340 research outputs found

    Modeling the Effects of Cap and Trade and a Carbon Offset Policy on Crop Allocations and Farm Income

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    A static, producer profit maximization framework is used to capture county level land use choice on the basis of profitability, greenhouse gas (GHG) emissions to the farm gate as well as soil carbon sequestration as affected by tillage and soil type. Policy scenarios of a 5% GHG cap on agricultural emissions in conjunction with a carbon offset payment system, designed to provide producer payments for net carbon footprint (GHG emissions – soil carbon sequestration) reductions compared to a baseline are evaluated to determine potential changes to land use and or producer income as a result of different policy scenarios. Results suggest that a policy solely targeted at emissions can be counterproductive in the sense that acreage reductions of more input-intensive crops also lead to soil carbon sequestration reductions. Producer income effects are largely negative unless carbon prices reach nearly $100 per ton.Cap and Trade, Carbon Sequestration, GHG Emissions, Agriculture, Agricultural and Food Policy, Environmental Economics and Policy, Q50, Q58, Q54,

    The Impact of Reducing Greenhouse Gas Emissions in Crop Agriculture: A Spatial- and Production-Level Analysis

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    With the Waxman-Markey Bill passing the House and the administration’s push to reduce carbon emissions, the likelihood of the implementation of some form of a carbon emissions policy is increasing. This study estimates the greenhouse gas (GHG) emissions of the six largest row crops produced in Arkansas using 57 different production practices predominantly used and documented by the University of Arkansas Cooperative Extension Service. From these GHG emission estimates, a baseline state “carbon footprint†was estimated and a hypothetical GHG emissions reduction of 5, 10, and 20 percent was levied on Arkansas agriculture using a cap-and-trade method. Using current production technology and traditional land use choices, results show that the trading of carbon-emitting permits to reduce statewide GHG emissions by 5 percent from the baseline would enhance GHG emissions efficiency measured as net crop farm income generated per unit of carbon emissions created. The 5 percent reduction in GHG emissions does cause marginal reductions in acres farmed and has marginal income ramifications. Beyond the 5 percent reduction target, gains in GHG emissions efficiency decline but remain positive in most counties through the 10 percent GHG reduction target. However, with a 10 percent GHG reduction, acreage and income reductions more than double compared to the 5 percent level. When GHG emissions are reduced by 20 percent from the baseline, the result is a major cropping pattern shift coupled with significant reductions in traditional row crop acreage, income, and GHG emissions efficiency.greenhouse gas emissions, carbon equivalents, sustainability, cap and trade, Environmental Economics and Policy, Resource /Energy Economics and Policy,

    How A Cap-and-Trade Policy of Green House Gases Could Alter the Face of Agriculture in the South: A Spatial and Production Level Analysis.

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    With the Waxman-Markey Bill passing the House and the Obama administration’s push to reduce carbon emissions, the likelihood of the implementation of some form of a carbon policy is increasing. This study estimates the greenhouse gas (GHG) emissions of the six largest crops produced in Arkansas using 63 different production practices as documented by University of Arkansas Cooperative Extension Service. From these GHG estimates a baseline state “carbon footprint” was estimated and a hypothetical cap-and-trade carbon reduction of 5, 10, and 20% was levied on Arkansas agriculture. Results show that while a modest reduction in GHG emissions (5%) would only affect crop allocations amongst certain crops while marginally reducing state net returns, a 20% reduction would cause major cropping pattern shifts with some traditional row crops nearly disappearing.Cap-and-Trade, carbon, sustainability, Agricultural and Food Policy, Environmental Economics and Policy, Q28, Q52, Q54, Q56,

    Modeling Pine as a Carbon Sequestering Crop in Arkansas

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    Carbon Sequestration, Loblolly Pine, Carbon Offset, Carbon Policy, Environmental Economics and Policy, Land Economics/Use, Resource /Energy Economics and Policy,

    Irrigation Restriction and Biomass Market Interactions: The Case of the Alluvial Aquifer

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    The U.S. Geological Survey has determined that irrigation in Arkansas’ Delta is unsustainable. This study examines how irrigation restrictions would affect county net returns to crop production. It also considers the effect of planting less water-intensive bioenergy crops—switchgrass and forage sorghum—in the event biofuel markets become a reality. Results suggest that sustainable irrigation restrictions without bioenergy crops would decrease producer returns by 28% in the region. Introducing these alternative crops would both reduce groundwater use and may restore state producer returns, albeit with significant spatial income redistribution to crop production throughout the state.biomass crops, ground water irrigation, spatial income redistribution, sustainability, Agribusiness, Agricultural and Food Policy, Crop Production/Industries, Environmental Economics and Policy, Financial Economics, Land Economics/Use, Political Economy, Resource /Energy Economics and Policy, Risk and Uncertainty, Q24, Q25, Q32, Q42, O13,

    How a National Carbon Policy Could Affect Grain Variety Selection: The Case of Rice in Arkansas

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    This study conducts a life cycle assessment (LCA) of carbon emissions and estimates the carbon sequestered in 14 commonly sown rice varieties across the Arkansas Delta. Given the uncertainty regarding future carbon legislation, and increased consumer and industry demand for “greener” products, this study estimates how potential carbon policies would affect rice cultivar selection Hybrid rice varieties, given their higher yield and higher yield per unit of green house gas (GHG) emission, are better positioned to take advantage of any increase in consumer demand for “greener” products and/or absorb any government policy better than conventional rice cultivars.Rice, Carbon Policy, Cap and Trade, Carbon Offset, Agricultural and Food Policy, Crop Production/Industries, Environmental Economics and Policy, Q52, Q54, Q58,

    Going, Going, Almost Gone: How the Depletion of the Alluvial Aquifer Will Affect Cropping Decisions in the Arkansas Delta

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    The U.S. Geological Survey (USGS) has determined that agricultural irrigation in Arkansas’ Delta is unsustainable with significant negative economic repercussions on producers net returns affected by the Alluvial aquifer. This study examines how irrigation restrictions in that region would affect county net returns to crop production. It also considers the effect of planting less water-intensive bioenergy crops in the event biofuel markets become a reality. A constrained optimization model determines acreage allocations and net returns under three irrigation scenarios: i) no irrigation restrictions, ii) irrigation restrictions that lead to a sustainable Alluvial aquifer, and iii) irrigation restrictions that would lengthen the life of the Alluvial aquifer. Hypothetical switchgrass and forage sorghum crops were then added to model the effect of a biofuel market. If crop production were conducting using irrigation levels that are sustainable, as defined by the USGS, producer net returns would decrease by 28% in the Alluvial region. Estimates show that the introduction of dedicated bioenergy crops could alleviate this downturn. If the price of switchgrass reached $46.40 per dry ton at the farmgate, it is possible to restore net returns to crop production across the state to pre-irrigation restriction levels, while Alluvial region producers now would suffer only a 9.5% reduction. Significant income redistribution to crop production thus exists with depleting ground water irrigation resources even with the introduction of an alternative markets.ground water irrigation, sustainability, biomass crops, Crop Production/Industries, Farm Management, Resource /Energy Economics and Policy,

    A longitudinal model for disease progression was developed and applied to multiple sclerosis

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    OBJECTIVES: To develop a model of disease progression using multiple sclerosis (MS) as an exemplar. STUDY DESIGN AND SETTINGS: Two observational cohorts, the University of Wales MS (UoWMS), UK (1976), and British Columbia MS (BCMS) database, Canada (1980), with longitudinal disability data [the Expanded Disability Status Scale (EDSS)] were used; individuals potentially eligible for MS disease-modifying drugs treatments, but who were unexposed, were selected. Multilevel modeling was used to estimate the EDSS trajectory over time in one data set and validated in the other; challenges addressed included the choice and function of time axis, complex observation-level variation, adjustments for MS relapses, and autocorrelation. RESULTS: The best-fitting model for the UoWMS cohort (404 individuals, and 2,290 EDSS observations) included a nonlinear function of time since onset. Measurement error decreased over time and ad hoc methods reduced autocorrelation and the effect of relapse. Replication within the BCMS cohort (978 individuals and 7,335 EDSS observations) led to a model with similar time (years) coefficients, time [0.22 (95% confidence interval {CI}: 0.19, 0.26), 0.16 (95% CI: 0.10, 0.22)] and log time [-0.13 (95% CI: -0.39, 0.14), -0.15 (95% CI: -0.70, 0.40)] for BCMS and UoWMS, respectively. CONCLUSION: It is possible to develop robust models of disability progression for chronic disease. However, explicit validation is important given the complex methodological challenges face

    Magnetic resonance imaging detects significant sex differences in human myocardial strain

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    <p>Abstract</p> <p>Background</p> <p>The pathophysiology responsible for the significant outcome disparities between men and women with cardiac disease is largely unknown. Further investigation into basic cardiac physiological differences between the sexes is needed. This study utilized magnetic resonance imaging (MRI)-based multiparametric strain analysis to search for sex-based differences in regional myocardial contractile function.</p> <p>Methods</p> <p>End-systolic strain (circumferential, longitudinal, and radial) was interpolated from MRI-based radiofrequency tissue tagging grid point displacements in each of 60 normal adult volunteers (32 females).</p> <p>Results</p> <p>The average global left ventricular (LV) strain among normal female volunteers (n = 32) was significantly larger in absolute value (functionally better) than in normal male volunteers (n = 28) in both the circumferential direction (Male/Female = -0.19 ± 0.02 vs. -0.21 ± 0.02; p = 0.025) and longitudinal direction (Male/Female = -0.14 ± 0.03 vs. -0.16 ± 0.02; p = 0.007).</p> <p>Conclusions</p> <p>The finding of significantly larger circumferential and longitudinal LV strain among normal female volunteers suggests that baseline contractile differences between the sexes may contribute to the well-recognized divergence in cardiovascular disease outcomes. Further work is needed in order to determine the pathologic changes that occur in LV strain between women and men with the onset of cardiovascular disease.</p
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