Greener Acres or Greener Waters? Potential U.S. Impacts of Agricultural Trade Liberalization

This paper examines the elimination of all agricultural policy distortions in all trading countries and agricultural production decisions in the United States, as well as subsequent environmental quality in the presence and absence of nondegradation environmental standards. The results suggest that trade liberalization has the potential to increase domestic production and boost agricultural returns by as much as 8.5 percent. Consumer surplus would likely fall, and the discharge of nutrients, sediment, and pesticides would likely increase. However, environmental policies can limit these adverse environmental impacts and mute the potential decrease in consumer surplus, while leaving increased returns to agricultural production.agriculture, trade reform, environment, nondegradation, Environmental Economics and Policy, International Relations/Trade,

THE BIG PICTURE: PRODUCTION AND ENVIRONMENTAL IMPACTS OF REDUCED US OBESITY

This paper assesses how successfully reducing the incidence of overweight and obesity in the US to meet public health objectives might influence agricultural production. We also examine the consequent agri-environmental effects of the production changes. Our estimates show that a reduction in aggregate consumption by between 2 and 6 percent, associated with public health goals being met, would lead to reduced production of primary agricultural commodities, increased exports, and reduced discharge of agricultural pollutants. In both cases, neither the estimated changes in commodity production nor the subsequent environmental impacts would be uniform across the landscape. Results indicate that in value terms, the largest changes (either positive or negative) in agricultural producer net returns would occur in the Corn Belt and the Lake States; conversely, the largest impacts on consumer surplus would occur in the Northeast and Pacific regions.Health Economics and Policy,

Raman Spectra of Hydrogen Peroxide in Condensed Phases. I. The Spectra of the Pure Liquid and Its Aqueous Solutions

The Raman spectrum of liquid 99.5% H2O2 has been obtained at 30° and −40°C and compared with the spectrum of 90% D2O2 at −40°C. Three bands not previously reported were observed and their assignment, together with that of the remaining bands, is discussed.Raman spectra were also obtained for aqueous solutions at 30° and −40°C over the complete concentration range. The interpretation is qualitatively in agreement with the results of other work which indicate that the addition of hydrogen peroxide to water results in more extensive hydrogen bonding and an increased degree of order in the solutions.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70695/2/JCPSA6-24-1-41-1.pd

High Quality Ultrathin Bi2Se3 Films on CaF2 and CaF2/Si by Molecular Beam Epitaxy with a Radio Frequency Cracker Cell

Here we report a method to fabricate high quality Bi2Se3 thin films using molecular beam epitaxy with a radio frequency cracker cell as an atomic selenium source. With rates close to exact stoichiometry, optimal layer-by-layer growth of high quality Bi2Se3 thin films with smooth surfaces, has been achieved on CaF2(111) substrates and Si(111) substrates with a thin CaF2 buffer layer(CaF2/Si). Transport measurements show a characteristic weak antilocalization mangnetoresistance, with emergence of weak localization in the ultrathin film limit. Quantum Oscillations attributed to the topological surface states have been observed, including in films on CaF2/Si

Promoting Program Evaluation Fidelity When Data Collectors Lack Research Design and Implementation Expertise

Within Extension, certain personnel, facilitators, and volunteers expected to conduct research in the form of program evaluation may have little or no training in effective research design and practices. This circumstance can lead to difficulties in the implementation of evaluation procedures, particularly with regard to program evaluation fidelity. In addition, a lack of familiarity with effective program evaluation and research methods may limit an individual\u27s understanding of the importance of evaluation itself, as well as the importance of fidelity in conducting an evaluation. Effective planning of, training in, and monitoring of program evaluation procedures is essential for maintaining fidelity and ensuring accurate evaluation of program outcomes

Resumming the large-N approximation for time evolving quantum systems

In this paper we discuss two methods of resumming the leading and next to leading order in 1/N diagrams for the quartic O(N) model. These two approaches have the property that they preserve both boundedness and positivity for expectation values of operators in our numerical simulations. These approximations can be understood either in terms of a truncation to the infinitely coupled Schwinger-Dyson hierarchy of equations, or by choosing a particular two-particle irreducible vacuum energy graph in the effective action of the Cornwall-Jackiw-Tomboulis formalism. We confine our discussion to the case of quantum mechanics where the Lagrangian is $L(x,\dot{x}) = (1/2) \sum_{i=1}^{N} \dot{x}_i^2 - (g/8N) [ \sum_{i=1}^{N} x_i^2 - r_0^2 ]^{2}$. The key to these approximations is to treat both the $x$ propagator and the $x^2$ propagator on similar footing which leads to a theory whose graphs have the same topology as QED with the $x^2$ propagator playing the role of the photon. The bare vertex approximation is obtained by replacing the exact vertex function by the bare one in the exact Schwinger-Dyson equations for the one and two point functions. The second approximation, which we call the dynamic Debye screening approximation, makes the further approximation of replacing the exact $x^2$ propagator by its value at leading order in the 1/N expansion. These two approximations are compared with exact numerical simulations for the quantum roll problem. The bare vertex approximation captures the physics at large and modest $N$ better than the dynamic Debye screening approximation.Comment: 30 pages, 12 figures. The color version of a few figures are separately liste

The differential regulation of Lck kinase phosphorylation sites by CD45 is critical for T cell receptor signaling responses

SummaryThe molecular mechanisms whereby the CD45 tyrosine phosphatase (PTPase) regulates T cell receptor (TCR) signaling responses remain to be elucidated. To investigate this question, we have reconstituted CD45 (encoded by Ptprc)-deficient mice, which display severe defects in thymic development, with five different expression levels of transgenic CD45RO, or with mutant PTPase null or PTPase-low CD45R0. Whereas CD45 PTPase activity was absolutely required for the reconstitution of thymic development, only 3% of wild-type CD45 activity restored T cell numbers and normal cytotoxic T cell responses. Lowering the CD45 expression increased CD4 lineage commitment. Peripheral T cells with very low activity of CD45 phosphatase displayed reduced TCR signaling, whereas intermediate activity caused hyperactivation of CD4+ and CD8+ T cells. These results are explained by a rheostat mechanism whereby CD45 differentially regulates the negatively acting pTyr-505 and positively acting pTyr-394 p56lck tyrosine kinase phosphorylation sites. We propose that high wild-type CD45 expression is necessary to dephosphorylate p56lck pTyr-394, suppressing CD4 T+ cell lineage commitment and hyperactivity

Quantum and Classical Dissipative Effects on Tunnelling in Quantum Hall Bilayers

We discuss the interplay between transport and dissipation in quantum Hall bilayers. We show that quantum effects are relevant in the pseudospin picture of these systems, leading either to direct tunnelling currents or to quantum dissipative processes that damp oscillations around the ground state. These quantum effects have their origins in resonances of the classical spin system.Comment: 12 pages. Minor changes from v

Tradeoff between short-term and long-term adaptation in a changing environment

We investigate the competition dynamics of two microbial or viral strains that live in an environment that switches periodically between two states. One of the strains is adapted to the long-term environment, but pays a short-term cost, while the other is adapted to the short-term environment and pays a cost in the long term. We explore the tradeoff between these alternative strategies in extensive numerical simulations, and present a simple analytic model that can predict the outcome of these competitions as a function of the mutation rate and the time scale of the environmental changes. Our model is relevant for arboviruses, which alternate between different host species on a regular basis.Comment: 9 pages, 3 figures, PRE in pres