Constraints on the conversion to sustainable production: the case of the Dutch potato chain

The question of how to make agriculture more sustainable is a timely topic. This paper examines the Dutch potato supply chain in the context of its surrounding network. Based on the chain network approach it identifies constraints on conversion to organic potato production from a business administration and a public administration perspective. Two obvious constraints are the demand for ecologically produced products and the problem of cultivating potatoes. However, the potential for conversion is also affected by the way the market and the supply chain are structured, by the coordination of activities, efficiency‐driven actors, relations and interdependencies between actors and by the asymmetrical distribution of power. Furthermore, conversion is constrained by the limited influence of network parties such as NGOs and current government policies. Based on the analysis, the paper questions whether the ecological approach (organic farming) will be more effective than strengthening a more generic approach stimulating the sustainability of the sector. Copyright © 2006 John Wiley & Sons, Ltd and ERP Environment.     

Protein and the demand for hard wheats*

Wheat protein is one of the most important specifications used in domestic and import purchase contracts and is used partly as a proxy for functional quality. The purpose of this article is to analyse the demand for wheat delineated by protein class. A choice‐based econometric model is specified and estimated using a novel dataset of pooled wheat shipments to individual importing countries. Buyers are importing countries that make purchase decisions among different protein levels. The model frames the choice in terms of attributes of the choice and of the importing countries. Results indicate that there have been shifts over time, and purchase probabilities are highly price elastic and vary across importing regions. Functional characteristics including wet gluten content and extraction rates have significant impacts on purchase probabilities. These results have implications for breeders as it clearly illustrates the role of protein and functional characteristics on demand. The results also have implications for analysts modelling wheat trade in that there are many factors impacting market segments that would not be captured in conventional demand specifications.     

“生命里甚至也有修伯特无言以对的时候”——王祯和对小人物命运的独特言说

台湾当代著名的乡土作家王祯和,用自己独特的文学之笔为读者描绘了一幅幅花莲小人物的命运画卷。他那让人物自然演出的命运观,独特的单一视角,以及丰富多元的语言,为小人物的塑造奠定坚实的基础。     

汽车时钟弹簧的应用

文章阐述了汽车时钟弹簧的定义及其在汽车中的应用,并着重介绍了时钟弹簧在汽车应用中的一些失效模式及装配过程中的各项注意事项,提出制造过程的质量控制要求与方法。     

膜片弹簧离合器的结构及故障诊断

论文介绍了膜片弹簧离合器的结构、原理及离合器打滑、分离不彻底、离合器接合不平顺、离合器异响等故障诊断。     

INFORMATION SEARCH BEHAVIORS OF COLLEGE STUDENTS FOR SPRING BREAK TRIP IN THE USA: AN APPLICATION OF SPECIALIZATION CONCEPT

The purpose of this study was to identify information search behaviors of college student travelers by applying the concept of specialization. Dividing the college travelers into groups of high‐, medium‐, and low‐leveled specialization, the research investigated the perceived value of information content and information sources, and identified the main information sources used to obtain information for their recent spring break trips. It was observed that the different specialization groups assigned different values to information content and sources. The differences in the choice of information channel also appear to be substantial. As a result, the findings of this study supported the idea that the specialization concept can be used as an alternative approach to segment travelers in a more comprehensive way, which combines past experience, prior knowledge, and involvement that are important to classify travelers.     

The Role of Risk Mitigation in Production Efficiency: A Case Study of Potato Cultivation in the Bolivian Andes

Using a stochastic production frontier to model potato production in Bolivia, we quantify the costs of environmental and activity diversification (AD) in the form of efficiency losses and yield forgone. We find that efficiency decreases with the number of fields in a geographical cluster, distance between the dwelling and a particular field, discontinuity between fields, and off‐farm income. However, environmental diversification (ED) is more detrimental than AD. Using spatial analysis of field and household efficiency measures, we assess production vulnerability to climatic shocks and the potential of ED in mitigating shocks. We find important spatial clusters of low and high efficiencies at the field level suggesting that climatic shocks influence efficiency measures. Household‐level efficiency measures exhibit random spatial patterns suggesting that on average households can mitigate the adverse effects of shocks through ED.     

柴油机气门弹簧制造工艺改进方法

柴油机气门弹簧是发动机的关键零件,它的质量直接影响到发动机的动态性能,优质弹簧对一台柴油机的性能影响不容小觑。文章阐述了柴油机气门弹簧的制造工艺,改进设计了一条从退磁到包装自动化生产线,并提出采用U型生产方式来解决目前生产车间存在的一些问题。     

春运市场民工流的经济学分析

从经济学的角度分析占春运市场重要份额的民工流成为弱势群体的原因、民工流成分的演变及其发展,根据民工流的分析,提出铁路部门在春运中应采取的措施,使铁路运输企业更新观念,研究制定以务工流为中心的客运快速反应体系,更好地占领春运市场。     

城市近郊地热温泉的旅游地理学意义——对河北藁城现象的思考

温泉业界的实践引发了一些关于旅游地理学的思考。传统的旅游地理学在大尺度上主要以人的水平移动及位于区位上的地面存在为基础建立自己的知识体系,然而技术进步正在改变着旅游地理环境,以旅游为目的的温泉开发热潮,让我们不仅关注温泉水的水平移动,也开始意识到一个垂直轴上的现象——地热从地下被搬到地面而成为温泉。通过藁城地热温泉建设实例,可对旅游资源的形成、景观建设、具有遗产保护意义的开发方位寻找、面向空港城市的市场开发和旅游扶贫等方面,进行具有旅游地理学意义的学术探讨。提出了若干具有原创性质的概念及情景,如垂直技术、利用先在构建景观、反遗产方向、空港城市客源开拓等。