昆明轨道交通站点周边地区城市设计探讨

轨道交通站点周边地区由于建设开发强度大,建筑密度高,其建筑群体空间往往对周边城市环境带来压迫感。本文以香港成熟轨道站点地区已经建成的城市现状作为实证研究对象,从建筑群体高度控制和开放开放空间设计两个方面,分析总结其城市空间设计经验,给昆明轨道站点周边地区的城市设计以启发。     

上海城乡经济多样化测度方法及其演变特征

以上海市为例,从作物多样化、产业发展多样化、土地利用结构多样化、城市经济功能多样化等视角,提出了相应的定量测度方法并展开实证分析。研究结果表明:11950年以来,尽管大多数区县的作物多样化程度趋于下降态势,但上海郊区的作物多样化程度依然较高;近郊区的作物多样化程度的下降幅度大于远郊区,且两者的作物多样化程度在1990年前后发生了明显改变。2改革开放以来,上海农业发展日益趋于多样化;上海工业则经历了"两升两降"的结构调整和优化过程,优势工业行业的集中化和专业化与其它工业行业的分散化和多样化交替演进;上海服务业的多样化程度总体上呈现在波动中上升的态势。31996年以来,上海土地利用结构多样化指数基本呈现上升趋势,且土地利用结构的多样化程度总体较高。41980年以来,上海城市经济功能多样化态势日益明显,产业结构升级与就业结构多样化互动发展。     

Estimating persistent and transient technical efficiency and their determinants in the presence of heterogeneity and endogeneity

We develop an estimation procedure that generates consistent estimates of the technology parameters, long-run (persistent) and short-run (transient) technical inefficiencies and the marginal effects of their determinants for the stochastic frontier model developed by Colombi et al. (2014, Journal of Productivity Analysis 42, 123) and Kumbhakar et al. (2014, Journal of Productivity Analysis 41, 321). Our approach accounts for three sources of potential endogeneity: (i) unobserved heterogeneity; (ii) simultaneity of input use with both types of technical efficiency; (iii) potential correlation of the noise term with the regressors. Using this approach we examine the effect of direct payments and farm size on the persistent and transient technical efficiency of French crop farms before and after the European Union's Common Agricultural Policy decoupling reform of 2003. Our results show that subsidy payments per hectare of utilised agricultural land had a significant positive effect on persistent technical efficiency and a significant negative effect on transient technical efficiency during the period before decoupling. For the period after the reform, the effect of subsidies is found to be significantly negative for persistent technical efficiency and insignificant for transient technical efficiency. The overall effect of subsidies on technical efficiency is found to be negative in both periods, albeit substantially lower in the period after decoupling. The effect of farm size on technical efficiency is found to be significant only for the period prior to the reform: it reduced persistent technical inefficiency but increased transient technical inefficiency during that period.     

Trends in Agricultural Incomes: An Analysis at the Select Crop and State Levels in India

India's agricultural sector is at a crossroads, facing challenges of stagnation in crop yields, non‐remunerative prices, falling crop incomes and tardy responses from public service systems. There are reports of peasant suicides due to non‐profitability of farming. However, scant empirical evidence is available on changes in real income and wages in the Indian agricultural sector. The present study uses data from the National Accounts Statistics and Cost of Cultivation Surveys to analyse the changes in real income and discusses the underlying reasons. The study reveals that the purchasing power of farmers has remained low and has worsened over recent years. The value of crop output has increased, but a disproportionate rise in input costs has resulted in a fall in crop incomes in several states, with the agriculturally developed Punjab being an exception. Interestingly, real wage rates for agricultural labour have shown an increasing trend, indicating improvement in the welfare of labour.     

Crop Insurance as a Strategy for Adapting to Climate Change

Financial insurance for extreme events can play an important role in hedging against the implications of climate change. This paper combines a comprehensive estimation strategy and a unique panel dataset to study the role of financial insurance in farmers' welfare under uncertainty. Data are drawn from a large Italian farm panel dataset. We find that (i) demand for insurance products is likely to increase in response to climatic conditions, and (ii) that the use of insurance reduces the extent of risk exposure. We also find that farms growing more crops are less likely to adopt the insurance scheme. This confirms what is found in the theoretical literature. Crop diversification can be a substitute for financial insurance in hedging against the impact of risk exposure on welfare.     

热轧带钢滚筒式切头飞剪关键技术进步

总结了30年来热轧带钢滚筒式切头飞剪关键技术进步,包括机械结构创新设计和最优化剪切系统等。