Bayesian Estimation and Selection of Nonlinear Vector Error Correction Models: The Case of the Sugar-Ethanol-Oil Nexus in Brazil

Nonlinear adjustment toward long-run price equilibrium relationships in the sugar-ethanol-oil nexus in Brazil is examined. We develop generalized bivariate error correction models that allow for cointegration between sugar, ethanol, and oil prices, where dynamic adjustments are potentially nonlinear functions of the disequilibrium errors. A range of models are estimated using Bayesian Monte Carlo Markov Chain algorithms and compared using Bayesian model selection methods. The results suggest that the long-run drivers of Brazilian sugar prices are oil prices and that there are nonlinearities in the adjustment processes of sugar and ethanol prices to oil price but linear adjustment between ethanol and sugar prices.     

Long‐Run Drift,Co‐Movement and Persistence in Real Wheat and Maize Prices

Trends in real prices for food commodities are both important and controversial. Paying particular attention to issues of methodology, this paper assesses the evidence for a downward drift in the real prices of wheat and maize. It is found that the apparent strength of that evidence depends substantially on whether the time series generating models are taken to be trend‐stationary or difference‐stationary, and on whether allowance is made, through incorporation of dummy variables in the models, for events in one or two extreme years. Once dummy variables are incorporated, we find little evidence against difference‐stationarity. The analysis then proceeds, through tests for cointegration, to the construction of error‐correction models linking the two prices and to the estimation of persistence of shocks in this bivariate framework. The paper presents modest evidence for downward drift in real grain prices of about 1 to 1.5 per cent per annum, shows that wheat and maize prices cointegrate and estimates that direct and cross‐persistence measures take values of less than unity.     

Basis Pricing, Futures-Cash Price Transmission and Appropriate Hedge Ratios: The Case of the Soybean Market in Ontario

The academic literature on the determination of risk-minimizing hedge ratios has apparently ignored the potential impact that the pricing strategies adopted by the grain elevators may have on the futures-cash price transmission, and therefore on the determination of the correct hedge ratio. This paper addresses this problem from a theoretical perspective, and then develops a model that is applied to the soybean market in Chatham, Ontario.
La littérature académique concernant la détermination des ratios de couverture à terme minimisant le risque a apparemment ignoré l'impact potential des stratégies des faiseurs de prix sur un marché sur la relation entre les prix spot et les prix à terme. II est possible que de ce fait ces stratégies influencent également la détermination du vrai ratio de couverture. Ce papier traite ce problème d'un point de vue théorique, puis vérifie ces résultats en les appliquant au cas du marché du soja à Chatham, Ontario.     

玉米在山西的传播引种及其经济作用

玉米在明代晚期即已传入山西，但直到光绪年间，玉米才在山西得到普遍种植。本文通过对山西与相邻各省在玉米引种时间上的比较分析，对山西各县区玉米别称的来源及玉米传入山西的途径和时间做了比较详细的梳理归纳，进而指出玉米这种高产作物对山西社会经济发展所起的促进作用。     

Estimating Investment Rigidity within a Threshold Regression Framework: The Case of U.S. Hog Production Sector

This article addresses the issues of investment/disinvestment asymmetry and a possible existence of a sluggish regime in the demand for a quasi-fixed input in the U.S. hog production sector. Adopting a new threshold estimation procedure, quarterly data from 1970 through 2002 are used to estimate a regime-dependent investment demand equation for a quasi-fixed input, taking sows as a proxy. The results support the existence of three regimes over alternative specifications precluding the sluggish regime, confirming the existence of asset fixity in hog production. The results also highlight the importance of accounting for investment rigidity when estimating hog supply and variable input demands.     

The Market Structure and Price Competition in China's Wheat Import Market:

This paper reveals that wheat exporters to China compete in an imperfectly competitive market. U.S. wheat exports face strong price competition from Argentina, Australia, Canada, and the European Community, but has a highly elastic demand in China. By adopting an aggressive promotion policy, the U.S. could reduce the market shares of Argentina and Canada. China would shift to wheat from Argentina, Australia, and Canada if U.S. wheat exports were interrupted because of high prices or non-price trade frictions. An expansion in China's wheat imports would accrue to wheat from Argentina and the U.S.     

Evaluating Alternative Policy Responses to Higher World Food Prices: The Case of Increasing Rice Prices in Madagascar

Higher world food prices have led many developing countries to adopt policies to mitigate the impact on low-income households. This article sets out a partial equilibrium framework to evaluate the efficiency, distributional, and revenue implications of alternative policy responses. The model is applied to evaluate tariff reductions and targeted transfers in Madagascar. Although lowering tariffs generates substantial efficiency gains, these accrue mainly to the top half of the welfare distribution, and poor net sellers are actually worse off. Developing a system of targeted direct transfers to poor households is likely to be a substantially more cost-effective approach to poverty alleviation.     

Protection, Price Discrimination and Inefficient Trade: The Case for Real Tariffication

The recent WTO dispute settlement panel ruled that Canada's current price pooling system for milk subsidizes exports in excess of Canada's 1994 GATT commitments. Policy reform must be undertaken. High domestic and low export prices are a combination favored by dairy producers and will likely continue. We believe that the system will evolve toward a pure price discrimination scheme, which would have the advantages of inducing lower exports and raising profits. We analyze trade liberalization by comparing tariff reductions to enlargements in minimum access commitments (MACs) when domestic production is controlled by a profit-maximizing state enterprise, which may or may not control imports. Even if we fail to account for administrative problems of MACs (e.g., choice of importers, punishment for noncompliance), MACs are inferior to tariffs because they promote inefficient trade. A state trader that would import under free trade has a tendency to export more under MACs than under tariffs. Because we assume that MACs must be filled, exporting is done to protect the high-price domestic market. Le comité de règlement des différends de l'OMC a statué il y a quelques années que le système actuel de mise en commun des prix du lait appliqué par le Canada subventionne les exportations au-delà des engagements pris au GATT en 1994. Une réforme structurale s'impose. Prix intérieurs élevés et faibles prix à l'exportation constituent la combinaison préférée des producteurs laitiers et, pour cette raison, appelée à se maintenir. À notre avis, le système évoluera vers un régime pur et simple de double prix, lequel aurait l'avantage à la fois de décourager l'exportation et de hausser les profits. Nous analysons les impacts de la libéralisation des échanges intemationaux en comparant la réduction de tarifs douaniers aux élargissements des engagements d'accès minimum (EAM), lorsque la production intérieure est contrôleépar une société d'État axée sur la maximisation des bénéfices, et nantie ou non de droits de regard sur les importations. Même en faisant abstraction des problèmes administratifs des EAM touchant, notamment, le choix des importateurs, les pénaltiés de non-conformité, les EAM sont inférieurs aux tarifs douaniers parce qu'ils créent des situations inefficientes dans les échanges extérieurs. Une société d'État qui importe sur le marché libre aura tendance à exporter davantage en régime de EAM qu‘en régime de tarifs douaniers. Comme nous présupposons que les EAM sont là pour être pleinement utilisés, le but de l'exportation est alors de protéger le niveau lucratif des prix sur le marché intérieur.     

Price Dynamics in a Vertical Sector: The Case of Butter

We develop a reduced-form model of price transmission in a vertical sector, allowing for refined asymmetric, contemporaneous and lagged, own and cross-price effects under time-varying volatility. The model is used to investigate the wholesale-retail price dynamics in the U.S. butter market. The analysis documents the nature of nonlinear price dynamics in a vertical sector. It finds strong evidence of asymmetric retail price responses, both in the short term and the longer term, but only weak evidence of asymmetric wholesale price responses. Asymmetric retail responses play a major role in generating a skewed distribution of butter prices. The empirical results indicate the presence of imperfect competition at the retail level.     

2009年国际粮价情况及2010年走势分析

2009年,在各国大规模的经济刺激政策影响下,全球经济从上年金融危机中复苏,国际主要大宗商品价格普遍上扬,但国际市场粮价却走出与其他商品完全不同的走势,分析个中原因,并对后危机时代粮价走势作出判断,具有重要意义。具体来看,今后一段时间,国际粮食市场供需关系将有所改善,国际粮价底部运行期即将完成,但高库存、低贸易将抑制涨幅,预计国际粮价将呈先稳后升走势。     

Wheat Policy Options in Sub-Saharan Africa: The Case of Zimbabwe

Like many countries in sub-Saharan Africa, Zimbabwe is experiencing rapid growth in wheat consumption and imports. Policy makers in Zimbabwe and elsewhere must decide whether increased domestic wheat production might reduce dependency on imports and at the same time contribute to economic efficiency and food security goals. The domestic resource cost framework was used to assess Zimbabwe's comparative advantage among six major irrigated crops and to measure the effects of current government policies on producer incentives. The results indicate that irrigated wheat production represents an efficient use of Zimbabwe's resources during times of abundant rainfall, but the nation enjoys a comparative advantage in tobacco, maize, and cotton production during times of water scarcity. Existing agricultural policies provide disincentives for commercial farmers, because private profitability is less than social profitability for the major irrigated crops. However, this tax occurs across all commodities with similar incidence, so that the private incentives among crops are not greatly distorted from their social pattern. Sensitivity analysis confirms the robustness of these findings under a range of possible future economic and political developments. The domestic resource cost approach used in this study provides an operational method for measuring comparative advantage and should be of interest to policy analysts throughout sub-Saharan Africa.     

Rejecting New Technology: The Case of Genetically Modified Wheat

Canada has stringent regulations covering the release of new wheat varieties, but the United States has virtually no regulations in this area. Monsanto Co. developed genetically modified (GM) spring wheat for North America, and made a commitment to the U.S. industry to release this new technology simultaneously in both Canada and the United States, or not at all. The Canadian regulatory bias against new varieties acted as a veto against GM wheat and caused Monsanto to shelve the technology in both countries in 2004. Substantial economic rents were foregone in North America due to the rejection of this new technology.     

地价与房价关系的探讨—江苏省徐州市的实证研究

现有的地价与房价关系研究主要集中于宏观层面,而对房地产市场的区域差异性关注不够.基于2000 2010年徐州市市区的住宅用途地价与房价的相关数据,在理论分析的基础上应用波动分析、协整分析及误差修正模型等计最分析方法,分析了该市地价与房价之间的关系.结果表明:在较长时间尺度上,徐州市市区的地价与房价存在稳定的均衡关系;在较短时间尺度上两者也存在相互影响,但房价的变动对地价的影响更大.     

Dynamic Supply Response and Welfare Effects of Technological Change on Perennial Crops: The Case of Cocoa in Malaysia

Modern biotechnology will generate crops with higher yields and enhanced resistance to pests and diseases. In the case of perennial crops, the age composition of the present stand, the farmers' willingness to invest, and the yield profiles of old and new trees determine the speed of adoption of the new technology and the timing of the effects on supply and demand conditions. We adapt conventional welfare measures to account for these factors in the Assessment of research induced supply shifts. The application to cocoa in Malaysia shows that consumers and adopting producers gain and non-adopters lose. Overall, 72% of the welfare gains go to the consumers.     

On Jumps and ARCH Effects in Natural Resource Prices: An Application to Pacific Northwest Stumpage Prices

Continuous-time models of natural resource prices usually preclude the possibility of large changes (jumps) resulting from unexpected events. To test for the presence of jumps and/or ARCH effects, we combine bounds and the Monte Carlo test technique to obtain finite-sample, level-exact p -values. We apply this methodology to stumpage prices from the Pacific Northwest and find evidence of jumps and ARCH effects. To assess the impact of neglecting jumps on the decision to harvest old-growth timber, we develop an autonomous, infinite-horizon stopping model for which we provide a new method of resolution. Our numerical results show the importance of modeling jumps explicitly.     

城市间相互作用对城市商业用地价格的影响——以江苏省为例

研究目的:研究城市间相互作用对城市商业用地价格的影响。研究方法:在对相关概念和理论进行系统回顾的基础上,以江苏省13个地级市为研究对象,采用多元线性回归方法进行研究。研究结果:(1)城市间相互作用是影响城市商业用地价格的重要因素之一,与城市商业用地地价水平呈正相关;(2)城市间相互作用对城市商业用地价格的影响在不同城市有较大差异。研究结论:将城市间相互作用引入城市土地价格研究,为评估区域性城市土地价格和完善中小城市基准地价更新提供理论依据。     

Farmers' Subjective Valuation of Subsistence Crops: The Case of Traditional Maize in Mexico

Shadow prices guide farmers' resource allocations, but for subsistence farmers who grow traditional crops they may bear little relationship with market prices. We theoretically derive shadow prices for a subsistence crop with nonmarket value, then estimate shadow prices of maize using data from a nationally representative survey of rural households in Mexico. Shadow prices are significantly higher than market prices for traditional but not improved maize varieties. They are particularly high in the indigenous areas of southern and southeastern Mexico, indicating large  de facto  incentives to maintain traditional varieties there.