EPA MANDATE WAIVERS CREATE NEW UNCERTAINTIES IN BIODIESEL MARKETS

Biodiesel, Biofuel Mandate, Waivers, Resource /Energy Economics and Policy, Q11, Q16, Q42, Q48,

Profitability of Irrigated Improved Pecan Orchards in the Southern Plains

The objective was to determine if an irrigated improved pecan orchard is economical relative to agronomic systems commonly implemented by producers that have access to irrigation. Results show that the improved pecan orchard is more profitable than competitive enterprises after a twenty year time frame, but is sensitive to pecan price, pecan yield and attitude toward risk.Profitability, Irrigated, Pecan, Orchard, Southern Plains, Crop Production/Industries, Farm Management, Land Economics/Use, Production Economics, Risk and Uncertainty,

Implications of the Low Carbon Fuel Standard for State and National Ethanol Use

Resource /Energy Economics and Policy,

Constraining the orbits of sub-stellar companions imaged over short orbital arcs

Imaging a star's companion at multiple epochs over a short orbital arc provides only four of the six coordinates required for a unique orbital solution. Probability distributions of possible solutions are commonly generated by Monte Carlo (MCMC) analysis, but these are biased by priors and may not probe the full parameter space. We suggest alternative methods to characterise possible orbits, which compliment the MCMC technique. Firstly the allowed ranges of orbital elements are prior-independent, and we provide means to calculate these ranges without numerical analyses. Hence several interesting constraints (including whether a companion even can be bound, its minimum possible semi-major axis and its minimum eccentricity) may be quickly computed using our relations as soon as orbital motion is detected. We also suggest an alternative to posterior probability distributions as a means to present possible orbital elements, namely contour plots of elements as functions of line of sight coordinates. These plots are prior-independent, readily show degeneracies between elements and allow readers to extract orbital solutions themselves. This approach is particularly useful when there are other constraints on the geometry, for example if a companion's orbit is assumed to be aligned with a disc. As examples we apply our methods to several imaged sub-stellar companions including Fomalhaut b, and for the latter object we show how different origin hypotheses affect its possible orbital solutions. We also examine visual companions of A- and G-type main sequence stars in the Washington Double Star Catalogue, and show that $\gtrsim50$ per cent must be unbound.Comment: Accepted for publication in MNRA

Biofuels: Impact of Selected Farm Bill Provisions and other Biofuel Policy Options

Agricultural and Food Policy, Resource /Energy Economics and Policy,

US BIOFUEL AND CLIMATE POLICIES DUEL OVER CELLULOSIC BIOMASS

Agricultural and Food Policy, Crop Production/Industries, Environmental Economics and Policy, International Relations/Trade, Resource /Energy Economics and Policy,

Model of the US Ethanol Market

This report estimates the effects of public policy options and external conditions on ethanol and agricultural commodity markets, farm income and government costs.Agricultural and Food Policy, Resource /Energy Economics and Policy,