INFLUENCE OF LAND TENURE ARRANGEMENTS ON GRAZING MANAGEMENT INCENTIVES

Land Economics/Use, Livestock Production/Industries,

FACTORS INFLUENCING OPTIMAL STOCKING RATES FROM A TENANT PERSPECTIVE

The terms of grazing lease contracts potentially influence the tenants incentive to preserve the vegetation resource. Annual stocking rate decisions dictate the degree of overgrazing, which can be cumulative over long periods of time. The objective of this study is to identify the impact the tenants planning horizon and cost structure specified in the lease contract has on his/her profit-maximizing stocking rate. A multi-period nonlinear programming model was developed to identify economically optimal stocking rates each year over a 24-year period. The model was solved under 1-, 4-, 8-, and 12-year leases on a per acre and per head basis. The relative importance of each lease alternative and input variable on the tenants optimal stocking rate was ranked based on standardized ordinary least squares coefficient estimates between input values and optimal stocking rates. Planning horizon and cost structure had a minor impact on optimal stocking rates relative to non-lease factors such as livestock prices and production costs. Holding other factors constant, per acre leases generated a 2% higher average stocking rate than per head leases. Optimal stocking rates were inversely related to the length of the lease. Twelve-year lease agreements generated 18 and 13% lower optimal stocking rater than the 1-year per acre and per head lease agreements, respectively. The optimal stocking rate difference between an 8-year and a 12-year lease was negligible, suggesting the 8-year lease would provide a similar incentive to protect vegetation as a lease with a longer planning horizon.Environmental Economics and Policy, Land Economics/Use,

Using learning styles theory to improve on-line learning through computer assisted diagnosis

Despite the success in a number of education and training environments of a variety of Learning Styles diagnostic tools1,2 and particularly the success of Honey and Mumford3, there still appears to be a scarcity of research, development and action on the application of this work to e-learning. When we compare developments around the issues of, for example, content development and pedagogy4, authoring and packaging tools5, virtual and managed learning environments and interoperability6, or accessibility of learning products and services for disabled people7, we find comparatively little research and comparatively very little application of Learning Styles thinking to the development of e-learning products, services, environments and practices

Surface structural changes of perovskite oxides during oxygen evolution in alkaline electrolyte

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2013.Cataloged from PDF version of thesis.Includes bibliographical references (p. 61-69).Perovskite oxides such Ba0.5Sr0.5Co0.8Fe0.8O3-6 (BSCF82) are among the most active catalysts for the oxygen evolution reaction (OER) in alkaline solution reported to date. In this work it is shown via high resolution transmission electron microscopy (HRTEM) and Raman spectroscopy that oxides such as BSCF82 rapidly undergoes amorphization at its surface under OER conditions, which occurs simultaneously with an increase in the pseudocapacitive current and OER activity. This amorphization was not detected at potentials below those where significant OER current was observed. Lower concentrations of Sr²- and Ba²- are found in the amorphous regions of BSCF82. Perovskite oxides with lower OER activities such as LaCoO₃ (LCO) and LaMnO₃ (LMO) remained crystalline under identical electrochemical conditions. In addition, the OER activity and tendency for amorphization are found to correlate with the oxygen p-band center as calculated using density functional theory. This work illustrates that the surface structure and stoichiometry of oxide catalysts can differ significantly from the bulk during catalysis, and that understanding these phenomena is critical for designing highly active and stable catalysts for the OER.by Kevin J. May.S.M