title: Solar wind fluctuations and the von Kármán–Howarth equations: The role of fourth-order correlations

authors: Oughton, Sean

subjects: interplanetary magnetic fields

abstract: The von Kármán-Howarth (vKH) hierarchy of equations relate the second-order correlations of the turbulent fluctuations to the third-order ones, the third-order to the fourth-order, and so on. We recently demonstrated [1] that for MHD, self-similar solutions to the vKH equations seem to require at least two independent similarity lengthscales (one for each Elsässer energy), so that compared to hydrodynamics a richer set of behaviors seems likely to ensue. Moreover, despite the well-known anisotropy of MHD turbulence with a mean magnetic field (B₀), the equation for the second-order correlation does not contain explicit dependence on B₀. We show that there is, however, implicit dependence on B₀ via the third-order correlations, which themselves have both explicit B₀-dependence and also their own implicit dependence through fourth-order correlations. Some subtleties and consequences of this implicit-explicit balance are summarized here. In addition, we present an analysis of simulation results showing that the evolution of turbulence can depend strongly on the initial fourth-order correlations of the system. This leads to considerable variation in the energy dissipation rates. Some associated consequences for MHD turbulence are discussed.

text: Solar wind fluctuations and the von Kármán–Howarth equations: The role of fourth-order correlations The von Kármán-Howarth (vKH) hierarchy of equations relate the second-order correlations of the turbulent fluctuations to the third-order ones, the third-order to the fourth-order, and so on. We recently demonstrated [1] that for MHD, self-similar solutions to the vKH equations seem to require at least two independent similarity lengthscales (one for each Elsässer energy), so that compared to hydrodynamics a richer set of behaviors seems likely to ensue. Moreover, despite the well-known anisotropy of MHD turbulence with a mean magnetic field (B₀), the equation for the second-order correlation does not contain explicit dependence on B₀. We show that there is, however, implicit dependence on B₀ via the third-order correlations, which themselves have both explicit B₀-dependence and also their own implicit dependence through fourth-order correlations. Some subtleties and consequences of this implicit-explicit balance are summarized here. In addition, we present an analysis of simulation results showing that the evolution of turbulence can depend strongly on the initial fourth-order correlations of the system. This leads to considerable variation in the energy dissipation rates. Some associated consequences for MHD turbulence are discussed.

year: 2013

title: En la periferia de la textualidad literaria: la tecnopoesía. [On the margins of literary textuality: Technopoetry].

authors: Lopez-Fernandez, Laura

subjects: tecnopoesía

abstract: La poesía experimental produce modos de conocimiento que difieren de las cartografías convencionales de representación y a su vez requieren modos de lectura alternativos. En este estudio se exploran tecnotextos de dos autores latinoamericanos que han creado nuevos modos de escritura. La tecnopoesía, como veremos, vive en los límites de la textualidad, la discursividad y el canon literario. IP Poetry de Gustavo Romano, y “Cypher” de Eduardo Kac, reciclan lenguajes escritos, orales, genéticos (ADN), lenguaje computacional, sonido, imagen, etc., al tiempo que activan la participación del lector y, paradójicamente, la naturaleza autopoética del poema, eliminando distancias entre proceso y producto y desafiando las expectativas de autoría y lectura. La democratización y manipulación de diversos lenguajes y tecnologías es un aspecto integral de la tecnopoesía que activa desde los márgenes, una nueva política de representación y contribuye a la reconceptualización de la poesía.

text: En la periferia de la textualidad literaria: la tecnopoesía. [On the margins of literary textuality: Technopoetry]. La poesía experimental produce modos de conocimiento que difieren de las cartografías convencionales de representación y a su vez requieren modos de lectura alternativos. En este estudio se exploran tecnotextos de dos autores latinoamericanos que han creado nuevos modos de escritura. La tecnopoesía, como veremos, vive en los límites de la textualidad, la discursividad y el canon literario. IP Poetry de Gustavo Romano, y “Cypher” de Eduardo Kac, reciclan lenguajes escritos, orales, genéticos (ADN), lenguaje computacional, sonido, imagen, etc., al tiempo que activan la participación del lector y, paradójicamente, la naturaleza autopoética del poema, eliminando distancias entre proceso y producto y desafiando las expectativas de autoría y lectura. La democratización y manipulación de diversos lenguajes y tecnologías es un aspecto integral de la tecnopoesía que activa desde los márgenes, una nueva política de representación y contribuye a la reconceptualización de la poesía.

year: 2019

title: Leadership: Going beyond personal will and professional skills to give life to Ka Hikitia

authors: Berryman, Mere

subjects: education policy

abstract: This paper investigates the Ka Hikitia Māori education policy and its subsequent influence in effecting system change towards Māori students’ achievement. It discusses how a Request for Proposal to the Ministry of Education’s Building on Success was conceptualised to support English-medium secondary schools across New Zealand to address this policy. The result, Kia Eke Panuku, is a professional learning and development response that works with Strategic Change Leadership Teams to create culturally responsive and relational contexts for learning, focused on Māori students enjoying and achieving educational success as Māori. It is argued that neither a political mandate for change nor a set of learned strategies by school personnel will truly bring about a changed reality for Māori students. Rather the reform must be led by transformative leaders who are driven by both the moral imperative to change and a keen sense of urgency to see this happen in our schools for Māori students and their home communities.
The major issues raised in this paper, and the solutions that have been reached thus far, can help inform others who are trying to raise the participation, inclusion and achievement of students who may currently be marginalised from formal education settings.

text: Leadership: Going beyond personal will and professional skills to give life to Ka Hikitia This paper investigates the Ka Hikitia Māori education policy and its subsequent influence in effecting system change towards Māori students’ achievement. It discusses how a Request for Proposal to the Ministry of Education’s Building on Success was conceptualised to support English-medium secondary schools across New Zealand to address this policy. The result, Kia Eke Panuku, is a professional learning and development response that works with Strategic Change Leadership Teams to create culturally responsive and relational contexts for learning, focused on Māori students enjoying and achieving educational success as Māori. It is argued that neither a political mandate for change nor a set of learned strategies by school personnel will truly bring about a changed reality for Māori students. Rather the reform must be led by transformative leaders who are driven by both the moral imperative to change and a keen sense of urgency to see this happen in our schools for Māori students and their home communities.
The major issues raised in this paper, and the solutions that have been reached thus far, can help inform others who are trying to raise the participation, inclusion and achievement of students who may currently be marginalised from formal education settings.

year: 2015