Accuracy of Trace Formulas

Using quantum maps we study the accuracy of semiclassical trace formulas. The role of chaos in improving the semiclassical accuracy, in some systems, is demonstrated quantitatively. However, our study of the standard map cautions that this may not be most general. While studying a sawtooth map we demonstrate the rather remarkable fact that at the level of the time one trace even in the presence of fixed points on singularities the trace formula may be exact, and in any case has no logarithmic divergences observed for the quantum bakers map. As a byproduct we introduce fantastic periodic curves akin to curlicues.Comment: 20 pages, uuencoded and gzipped, 1 LaTex text file and 9 PS files for figure

Livestock and the Environment: A National Pilot Project. The Policy Space, Economic Model, and Environmental Model Linkages

To address the growing problem of environmental degradation from livestock operations, the U.S. Environmental Protection Agency has sponsored a multidisciplinary project called Livestock and the Environment: A National Pilot Project (NPP). This report details the linkages among the policy space, the dairy farm economic model, and the environmental fate and transport simulation models. A summary of the NPP\u27s conceptual framework illustrates the overall model organization and linkages within the NPP

Compromise Solution for Economic-Environmental Decisions in Agriculture

Least cost production versus the environmental on- and off-site erosion damage of agriculture is evaluated in a policy context for a major Corn Belt watershed. Compromise programming, previously utilized in firm-level multi-criteria decision making problems is applied to a regional agricultural production model with environmental policy goal trade-offs. The crop sector model allocates land, water, labor, capital, and commodity-program base acres to crop production. Production options include four conservation practices, three tillage methods, and several crop rotations. Crop yield and fertilizer levels are dependent upon erosion. Cropping options selected allow for both wind and water erosion. The vector of objectives include three minimization functions: current production cost, future value of productivity loss, and sediment damage. Vector optimization technique was used to generate the payoff matrix containing efficient but simultaneously unobtainable solutions. Given the ideal but infeasible solution vector we generated efficient solutions in the compromise subset corresponding to the L1. L2. and Loo metrics. Trade-off relations were developed using the noninferior set estimation technique

Semiclassical properties and chaos degree for the quantum baker's map

We study the chaotic behaviour and the quantum-classical correspondence for the baker's map. Correspondence between quantum and classical expectation values is investigated and it is numerically shown that it is lost at the logarithmic timescale. The quantum chaos degree is computed and it is demonstrated that it describes the chaotic features of the model. The correspondence between classical and quantum chaos degrees is considered.Comment: 30 pages, 4 figures, accepted for publication in J. Math. Phy

The Economic and Environmental Indicators for Evaluating the National Pilot Project on Livestock and the Environment

The livestock and dairy industries are consolidating and concentrating within confined geographical areas. Accompanying these structural adjustments that are under way in the dairy and livestock industries is the potential for increased point and nonpoint source pollution problems from animal waste disposal. An assessment of optimal policies and best management practices to control pollution from CAFOs requires an integrated evaluation of economic and environmental consequences from alternative policies and practices. To perform this integrated assessment, a set of important economic and environmental indicators that these policies will affect have to be identified. This paper reviews indicators used in other site-specific studies and recommends a feasible set of economic and environmental indicators for the national pilot project

Entanglement between two subsystems, the Wigner semicircle and extreme value statistics

The entanglement between two arbitrary subsystems of random pure states is studied via properties of the density matrix's partial transpose, $\rho_{12}^{T_2}$. The density of states of $\rho_{12}^{T_2}$ is close to the semicircle law when both subsystems have dimensions which are not too small and are of the same order. A simple random matrix model for the partial transpose is found to capture the entanglement properties well, including a transition across a critical dimension. Log-negativity is used to quantify entanglement between subsystems and analytic formulas for this are derived based on the simple model. The skewness of the eigenvalue density of $\rho_{12}^{T_2}$ is derived analytically, using the average of the third moment over the ensemble of random pure states. The third moment after partial transpose is also shown to be related to a generalization of the Kempe invariant. The smallest eigenvalue after partial transpose is found to follow the extreme value statistics of random matrices, namely the Tracy-Widom distribution. This distribution, with relevant parameters obtained from the model, is found to be useful in calculating the fraction of entangled states at critical dimensions. These results are tested in a quantum dynamical system of three coupled standard maps, where one finds that if the parameters represent a strongly chaotic system, the results are close to those of random states, although there are some systematic deviations at critical dimensions.Comment: Substantially improved version (now 43 pages, 10 figures) that is accepted for publication in Phys. Rev.

The 1989 Recommended Pesticide and Nitrogen Use Survey: Description and Policy Applications

The public and the agricultural community are concerned with the impact of agrichemical use on the environment. Of particular concern is the impact of pesticides and nitrogen on the quality of surface and ground waters (Nielson and Lee 1987). Although a national effort is under way to address agricultural contributions to water contamination, lack of data is hindering progress. Data are needed to characterize agrichemical use and its subsequent fate and transport throughout the ecosystem. Reliable data are vital for informed policy decisions weighing the potential risks and benefits (Delwiche 1970). In the absence of that data about total amounts of agrichemicals being used on crops and the rates and methods of application, it is difficult to describe the link between agricultural porduction practices and environmental quality, or to assess the impacts of programs and policies addressing water quality. This report documents the 1989 Recommended Pesticide and Nitrogen Use Survey. The survey was conducted to alleviate part of the data deficiency by collecting detailed information on recommended pesticide and nitrogen uses and application practices in 48 states. Information on usage was obtained by crop, tillage practice, and soil texture. Crops covered in the survey included alfalfa, barley, corn grain, corn silage, cotton oats, pasture, other hay, peanuts, sorghum grain, sorghum silage, soybeans, spring and winter wheat, and sunflowers. Tillage practices included spring and fall plow conventional tillage, conservation tillage, ridge tillage, and no tillage. By providing detailed information on the rate and total amount of agrichemicals applied to the soil surface, the survey provides data for investigating the behavioral and economic links between environmental quality and decision making within agricultural production. In addition, the data can be used in assesing the impacts of policies and porgrams addressing water quality

Dynamics and Trends in the U.S. Dairy Industry

Fueled by economic forces, dairy sector policies, technological progress, and strict environmental regulations the U.S. dairy industry is consolidating into large, confined animal feedlot operations (CAFOs) and concentrating in a few localized areas. These structural changes produced a disproportionate impact on the local areas, exacerbating local dairy waste pollution problems because of introducing manure nutrients at a rate far in excess of environmental assimilative capacity. The national, regional, and state-level trends in the dairy industry are examined, with the objective of identifying forces that are responsible for this structural change. The structural change will create winners and losers among traditional dairy farms, rural communities, and environmental integrity. Therefore, public policy has an important role to play in balancing the cost of a changing dairy industry with the benefits to society at large from a more economically efficient and environmentally sound industry