经济增长和人口集聚对城市环境空气质量的影响及区域分异——以第一阶段实施新空气质量标准的74个城市为例

为评估经济增长和人口集聚对城市环境空气质量的影响,寻求源头改善城市环境空气质量的可行路径,以第一阶段实施新空气质量标准的74个城市为例,基于输出导向的数据包络分析模型,以经济和人口指标为输入,以城市环境空气质量指数为输出,计算城市经济增长和人口集聚的整体效率,表征经济增长和人口集聚对城市环境空气质量的影响。结果表明:三大城市群中,京津冀的环境影响比长三角大26.0%,长三角比珠三角大11.2%;省会城市中,中部地区的环境影响最大,东北地区其次,西部地区第三,东部地区最小。快速推进的工业化和城镇化,投资拉动冶金、能源重化工产业和房地产业高速发展,土地财政助推人口密度不断提高,使得大气污染物在城市局地范围内、短时间、大量集中排放,远超城市大气环境容量,是造成城市环境空气质量明显下降的根本原因。改善城市环境空气质量,必须从环境影响源头入手,加快经济转型升级步伐,适度、有序推进人口城镇化。     

农村土地集体所有制对劳资关系形成的积极影响及启示

农村土地集体所有制作为一种"普照的光",使中国劳资关系形成跨越了残酷的原始积累阶段,避免了劳资关系发展初期易发的尖锐冲突,使中国劳资关系伴随着工业化城市化进程协调发展。社会主义公有制不仅需要而且可以与市场经济相结合,并使市场经济的作用得到有益发挥。必须坚定不移走社会主义道路,积极发挥社会主义基本制度的优势,更好更快地推进中国现代化进程,实现中华民族伟大复兴。     

小城镇建设与土地利用问题及对策——以南京市为例

小城镇建设是社会各界关注的热点,其中一个核心问题就是土地利用问题。本文分析了小城镇建设对土地集约利用的正负面影响。以南京市为例,提出了小城镇发展过程中的诸多问题,并对兼顾小城镇健康发展和土地合理利用的对策及机制进行了探讨。     

Public Open Access and Private Timber Harvests: Theory and Application to the Effects of Trade Liberalization in Mexico

A common popular assertion is that trade liberalization encourages deforestation. But whether this is true depends on how trade policies affect the allocation of land among competing uses and how they influence illegal cutting of public forests. A model is presented that allows for forests to be either public or private, and public forests are divided into protected (or managed) and threatened categories. Effects of price changes are shown on each part of the forest. An empirical version of the model is applied to the case of Mexico with NAFTA. Most scenarios considered show that NAFTA will have positive long-run effects on forest cover in Mexico but that this is net of losses on private lands.     

Entry restrictions and the determination of quality

Entry restrictions are a common form of regulation in markets and occupations, either as a means of limiting the size of a market or affecting the quality of products or services provided by it. This paper analyzes demand, cost and informational characteristics that affect the impact of this type of policies on the quality mix of products provided by an industry and the welfare of its consumers. Selective increases in the costs of entry such as licensing requirements and direct restrictions with competitive bidding for entry rights are considered. We analyze the effects of these policies on entry decisions and also the additional selection effects that are obtained when exit is allowed for and the rights to participate in an industry can be freely traded.     

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.     

Land Allocation between Food and Energy

Many countries are promoting biofuels as a substitute for scarce oil. This paper develops a dynamic model of land allocation between food and energy and shows how the model can be calibrated using standard optimization techniques. Some possible implications of the trade-offs between food and energy are discussed. Specifically, we show that the effect of mandates is mainly felt through increased land conversion, which increases indirect carbon emissions Crude oil prices do not decrease significantly because of leakages.     

城市网络发育特征及其对城市竞争力的影响--基于珠三角主要金融行业148家企业选址数据

新城市主义的城市网络作为城市关系研究的新范式越来越受到关注。基于珠三角主要金融行业148家企业选址数据,借鉴城市联锁网络模型,实证分析城市网络发育特征及其形成的行业动因,进而探讨了城市网络外部性对城市竞争力的影响。研究结果表明,珠三角城市群已初步形成以“深圳-广州”为核心的“核心-边缘”网络层级结构。保险业较之于银行业和证券业对于城市网络具有更大的贡献弹性。城市链接率与城市竞争力的弹性分析表明,城市网络外部性对城市竞争力提升具有明显的正向促进作用。     

广东相对资源承载力与可持续发展问题

本文提出了相对资源承载力的研究思路和方法,计算了1978-1995年广东省相对土地资源承载力、相对经济资源承载力和综合承载力及其变化过程.研究表明①经济资源是广东省人口的主要承载资源;②1989年以后,广东省的综合承载力超过实际人口数量,进入相对富余状态;③相对土地资源承载力与相对经济资源承载力的不协调发展是广东可持续发展中存在的主要问题之一.     

析我国城市建立无人岛的必要性

当前城市绿地景观规划只注重景观的经济和社会价值,忽视景观的环境和生态内涵.要推动中国的城市化向可持续发展方式的转变,应该着眼于更高体系的城市绿地规划.