Urban cultivation in Accra: an examination of the nature, practices, problems, potentials and urban planning implications

The literature on urban farming in Sub-Saharan African cities reveals that most studies have been conducted in Eastern, Southern and Central African cities. A few have focused on West Africa, including Sierra Leone, Guinea Bissau, and Cameroon. In Ghana there is a paucity of information on urban farming. The purpose of this paper is to examine the status of urban cultivation in Accra, Ghana's capital, reviewing existing research, and to present new empirical findings on urban cultivation emphasizing on its history, nature, practices, problems, potentials and urban planning implications.     

三代领导人城市布局思想与政策绩效分析

城市作为社会、经济、文化活动空间集聚面形成了社会景观, 其产生和发展是各种社会经济要素的空间流动和地理集中的结果。城市不但是人口集聚地, 而且成为各种产业的集聚中心。本文所及的城市布局、规范的范围始于新中国建立。20世纪50年来, 三代领导人在城市布局理论、方法和实践上的特色有许多值得总结的东西     

美国城市化经验对江苏城市化战略的启示

美国城市化经历了发生、发展、成熟的完整过程 ,具体表现为集中和分散两个显著特征 ;我国江苏城市化进程中的独特现象与美国城市化形成鲜明对比 ,通过比较、借鉴 ,江苏必须走出一条符合省情的城市化道路。     

Urban Housing as an Issue of Redistribution through Planning? The Case of Dhaka City

The rapid growth of population, the mushrooming of poor settlements and unplanned urbanization have crucial implications for the efficiency and equity of urban services. The resultant infringements of critical human rights throw into focus the importance of housing as a social policy issue. Urban services are strained in Dhaka city. Urban management has been disrupted as a result of spatial encroachment and environmental degradation. In addition to land scarcity, land speculation and endemic corruption, the high price of land is also a product of the system of land registration. The dearth of valuable urban land, together with delays in urban planning and its implementation, have made the acquisition of land for housing prohibitively expensive for middle and low‐income households. Consequently, the quality of the housing environment is deteriorating. The problem of housing finance is intrinsically linked to its affordability, being currently the prerogative only of the affluent. This article delineates the inherent lack of integrated urban planning, the lacunae within institutions responsible for urban management – and, contextually, the nature of housing as a social policy issue, where reinforced, coordinated planning and administration could ensure distributive benefits even to the poor.     

Automobile prices and protection: The U.S.-Japan trade restraint

We examine the effects of the U.S.-Japan trade restraint on automobile prices and quality upgrading, for both Japanese imports and American small cars. From April 1981 to April 1984 the suggested retail price of all Japanese models increased by 15.8 percent, or 5.3 percent per year. We find that nearly the entire amount of this rise can be explained by the upgrading of individual models. This upgrading may benefit consumers who would purchase a luxury import in any case, but harms those who desire the basic imports. In addition to upgrading, we conclude that a second cost of the trade restraint has been to prevent the yen depreciation from being passed onto American consumers, in terms of lower imported auto prices. For U.S. small cars we find a 9.1 percent rise in the suggested retail price, or 3 percent per year, with a fraction of this amount due to model upgrading. If the yen depreciation had led to lower import prices without the trade restraint, then we expect that U.S. auto prices would have been lower, too.     

从经济学视角谈科学育才之路

在现阶段高校毕业生面临着社会对他们的有效需求不足的问题,从而必须面对社会对高素质人才的需求同高校毕业生供给相对过剩这一结构性供需矛盾。本文从经济学角度分析产生这种矛盾的原因,进而提出只要高校学生工作措施得当,政策有针对性,就有可能缓解上述供需矛盾。     

西部大开发中新疆城镇发展的对策研究

实施西部大开发是国家提出的一项重大战略决策。城市是社会经济发展的一个重要组成部分 ,如何对待城市的发展问题 ,关系到西部地区开发成败的关键。本文首先分析了新疆城镇发展的主导因素 ,指出以政府为主导的发展模式是新疆城镇发展缺乏内在动力的原因。然后从城镇空间分布及城镇体系等方面分析了目前新疆城镇发展的主要特征及存在的问题。最后在以上分析的基础上 ,提出了今后城镇发展的对策与建议     

如何定义“大国”？

 摘　　要:本文通过对各种关于“大国”定义的总结和分析，根据经济学原理给出了关于经济学意义的“大国”的定义。并分析了这种定义的优势，以及在该定义下进一步研究“大国”问题的方向     

历届诺贝尔经济学奖得主评介

举世瞩目的诺贝尔经济学奖得主及其学术成就 ,对我国“入世”后市场经济的发展及其与世界经济的接轨 ,都具有十分重要的指导作用     

Tree health mapping with multispectral remote sensing data at UC Davis, California

Tree health is a critical parameter for evaluating urban ecosystem health and sustainability. Traditionally, this parameter has been derived from field surveys. We used multispectral remote sensing data and GIS techniques to determine tree health at the University of California, Davis. The study area (363 ha) contained 8,962 trees of 215 species. Tree health conditions were mapped for each physiognomic type at two scales: pixel and whole tree. At the pixel scale, each tree pixel within the tree crown was classified as either healthy or unhealthy based on vegetation index values. At the whole tree scale, raster based statistical analysis was used to calculate tree health index which is the ratio of healthy pixels to entire tree pixels within the tree crown. The tree was classified as healthy if the index was greater than 70%. Accuracy was checked against a random sample of 1,186 trees. At the whole tree level, 86% of campus trees were classified as healthy with 88% mapping accuracy. At the pixel level, 86% of the campus tree cover was classified as healthy. This tree health evaluation approach allows managers to identify the location of unhealthy trees for further diagnosis and treatment. It can be used to track the spread of disease and monitor seasonal or annual changes in tree health. Also, it provides tree health information that is fundamental to modeling and analysis of the environmental, social, and economic services produced by urban forests.