2,166 research outputs found

    Impact of Biofuel Industry Expansion on Grain Utilization and Distribution: Preliminary Results of Iowa Grain and Biofuel Survey

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    This paper examines the impact of biofuel expansion on grain utilization and distribution at the state and cropping district level as most of grain producers and handlers are directly influenced by the local changes. We conducted a survey to understand the utilization and flows of corn, ethanol and its co-products, such as dried distillers grains (DDG) in Iowa. Results suggest that the rapidly expanding ethanol industry has a significant impact on corn utilization in Iowa. Comparing to the earlier survey results, ethanol plants drew a considerable amount of corn away from traditional destination markets, such as feeders or export markets. A major portion of corn supplies came from in-state sources, while the sales of Iowa ethanol and DDG were dominated by out-of-state buyers.biofuel, grain, utilization, Marketing,

    Quantum anomalous Hall states in the pp-orbital honeycomb optical lattices

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    We study the quantum anomalous Hall states in the pp-orbital bands of the honeycomb optical lattices loaded with the single component fermions. Such an effect has not been realized in both condensed matter and cold atom systems yet. By applying the available experimental technique developed by Gemelke \textit{et al.} to rotate each lattice site around its own center, the band structures become topologically non-trivial. At a certain rotation angular velocity Ω\Omega, a flat band structure appears with localized eigenstates carrying chiral current moments. With imposing the soft confining potential, the density profile exhibits a wedding-cake shaped distribution with insulating plateaus at commensurate fillings. Moreover, the inhomogeneous confining potential induces dissipationless circulation currents whose magnitudes and chiralities vary with the distance from the trap center. In the insulating regions the Hall conductances are quantized, and in the metallic regions the directions and magnitudes of chiral currents cannot be described by the usual local-density-approximation. The quantum anomalous Hall effects are robust at temperature scales small compared to band gaps, which increases the feasibility of experimental realizations.Comment: 15 pages, 13 figure

    Mitigating Land Use Changes From Biofuel Expansion: An Assessment of Biofuel Feedstock Yield Potential in APEC Economies

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    The emerging biofuel sector has drawn great interest as an alternative source of fuel for transportation. The expansion of biofuels greatly impacts world agricultural markets, since currently, the primary feedstocks for ethanol and biodiesel production are field crops and their derived products. There is great interest in the potential of countries to expand their biofuel sectors through increased production of feedstocks. The long-term potential for developing first-generation biofuels in many countries depends on a large and constant supply of feedstocks. This may be achieved in two ways: land extensification and/or land intensification. However, expansion of land area comes with a number of environmental challenges highlighted by the recent debate on indirect land use change brought about by biofuel expansion (Searchinger et al., 2008; Fargione et al., 2008). Therefore, land intensification through yield growth, and production of second-generation biofuel feedstocks, such as crop residues and perennial grass on marginal land, are generally seen as critical factors for sustainable development of biofuels as well as mitigation of land use changes. In this context, it is essential to gain a better understanding of the yield trends and the future yield potential of biofuel feedstocks to help determine the impact of biofuel expansion on agricultural markets. Therefore, the aim of this analysis is to review and analyze historical and projected trends of crop yields, particularly for crops used in biofuel production. One of our major interests is the impact of crop prices on yields in the long run, given that the increased production of biofuels from crops has created a perceived permanent increase in crop prices. Based on this analysis, we draw conclusions regarding the yield potential of biofuel feedstocks. We focus our analysis on APEC economies because of their rapidly growing interest in biofuel development and the diversified agricultural production among member countries. Comparing average annual growth in crop yields across APEC economies and across crops, we find that the crop yield growth rates vary significantly. Corn ranks among the crops with the largest yield improvement in a significant number of the APEC economies, mostly due to increased fertilizer use and biotechnology. The analysis also reveals that sugarcane yields have been fairly stable with the exception of significant growth in China, Philippines and Thailand. One of the highest soybean yields is seen in the United States, which is a major producer. Soybean yields in China and Indonesia are lower relative to the United States, but show much lower variability over time. In the past decade, palm oil yields have increased dramatically in Indonesia. Further analysis reveals that an economy, like the United States, which already has high yield levels for the majority of crops, experiences relatively lower yield growth rates relative to other economies. On the other hand, economies like Philippines and Malaysia have relatively lower corn yields but high yield growth rates, which indicate a higher potential for increasing crop production through yield increases rather than land expansion. Yield growth rates for most crops in most APEC economies fall in the lower to medium range although there is significant variance in yields among the economies. This variation could be due to the fact that some economies have adopted mechanization and new technologies in their crop production, whereas other economies rely heavily on labor and basic inputs. Hence, economies with high technical advantage have the potential to improve crop yields by continuous development in biotechnology. In contrast, economies with less technological resources may enhance crop yields through increasing input utilization including more capital intensive inputs. We also compute yield elasticities with respect to a time trend variable for the major crops in APEC economies. For most but not all APEC economies, the coefficient estimates are statistically significant. There is wide variation in the magnitude of the elasticities among economies and crops, some even with a negative elasticity. When comparing among crops, we see that corn yields show relatively higher elasticities with respect to time trend. Across APEC economies, China shows consistent yield response over time for all crops. Across crops, sorghum has the highest elasticity in China, corn in the Philippines, sugar beet in Canada, wheat in New Zealand, rice in Indonesia, and sugarcane in Malaysia. In addition to the increased production in primary crops, yield growth would also translate to an increase in available crop residues. According to Milbrandt and Overend (2008), ethanol from currently available crop residues could potentially displace about 33% of gasoline consumption in the APEC region, assuming that cost-competitive technologies for production of ethanol from second-generation lignocellulosic feedstocks can be deployed. Thus, given average yield growth projections for certain crops in APEC economies, our calculations show that the United States could potentially displace an additional 2% of gasoline from corn residue, Australia an additional 9% of gasoline from wheat residue, and Thailand an additional 3.5% from sugarcane residue, without increasing land for biofuel production. The analysis concludes that in terms of first-generation biofuels, yield growth is imperative for the long-term potential of biofuel expansion if land extensification is to be minimized. Biofuel expansion may imply increased land use for feedstock production in the medium term, but growth in feedstock yields will tend to mitigate the impact on crop prices and land use over the longer term. Additionally, long-term expansion of biofuels may have to rely on the economic viability of production from lignocellulosic feedstocks. Based on the data analysis, APEC economies have the capability and the capacity to increase feedstock yields for biofuel production, particularly the economies that have relatively lower yield levels and are further away from their yield plateau levels. However, this requires targeting yield-enhancing activities including investments in agricultural R&D, better farm practices, and increased input use. Some of the practices that already have resulted in yield improvements in some countries, such as extension services and fertilizer subsidies, could be transferred to other economies. Countries could also provide incentives, such as tax reductions or government payments, which have proven to be successful in inducing farmers to invest in yield-improving technologies. However, it is crucial that each economy should identify its own advantage in terms of productivity improvements for its agricultural commodities. To achieve yield growth, countries should create an environment conducive to technological change and diffusion of new technology through public R&D and incentives for private R&D investments. References: Fargione, J., J. Hill, D. Tilman, S. Polasky, and P. Hawthorne. 2008. “Land Clearing and the Biofuel Carbon Debt”, Science, February 29: 1235-1238. Milbrandt, A. and R.P. Overend. 2008. “Survey of Biomass Resource Assessments and Assessment Capabilities in APEC Economies.” Energy Working Group, Asia-Pacific Economic Cooperation, APEC# 208-RE-01.9. Searchinger, T., R. Heimlich, R. Houghton, F. Dong, A. Elobeid, J. F. Fabiosa, S. Tokgoz, D. J. Hayes, T. Yu. 2008. “Factoring Greenhouse Gas Emissions from Land Use Change into Biofuel Calculations”, Science, February 29:1238-1240.biofuels, yield growth, APEC, Land Economics/Use, Productivity Analysis,

    Evaluating the Production and Price Impacts of Biotechnology Application in Crop Markets

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    Biotechnology crop traits have been applied on a widespread commercial global basis since 1996, making it the most rapidly adopted crop technology in agriculture. The primary biotechnologies used have included technology delivering herbicide tolerance and insect resistance for crops, such as corn, soybeans, cotton, and canola. This technology has provided farmers with productivity improvements through a combination of yield improvements and cost reductions. Thus, this technology has had an impact on prices of cereals and oilseeds (and their derivatives) both in countries where biotech traits were applied and in the global market. Realizing the surging significance of biotechnology application in global crop markets, this study first summarizes the productivity impacts of biotech crops on production; secondly, aims to quantify the impact of the use of biotech traits on production, utilization and prices of corn, soybeans, and canola as well as other crops where the biotechnology is not utilized.biotech crops, prices, yield, soybeans, corn, canola, partial-equilibrium model, price effects, Demand and Price Analysis, Productivity Analysis,

    Next-to-leading-order corrections to exclusive processes in kTk_T factorization

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    We calculate next-to-leading-order (NLO) corrections to exclusive processes in kTk_T factorization theorem, taking πγγ\pi\gamma^*\to\gamma as an example. Partons off-shell by kT2k_T^2 are considered in both the quark diagrams from full QCD and the effective diagrams for the pion wave function. The gauge dependences in the above two sets of diagrams cancel, when deriving the kTk_T-dependent hard kernel as their difference. The gauge invariance of the hard kernel is then proven to all orders by induction. The light-cone singularities in the kTk_T-dependent pion wave function are regularized by rotating the Wilson lines away from the light cone. This regularization introduces a factorization-scheme dependence into the hard kernel, which can be minimized in the standard way. Both the large double logarithms ln2kT\ln^2k_T and ln2x\ln^2 x, xx being a parton momentum fraction, arise from the loop correction to the virtual photon vertex, the former being absorbed into the pion wave function and organized by the kTk_T resummation, and the latter absorbed into a jet function and organized by the threshold resummation. The NLO corrections are found to be only few-percent for πγγ\pi\gamma^*\to\gamma, if setting the factorization scale to the momentum transfer from the virtual photon.Comment: 13 pages; version to appear in Physical Review
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