title: Steady state kinetics of the glutamate dehydrogenase from an archaebacterial extreme thermophile, isolate AN1

authors: Hudson, R.C.

subjects: glutamate dehydrogenase

abstract: A steady state kinetic study was carried out with the glutamate dehydrogenase from the thermophilic, archaebacterial isolate AN1. Initial velocity studies of the oxidative deamination reaction showed the mechanism is sequential and indicated that the order of substrate addition is random, while inhibition studies with products and substrate analogues suggested a strong preference for NADP⁺ to bind first. Initial velocity studies of the reductive amination reaction showed that the mechanism is sequential and indicated that the order of substrate addition is random, while product inhibition studies and the effect of substrate saturation on the initial velocity suggested that the preferred order of substrate addition is NADPH, 2-ketoglutarate, ammonia.

text: Steady state kinetics of the glutamate dehydrogenase from an archaebacterial extreme thermophile, isolate AN1 A steady state kinetic study was carried out with the glutamate dehydrogenase from the thermophilic, archaebacterial isolate AN1. Initial velocity studies of the oxidative deamination reaction showed the mechanism is sequential and indicated that the order of substrate addition is random, while inhibition studies with products and substrate analogues suggested a strong preference for NADP⁺ to bind first. Initial velocity studies of the reductive amination reaction showed that the mechanism is sequential and indicated that the order of substrate addition is random, while product inhibition studies and the effect of substrate saturation on the initial velocity suggested that the preferred order of substrate addition is NADPH, 2-ketoglutarate, ammonia.

year: 1995

title: Magnitude and controls on the net carbon balance of a New Zealand raised bog

authors: Goodrich, Jordan Paul

subjects: peatland

abstract: Peatlands play an important role in the Earth system as both persistent carbon dioxide (CO₂) sinks and methane (CH₄) sources. However, large uncertainties remain in our understanding of peatland carbon cycle – climate feedbacks. The majority of research has been conducted in the Northern Hemisphere as most of the global peatland area is located there. Few data have been collected in Southern Hemisphere peatlands and there is a limited basis for predicting how these systems will respond to changing climatic drivers and other anthropogenic forcings such as drainage for agriculture. Furthermore, it is unclear whether our knowledge of peatland functioning and carbon (C) cycling from the Northern Hemisphere translates to systems that have developed under different climatic and hydrologic settings with unique vegetation.  

To gain a better understanding of peatland carbon and greenhouse gas exchange in a globally distinct and unique peatland type, I used eddy covariance to measure net ecosystem CO₂ exchange (NEE) and CH₄ flux (FCH₄)  in an undisturbed New Zealand raised bog over ~2.5 years. The overarching goals of this research were to determine magnitudes of the main components of the ecosystem C budget, gross primary production (GPP), ecosystem respiration (ER), and FCH₄, and their sensitivity to environmental and physical drivers. 

With respect to CO₂ exchange, high VPD periods restricted the light-saturated photosynthetic capacity during clear sky days. Elevated VPD was also the only condition that led to reductions in daily total GPP, a response likely triggered to reduce transpiration water losses. These results have important implications for the future C sink strength of New Zealand peatlands given a trend toward drier summers with clearer skies and higher VPD.

With respect to FCH₄, a severe drought during summer 2013 allowed me to explore the interacting controls of temperature and water table depth. During 2012, a relatively average meteorological year, annual total FCH₄ was 21.5 g CH₄⁻ C m⁻² yr⁻1, whereas total FCH₄ during the drought year (2013) was 14.5 g CH₄⁻C m⁻² yr⁻¹. I found that water table depth was the most important overarching control on FCH₄ over various timescales from weekly to inter-annual. Water table depth regulated the temperature sensitivity of FCH₄, which was highest when the water table was within 50 – 80 mm of the surface. This depth range corresponds to the relatively shallow rooting zone of the dominant vegetation, which may provide much of the substrate for methane production.

Kopuatai bog was a very strong C sink compared to Northern Hemisphere bogs and fens. Despite the elevated ER during the drought year, Kopuatai was a sink of 74.5 gC m⁻², which is at the high end of published Northern Hemisphere estimates. The more average meteorological year (2012) resulted in a much larger sink of 152 gC m⁻². This work has revealed the importance of atmospheric controls on plant CO₂ uptake and hydrologic (i.e. water table) effects on ecosystem respiration and FCH₄, when considering the overall C balance. These effects imply that the future C sink capacity of Kopuatai bog may be reduced due to the long-term trend toward drier, sunnier summers and more frequent droughts in the region.

text: Magnitude and controls on the net carbon balance of a New Zealand raised bog Peatlands play an important role in the Earth system as both persistent carbon dioxide (CO₂) sinks and methane (CH₄) sources. However, large uncertainties remain in our understanding of peatland carbon cycle – climate feedbacks. The majority of research has been conducted in the Northern Hemisphere as most of the global peatland area is located there. Few data have been collected in Southern Hemisphere peatlands and there is a limited basis for predicting how these systems will respond to changing climatic drivers and other anthropogenic forcings such as drainage for agriculture. Furthermore, it is unclear whether our knowledge of peatland functioning and carbon (C) cycling from the Northern Hemisphere translates to systems that have developed under different climatic and hydrologic settings with unique vegetation.  

To gain a better understanding of peatland carbon and greenhouse gas exchange in a globally distinct and unique peatland type, I used eddy covariance to measure net ecosystem CO₂ exchange (NEE) and CH₄ flux (FCH₄)  in an undisturbed New Zealand raised bog over ~2.5 years. The overarching goals of this research were to determine magnitudes of the main components of the ecosystem C budget, gross primary production (GPP), ecosystem respiration (ER), and FCH₄, and their sensitivity to environmental and physical drivers. 

With respect to CO₂ exchange, high VPD periods restricted the light-saturated photosynthetic capacity during clear sky days. Elevated VPD was also the only condition that led to reductions in daily total GPP, a response likely triggered to reduce transpiration water losses. These results have important implications for the future C sink strength of New Zealand peatlands given a trend toward drier summers with clearer skies and higher VPD.

With respect to FCH₄, a severe drought during summer 2013 allowed me to explore the interacting controls of temperature and water table depth. During 2012, a relatively average meteorological year, annual total FCH₄ was 21.5 g CH₄⁻ C m⁻² yr⁻1, whereas total FCH₄ during the drought year (2013) was 14.5 g CH₄⁻C m⁻² yr⁻¹. I found that water table depth was the most important overarching control on FCH₄ over various timescales from weekly to inter-annual. Water table depth regulated the temperature sensitivity of FCH₄, which was highest when the water table was within 50 – 80 mm of the surface. This depth range corresponds to the relatively shallow rooting zone of the dominant vegetation, which may provide much of the substrate for methane production.

Kopuatai bog was a very strong C sink compared to Northern Hemisphere bogs and fens. Despite the elevated ER during the drought year, Kopuatai was a sink of 74.5 gC m⁻², which is at the high end of published Northern Hemisphere estimates. The more average meteorological year (2012) resulted in a much larger sink of 152 gC m⁻². This work has revealed the importance of atmospheric controls on plant CO₂ uptake and hydrologic (i.e. water table) effects on ecosystem respiration and FCH₄, when considering the overall C balance. These effects imply that the future C sink capacity of Kopuatai bog may be reduced due to the long-term trend toward drier, sunnier summers and more frequent droughts in the region.

year: 2015

title: Kia matatau ki te reo: Factors influencing the development of proficiency in te reo Māori with adult learners

authors: Rātima, Matiu Tai

subjects: te reo Māori

abstract: This thesis sought to answer the question: what factors help or hinder adult Māori second language learners to become proficient speakers of te reo Māori? I ask this question at a moment in history when te reo, like other indigenous languages, sits on the edge of a precipice in terms of its survival as a living language. Ambivalence and inaction will almost certainly constitute a push towards oblivion. Nothing less than concerted effort can pull te reo back from the brink. But what kind of concerted effort is needed and how can individual learners optimise their efforts to learn te reo?
Te reo must survive because, as Sir James Henare put it, ‘ko te reo te hā o te Māoritanga’, meaning ‘the language is the essence of Māori culture.’ Without te reo the very survival of Māori people as Māori is in doubt. My questions and the thesis occupy a multidisciplinary space, drawing on research from adult second language acquisition, teaching pedagogy and language revitalisation. The thesis makes an original contribution to all three bodies of literature by examining data from a previously untapped source; successful adult Māori language learners. 
I interviewed 17 participants. All highly proficient second language speakers of te reo. All learned te reo as adults.  Adult second language learning of endangered languages is broadly acknowledged in Second Language Acquisition (SLA) as essential to re-establishing Intergenerational Transmission of Language (ITL) in the home to ensure an endangered language is passed on to future generations.
The interview questionnaire was based loosely on 10 help/hinder factors I identified through a review of the literature from the three research fields (adult second language acquisition, teaching pedagogy and language revitalisation). The ten factors identified in the review were; language aptitude, age, learner attitudes and motivation, learning strategies, instruction, agency and anxiety, wairua (the spiritual dimension), demography, language status, and language planning.

text: Kia matatau ki te reo: Factors influencing the development of proficiency in te reo Māori with adult learners This thesis sought to answer the question: what factors help or hinder adult Māori second language learners to become proficient speakers of te reo Māori? I ask this question at a moment in history when te reo, like other indigenous languages, sits on the edge of a precipice in terms of its survival as a living language. Ambivalence and inaction will almost certainly constitute a push towards oblivion. Nothing less than concerted effort can pull te reo back from the brink. But what kind of concerted effort is needed and how can individual learners optimise their efforts to learn te reo?
Te reo must survive because, as Sir James Henare put it, ‘ko te reo te hā o te Māoritanga’, meaning ‘the language is the essence of Māori culture.’ Without te reo the very survival of Māori people as Māori is in doubt. My questions and the thesis occupy a multidisciplinary space, drawing on research from adult second language acquisition, teaching pedagogy and language revitalisation. The thesis makes an original contribution to all three bodies of literature by examining data from a previously untapped source; successful adult Māori language learners. 
I interviewed 17 participants. All highly proficient second language speakers of te reo. All learned te reo as adults.  Adult second language learning of endangered languages is broadly acknowledged in Second Language Acquisition (SLA) as essential to re-establishing Intergenerational Transmission of Language (ITL) in the home to ensure an endangered language is passed on to future generations.
The interview questionnaire was based loosely on 10 help/hinder factors I identified through a review of the literature from the three research fields (adult second language acquisition, teaching pedagogy and language revitalisation). The ten factors identified in the review were; language aptitude, age, learner attitudes and motivation, learning strategies, instruction, agency and anxiety, wairua (the spiritual dimension), demography, language status, and language planning.

year: 2013