title: A mechanism for ultra-slow oscillations in the cortical default network

authors: Steyn-Ross, Moira L.

subjects: default network

abstract: When the brain is in its noncognitive “idling” state, functional MRI measurements reveal the activation of default cortical networks whose activity is suppressed during cognitive processing. This default or background mode is characterized by ultra-slow BOLD oscillations (∼0.05 Hz), signaling extremely slow cycling in cortical metabolic demand across distinct cortical regions. Here we describe a model of the cortex which predicts that slow cycling of cortical activity can arise naturally as a result of nonlinear interactions between temporal (Hopf) and spatial (Turing) instabilities. The Hopf instability is triggered by delays in the inhibitory postsynaptic response, while the Turing instability is precipitated by increases in the strength of the gap-junction coupling between interneurons.We comment on possible implications for slow dendritic computation and information processing.

text: A mechanism for ultra-slow oscillations in the cortical default network When the brain is in its noncognitive “idling” state, functional MRI measurements reveal the activation of default cortical networks whose activity is suppressed during cognitive processing. This default or background mode is characterized by ultra-slow BOLD oscillations (∼0.05 Hz), signaling extremely slow cycling in cortical metabolic demand across distinct cortical regions. Here we describe a model of the cortex which predicts that slow cycling of cortical activity can arise naturally as a result of nonlinear interactions between temporal (Hopf) and spatial (Turing) instabilities. The Hopf instability is triggered by delays in the inhibitory postsynaptic response, while the Turing instability is precipitated by increases in the strength of the gap-junction coupling between interneurons.We comment on possible implications for slow dendritic computation and information processing.

year: 2011

title: Temporal evolution of a high-k andesitic magmatic system: Taranaki Volcano, New Zealand

authors: Zernack, Anke V.

subjects: Taranaki/Egmont Volcano

abstract: Taranaki (Mt. Egmont) in the western North Island of New Zealand is a high-K andesite volcano with an eruptive history extending over more than 200 kyr. In general, petrological research has concentrated on the post-10 ka record of the modern edifice. This study focuses on the earlier history, which is recorded in 11 major pre-7 ka debris avalanche deposits. Each of these formed as a result of a catastrophic collapse of the edifice of the time. The clast assemblages of these deposits provide insights into the chemical compositions of magmas erupted during the earlier stages of activity of the volcano and form the basis for a new chemo-stratigraphic analysis of the pre-10 ka volcanic succession. Sample suites from the studied debris avalanche deposits show a progressive enrichment in K₂O and large ion lithophile elements (LILE), reflecting a gradual evolution to high-K andesite. The early magmatic system (pre-100 ka) produced a wide range of compositions including relatively primitive basalts and basaltic andesites. These rocks contain phenocryst assemblages that indicate crystallization within the lower crust or mantle, including a broad range of clinopyroxene compositions, high-Al₂O₃ hornblende, olivine and phlogopite. A higher proportion of high-silica compositions in the younger sample suites and the appearance of late-stage, low-pressure mineral phases, such as high-TiO₂ hornblende, biotite and Fe-rich orthopyroxene, reflect a gradual shift to more evolved magmas with time. These new data are interpreted to reflect a multi-stage origin for Taranaki andesites. Parental magmas were generated within a lower crustal ‘hot zone’, which formed as a result of repeated intrusions of primitive melts into the lower crust. The geochemical and mineralogical evidence indicates that prior to 100 ka this zone was relatively thin and cold, so that primitive magmas were able to rise rapidly through the crust without significant interaction and modification. As the hot zone evolved, larger proportions of intruded and underplated mafic material were partially remelted, and interaction of these melts with fractionating mantle-derived magmas generated progressively more K- and LILE-enriched compositions. A complex and dispersed magma assembly and storage system developed in the upper crust where the hot-zone melts were further modified by fractional crystallization and magma mixing and mingling.

text: Temporal evolution of a high-k andesitic magmatic system: Taranaki Volcano, New Zealand Taranaki (Mt. Egmont) in the western North Island of New Zealand is a high-K andesite volcano with an eruptive history extending over more than 200 kyr. In general, petrological research has concentrated on the post-10 ka record of the modern edifice. This study focuses on the earlier history, which is recorded in 11 major pre-7 ka debris avalanche deposits. Each of these formed as a result of a catastrophic collapse of the edifice of the time. The clast assemblages of these deposits provide insights into the chemical compositions of magmas erupted during the earlier stages of activity of the volcano and form the basis for a new chemo-stratigraphic analysis of the pre-10 ka volcanic succession. Sample suites from the studied debris avalanche deposits show a progressive enrichment in K₂O and large ion lithophile elements (LILE), reflecting a gradual evolution to high-K andesite. The early magmatic system (pre-100 ka) produced a wide range of compositions including relatively primitive basalts and basaltic andesites. These rocks contain phenocryst assemblages that indicate crystallization within the lower crust or mantle, including a broad range of clinopyroxene compositions, high-Al₂O₃ hornblende, olivine and phlogopite. A higher proportion of high-silica compositions in the younger sample suites and the appearance of late-stage, low-pressure mineral phases, such as high-TiO₂ hornblende, biotite and Fe-rich orthopyroxene, reflect a gradual shift to more evolved magmas with time. These new data are interpreted to reflect a multi-stage origin for Taranaki andesites. Parental magmas were generated within a lower crustal ‘hot zone’, which formed as a result of repeated intrusions of primitive melts into the lower crust. The geochemical and mineralogical evidence indicates that prior to 100 ka this zone was relatively thin and cold, so that primitive magmas were able to rise rapidly through the crust without significant interaction and modification. As the hot zone evolved, larger proportions of intruded and underplated mafic material were partially remelted, and interaction of these melts with fractionating mantle-derived magmas generated progressively more K- and LILE-enriched compositions. A complex and dispersed magma assembly and storage system developed in the upper crust where the hot-zone melts were further modified by fractional crystallization and magma mixing and mingling.

year: 2011

title: The contribution of family literacy programmes to the wellbeing of individuals, families and communities

authors: Furness, Jane Amanda

subjects: Adult Literacy Strategy

abstract: Approaches to literacy education named as ‘family literacy programmes’ first emerged in Aotearoa New Zealand in the early 2000s amidst considerable enthusiasm. Such approaches involve adults, children, or both in literacy learning in the contexts of home and family life. They are part of a wider field, established internationally, of academic and practical endeavour encompassing studies of the literacy practices of family members, studies of parents’ support of children’s literacy development, and studies of programmes aimed at enhancing family members’ literacy abilities, and the evaluations of such programmes. It is a contentious field, with divergent views of what constitutes both literacy and family, leading to differing expectations of what programmes are for and what they might achieve. From a moral perspective, hopes for such approaches, which hold much intuitive and culturally-located appeal, must be set against the concerning disparities in wellbeing between different groups, evident and growing in New Zealand as elsewhere. 

The study set out to explore the effects of a range of family-focused approaches in New Zealand, and their characteristics that seemed important in achieving relevant and meaningful outcomes for participants and their families. An important aim of the study was to encourage the essential conversation concerning the ideological and research-informed basis on which policies and practices should be developed to best suit our contexts, and that have people’s overall wellbeing, as well as their literacy development, in mind. The study traced the experiences of nineteen mainly Māori, Pacific and Pākehā adult participants in four varying family-focused literacy programmes located in different kinds of communities, drawing on Kaupapa Māori methodologies in its approach. Conversational interviews with the adult participants, programme staff and others who knew the participants well, repeated over 18 months, as well as participant observations of programme sessions and programme documentation, formed an extensive data set for latent theoretical thematic analysis. I identified literacy and other changes in the participants’ lives; synergistic links between factors influencing the programme effects, ‘flow on’ of effects to wider aspects of the participants’ lives and to their families and communities, and links to the personal, relational and collective wellbeing of individuals, families and communities.

The findings demonstrate that there are complex influences on programmes such that effects are highly individualised, but that there is nevertheless a tangible, discernable process in play as people journey from participation to wellbeing, in which literacy enhancement, familiarity with new literacies, and new uses of literacies, are involved. The study suggests a disjuncture between current literacy education policy and the hopes, aspirations and real lives of many people for whom the programmes are intended and who wish to contribute to their families and communities despite their complex and often fraught lives. It also demonstrates that a deep level of care and holistic concern is possible in a programme which also achieves literacy skill development. Recognition of people’s whole selves including their problems and their existing abilities in programme content and approach demonstrated the ‘respectful relevance’ that appears crucial to the involvement and the positive (useful and meaningful) outcomes that were observed. It demonstrated that a broad and inclusive evaluative lens offers the best hope for full appreciation of the contribution of programmes such as these, when the overall wellbeing of families, communities and society as a whole is placed at the centre of literacy work. 

The study offers new and urgently-needed ecological systems-based models within a wellbeing orientation to family literacy theory. These have implications for the future development of programmes in Aotearoa New Zealand and provide frameworks against which programmes internationally may consider their work afresh. The study calls for greater community relevance in family literacy based on local values and aspirations.

text: The contribution of family literacy programmes to the wellbeing of individuals, families and communities Approaches to literacy education named as ‘family literacy programmes’ first emerged in Aotearoa New Zealand in the early 2000s amidst considerable enthusiasm. Such approaches involve adults, children, or both in literacy learning in the contexts of home and family life. They are part of a wider field, established internationally, of academic and practical endeavour encompassing studies of the literacy practices of family members, studies of parents’ support of children’s literacy development, and studies of programmes aimed at enhancing family members’ literacy abilities, and the evaluations of such programmes. It is a contentious field, with divergent views of what constitutes both literacy and family, leading to differing expectations of what programmes are for and what they might achieve. From a moral perspective, hopes for such approaches, which hold much intuitive and culturally-located appeal, must be set against the concerning disparities in wellbeing between different groups, evident and growing in New Zealand as elsewhere. 

The study set out to explore the effects of a range of family-focused approaches in New Zealand, and their characteristics that seemed important in achieving relevant and meaningful outcomes for participants and their families. An important aim of the study was to encourage the essential conversation concerning the ideological and research-informed basis on which policies and practices should be developed to best suit our contexts, and that have people’s overall wellbeing, as well as their literacy development, in mind. The study traced the experiences of nineteen mainly Māori, Pacific and Pākehā adult participants in four varying family-focused literacy programmes located in different kinds of communities, drawing on Kaupapa Māori methodologies in its approach. Conversational interviews with the adult participants, programme staff and others who knew the participants well, repeated over 18 months, as well as participant observations of programme sessions and programme documentation, formed an extensive data set for latent theoretical thematic analysis. I identified literacy and other changes in the participants’ lives; synergistic links between factors influencing the programme effects, ‘flow on’ of effects to wider aspects of the participants’ lives and to their families and communities, and links to the personal, relational and collective wellbeing of individuals, families and communities.

The findings demonstrate that there are complex influences on programmes such that effects are highly individualised, but that there is nevertheless a tangible, discernable process in play as people journey from participation to wellbeing, in which literacy enhancement, familiarity with new literacies, and new uses of literacies, are involved. The study suggests a disjuncture between current literacy education policy and the hopes, aspirations and real lives of many people for whom the programmes are intended and who wish to contribute to their families and communities despite their complex and often fraught lives. It also demonstrates that a deep level of care and holistic concern is possible in a programme which also achieves literacy skill development. Recognition of people’s whole selves including their problems and their existing abilities in programme content and approach demonstrated the ‘respectful relevance’ that appears crucial to the involvement and the positive (useful and meaningful) outcomes that were observed. It demonstrated that a broad and inclusive evaluative lens offers the best hope for full appreciation of the contribution of programmes such as these, when the overall wellbeing of families, communities and society as a whole is placed at the centre of literacy work. 

The study offers new and urgently-needed ecological systems-based models within a wellbeing orientation to family literacy theory. These have implications for the future development of programmes in Aotearoa New Zealand and provide frameworks against which programmes internationally may consider their work afresh. The study calls for greater community relevance in family literacy based on local values and aspirations.

year: 2012