Magmatic focusing to mid-ocean ridges: the role of grain size variability and non-Newtonian viscosity

Melting beneath mid-ocean ridges occurs over a region that is much broader than the zone of magmatic emplacement to form the oceanic crust. Magma is focused into this zone by lateral transport. This focusing has typically been explained by dynamic pressure gradients associated with corner flow, or by a sub-lithospheric channel sloping upward toward the ridge axis. Here we discuss a novel mechanism for magmatic focusing: lateral transport driven by gradients in compaction pressure within the asthenosphere. These gradients arise from the co-variation of melting rate and compaction viscosity. The compaction viscosity, in previous models, was given as a function of melt fraction and temperature. In contrast, we show that the viscosity variations relevant to melt focusing arise from grain-size variability and non-Newtonian creep. The asthenospheric distribution of melt fraction predicted by our models provides an improved ex- planation of the electrical resistivity structure beneath one location on the East Pacific Rise. More generally, although grain size and non-Newtonian viscosity are properties of the solid phase, we find that in the context of mid-ocean ridges, their effect on melt transport is more profound than their effect on the mantle corner-flow.Comment: 20 pages, 4 figures, 1 tabl

Career progress and career barriers: Women MBA graduates in Canada and the UK

This article explores the career progress of female MBA graduates in Canada and the UK and the nature of career barriers experienced in each context. Results suggest that while Canadian women have similar career profiles to men, women in the UK lag behind their male counterparts after graduation from the course. At the same time, UK women encounter more intractable career barriers in the form of negative attitudes and prejudice. A model of the ‘MBA effect’ is proposed in terms of how the qualification may impact on career barriers. This incorporates three different types of barriers which are seen to operate at the individual level (person centred barriers) and at the intermediate/organizational level (organizational culture and attitudes, corporate practices) as well as, at the macro level, the impact of legislative frameworks. Results from the UK and Canadian surveys are discussed in relation to this model and in the context of feminist theory and women in management literature

Solar Modulation of the Galactic Helium Spectrum Above 30 Mev Per Nucleon

Time measurements of differential energy spectra and flux of primary helium nuclei by use of charged particle telescope

Acceleration of particles in the earth's shock transition region and beyond

Acceleration of particles in earth shock transition region and beyon

Public Hazard, Personal Peril: The Impact of Non-Governmental Organizations in the Environmental Justice Movement

This article argues that the local emphasis of what I call micromovements that form the larger Environmental Justice Movement could gain more traction from relationships with Non-Governmental Organizations. Such partnerships are emerging on a national level; however, since the localized movements communicate with, but are not partners with, national organizations such as the National Black Environmental Network, it is unclear how such partnerships add value to the activities of local groups. Moreover, some partnerships are forged for the organization of a specific event such as a conference or working group study Part II of this article discusses an overview of the history of the Environmental Justice Movement and legal remedies available for environmental justice claims. Part III addresses the partnerships between nongovernmental organizations and grassroots movements focusing specifically on one community\u27s struggle with Velsicol Chemical Corporation. Finally, Part VI discusses the obstacles grassroots movement leaders face in trying to change policy and protect their community and how NGOs can be helpful to these efforts

Public Hazard, Personal Peril: The Impact of Non-Governmental Organizations in the Environmental Justice Movement

This article argues that the local emphasis of what I call micromovements that form the larger Environmental Justice Movement could gain more traction from relationships with Non-Governmental Organizations. Such partnerships are emerging on a national level; however, since the localized movements communicate with, but are not partners with, national organizations such as the National Black Environmental Network, it is unclear how such partnerships add value to the activities of local groups. Moreover, some partnerships are forged for the organization of a specific event such as a conference or working group study Part II of this article discusses an overview of the history of the Environmental Justice Movement and legal remedies available for environmental justice claims. Part III addresses the partnerships between nongovernmental organizations and grassroots movements focusing specifically on one community\u27s struggle with Velsicol Chemical Corporation. Finally, Part VI discusses the obstacles grassroots movement leaders face in trying to change policy and protect their community and how NGOs can be helpful to these efforts

From the Stage to the World: The Moralizing Methods of Sir Richard Steele

This thesis looks at the life and literary works of Sir Richard Steel as they relate to his well-defined moral code. It analyzes the sentimentality and comedy which he works into his narratives and discusses how he uses these methods to communicate his sense of morality to his audience