HOW COMPETITIVE IS THE WORLD WHEAT MARKET?

Japan is one of the largest importers of wheat in the world, with imports originating from three countries, Australia, Canada, and the United States. Australia, Canada, and Japan all use a government single-desk agency to control wheat trade. Many previous studies on competition in the world grain trade have argued the market is imperfectly competitive, and they often point to the Japanese market. We study the Japanese wheat import market for this reason, but find no compelling evidence of imperfect competition.wheat trade, competition, Crop Production/Industries, International Relations/Trade, F14, L10, Q17,

Metal Distributions, Efficient n-Type Doping, and Evidence for in-Gap States in TiNiM_<i>y</i>Sn (M = Co, Ni, Cu) half-Heusler Nanocomposites

XNi1+ySn nanocomposites consisting of a XNiSn half-Heusler (HH) matrix with segregated XNi2Sn Full Heusler (FH) inclusions promise improvements in thermoelectric efficiencies. We extend recent research by reporting on TiNiMySn (0 ≤ y ≤ 1) nanocomposites with M = Co (3d9), Ni (3d10) and Cu (3d104s1). Neutron powder diffraction reveals that the Ni and Cu series produce a matrix of TiNiSn with nanosegregated TiNi2Sn and TiNi1+dCu1–dSn, respectively. For the Co series, the Co inserts into both phases to obtain a TiNi1–yCoySn matrix with nanosegregated TiNi2–yCoySn. Systematic changes in Seebeck coefficient (S) and electrical resistivity (ρ) are observed in all three series. For M = Ni, changes in S and ρ are attributed to in-gap states arising from the nanosegregation. The M = Co composites show a complex interplay between the hole doped TiNi1–yCoySn matrix and similar in-gap states, where the p- to n-type transition temperature increases but the maximum S remains unchanged at +30 μV K–1. The 4s1 electron for M = Cu is delocalized in the HH matrix, leading to metal-like ρ(T) and up to 100% improved thermoelectric power factors compared to TiNiSn (S2/ρ = 2 mW m–1 K–2 at 600–700 K for y = 0.025). These results broaden the range of segregated FH phases that could be used to enhance HH thermoelectric performance

Influence of thickness and interface on the low-temperature enhancement of the spin Seebeck effect in YIG films

The temperature dependent longitudinal spin Seebeck effect (LSSE) in heavy metal (HM)/Y3Fe5O12 (YIG) hybrid structures is investigated as a function of YIG film thickness, magnetic field strength, and different HM detection material. The LSSE signal shows a large enhancement with reducing the temperature, leading to a pronounced peak at low temperatures. We find the LSSE peak temperature strongly depends on the film thickness as well as on the magnetic field. Our result can be well explained in the framework of magnon-driven LSSE by taking into account the temperature dependent effective propagation length of thermally excited magnons in bulk. We further demonstrate that the LSSE peak is significantly shifted by changing the interface coupling to an adjacent detection layer, revealing a more complex behavior beyond the currently discussed bulk effect. By direct microscopic imaging of the interface, we correlate the observed temperature dependence with the interface structure between the YIG and the adjacent metal layer. Our results highlight the role of interface effects on the temperature dependent LSSE in HM/YIG system, suggesting that the temperature dependent spin current transparency strikingly relies on the interface conditions

Impact of randomly distributed dopants on Ω-gate junctionless silicon nanowire transistors

This paper presents experimental and simulation analysis of an Ω-shaped silicon junctionless nanowire field-effect transistor (JL-NWT) with gate lengths of 150 nm and diameter of the Si channel of 8 nm. Our experimental measurements reveal that the ON-currents up to 1.15 mA/μm for 1.0 V and 2.52 mA/μm for the 1.8-V gate overdrive with an OFF-current set at 100 nA/μm. Also, the experiment data reveal more than eight orders of magnitude ON-current to OFF-current ratios and an excellent subthreshold slope of 66 mV/dec recorded at room temperature. The obtained experimental current-voltage characteristics are used as a reference point to calibrate the simulations models used in this paper. Our simulation data show good agreement with the experimental results. All simulations are based on drift-diffusion formalism with activated density gradient quantum corrections. Once the simulations methodology is established, the simulations are calibrated to the experimental data. After this, we have performed statistical numerical experiments of a set of 500 different JL-NWTs. Each device has a unique random distribution of the discrete dopants within the silicon body. From those statistical simulations, we extracted important figures of merit, such as OFF-current and ON-current, subthreshold slope, and voltage threshold. The performed statistical analysis, on samples of those 500 JL-NWTs, shows that the mean ID-VGs characteristic is in excellent agreement with the experimental measurements. Moreover, the mean ID-VGs characteristic reproduces better the subthreshold slope data obtained from the experiment in comparison to the continuous model simulation. Finally, performance predictions for the JL transistor with shorter gate lengths and thinner oxide regions are carried out. Among the simulated JL transistors, the configuration with 25-nm gate length and 2-nm oxide thickness shows the most promising characteristics offering scalable designs

High resolution structural characterisation of laser-induced defect clusters inside diamond

Laser writing with ultrashort pulses provides a potential route for the manufacture of three-dimensional wires, waveguides and defects within diamond. We present a transmission electron microscopy (TEM) study of the intrinsic structure of the laser modifications and reveal a complex distribution of defects. Electron energy loss spectroscopy (EELS) indicates that the majority of the irradiated region remains as $sp^3$ bonded diamond. Electrically-conductive paths are attributed to the formation of multiple nano-scale, $sp^2$-bonded graphitic wires and a network of strain-relieving micro-cracks

THE URUGUAY ROUND AGREEMENT ON AGRICULTURE: AN EVALUATION

Contact for this paper: Laura Bipes/University of Minnesota/Department of Applied Economics/ 1994 Buford Avenue./ St. Paul, MN 55108 USA. From the start, agriculture played a central role in the Uruguay Round of GATT trade negotiations. The Punta del Este Declaration called for a solution to the problems facing agricultural trade through modified trade rules and an agreement to lower protection levels. It was recognized that such an improvement implied negotiations on the national farm policies as well as just trade policies. The time that it took to reach agreement reflected the political sensitivity and technical complexity of this task. The Agreement embodied in the Final Act of the Uruguay Round breaks new ground for agriculture, and takes a big step towards placing this sector of world trade under rules more consistent with those in operation in other areas. However, the degree of liberalization of markets is modest, and much remains to be done in future rounds of negotiations. The most far-reaching element in the Agreement is a change in the rules regarding market access. With very few exceptions, all participating countries have agreed to convert all existing non-tariff barriers (along with unbound tariffs) into bound duties and not to introduce new non-tariff measures. Negotiations agreed to reduce these new bound tariffs, as well as tariffs already bound earlier, according to Schedules included as a part of the Agreement. "Tariffication" will impose changes in import policies for a number of countries. Canada will replace import quotas for dairy and poultry products with tariffs, initially at a high level. The European Union will replace its variable levy with tariffs, though a maximum duty-paid price for cereals has been negotiated which puts a limit on the tariff charged. Latin American countries have generally engaged in tariffication in recent years in advance of the Uruguay Round Agreement: for these, and other countries their tariffs will now be bound. The US will forgo the use of Section 22 import quotas and the negotiation of voluntary export restraint agreements with beef suppliers, but the impact on these markets is likely to be small. Japan and Korea have been allowed to delay tariffication in the case of rice for the next few years. The Agreement provides in cases of tariffication for "minimum access opportunities", to guard against the impact of high initial tariff rates. This will open up reduced-tariff quotas for a number of products including beef, cereals and fruits and vegetables. The quotas will be expanded to about 5 percent of consumption over the 6 year period. Japan and Korea have agreed to a greater expansion of market access for rice in compensation for the delay in introducing tariffs. The ability of countries to control export subsidies in agricultural markets was one of the main issues under discussion in the negotiation. Under the Agreement, countries accept commitments on reducing expenditure on export subsidies as well on the quantity of subsidized exports. This will limit export subsidies by the EU and other countries, for such products as wheat, dairy products and beef, and should lead to firmer world market prices in these commodities. These quantities are also expressed in the Schedules which form part of the Agreement. Countries have also agreed not to apply export subsidies to commodities not subsidized in the base period. The Agreement also sets rules and commitments for domestic support policies. It defines a set of policies which are deemed to be less trade-distorting than others, and allocates them to a "green box" which is broadly immune to challenge. Other policies not sheltered in this way are subject to reduction through a limit on the total support given by domestic subsidies and administered prices. It was decided that neither the U.S. deficiency payments (under current legislation) nor the new hectarage compensation payments under the reformed Common Agricultural Policy of the EU need to be reduced. It was also agreed that subsidies that conform to the new rules are sheltered from international challenge under the GATT. Developing Countries generally face less stringent commitments, having 10 years rather than six to make the changes, and having to meet only two-thirds of the reduction targets. In addition, development policies are included broadly in the "green box". Along with the provisions on domestic and trade policies in the Agreement, participants also concluded an Agreement on Sanitary and Phytosanitary Measures (SPS Agreement). The goal was to make it easier to distinguish between genuine health and safety issues and disguised protection. The right of countries to set their own safety and health standards is reaffirmed, but with the provision that such standards should be based on scientific justification and that use be made of international standards where possible. The extent to which the Agreement will lead to greater market access, curb export subsidies and modify domestic policies in the next few years can only be determined from a detailed inspection of the Schedule of commitments made by the individual countries. Paradoxically, the immediate impact on national policies is likely in most cases to be small. Many countries have been engaged in a process of reducing government support to agriculture, and making such support more closely targetted to needs, in advance of the outcome of the Round. Policy reforms in the EU, Canada, Sweden, Australia and New Zealand, along with much of Latin America, have been strongly influenced by the negotiations in the Uruguay Round. The Agreement thus takes on the task of supporting and locking-in such reforms, and encouraging them in other countries. In some aspects the Agreement falls short of expectations (or at least initial demands). It does not constitute a major move toward free trade in agricultural products: the cost of changing the rules has been to give up some degree of liberalization. The tariffs which countries will impose in place of non-tariff barriers are in many cases so high that trade will be restricted to the agreed access quantities. Export subsidy programs will continue though at a reduced level. The major pressure to reinstrument farm policies will continue to be from domestic budget constraints. It will take further rounds of negotiations to reduce protection in agricultural markets to a level comparable to that for most manufactured products. However, with the rule changes and the new types of country commitments agreed, a much more promising basis bas been created for future negotiations.International Relations/Trade,

Synthesis of H_xLi_1-xLaTiO₄ from quantitative solid-state reactions at room temperature

The layered perovskite HLaTiO4 reacts stoichiometrically with LiOH·H2O at room temperature to give targeted compositions in the series HxLi1-xLaTiO4. Remarkably, the Li+ and H+ ions are quantitatively exchanged in the solid state and this allows stoichiometric control of ion exchange for the first time in this important series of compounds

Symmetry reduction and shape effects in concave chiral plasmonic structures

Chiral metamaterials have shown a number of interesting properties which result from the interaction of the chiral near-field they produce with light and matter. We investigate the influence of structural imperfections on the plasmonic properties of a chiral gold “gammadion”, using electron energy loss spectroscopy to directly inform simulations of realistic, imperfect structures. Unlike structures of simple convex geometry, the lowest energy modes of the ideal concave gammadion have a quadrupole and dipole character, with the mode energies determined by the nature of electrostatic coupling between the gammadion arms. These modes are strongly affected by structural imperfections that are inherent to the material properties and lithographic patterning. Even subwavelength-scale imperfections reduce the symmetry, lift mode degeneracies convert dark modes into bright ones and significantly alter the mode energy, its near-field strength, and chirality. Such effects will be common to a number of multitipped concave structures currently being investigated for the chiral fields they support

How Competitive is the World Wheat Market?

Japan is one of the largest importers of wheat, with imports originating from three countries, Australia, Canada, and the United States. Australia, Canada and Japan all use a government single-desk agency to control wheat trade. Many previous studies on competition in the world grain trade have argued the market is imperfectly competitive, and they often point to the Japanese market. We study the Japanese wheat import market for this reason, but find no compelling evidence of imperfect competition on the exporters’ side

Designing a fully compensated half-metallic ferrimagnet

Recent experimental work on Mn2RuxGa demonstrates its potential as a compensated ferrimagnetic half-metal (CFHM). Here we present a set of high-throughput ab initio density functional theory calculations and detailed experimental characterisation, that enable us to correctly describe the nominal Mn2RuxGa thin films, in particular with regard to site-disorder and defects. We then construct models that accurately capture all the key features of the Mn-Ru-Ga system, including magnetic compensation and the spin gap at the Fermi level. We find that electronic doping is neccessary, which is achieved with a Mn/Ga ratio smaller than two. Our study shows how composition and substrate-induced biaxial strain can be combined to design a ferrimagnetic half-metal with a compensation point close to room temperature