title: Conditions for sustainment of magnetohydrodynamic turbulence driven by Alfvén waves

authors: Dmitruk, Pablo

subjects: Alfvén waves

abstract: In a number of space and astrophysical plasmas,turbulence is driven by the supply of wave energy. In the context of incompressible magnetohydrodynamics (MHD) there are basic physical reasons, associated with conservation of cross helicity, why this kind of driving may be ineffective in sustaining turbulence. Here an investigation is made into some basic requirements for sustaining steady turbulence and dissipation in the context of incompressible MHD in a weakly inhomogeneous open field line region, driven by the supply of unidirectionally propagating waves at a boundary. While such wave driving cannot alone sustain turbulence, the addition of reflection permits sustainment. Another sustainment issue is the action of the nonpropagating or quasi-two dimensional part of the spectrum; this is particularly important in setting up a steady cascade. Thus, details of the waveboundary conditions also affect the ease of sustaining a cascade. Supply of a broadband spectrum of waves can overcome the latter difficulty but not the former, that is, the need for reflections. Implications for coronal heating and other astrophysical applications, as well as simulations, are suggested.

text: Conditions for sustainment of magnetohydrodynamic turbulence driven by Alfvén waves In a number of space and astrophysical plasmas,turbulence is driven by the supply of wave energy. In the context of incompressible magnetohydrodynamics (MHD) there are basic physical reasons, associated with conservation of cross helicity, why this kind of driving may be ineffective in sustaining turbulence. Here an investigation is made into some basic requirements for sustaining steady turbulence and dissipation in the context of incompressible MHD in a weakly inhomogeneous open field line region, driven by the supply of unidirectionally propagating waves at a boundary. While such wave driving cannot alone sustain turbulence, the addition of reflection permits sustainment. Another sustainment issue is the action of the nonpropagating or quasi-two dimensional part of the spectrum; this is particularly important in setting up a steady cascade. Thus, details of the waveboundary conditions also affect the ease of sustaining a cascade. Supply of a broadband spectrum of waves can overcome the latter difficulty but not the former, that is, the need for reflections. Implications for coronal heating and other astrophysical applications, as well as simulations, are suggested.

year: 2001

title: Ownership structure and firm financial performance: Evidence from panel data in Sri Lanka

authors: Wellalage, Nirosha Hewa

subjects: ownership structure

abstract: This study investigates the effects of equity ownership structure on financial performance of Sri Lankan listed businesses. Using dynamic panel generalised method of moment this study finds an inverse hump shape relationship between insider ownership and firm financial performance. The results of this study confirm that the effect of insider ownership on firm performance is more positive and significant where legal protection for investors is weak. It suggests that although new legislative reforms have been enacted, Sri Lankan companies are highly dependent on internal governance mechanisms. There is potential merit in promulgating new rules to control the expropriation of minority shareholders.

text: Ownership structure and firm financial performance: Evidence from panel data in Sri Lanka This study investigates the effects of equity ownership structure on financial performance of Sri Lankan listed businesses. Using dynamic panel generalised method of moment this study finds an inverse hump shape relationship between insider ownership and firm financial performance. The results of this study confirm that the effect of insider ownership on firm performance is more positive and significant where legal protection for investors is weak. It suggests that although new legislative reforms have been enacted, Sri Lankan companies are highly dependent on internal governance mechanisms. There is potential merit in promulgating new rules to control the expropriation of minority shareholders.

year: 2012

title: Maori & Psychology Research Unit annual report 2006

authors: Rua, Mohi

subjects: Maori and Psychology Research Unit

abstract: Annual report of the Maori and Psychology Research Unit (MPRU) 2006. The unit was established in August of 1997. The unit is designed to provide a catalyst and support network for enhancing research concerning the psychological needs, aspirations, and priorities of Maori people. The MPRU is well situated to draw together skilled and experienced interdisciplinary research groups by networking and establishing working relationships with staff and students within the Faculty of Arts and Social Sciences, the University, and the wider community.

text: Maori & Psychology Research Unit annual report 2006 Annual report of the Maori and Psychology Research Unit (MPRU) 2006. The unit was established in August of 1997. The unit is designed to provide a catalyst and support network for enhancing research concerning the psychological needs, aspirations, and priorities of Maori people. The MPRU is well situated to draw together skilled and experienced interdisciplinary research groups by networking and establishing working relationships with staff and students within the Faculty of Arts and Social Sciences, the University, and the wider community.

year: 2006