Pareto-improving social optimal pricing schemes based on bottleneck permits for managing congestion at a merging section

Akamatsu, Sato, and Nguyen (2006 Akamatsu, T., Sato, S., &; Nguyen, X. L. (2006). Tradable time-of-day bottleneck permits for morning commuters (in Japanese). JSCE Journal of Infrastructure Planning 62(4), 605–620.[Crossref] , [Google Scholar]) proposed a first-best pricing scheme based on the concept of bottleneck permits. The scheme allows permit holders to pass a bottleneck at specified times and is shown to be able to minimize social cost. However, the scheme is not always Pareto-improving in that it may harm some drivers. The objective of this study is to design Pareto-improving pricing scheme with bottleneck permits for a V-shaped two-to-one merge bottleneck. First, the paper formulates the morning commute model in the network and describes the arrival time choice equilibrium in the network with merging bottleneck. Secondly, we show that the first-best pricing scheme with bottleneck permits for this V-shaped network does not always achieve a Pareto improvement, with the cost of one group of drivers is increased by the permit pricing, a phenomena akin to the bottleneck paradox of Arnott, de Palma, and Lindsey (1993 Arnott, R., de Palma, A., &; Lindsey, R. (1993). Properties of dynamic traffic equilibrium involving bottlenecks, including a paradox and metering. Transportation Science 27(2), 148–160.[Crossref], [Web of Science ®] , [Google Scholar]). We propose three implementations of bottleneck permits for Pareto-improving: (1) merging priority rule is included in the bottleneck permits scheme by creating different market for each origin; (2) the permit revenues are refunded as monetary compensation to drivers whose cost is increased; and (3) the permit revenues are used to expand bottleneck capacity. For each implementation, we derive their equilibrium solutions and demonstrate that the Pareto improvement is achieved and social cost is decreased by using the permit revenues for expanding the bottleneck capacity.     

But are they Meritorious? Genetic Productivity Gains under Plant Intellectual Property Rights

The objective of this paper is to evaluate the effect of Plant Variety Protection (PVP) on the productive merit/yield increases of US seed varieties. As an example, we use wheat varieties, which are and have been available as both protected and unprotected under PVP from both the public and private sectors. We find evidence that PVP has contributed to the genetic improvement of wheat, using varietal trial data from Washington State. As the private open‐pollinated varieties exist only because of PVP and are higher yielding, these results indicate a clear public benefit from PVP.     

高职铸造专业实训改进研究与实施

为了提高高职学院铸造专业学生实训效果,通过消失模铸造改进传统木模手工造型,既提高了学生实际动手能力,又使学生掌握了该门先进铸造技术,增强了学生就业竞争能力。     

基于DEA的物流产业效率测度实证研究——基于我国31个省、市、自治区2008年投入产出数据

文章运用DEA的CCR模型和“超效率”(Super-Efficiency)模型,根据我国31个省、市、自治区2008年物流产业投入产出数据,利用Deap2.1和DEA-Sotver-J.V两个软件对物流产业投入产出效率进行实证研究.结果表明:以上海为代表的15个省市、自治区物流产业投入产出这到相对有效,以北京为代表16个省、市、自治区存在投入冗余,以内蒙古为代表的欠发达地区存在投入不足,产出效率偏低.同时,在非DEA有效省、市、自治区,表现出规模效率大于纯技术效率,进而影响了相对效率,文章对此进行投影分析,并以内蒙古为例,探讨了物流产业投入产出如何实施DEA效率改进.     

Achievements and gaps in tef productivity improvement practices in the marginal areas of Northern Ethiopia: implications for future research directions

Tef is the most important crop in Ethiopia and is well-adapted to growing environments, but grain yields are low. The government is therefore promoting the adoption of improved varieties, inorganic fertilizers and new planting techniques. This study gathered information on the use of new agronomic practices and barriers to their adoption through a semi-structured questionnaire administered to 60 farmers or respondents from each of 4 districts of Tigray region in northern Ethiopia viz Laelay-Maichew, Medebay-Zana, Ahferom and Alamata. Data were coded and analysed using SPSS software. Except for animal feed and crop rotation, there were significant differences between districts in the relative importance of several criteria for different uses. Improved varieties were used by the majority of respondents in all districts and fertilizers in all except Alamata where severe moisture stress dictated the choice of variety and reduced fertilizer application. Weed control was mainly by hand except in Alamata where chemical control was common because of the predominance of broad-leaved weeds. Transplanting maximized the yield of tef, but a cost–benefit analysis showed that row sowing was more profitable. The study concluded that new varieties better adapted to the likelihood of reduced rainfall and that respond efficiently to fertilizer inputs need to be developed. Until suitable technologies are available, high labour costs would in part dictate some agronomic practices, even if this led to lower yields.     

新时代耕地占补平衡的逻辑根源、模式探索与管理创新——基于“新时代耕地占补平衡方式改进与管理创新研讨会”的思考

研究目的:对耕地占补平衡的发展阶段与政策绩效、存在问题与逻辑根源进行分析,对改进方式进行探讨,进而提出管理创新建议,为新时代耕地占补平衡政策实施提供科学依据,为促进城乡融合、扶贫攻坚和乡村振兴提供参考。研究方法:综合分析与系统推理。研究结果:(1)耕地占补平衡存在实质性不平衡、时空性不平衡、政策性弱化等微观、中观及宏观层面问题;(2)在数量方面,通过盘活宅基地增量、存量和完善易地调剂方式,统筹城乡和区域平衡来实现数量占补平衡。(3)在质量方面,通过优化建设用地约束指标、完善耕地质量评价、规范耕作层保护与再利用等促进耕地质量占补平衡。(4)在生态方面,通过完善指标调剂的价格内涵、扩大耕地补偿标准范围、转变耕地补充途径等实现耕地生态占补平衡。研究结论:建议做好顶层设计,抓好规划引领,构建耕地占补平衡与城乡要素流动的平衡机制,建立耕地占补平衡后续生态管护长效机制,提升软硬实力等。     

The impact of conservation tillage on maize yield and input demand: the case of smallholder farmers in north‐west Ethiopia

This study analyses the economics of conservation tillage (CT) with respect to its effect on maize yield and chemical fertiliser, herbicide, and female and male labour demand. We estimate production and input demand functions using seemingly unrelated regressions on plot‐level cross‐sectional farm household data collected in the north‐west of Ethiopia. A two‐step control function is applied to address potential endogeneity bias due to the inclusion of the CT adoption decision as an explanatory variable. Our results show that CT increases maize yield and chemical fertiliser demand. Additionally, the results show that the adoption of CT reduces female and male labour required for crop production. However, this is achieved through the increased use of herbicides, which might have an undesirable health and environmental effects.     

生物工程技术在食品工业领域中的应用

生物工程技术作为21世纪的高新技术,在各个领域都能发挥出极关键作用.随着新技术的发展,生物工程技术在食品工业领域中更是绽放出了夺目的光彩.在本文中,笔者针对生物工程技术在食品资源开发、食品加工、食品资源安全检测、传统食品改良等方面的应用做出阐述,希望能为相关从业者提供新的工作思路.     

财政收支分类改革后财政科技投入构成分析及政策启示

财政收支分类改革后科技投入的科目、构成发生了很大变化,本文在对新旧科目转换对比的基础上,分析了新科目下科技投入构成及重点科目,给出建设"创新型"国家的科技投入政策启示。     

安徽省科技投入与经济增长关系的计量分析

随着科学技术的快速发展,科技投入对经济增长的作用越来越明显。本文依据安徽省1992—2009年间科技投入与经济增长的有关数据变量,应用SPSS、Eviews等软件研究安徽省科技投入与经济增长两指标之间的互动关系,建立了反映两者长期协整关系的模型,并对两序列进行格兰杰因果检验。研究结果表明：安徽省科技投入与经济增长间存在长期稳定的均衡关系,且两者间存在单项因果关系。最后根据研究结果,提出一些建议。