Deriving a Flexible Mixed Demand System: The Normalized Quadratic Model

This article deals with the specification of a locally flexible and theory-consistent system of mixed demand functions, a framework that allows for a rich set of possibilities about what is assumed as exogenous in a demand model. A coherent mixed demand system is derived by using the restricted expenditure function typically studied in the related area of rationed demands. The method is implemented by a new normalized quadratic (NQ) parameterization of the restricted expenditure function. The resulting NQ mixed demand system is illustrated with an application to a nine-good model of the Italian demand for vegetables.     

A Structural Econometric Model of Joint Consumption of Goods and Recreational Time: An Application to Pick-Your-Own Fruit

This article develops a structural econometric consumer demand model for goods, which have time and monetary costs, and where time spent obtaining the goods also enters into the utility function. The model is used to analyze customers' decision to buy pick-your-own versus preharvested strawberries at North Carolina pick-your-own fruit operations. The analysis distinguishes the effect of time as a resource constraint and time that provides utility. Demand for strawberries sold at the operations is price elastic, and demand for pick-your-own strawberries is less price elastic than demand for preharvested strawberries.     

Nonlinear Dynamics and Structural Change in the U.S. Hog–Corn Cycle: A Time-Varying STAR Approach

The linearity of the U.S. hog–corn cycle has been questioned by Chavas and Holt (1991) . Even so, attempts have not been made to model the potential nonlinear dynamics in the hog–corn cycle by using regime-switching models. One popular alternative is Teräsvirta's smooth transition autoregressive (STAR) model, which assumes regime switching is endogenous and potentially smooth. In this article, we examine monthly data for the U.S. hog–corn cycle, 1910–2004. A member of the STAR family, the time-varying STAR, is fitted to the data and its properties examined. We find evidence of nonlinearity, regime-dependent behavior, and time-varying parameter change.     

结构方程模型森林康养消费需求因素分析

以计划行为理论为基础进行设计问卷,结合实地调研与在线问卷调查数据,运用结构方程模型研究现阶段中国居民森林康养消费需求的影响机制。结果表明:中国森林康养产业普及程度较浅,深度的森林康养内容认知与发展进展很浅薄;森林康养消费需求会促使居民的消费行为,而态度、知觉控制会显著正向影响居民的消费需求,态度、规范与知觉控制之间影响显著。因此,应设计多层次森林康养产品,鼓励森林康养养老,助力脱贫攻坚;提升居民参与森林康养的客观能力,奠定消费战略的基础;研究康养理论,推行康养理念,设计康养服务产品;政企协力推进,构建政-企-森-居-社会协调发展新模式,以便促进森林康养良好发展。     

International market integration and demand: An analysis of the Norwegian and Danish herring market

This article provides a method where pre-tests for international market integration are used to identify market structures before estimating demand systems. The method is applied to the analysis of the European herring market. A Vector Auto Regressive model in Error Correction form is used to identify co-integration vectors between price series and, based on this, to test for the Law of One Price. The Law of One Price is in force between the landing markets for herring in the two largest global supplier countries, Norway and Denmark. Therefore, an inverse demand function is estimated for the combined Norwegian and Danish market. The results are used in the interpretation of the significant increase in the prices of herring on the Danish ex-vessel market in 2001, given the stability of the Danish market. The implication is that even though Denmark did not export to the main Norwegian export markets in the former Soviet Union and Eastern Europe, the Danish landing price is influenced by the situation there.     

土地利用变化动态模型的比较分析与评价

土地利用变化动态模型,已成为区域土地利用研究过程中重要的系统性方法。基于不同研究途径、研究目的和不同分析角度的动态模型具有不同的建模机理和解释功能,动态的、基于过程的模型比经验的、随机的和静态的模型更适合于预测土地利用变化的趋势。建立在不同空间分析基础之上的动态模型在表现形式和分析能力上有其不同的优缺点。本文通过对其优缺点的分析评价,提出了建模的新思路,为土地利用动态变化的研究方法作出新的尝试与探索。     

The Impact of Electronic Clock Auction Systems on Shellfish Prices: Econometric Evidence from a Structural Change Model

Economic theory suggests that different auction systems may lead to different price equilibria under specific conditions. By changing the trading rules, the introduction of electronic clock auction systems (ECAS) on primary fish markets is likely to modify the price formation process. A relationship between the prices of live prawns (Nephrops norvegicus) in two French ports where different ECAS have been successively introduced is estimated through two univariate models and a vector autoregressive model applied to stationary weekly data series. Using a recent multiple break searching procedure (Econometrica, Vol. 66, 1998, 47; Journal of Applied Econometrics, Vol. 18, 2003, 1; Econometrics Journal, Vol. 6, 2003, 72), a single structural change matching the date of implementation is discovered in the two ports and shows a different impact partly explained by the type of auction system in force. The introduction of the Euro in January 2002 also appeared to play an influential role in the adoption of electronic clock auction markets.     

Regional Shifts in Pork Production: Implications for Competition and Food Safety

U.S. pork production and processing is consolidating in larger, more economically efficient units, and shifting from the Midwest into the Southeast. A regional model of farm supply and processing demand shows that smaller Midwest operations can survive only if processing capacity remains concentrated in that region. Salmonella incidence is higher in the Southeast and on larger farms. Restricting salmonella incidence in hogs delivered for processing to the minimum feasible level would increase total industry costs by 3%, due to increased production and delivery costs. It would also increase the comparative advantage of farms and processing firms in the Midwest.     

Household food consumption in Turkey: a reply

We reply to the Comment by Drichoutis et al. regarding somemethodological and estimation issues arising from our paper.In particular, we compare the elasticities reported in the originalpaper with those obtained using estimation procedures suggestedby Drichoutis et al. We find that the differences are very small.     

兰州市土地利用变化驱动因素分析与预测

在RS与GIS支持下,建立了兰州市1995年、2000年土地利用变化数据库;结合1985年和1990年土地利用调查数据,采用因子分析模型对引起兰州市土地利用变化的驱动因素进行了分析;运用Markov与GM(1,1)两种预测方法对研究区未来的土地利用变化趋势进行了预测;两种预测方法的预测结果吻合度较高,研究区土地利用变化的总趋势为耕地、未利用土地持续减少;林地、城镇工矿居民地面积持续增加;草地面积也有明显的减少;水域相对较稳定。     

Global food demand,productivity growth,and the scarcity of land and water resources: a spatially explicit mathematical programming approach

In the coming decades, an increasing competition for global land and water resources can be expected, due to rising demand for food and bio‐energy production, biodiversity conservation, and changing production conditions due to climate change. The potential of technological change in agriculture to adapt to these trends is subject to considerable uncertainty. In order to simulate these combined effects in a spatially explicit way, we present a model of agricultural production and its impact on the environment (MAgPIE). MAgPIE is a mathematical programming model covering the most important agricultural crop and livestock production types in 10 economic regions worldwide at a spatial resolution of three by three degrees, i.e., approximately 300 by 300 km at the equator. It takes regional economic conditions as well as spatially explicit data on potential crop yields and land and water constraints into account and derives specific land‐use patterns for each grid cell. Shadow prices for binding constraints can be used to valuate resources for which in many places no markets exist, especially irrigation water. In this article, we describe the model structure and validation. We apply the model to possible future scenarios up to 2055 and derive required rates of technological change (i.e., yield increase) in agricultural production in order to meet future food demand.     

A causal analysis framework for land-use change and the potential role of bioenergy policy

We propose a causal analysis framework to increase understanding of land-use change (LUC) and the reliability of LUC models. This health-sciences-inspired framework can be applied to determine probable causes of LUC in the context of bioenergy. Calculations of net greenhouse gas (GHG) emissions for LUC associated with biofuel production are critical in determining whether a fuel qualifies as a biofuel or advanced biofuel category under regional (EU), national (US, UK), and state (California) regulations. Biofuel policymakers and scientists continue to discuss to what extent presumed indirect land-use change (ILUC) estimates should be included in GHG accounting for biofuel pathways. Current estimates of ILUC for bioenergy rely largely on economic simulation models that focus on causal pathways involving global commodity trade and use coarse land-cover data with simple land classification systems. This paper challenges the application of such models to estimate global areas of LUC in the absence of causal analysis. The proposed causal analysis framework begins with a definition of the change that has occurred and proceeds to a strength-of-evidence approach that includes plausibility of relationship, completeness of causal pathway, spatial co-occurrence, time order, analogous agents, simulation model results, and quantitative agent–response relationships. We discuss how LUC may be allocated among probable causes for policy purposes and how the application of the framework has the potential to increase the validity of LUC models and resolve controversies about ILUC, such as deforestation, and biofuels.     

Agriculture and global climate stabilization: a public good analysis

The stabilization of global climate presents one of the most complex problems in public good provision the world has faced. Continuation of “business as usual” policies, leading to warming of more than 2 degrees over the next year, will produce significant damage to agricultural systems and catastrophic damage to the natural ecosystems that ultimately support agriculture. The best solution to the public goods problem is a “contract and converge” agreement in which the ultimate outcome is a common global entitlement to CO₂ emissions per person.     

Land change in the Brazilian Savanna (Cerrado), 1986–2002: Comparative analysis and implications for land-use policy

The Brazilian Cerrado, a biodiverse savanna ecoregion covering 1.8 million km² south and east of the Amazon rainforest, is in rapid decline because of the expansion of modern agriculture. Previous studies of Cerrado land-use and land-cover (LULC) change imply spatial homogeneity, report widely varying rates of land conversion, use ambiguous LULC categories, and generally do not attempt to validate results. This study addresses this gap in the literature by analyzing moderate-resolution, multi-spectral satellite remote sensing data from 1986 to 2002 in two regions with identical underlying drivers. Unsupervised classification by the ISODATA algorithm indicates that Cerrado was converted to agro-pastoral land covers in 31% (3646 km²) of the study region in western Bahia and 24% (3011 km²) of the eastern Mato Grosso study region, while nearly 40% (4688 km² and 5217 km², respectively) of each study region remained unchanged. Although aggregate land change is similar, large and contiguous fragments persist in western Bahia, while smaller fragments remain in eastern Mato Grosso. These findings are considered in the current context of Cerrado land-use policy, which is dominated by the conservation set-aside and command-control policy models. The spatial characteristics of Cerrado remnants create considerable obstacles to implement the models; an alternative approach, informed by countryside biogeography, may encourage collaboration between state officials and farmer-landowners toward conservation land-use policies.