Measuring the Impacts of US Export Promotion Program for Wheat in Selected Importing Regions

We examine the impacts of major factors affecting the export demand of wheat with a special focus on the impacts of export promotion programs on US wheat. Study results show negative impacts of own-price and real exchange rate on export demand of wheat, while the real GDP, price of corn, and export promotion expenditure had positive and significant impacts. The per dollar returns to wheat export promotion expenditures were $1.49,$0.42, and $2.01 for Middle East, Pacific Rim, and Mexico, respectively.International Relations/Trade,

A 3D topological insulator quantum dot for optically controlled quantum memory and quantum computing

We present the model of a quantum dot (QD) consisting of a spherical core-bulk heterostructure made of 3D topological insulator (TI) materials, such as PbTe/Pb$_{0.31}$Sn$_{0.69}$Te, with bound massless and helical Weyl states existing at the interface and being confined in all three dimensions. The number of bound states can be controlled by tuning the size of the QD and the magnitude of the core and bulk energy gaps, which determine the confining potential. We demonstrate that such bound Weyl states can be realized for QD sizes of few nanometers. We identify the spin locking and the Kramers pairs, both hallmarks of 3D TIs. In contrast to topologically trivial semiconductor QDs, the confined massless Weyl states in 3D TI QDs are localized at the interface of the QD and exhibit a mirror symmetry in the energy spectrum. We find strict optical selection rules satisfied by both interband and intraband transitions that depend on the polarization of electron-hole pairs and therefore give rise to the Faraday effect due to Pauli exclusion principle. We show that the semi-classical Faraday effect can be used to read out spin quantum memory. When a 3D TI QD is embedded inside a cavity, the single-photon Faraday rotation provides the possibility to implement optically mediated quantum teleportation and quantum information processing with 3D TI QDs, where the qubit is defined by either an electron-hole pair, a single electron spin, or a single hole spin in a 3D TI QD. Remarkably, the combination of inter- and intraband transition gives rise to a large dipole moment of up to 450 Debye. Therefore, the strong-coupling regime can be reached for a cavity quality factor of $Q\approx10^{4}$ in the infrared wavelength regime of around $10\:\mu$m.Comment: 19 pages, 11 figures, RevTe

FORECASTING IRRIGATION WATER DEMAND: A STRUCTURAL AND TIME SERIES ANALYSIS

An expected utility model was developed to capture the impacts of wealth, other economic, and institutional factors on irrigation acreage allocation decisions. Predicted water demand is derived from an expected utility structural model and various ARIMA models. No significant differences arise between forecasted irrigation acreage and, thereby, amount of forecasted water demand between econometric and time series models. However, estimates of water demand differ significantly from a Blaney-Criddle-based physical model. Keywords: water forecasting, acreage response, water slippage, BC formulawater forecasting, acreage response, water slippage, BC formula, Land Economics/Use, Resource /Energy Economics and Policy,

UPSTREAM EFFECTS OF GENERIC ADVERTISING: THE CASE OF CATFISH

Muth's model is adapted to determine the effects of generic advertising on upstream factor markets in a competitive industry where funds for promotion are raised through a feed tax. Optimality conditions indicate that a feed tax is an inferior funding mechanism. That is, the resulting promotion budget, in general, is too small to maximize producer surplus at the farm level. Applying the model to the U.S. catfish industry, results suggest that raising the feed tax from $5 to$6 per ton is welfare increasing for farm, feed, and non-feed sectors alike. Distributional analysis suggests that the processing sector captures most of the long-term benefits (51%), followed by the non-feed sector (42%). Despite the feed sector's modest share of total benefits (7%), owing to tax shifting its long-run benefit-cost ratio (1.8:1) is favorable. Because feed and non-feed inputs are gross substitutes, the feed tax generates a positive externality for non-feed suppliers. Accounting for this externality raises the non-feed sector's net benefit by 36%. Overall, about one-half of the program's long-term net benefits accrue to input suppliers.Resource /Energy Economics and Policy,

MEETING THE KYOTO TARGET THROUGH CONSERVATION TILLAGE AND ITS IMPLICATION FOR NATURAL CAPITAL MAINTENANCE, PRODUCTION EFFICIENCY, AND SUSTAINABILITY

According to Article 3.4 of the Kyoto Protocol, agricultural soil could be used as a sink for carbon sequestration and hence it may provide an alternative venue to sequester the greenhouse gas emission. US plans to reduce the carbon emission amount by seven percent below the 1990 level within the target date of 2008-2012. The major approaches to achieve the goal targeted by Kyoto Protocol in US are through fossil fuel tax and increasing forest area by afforestation. This means fossil fuel price will increase which will have a direct impact to conventional tillage cost. As a result farmers would be motivated to use less machinery operation in farming and hence may use conservation tillage in farming practices. Rather than cause and effect relationship created by fuel price increase, conservation tillage itself has been considered as a method suggested to increase carbon sequestration. We analyze the economic and environmental roles of conservation tillage in carbon sequestration. The use of conservation tillage helps to sequester carbon in the form of soil organic matter. We examined the potential of conservation tillage in sequestering carbon and its role in increasing soil natural capital and thus the productivity of soil. We then used the concept of production efficiency to calculate the benefits of soil carbon sequestration using sustainability criteria. The detail of carbon sequestration and soil natural capital buildup were demonstrated using conservation tillage practiced in cotton production in Georgia. Four systems of conservation tillage encompassing both chemical and organic source of plant nutrients were compared for their capacity to sequester carbon. Organic matter buildups were faster in a system with conservation tillage and organic sources of nutrient compared to conventional tillage. Result indicated that in a system with a slow buildup of natural capital, production efficiency was not significant. This has resulted the system to be unprofitable in the short run and unsustainable in the long run. The system with a high amount of organic matter increases the production efficiency of applied inputs and also plays an important role in substituting chemical fertilizers. Alternative tillage management systems were evaluated for their sustainability using total factor productivity. It was found that conservation tillage meets criteria of sustainability more often than the management system containing conventional tillage. Conservation tillage was found to be the best alternative not only to sequester carbon but also developing natural capital-based sustainable system.Kyoto protocol, Carbon sequestration, Natural capital, Production efficiency, Sustainability, Environmental Economics and Policy, Productivity Analysis,