title: Purification and characterization of Ak.1 protease, a thermostable subtilisin with a disulphide bond in the substrate-binding cleft

authors: Toogood, Helen S.

subjects: calcium binding

abstract: Ak.1 protease, a thermostable subtilisin isolated originally from Bacillus st. Ak.1, was purified to homogeneity from the Escherichia coli clone PB5517. It is active against substrates containing neutral or hydrophobic branched-chain amino acids at the P₁ site, such as valine, alanine or phenylalanine. The Km and kcat of the enzyme decrease with decreasing temperature, though not to the same degree with all substrates, suggesting that specificity changes with temperature. The protease is markedly stabilized by Ca²⁺ ions. At 70 °C, a 10-fold increase in Ca²⁺ concentration increases the half-life by three orders of magnitude. Ak.1 protease is stabilized by Ca²⁺ to a greater extent than is thermitase. This may be due, in part, to the presence of an extra Ca²⁺-binding site in Ak.1 protease. Other metal ions, such as Sr²⁺, increase the thermostability of the enzyme, but to a significantly lower degree than does Ca²⁺. The structure of the protease showed the presence of a disulphide bond located within the active-site cleft. This bond influences both enzyme activity and thermostability. The disulphide bond appears to have a dual role: maintaining the integrity of the substrate-binding cleft and increasing the thermostability of the protease. The protease was originally investigated to determine its usefulness in the clean-up of DNA at high temperatures. However, it was found that this protease has a limited substrate specificity, so this application was not explored further.

text: Purification and characterization of Ak.1 protease, a thermostable subtilisin with a disulphide bond in the substrate-binding cleft Ak.1 protease, a thermostable subtilisin isolated originally from Bacillus st. Ak.1, was purified to homogeneity from the Escherichia coli clone PB5517. It is active against substrates containing neutral or hydrophobic branched-chain amino acids at the P₁ site, such as valine, alanine or phenylalanine. The Km and kcat of the enzyme decrease with decreasing temperature, though not to the same degree with all substrates, suggesting that specificity changes with temperature. The protease is markedly stabilized by Ca²⁺ ions. At 70 °C, a 10-fold increase in Ca²⁺ concentration increases the half-life by three orders of magnitude. Ak.1 protease is stabilized by Ca²⁺ to a greater extent than is thermitase. This may be due, in part, to the presence of an extra Ca²⁺-binding site in Ak.1 protease. Other metal ions, such as Sr²⁺, increase the thermostability of the enzyme, but to a significantly lower degree than does Ca²⁺. The structure of the protease showed the presence of a disulphide bond located within the active-site cleft. This bond influences both enzyme activity and thermostability. The disulphide bond appears to have a dual role: maintaining the integrity of the substrate-binding cleft and increasing the thermostability of the protease. The protease was originally investigated to determine its usefulness in the clean-up of DNA at high temperatures. However, it was found that this protease has a limited substrate specificity, so this application was not explored further.

year: 2000

title: Competing voices: Dialogic perspectives on Chinese children’s use of touch screen devices in a New Zealand early childhood education setting

authors: Cao, Dandan

subjects: Early childhood education

abstract: Internationally, preschool children’s use of touch screen devices is increasingly discussed from the perspectives of teachers and or caregivers. However, there is little discussion of this topic from a cross-cultural perspective. Furthermore, children’s own voices on their touch screen experiences are missing in the discourse. This study considers Chinese immigrant preschool children’s experiences of touch screen devices in a New Zealand Early Childhood Education (ECE) setting, aiming to discern the competing Voices of New Zealand ECE teachers, Chinese immigrant caregivers and children themselves. To achieve this aim, initially I sought to understand everyday touch screen use from the perspectives of New Zealand ECE teachers and Chinese immigrant caregivers, then explore children’s voices in this discussion by videoing their engagement with touch screens, and finally explore a possible new layer of competing Voices between adults and children. 
I set out to interrogate touch screen use by young learners in a social and aesthetic way by applying Mikhail Bakhtin’s dialogic theory to explore the potential for competing voices around preschool children’s touch screen use. I used the genre as my unit of analysis as it allowed me to examine voices, not only through utterances but also gestural expressions across different spaces. I used Heteroglossia as a central framework for analysis because it enabled me to understand multiple voices in social interaction. A visual method was used to collect the data because this method enabled me to see multiple forms of children’s voices in addition to their utterances, and to identify further competing voices through children’s employment of various genres when using touch screens across ECE centre and home contexts.
The Voice of conditional support and the Voice of opposition or reluctance were identified as competing Voices within and across New Zealand ECE teachers, and within and across Chinese caregivers. The findings highlight that the Voices of teachers and caregivers in my study are not necessarily in competition with each other, but are instead in competition within and across each group. Six genres were recognised during children’s touch screen use: the adult-led learning genre, the compliance genre, the invisible speaker genre, the child-led learning genre, the resistance genre and the whisper genre. Through these genres, children’s Outside-in Voice and Inside-out Voice were identified according to the source of voices. The Outside-in Voice reflects the influence of adults’ voices on the child, while the Inside-out Voice illustrates the child’s agency in expressing their inner voices. Building on the tension within children’s Voices, a new layer of competing Voices between adults and children was discerned: the Voice of adult power and the Voice of child agency.
My findings have implications for children, ECE teachers, caregivers and policymakers. Children could be supported to express their voices on issues that affect their lives and to spend more time on free play. Implications for ECE teachers are that teachers need to be invited and given support to understand the complexity of children’s voices through genres. Teachers need to be helped to appreciate that there are benefits of standing back and giving children space to be creative and learn collaboratively and or independently. Caregivers could be encouraged to relax some of their authority, to listen to children’s voices and to include children’s voices in decision-making on issues that affect them. Caregivers could also consider the conditions they place around their child’s touch screen use such as time limit and the extent of scaffolding. Policymakers would be advised to provide teachers with professional learning and development with regard to how to scaffold children’s touch screen use and digital play into play-based learning. 
Areas for research include further investigation of the genres children employ during touch screen use and the use of interpretations other than Bakhtinian dialogism to do this. Research could focus on the touch screen learning experiences of a wider group of children, including children who are immigrants and children of different ages in different cultural contexts.

text: Competing voices: Dialogic perspectives on Chinese children’s use of touch screen devices in a New Zealand early childhood education setting Internationally, preschool children’s use of touch screen devices is increasingly discussed from the perspectives of teachers and or caregivers. However, there is little discussion of this topic from a cross-cultural perspective. Furthermore, children’s own voices on their touch screen experiences are missing in the discourse. This study considers Chinese immigrant preschool children’s experiences of touch screen devices in a New Zealand Early Childhood Education (ECE) setting, aiming to discern the competing Voices of New Zealand ECE teachers, Chinese immigrant caregivers and children themselves. To achieve this aim, initially I sought to understand everyday touch screen use from the perspectives of New Zealand ECE teachers and Chinese immigrant caregivers, then explore children’s voices in this discussion by videoing their engagement with touch screens, and finally explore a possible new layer of competing Voices between adults and children. 
I set out to interrogate touch screen use by young learners in a social and aesthetic way by applying Mikhail Bakhtin’s dialogic theory to explore the potential for competing voices around preschool children’s touch screen use. I used the genre as my unit of analysis as it allowed me to examine voices, not only through utterances but also gestural expressions across different spaces. I used Heteroglossia as a central framework for analysis because it enabled me to understand multiple voices in social interaction. A visual method was used to collect the data because this method enabled me to see multiple forms of children’s voices in addition to their utterances, and to identify further competing voices through children’s employment of various genres when using touch screens across ECE centre and home contexts.
The Voice of conditional support and the Voice of opposition or reluctance were identified as competing Voices within and across New Zealand ECE teachers, and within and across Chinese caregivers. The findings highlight that the Voices of teachers and caregivers in my study are not necessarily in competition with each other, but are instead in competition within and across each group. Six genres were recognised during children’s touch screen use: the adult-led learning genre, the compliance genre, the invisible speaker genre, the child-led learning genre, the resistance genre and the whisper genre. Through these genres, children’s Outside-in Voice and Inside-out Voice were identified according to the source of voices. The Outside-in Voice reflects the influence of adults’ voices on the child, while the Inside-out Voice illustrates the child’s agency in expressing their inner voices. Building on the tension within children’s Voices, a new layer of competing Voices between adults and children was discerned: the Voice of adult power and the Voice of child agency.
My findings have implications for children, ECE teachers, caregivers and policymakers. Children could be supported to express their voices on issues that affect their lives and to spend more time on free play. Implications for ECE teachers are that teachers need to be invited and given support to understand the complexity of children’s voices through genres. Teachers need to be helped to appreciate that there are benefits of standing back and giving children space to be creative and learn collaboratively and or independently. Caregivers could be encouraged to relax some of their authority, to listen to children’s voices and to include children’s voices in decision-making on issues that affect them. Caregivers could also consider the conditions they place around their child’s touch screen use such as time limit and the extent of scaffolding. Policymakers would be advised to provide teachers with professional learning and development with regard to how to scaffold children’s touch screen use and digital play into play-based learning. 
Areas for research include further investigation of the genres children employ during touch screen use and the use of interpretations other than Bakhtinian dialogism to do this. Research could focus on the touch screen learning experiences of a wider group of children, including children who are immigrants and children of different ages in different cultural contexts.

year: 2021

title: Māori data governance model

authors: Kukutai, Tahu

abstract: This report describes the Māori Data Governance Model that has been designed by Māori data experts for use across the Aotearoa New Zealand public service. Māori data is a taonga that requires culturally grounded models of protection and care. The Model provides guidance for the system-wide governance of Māori data, consistent with the Government’s responsibilities under te Tiriti o Waitangi. The Model is intended to assist all agencies to undertake Māori data governance in a way that is values-led, centred on Māori needs and priorities, and informed by research. This is important because existing government data processes and practices are failing to meet Māori informational needs.

The Vision, Tuia te korowai o Hine-Raraunga – Data for self-determination, enables iwi, hapū and Māori organisations, businesses and communities to pursue their own goals for cultural, social, economic and environmental wellbeing. Eight Data Pou or pillars define critical areas of data governance and specify the actions that should be undertaken to realise six desired outcomes. The Model does not cover every element of data governance; instead, it focuses on key priorities and actions, against which agencies can assess their level of data maturity. The Model explicitly recognises the need for changes to system leadership, policies and legal settings so that Māori can exercise authority over Māori data to reduce unethical data use and strengthen outcomes for individuals, whānau and communities. The report also identifies the need for strategic investment in a Mana Motuhake data system that sits outside of the public sector to ensure iwi and hapū sovereignty over iwi and hapū data.

text: Māori data governance model This report describes the Māori Data Governance Model that has been designed by Māori data experts for use across the Aotearoa New Zealand public service. Māori data is a taonga that requires culturally grounded models of protection and care. The Model provides guidance for the system-wide governance of Māori data, consistent with the Government’s responsibilities under te Tiriti o Waitangi. The Model is intended to assist all agencies to undertake Māori data governance in a way that is values-led, centred on Māori needs and priorities, and informed by research. This is important because existing government data processes and practices are failing to meet Māori informational needs.

The Vision, Tuia te korowai o Hine-Raraunga – Data for self-determination, enables iwi, hapū and Māori organisations, businesses and communities to pursue their own goals for cultural, social, economic and environmental wellbeing. Eight Data Pou or pillars define critical areas of data governance and specify the actions that should be undertaken to realise six desired outcomes. The Model does not cover every element of data governance; instead, it focuses on key priorities and actions, against which agencies can assess their level of data maturity. The Model explicitly recognises the need for changes to system leadership, policies and legal settings so that Māori can exercise authority over Māori data to reduce unethical data use and strengthen outcomes for individuals, whānau and communities. The report also identifies the need for strategic investment in a Mana Motuhake data system that sits outside of the public sector to ensure iwi and hapū sovereignty over iwi and hapū data.

year: 2023