城市扩张与集约农业背景下浅层地下水重金属污染特征空间分析

地下水是城乡结合部和农村地区的重要饮用水源之一,城市的扩张和农业集约经营对地下水的影响日益明显。本文以典型区—沈阳沈北新区为例,以地下水重金属为评价指标,采用经典统计和地统计的方法,分析城乡交错地区地下水污染程度和空间分异性特征,旨在为类似地区土地利用规划和地下水环境管理提供科学依据。结果显示:Fe、Mn超标率较高,分布范围较广;Cd、Hg分布集中,受城镇化的影响较为明显;Pb与集中养殖产业分布关系密切;As的分布与当地化工企业有关;Fe、Mn空间变异性强,空间异质性主要受自然条件等结构性因素控制;Cd、Pb、Hg空间变异性中等,As空间变异性弱,Cd、Pb、Hg、As这四种元素空间异质性的形成主要受人为活动等随机因素的影响;初步发现Fe和Mn,Mn和As有相似的来源。     

中国制造业的市场集中、地理集聚与企业绩效

本文研究我国制造业的市场结构与地理分布对企业全要素生产率的影响.以中国工业企业数据库的大样本数据为基础,采用LP法计算企业生产率,构造市场集中度指标和地方化经济、城市化经济两个集聚指标,进行了多方位的计量检验.研究结果表明,制造业的市场集中不利于企业生产率的提高,代表专业化水平的地方化经济促进了企业生产率的提升,度量行业间多样化集聚的城市化经济对企业生产率没有显著的影响.市场集中对出口企业的负面影响不明显,控制市场集中和地理集聚后,出口企业生产率高于非出口企业,出口的“生产率悖论”并不存在.     

中国制造业地理集聚的成因与趋势

改革开放以来,中国的制造业空间格局发生了显著的重构。本文基于中国省区尺度的制造业数据,描述了改革开放以来到2008年期间的中国制造业的空间集聚的变化趋势和特征。总体上,现阶段中国的制造业地理集聚程度较高,主要集聚在东部沿海地区。然而中国制造业地理集聚存在显著的产业差异,依赖于特定自然资源投入的产业,地理集聚程度相对较低,而依赖大量中间产品投入的资本技术密集型产业的地理集聚度则较高。劳动密集型产业由于是外资主导并且以出口为主,高度集中在沿海省区。中国的产业集聚变化趋势具有明显的阶段性特征,从上个世纪90年代初开始,产业地理集聚程度上升进入了加速期,地理集聚程度在2004年左右达到顶峰。本文回顾了中国产业地理集聚的理论和实证研究,传统的贸易理论、新经济地理学理论和集聚经济理论是理解中国的产业集聚的重要视角,但中国转型经济的特殊制度环境下,市场化、全球化和地方分权对中国制造业业集聚和分散具有显著影响。随着中国经济转型的深化及其在全球经济体中地位的调整,全球力量与地方力量的相互作用将不断重塑中国的制造业地理格局。     

Trade policy and specialization in developing countries

This paper examines the impact of trade policy on specialization patterns in ten Latin American countries over the period 1985–1998. These countries are natural case studies because in the last decades they implemented comprehensive trade liberalization programs, both generally and preferentially, starting from relatively high tariff protection levels. Our econometric results suggest that reducing own most favored nation tariffs is associated with increasing manufacturing production specialization. Furthermore, we find that preferential trade liberalization and differences in the degree of unilateral openness have resulted in increased dissimilarities in manufacturing production structures across countries. These results are robust across specialization measures and estimation methods.

省域环境技术效率空间视角分析

通过构建环境污染综合指数,本文首先采用SBM非期望产出模型测度了我国29个省（市）2000—2009年环境技术效率。在此基础上运用探索性空间数据分析,结果发现省域间环境技术效率存在显著的空间依赖性,其自相关性已不容忽视。通过进一步利用空间面板数据模型对其影响因素进行实证分析后的研究结果表明：一个地区的环境技术效率与其所处位置及周边环境密切相关,并且受到邻近省份结构性差异误差冲击,这体现为各省份在经济发展水平、FDI、对外开放度和治理投资额等空间影响因素的差异。经济发展水平、外商直接投资和对外开放度均显著提升了各省份环境技术效率,而产业结构、环境治理投资额与环境技术效率负相关,环境治理投资效果并不显著。     

Spatial externalities and agglomeration in a competitive industry

We introduce spatial spillovers as an externality in the production function of competitive firms operating within a finite spatial domain under adjustment costs. Spillovers may attenuate with distance and the overall externality could contain positive and negative components with the overall effect being positive. We show that when the spatial externality is not internalized by firms, spatial agglomerations may emerge endogenously in a competitive equilibrium. The result does not require increasing returns at the private or the social level, increasing marginal productivity of private capital with respect to the externality, or location advantages. In fact agglomerations may emerge with decreasing returns to scale, declining marginal productivity of private capital with respect to the externality, and no location advantage. The result depends on the interactions between the structures of production technology and spatial effects as shown in the paper. No agglomerations emerge at the social optimum when spillovers are internalized and diminishing returns both from the private and the social point of view prevail. Numerical experiments with Cobb–Douglas and CES technologies and an isoelastic demand confirm our theoretical predictions.     

Moving out or living on a mound? Jointly planning a Dutch flood adaptation project

All over the world spatial flood risk management policies are on the rise. This paper analyses the planning process for the Overdiepse polder, a so-called “Room for the River” project in the Netherlands. After high water in the 1990s, the Dutch government changed its flood risk management policy. While before 2000 it leaned heavily on dikes to separate water from land, after that year spatial measures to “let the water flow” were introduced. This required the integration of two formerly separated policy domains: flood risk management and land use planning. In the densely populated and economically highly developed Netherlands, returning space to the river unavoidably impacts on the lives and livelihoods of those who live and work along the rivers. Therefore, such spatial measures to decrease flood risk have to be negotiated with various stakeholders. The planning process towards making the Overdiepse polder suitable for temporary water storage deserves more in-depth analysis. We describe and analyze the development of relationships between key actors in the planning process, with a focus on planning practices rather than on assumptions about the existence of certain types and qualities of relationships. We conclude, among others, that citizen involvement can, under specific socio-political and institutional conditions, build trust among stakeholders and increase local legitimacy for interventions by government agencies. However, it should not be idealized as “self-governance” or assumed to be part of a unidirectional change in water interventions towards new relationships between actors.     

Employment centers and travel behavior: exploring the work commute of Mumbai’s rapidly motorizing middle class

In the Greater Mumbai Region (GMR), jobs and housing are agglomerating in nodes in the periphery of Mumbai City. However, current transportation investments focus on strengthening connections within Mumbai City, while these outlying nodes have received less attention. As housing and jobs move out, given limited travel choices, the need for mobility nudges many middle class Indian households into owning private vehicles. Using household travel survey data from the GMR, this paper develops an understanding of how worker’s trips are different for those who commute to the city versus the exurbs. Socio-economic and transportation indicators for middle class workers going to the city versus the exurbs show that these populations are quite similar demographically. However, those traveling to the exurbs, on average, tend to be at a socio-economic disadvantage with respect to income, education and out-of-pocket travel burdens. Those traveling to exurban work locations have shorter travel times and trip distances, and make much higher use of walking, biking, rickshaws, and motorized two-wheelers compared to commuters to Mumbai City. Across the GMR, car users travel longer and farther compared to motorized two-wheeler users. On average, traveling by a private vehicle is faster than bus or rickshaw travel revealing advantages of private vehicle use. These mode choices in the middle class have resulted in rapid motorization and negative externalities such as traffic congestion and emissions. Evidence of large increases in motorized two-wheelers and cars in India suggests that these modes will likely keep growing, unless competing efficient travel options are supplied.     

The Role of Built,Human, Social,and Natural Capital in Determining Land Values,and the Influence of Demographics upon this Relationship

Abstract

We use various statistical methods to compare the extent to which different households are willing to invest in and pay for access to four types of capital—built, human, natural, and social. We further assess to what extent such preferences can be predicted by a measure of neighbourhood demographics. We develop indicators for each of the four types of capital at the census block group level for Baltimore, MD, USA. We use analysis of variance to examine differences in these indicators between demographic groups and multiple linear regression to examine the influence on unimproved land values of the four types of capital.     

Insurgent Building: Emerging Spatial Politics in the Bedouin–State Conflict in Israel

In the conflict between Bedouin representatives and government authorities in the southern Israeli Negev, the term ‘insurgent building’ refers to the construction of buildings erected in the full expectation that they will be demolished by the Israeli police shortly thereafter. This article analyses how insurgent building is employed as a spatial practice by emerging political actors to claim contested Bedouin landownership. Importantly, insurgent building relies on the ability of media and advocacy organizations to mobilize behind the issue. Most of the relevant scholarship takes the interpretative categories advanced by these actors at face value. Following anthropological debates regarding objectification and categorization, I examine the context of a specific case of insurgent building. Emerging political actors who employ insurgent building often rely on predefined ethnic categories and clear‐cut people–state polarities. This case demonstrates the need for a more differentiated understanding of multilayered local dynamics than the one offered by mainstream linear interpretations. At a more abstract level, political actors contribute to the reproduction of the very categories against which they mobilize.