focus is on the three dimensions of racism in psychology in Aotearoa New Zealand: its costs, systems and the potential responses that exist. Content: To set the scene, the session will begin with a 30-minute presentation that outlines evidence from three WERO studies on different levels of racism affecting indigenous Māori and minoritised groups. First study presents findings from a desktop analysis of papers across university psychology departments. The findings will be compared with previous studies (Levy, 2007; Levy & Waitoki, 2015) to identify the changes in inclusion of Māori and culturally focused paper at different timepoints. The second study involves semi-structured interviews with Māori students enrolled in clinical psychology training programmes (n = 19) to understand the extent of cultural responsiveness, support, disparities, and representation within programmes. The third study draws on preliminary survey findings with directors of training programmes to depict the progress towards including taha Māori and cultural competency in the psychology curriculum since the studies by Abbott and Durie (1987) and Nathan (1999). The rest of the session will be conducted as a wānanga or a forum that includes a panel discussion amongst WERO research team while allowing for a reciprocal exchange of knowledge with the attendees. Opportunities will be provided for attendees to ask questions, provide feedback to the research analyses and findings, and share their experiences of witnessing or encountering racism in psychology. The session will be opened with a karakia (prayer) and attendees to be offered manaakitanga (hospitality) and tikanga (custom) to ensure cultural safety. Goals: In this session, the research team will bring the evidence derived from robust analyses on existence and ramifications of racism in psychology to the fore. These findings will be integrated with the Waitangi Tribunal claim (Levy, 2018) to shed light on the manifestations of racism across systems and agents responsible for the regulation, training and employment of psychologists. Findings will be used to inform ways for all in psychology to embark on Te Tiriti-focused, culturally-competent and equitable approaches in the quest of indigenising the psychology discipline and advancing it to be relevant to the multicultural nature of Aotearoa populations.

year: 2023-03-25