Habitat and commodity production trade-offs in coastal Oregon

Ecological, economic, and social goals are important in natural resource management, and should be analyzed in concert when, for example, one wishes to consider the impact(s) of potential forest policies on such goals. The current article describes a large-scale, integrated trade-off analysis, for coastal Oregon (USA). It considers two key management goals for both private and public forest landowners—producing timber and developing and maintaining wildlife habitat—using variations on typical management policies. The proposed model employs a heuristic to schedule harvests in an attempt to produce a high, even level of timber volume. Constraints include those related to the maximum clearcut size, green-up period, and minimum harvest age. Habitat capability for the northern spotted owl (Strix occidentalis caurina) is computed using a spatial model, and reported as an output of the forest plan. The spatial model we used is the most advanced methodology for estimating spotted owl habitat quality. The problem formulation accounts for many of the concerns regarding strategic and tactical planning voiced by forest managers in the Pacific Northwest (USA) region. Our analysis suggests that increasing the minimum harvest age of forests in coastal Oregon has the greatest effect (vs. maximum clearcut size and minimum green-up [regrowth] period) on spotted owl habitat capability index levels. At the same time, however, even-flow harvest levels (highest and most even level of timber volume produced over time) are negatively affected as near-term harvests become more difficult to schedule.     

Land use regulation and new construction

This paper describes the relationship between land use regulation and residential construction. We characterize regulations as either adding explicit costs, uncertainty, or delays to the development process. The theoretical framework suggests that the effects on new construction vary by the type of regulation. Using quarterly data from a panel of 44 U.S. metropolitan areas between 1985 and 1996, we find that land use regulation lowers the level of the steady-state of new construction. Our estimates suggest that metropolitan areas with more extensive regulation can have up to 45 percent fewer starts and price elasticities that are more than 20 percent lower than those in less-regulated markets. One implication of regulations that lengthen the development process is that the short- and long-run effects of demand shocks will vary relative to conditions in markets without such delays. We find support for this observation in the data. As well, we find other differences by type of regulation: development or impact fees have relatively little impact on new construction, but regulations that lengthen the development process or otherwise constrain new development have larger and more significant effects.     

Land use dynamics and the environment

This paper builds a benchmark framework to study optimal land use, encompassing land use activities and environmental degradation. We focus on the spatial externalities of land use as drivers of spatial patterns: land is immobile by nature, but local actions affect the whole space since pollution flows across locations resulting in both local and global damages. We prove that the decision maker problem has a solution, and characterize the corresponding social optimum trajectories by means of the Pontryagin conditions. We also show that the existence and uniqueness of time-invariant solutions are not in general guaranteed. Finally, a global dynamic algorithm is proposed in order to illustrate the spatial-dynamic richness of the model. We find that our simple set-up already reproduces a great variety of spatial patterns related to the interaction between land use activities and the environment. In particular, abatement technology turns out to play a central role as pollution stabilizer, allowing the economy to reach a time-invariant equilibrium that can be spatially heterogeneous.     

Equilibria in a large production economy with an infinite dimensional commodity space and price dependent preferences

We prove the existence of a competitive equilibrium in a production economy with infinitely many commodities and a measure space of agents whose preferences are price dependent. We employ a saturated measure space for the set of agents and apply recent results for an infinite dimensional separable Banach space such as Lyapunov’s convexity theorem and an exact Fatou’s lemma to obtain the result.     

Land use and zoning in the central business district

A model of a small, open central business district (CBD) is used to derive the conditions that define the market-equilibrium and rent-maximizing CBD. It is shown that, in general, the market equilibrium CBD radius differs from the rent-maximizing CBD radius. Land-use zoning will, under certain conditions, increase the aggregate net return on CBD land.     

城市化与土地可持续利用

指出土地利用作为人类社会基础性的生产活动时刻受到城市化的影响 ,许多当前所面临的土地利用问题或多或少都是因城市化而带来的 ;分析了城市化进程对土地利用的作用机理 ;揭示了影响土地可持续利用的因素     

紧凑城市发展中的土地利用理念

紧凑城市理论是发达国家和地区指导城市实现可持续发展的重要理论之一,其中蕴含着丰富的土地利用理。念和思想。针对紧凑城市理论与实践,梳理了现有的主要研究文献并剖析了荷兰、日本和我国香港三个典型以紧凑为导向的国家和地区的城市发展案例,分析了紧凑城市理论的主要内涵和实践特点,重点探讨了紧凑城市发展中的土地利用理念和特征。结合国家“十二五”规划纲要关于推进城镇化健康发展的要求,指出我国城市土地利用应借鉴紧凑城市发展理论及土地利用的核心理念,以提升我国城市土地可持续利用的水平,推进新时期城镇化的健康发展。     

土地紧缺与开发区用地规模

经过二十多年的发展,我国开发区建设进入了一个新的转型期,土地危机已经严重影响到开发区的进一步发展。基于转型期开发区自身规划理论的缺陷,分析其问题产生的根源,提出要重视规划的本质和过程,研究合理的开发区规模以及适应变化的弹性结构等规划建议。     

Risk premia and seasonality in commodity futures

We develop and estimate a multifactor affine model of commodity futures that allows for stochastic seasonality. We document the existence of stochastic seasonal fluctuations in commodity futures and that properly accounting for the cost‐of‐carry curve requires at least three factors. We estimate the model using data on heating oil futures and analyze the contribution of the factors to risk premia. Correctly specifying seasonality as stochastic is important to avoid erroneously assigning those fluctuations to other risk factors. We also estimate a nonlinear version of the model that imposes the zero lower bound on interest rates and find similar results.     

Price formation in commodity markets

This paper develops a theory-consistent market model for storable commodities and illustrates its characterization of the data-generating process for a set of major traded commodities. The dynamics of the system incorporate recent advances in modelling techniques. Cointegrated variables in the demand functions are represented by the error correction mechanism (ECM), and expected prices in the stock demand relationship are generated by a rational expectations process. The outside-sample performance of the model is tested against the pure time-series model used to formulate expected prices, and is shown to have a smaller mean square error than that of the time-series model. Thus the model provides comparatively efficient forecasts and, unlike models constructed in their reduced form, permits consideration of key behavioural relationships in commodity markets.     

改善商品包装的若干思考

在现代市场经济的发展中,商品包装承担着保护商品、便利储运和宣传、美化商品的作用.它的重要性日益为生产厂家、商家和消费者所重视.我国传统的商品包装式样单调,只注重保护商品,忽视了它的宣传和美化商品的作用,现已逐步为注重美观大方,讲究经济实用、突出广告宣传之功能的现代意识所替代.     

Land use externalities, open space preservation, and urban sprawl

Parcel data on residential land conversion are used to investigate how land use externalities influence the rate of development and modify policies designed to manage urban growth and preserve open space. Several “smart growth” policies are found to significantly influence land conversion, including a development clustering policy that concentrates development and generates preserved open space. In addition to directly affecting a parcel's hazard rate of conversion, this policy is found to affect neighboring parcels' conversion by generating a positive open space externality that hastens their development. The implication that the clustering policy could generate a more sprawled pattern of development is explored using spatial simulation.     

Exchange rate volatility and Spanish-American commodity trade flows

A number of recent studies have tested the impact of exchange rate volatility on trade flows, particularly for individual commodities, for various country pairs. These have found that risk can increase as well as decrease trade, but that oftentimes industries are not affected. This study examines trade between the United States and Spain over the period from 1962 to 2009, for 131 U.S. export industries and 88 import industries. We find that exchange rate volatility has short-run and long-run effects in only a fraction of the cases, but that exports respond more to increased uncertainty than imports do. In all, only 35 of the 74 U.S. export industries are affected (11 positive, 24 negative), whilst only three out of 37 import industries have positive coefficients and 11 have negative ones. We find no evidence that durable or nondurable goods are more likely to respond to volatility, whilst small industries or specialized goods might show more of a positive response.     

Cointegration and joint efficiency of international commodity markets

This paper investigates the semi-strong efficiency hypothesis in the international commodity markets of four industrialized countries, using vector autoregression (VAR) and cointegration techniques. Efficiency in these markets requires the corresponding real exchange rates to be martingales with respect to any information set available in the public domain. In the context of a VAR consisting only of real exchange rates, we show that necessary and sufficient conditions for joint efficiency of all the markets under consideration amount to the VAR being of order one (Markovness) and non-cointegrated. On the contrary, in a VAR extended by other potentially “relevant” variables, such as the corresponding real interest rates, non-cointegration and Markovness are only sufficient conditions for the same commodity markets to be characterized as jointly efficient. We also suggest methods for efficiency testing in each individual market within a cointegrated VAR and, finally, we discuss possible long-run linkages among the real exchange rates and real interest rates in association with efficiency in the commodity markets. JEL Classification Number: F31     

Forecasting inflation using commodity price aggregates

This paper shows that for five small commodity-exporting countries that have adopted inflation targeting monetary policies, world commodity price aggregates have predictive power for their CPI and PPI inflation, particularly once possible structural breaks are taken into account. This conclusion is robust to using either disaggregated or aggregated commodity price indexes (although the former perform better), the currency denomination of the commodity prices, and to using mixed-frequency data. In pseudo out-of-sample forecasting, commodity indexes outperform the random walk and AR(1) processes, although the improvements over the latter are sometimes modest.     

入股土地使用权也属企业资产

案例某市A公司原是国有企业,使用的土地是由国家无偿划拨的。1998年,企业进行股份制改造改制时国家以土地使用权作价出资(入股)。近几年由于经营管理不善,企业正准备宣告破产。     

Land use in a circular city: Some numerical results

In a previous paper (“Land Use in a Circular City”, Journal of Economic Theory, 1974), I considered efficient land use and travel patterns in a circular city consisting of a homogeneous economic activity and a network of radial and circumferential roads. My analysis assumed that under decentralized optimum conditions, the price of traveling circumferentially through a radian would increase with distance from the city center. Under this and a second pricing assumption, an optimum would involve either restricting inward trip penetration or providing travelers with an inner ring road. This paper provides numerical illustrations of the optimum when trip penetration is restricted. The results suggest that the underlying pricing assumptions are likely not valid.     

浅谈电视拍摄及制作中对比手法的运用

这篇文章是作者在工作实践中的体会。作者担任四院设计的多部片子的创作、拍摄、编辑工作，由于巧妙的运用了对比手法，使得影片获得了成功。文中结合作者多年的工作经验，并参考大量优秀的拍摄技巧，探讨了电视拍摄及制作中对比手法。     

Monetary policy,global liquidity and commodity price dynamics

This paper examines the interactions between money, interest rates, goods and commodity prices at a global level. Aggregated data for major OECD countries are therefore analysed in a cointegrated VAR framework. Our empirical results for the period ranging from the 1970s to 2008 support the view that, when controlling for interest rate changes and thus different monetary policy stances, money (defined as a global liquidity aggregate) is still a key factor to determine the long-run homogeneity of commodity and goods prices movements.