title: Micro-eukaryotic diversity in hypolithons from Miers Valley, Antarctica

authors: Gokul, Jarishma K.

subjects: Antarctica

abstract: The discovery of extensive and complex hypolithic communities in both cold and hot deserts has raised many questions regarding their ecology, biodiversity and relevance in terms of regional productivity. However, most hypolithic research has focused on the bacterial elements of the community. This study represents the first investigation of micro-eukaryotic communities in all three hypolith types. Here we show that Antarctic hypoliths support extensive populations of novel uncharacterized bryophyta, fungi and protists and suggest that well known producer-decomposer-predator interactions may create the necessary conditions for hypolithic productivity in Antarctic deserts.

text: Micro-eukaryotic diversity in hypolithons from Miers Valley, Antarctica The discovery of extensive and complex hypolithic communities in both cold and hot deserts has raised many questions regarding their ecology, biodiversity and relevance in terms of regional productivity. However, most hypolithic research has focused on the bacterial elements of the community. This study represents the first investigation of micro-eukaryotic communities in all three hypolith types. Here we show that Antarctic hypoliths support extensive populations of novel uncharacterized bryophyta, fungi and protists and suggest that well known producer-decomposer-predator interactions may create the necessary conditions for hypolithic productivity in Antarctic deserts.

year: 2013-02-22

title: Assessment of roughness and chemical modification in determining the hydrophobic properties of metals

authors: Larmour, Iain A.

subjects: chemistry

abstract: “Etch and coat” methods, potentially useful for large scale production of superhydrophobic surfaces on metals, have been extended by introduction of a thin 20 nm Au interlayer which allowed thiol surface modifiers to be investigated. Fe, Ti and Zn surfaces modified in this way with a polyfluorothiol generally had lower contact angles, θ, than their silane modified equivalents but were more uniform and reproducible. The higher θ values for silanes appear to be associated with an increased effective roughness that is not seen in the thiol coatings, which follow the underlying surface. For Fe, Ti and Zn, θ increased to a maximum with etching time but then decreased significantly. Electron microscopy of samples etched for long times showed fewer grain boundaries, suggesting that the loss of hydrophobicity was related to reduced roughness. This was confirmed through quantitative measurements of roughness parameters which were directly correlated with the observed contact angles through the Wenzel equation. The observation of this behaviour for 3 different metals suggests it is a general effect and the assumption that increased etch times will give increased roughness is incorrect. Although etching , Au coating and thiol modification did not provide sufficient roughness for superhydrophobicity, electrodeposition of a Cu layer onto the metal substrates followed by electroless deposition of silver gave uniform surfaces with very high contact angles (up to θ = 168.9°) and low roll-off angles (α < 1°). This method is sufficiently simple and inexpensive to be suitable for application on industrial scales, for example in marine or aeronautical engineering.

text: Assessment of roughness and chemical modification in determining the hydrophobic properties of metals “Etch and coat” methods, potentially useful for large scale production of superhydrophobic surfaces on metals, have been extended by introduction of a thin 20 nm Au interlayer which allowed thiol surface modifiers to be investigated. Fe, Ti and Zn surfaces modified in this way with a polyfluorothiol generally had lower contact angles, θ, than their silane modified equivalents but were more uniform and reproducible. The higher θ values for silanes appear to be associated with an increased effective roughness that is not seen in the thiol coatings, which follow the underlying surface. For Fe, Ti and Zn, θ increased to a maximum with etching time but then decreased significantly. Electron microscopy of samples etched for long times showed fewer grain boundaries, suggesting that the loss of hydrophobicity was related to reduced roughness. This was confirmed through quantitative measurements of roughness parameters which were directly correlated with the observed contact angles through the Wenzel equation. The observation of this behaviour for 3 different metals suggests it is a general effect and the assumption that increased etch times will give increased roughness is incorrect. Although etching , Au coating and thiol modification did not provide sufficient roughness for superhydrophobicity, electrodeposition of a Cu layer onto the metal substrates followed by electroless deposition of silver gave uniform surfaces with very high contact angles (up to θ = 168.9°) and low roll-off angles (α < 1°). This method is sufficiently simple and inexpensive to be suitable for application on industrial scales, for example in marine or aeronautical engineering.

year: 2008

title: 1999 Professorial Address: Nau te rourou, naku te rourou… Māori education: setting an agenda.

authors: Bishop, Russell

subjects: educational outcomes

abstract: Current educational policies and practices in Aotearoa/New Zealand were developed and continue to be developed within a framework of power imbalances, which effects Maori the greatest. An alternative model that seeks to address indigenous Māori aspirations and Treaty of Waitangi guarantees for self determination is presented here. This model suggests how a tertiary teacher education institution might create learning contexts wherein power-sharing images, principles and practices will facilitate successful participation by Māori students in mainstream classrooms. This model constitutes the classroom as a place where young people's sense-making processes (cultures) are incorporated and enhanced, where the existing knowledges of young people are seen as "acceptable" and "official" and where the teacher interacts with students in such a way that new knowledge is co-created. Such a classroom will generate totally different interaction and participation patterns and educational outcomes from a classroom where knowledge is seen as something that the teacher makes sense of and then passes on to students.

text: 1999 Professorial Address: Nau te rourou, naku te rourou… Māori education: setting an agenda. Current educational policies and practices in Aotearoa/New Zealand were developed and continue to be developed within a framework of power imbalances, which effects Maori the greatest. An alternative model that seeks to address indigenous Māori aspirations and Treaty of Waitangi guarantees for self determination is presented here. This model suggests how a tertiary teacher education institution might create learning contexts wherein power-sharing images, principles and practices will facilitate successful participation by Māori students in mainstream classrooms. This model constitutes the classroom as a place where young people's sense-making processes (cultures) are incorporated and enhanced, where the existing knowledges of young people are seen as "acceptable" and "official" and where the teacher interacts with students in such a way that new knowledge is co-created. Such a classroom will generate totally different interaction and participation patterns and educational outcomes from a classroom where knowledge is seen as something that the teacher makes sense of and then passes on to students.

year: 2000