title: Ion parallel viscosity and anisotropy in MHD turbulence

authors: Oughton, Sean

subjects: magnetohydrodynamics (MHD)

abstract: We report on results from direct numerical simulation of the incompressible three- dimensional magnetohydrodynamic (MHD) equations, modified to incorporate viscous dissipation via the strongly anisotropic ion-parallel viscosity term. Both linear and nonlinear cases are considered, all with a strong background magnetic field. It is found that spectral anisotropy develops in almost all cases, but that the contribution from effects associated with the ion-parallel viscosity is relatively weak compared with the previously reported nonlinear process. Furthermore, and in contrast to this earlier work, it is suggested that when B₀ is large, the anisotropy will develop and persist for many large-scale turnover times even for non-dissipative runs. Resistive dissipation is found to dominate over viscous even when the resistivity is several orders of magnitude smaller than the ion parallel viscosity. A variance anisotropy effect and anisotropy dependence on the polarization of the fluctuations are also observed.

text: Ion parallel viscosity and anisotropy in MHD turbulence We report on results from direct numerical simulation of the incompressible three- dimensional magnetohydrodynamic (MHD) equations, modified to incorporate viscous dissipation via the strongly anisotropic ion-parallel viscosity term. Both linear and nonlinear cases are considered, all with a strong background magnetic field. It is found that spectral anisotropy develops in almost all cases, but that the contribution from effects associated with the ion-parallel viscosity is relatively weak compared with the previously reported nonlinear process. Furthermore, and in contrast to this earlier work, it is suggested that when B₀ is large, the anisotropy will develop and persist for many large-scale turnover times even for non-dissipative runs. Resistive dissipation is found to dominate over viscous even when the resistivity is several orders of magnitude smaller than the ion parallel viscosity. A variance anisotropy effect and anisotropy dependence on the polarization of the fluctuations are also observed.

year: 1996

title: Schooling of labouring migrants, Surrey to Wellington 1841-1844

authors: Middleton, Sue

subjects: 1840s

abstract: Purpose – In the early 1840s Edward Gibbon Wakefield's New Zealand Company recruited “emigrants of the labouring classes” promising: “every one of them who is industrious and thrifty, may be sure to become not merely an owner of land, but also in his turn an employer of hired labourers, a master of servants.” Letters sent “Home” to Ham (a village in Surrey, UK) from Wellington between 1841-1844, by a group of labouring families, project textual personae consistent with this liberal image. The purpose of this paper is to explore educational processes involved in the production of these colonial identities. 
Design/methodology/approach – The letters are read in relation to archival resources: the curriculum of the National School and alternative educational models in Ham, records of schools provided in Wellington, and pedagogical intentions signalled in the records of the New Zealand Company. 
Findings – Arguing that migration resulted in a radical change in the subjectivity of these labouring class families, this paper contrasts the curricula of the “National School” attended by these children in Ham with the more secular offerings in Wellington. Their “National School” taught Ham's lower orders to accept their God-given “stations” in life. Radical critique was suppressed. In Wellington the first schools, such as the Mechanics’ Institute, were non-denominational, prioritising practical knowledge. Foundations for a secular society based on liberal values were laid. 
Originality/value – There is little educational research on how participation in the Wakefield scheme transformed those who, in rural England, were required to remain subservient members of the power orders, into the enterprising independent subjects required in the new colony.

text: Schooling of labouring migrants, Surrey to Wellington 1841-1844 Purpose – In the early 1840s Edward Gibbon Wakefield's New Zealand Company recruited “emigrants of the labouring classes” promising: “every one of them who is industrious and thrifty, may be sure to become not merely an owner of land, but also in his turn an employer of hired labourers, a master of servants.” Letters sent “Home” to Ham (a village in Surrey, UK) from Wellington between 1841-1844, by a group of labouring families, project textual personae consistent with this liberal image. The purpose of this paper is to explore educational processes involved in the production of these colonial identities. 
Design/methodology/approach – The letters are read in relation to archival resources: the curriculum of the National School and alternative educational models in Ham, records of schools provided in Wellington, and pedagogical intentions signalled in the records of the New Zealand Company. 
Findings – Arguing that migration resulted in a radical change in the subjectivity of these labouring class families, this paper contrasts the curricula of the “National School” attended by these children in Ham with the more secular offerings in Wellington. Their “National School” taught Ham's lower orders to accept their God-given “stations” in life. Radical critique was suppressed. In Wellington the first schools, such as the Mechanics’ Institute, were non-denominational, prioritising practical knowledge. Foundations for a secular society based on liberal values were laid. 
Originality/value – There is little educational research on how participation in the Wakefield scheme transformed those who, in rural England, were required to remain subservient members of the power orders, into the enterprising independent subjects required in the new colony.

year: 2011

title: Historical translocations by Maori may explain the distribution and genetic structure of a threatened surf clam in Aotearoa (New Zealand)

authors: Ross, Philip M.

subjects: Science & Technology

abstract: The population genetic structure of toheroa (Paphies ventricosa), an Aotearoa (New Zealand) endemic surf clam, was assessed to determine levels of inter-population connectivity and test hypotheses regarding life history, habitat distribution and connectivity in coastal vs. estuarine taxa. Ninety-eight toheroa from populations across the length of New Zealand were sequenced for the mitochondrial cytochrome c oxidase I gene with analyses suggesting a population genetic structure unique among New Zealand marine invertebrates. Toheroa genetic diversity was high in Te Ika-a Māui (the North Island of New Zealand) but completely lacking in the south of Te Waipounamu (the South Island), an indication of recent isolation. Changes in habitat availability, long distance dispersal events or translocation of toheroa to southern New Zealand by Māori could explain the observed geographic distribution of toheroa and their genetic diversity. Given that early-Māori and their ancestors, were adept at food cultivation and relocation, the toheroa translocation hypothesis is plausible and may explain the disjointed modern distribution of this species. Translocation would also explain the limited success in restoring what may in some cases be ecologically isolated populations located outside their natural distributions and preferred niches.

text: Historical translocations by Maori may explain the distribution and genetic structure of a threatened surf clam in Aotearoa (New Zealand) The population genetic structure of toheroa (Paphies ventricosa), an Aotearoa (New Zealand) endemic surf clam, was assessed to determine levels of inter-population connectivity and test hypotheses regarding life history, habitat distribution and connectivity in coastal vs. estuarine taxa. Ninety-eight toheroa from populations across the length of New Zealand were sequenced for the mitochondrial cytochrome c oxidase I gene with analyses suggesting a population genetic structure unique among New Zealand marine invertebrates. Toheroa genetic diversity was high in Te Ika-a Māui (the North Island of New Zealand) but completely lacking in the south of Te Waipounamu (the South Island), an indication of recent isolation. Changes in habitat availability, long distance dispersal events or translocation of toheroa to southern New Zealand by Māori could explain the observed geographic distribution of toheroa and their genetic diversity. Given that early-Māori and their ancestors, were adept at food cultivation and relocation, the toheroa translocation hypothesis is plausible and may explain the disjointed modern distribution of this species. Translocation would also explain the limited success in restoring what may in some cases be ecologically isolated populations located outside their natural distributions and preferred niches.

year: 2018