城市工业用地产出率影响因素及区域比较—— 地级城市面板数据分析

研究目的:发现城市工业用地产出率影响因素及其影响程度和区域差异,提出相应对策以促进工业集约用地。研究方法:根据土地功能理论和经济主体动力学关系导向原则构建城市工业用地产出率双向固定效应模型,利用地级城市面板数据估计并检验工业用地产出率影响因素及作用程度并进行区域比较。研究结果:城市工业用地投资强度、就业密度和全要素生产率对1999年来城市工业用地产出率增长的贡献率分别为21.3%、-7%和85.7%;它们对工业用地产出率的边际贡献由于东中西部工业用地集约度、产业类型、劳动素质不同而呈现出区域差异。研究结论:应遏制各地尤其是中西部工业新区建设中粗放用地行为、促进工业投资并加强工业区生活配套以提升投资强度和就业密度,应在工业用地配置和评价中更加重视全要素生产率指标,应推动中西部地区工业升级并在营商环境、基础设施等方面缩小与东部的差距。     

中国城市土地经济密度的分布动态演进

研究目的:探究城市土地经济密度的整体分布特征及其演进规律,为实现城市土地利用系统与城市社会经济系统的高效融合及协调发展提供指导与参考。研究方法:核密度估计,马尔科夫链。研究结果:(1)中国城市土地经济密度的整体水平不断提高,但存在着显著的空间非均衡特征,基本呈现出东部地区中部地区西部地区的地理格局;(2)在全国层面和东、中、西部三大区域层面,城市土地经济密度的地区差距在样本考察期内都不断加剧,且各地区城市土地经济密度在发展过程中都出现过不同程度的极化现象;(3)中国不同水平城市土地经济密度之间的流动性较差,各省份在总体城市土地经济密度分布中的相对位置比较稳定,且城市土地经济密度的长期均衡状态将处于中高水平和高水平。研究结论:采取差异化的城市土地利用管控策略和经济调控策略,实现东部、中部和西部地区城市土地利用与经济发展的协同共进。     

合肥市产业结构与土地经济密度的关联协调研究

研究目的:探讨合肥市产业结构与土地经济密度的内在关系及相互作用,为区域产业结构调整优化和土地利用规划提供参考。研究方法:灰色关联度模型,协调度模型。研究结果:产业结构合理化和产业结构高级化对土地经济密度的影响作用显著;劳动生产率与土地经济密度的增长幅度一致时,二者的关联性强;第二产业占比大于第三产业且超出范围较小时,产业结构高级化水平仍较高;产业结构和土地经济密度保持较高关联、协调性时,二者相互促进。研究结论:在一定的经济发展阶段产业结构与土地经济密度密切相关,通过调整劳动生产率增速、GDP增速和各产业占比状况,能使二者的相互促进作用达到最优。     

Economies of traffic density and scale in the integrated air cargo industry: The cost structures of FedEx Express and UPS Airlines

This paper examines the cost structures of the leading integrated air cargo carriers, FedEx Express and UPS Airlines. A total cost model is estimated for the two carriers using quarterly data on domestic operations and costs over a nine-year period (2003–2011). The estimated model indicates that the integrated industry exhibits increasing returns to traffic density and constant returns to scale. Accounting for carrier-specific differences in cost structure and network size, FedEx Express is found to be more cost-efficient than UPS Airlines. Looking at the carriers individually, UPS Airlines exhibits substantial economies of traffic density and constant returns to scale while FedEx Express' cost structure is characterized by weak economies of density and constant returns to scale. The combined effect of returns to density and returns to scale on the cost structures of integrated carriers is captured by economies of size. Both FedEx Express and UPS Airlines exhibit economies of size, indicating that carriers in the integrated industry can be more cost efficient by making appropriate adjustments to their network size as their output grows. Moreover, the relative cost-efficiencies of the carriers are reversed when their network-size differences are not controlled.     

高密度电法在地基塌陷区勘察中的应用

通过高密度电法快速采集地电断面结构信息，准确反映不良地质体的二维分布情况。为查明地基塌陷的诱发原因和地基处理提供了依据。通过实例证明该方法工作效率高、信息量大及在实际应用中的良好效果。     

我国企业协会的覆盖率及其相关制度的再设计

企业协会要行使行业代表、行业管理职能必须具有高的行业覆盖率。由于形成的途经的不同和产业链的细分，我国许多行业中普遍存在着“一业多会”现象，导致了企业协会的覆盖率降低、内耗严重，协会的应有功能无法充分发挥。研究表明：走出“一业多会”困境的出路在于强制入会制度的实施、政府背景的隐退和业务主管部门的取消，以及政府行业管理职能的择优转移和“第三部门”的形成。     

The perception of biotechnology in agro-forestry: The opinion of undergraduates and researchers

Genetically modified organisms (GMOs) cropping promoted by different researchers, and the subsequent crisis regarding the safety of food derived from them, has resulted in strong public mistrust towards the authorities, both scientific and political. The aim of this work is to investigate the perception of Italian undergraduates and researchers towards the introduction of GMOs in agro-forestry. The factors determining attitudes towards GMOs were examined by means of 66 questions divided into three units: Knowledge, Opinon, Trust. Anagrafic and socio-cultural information were also analyzed. Data was processed through a multivariate analysis approach. The hierarchical clustering on undergraduates and researchers allowed to distinguish clusters of respondents skilled in biotechnology from those skilled in off-topic disciplines. Principal component analysis and K-means demonstrated that the positive or negative opinion toward GMOs, as for undergraduates, does not depend on their knowledge, but it is associated with the level of trust in the institutions. On the contrary, for researchers, it is related to their expertise level, without any linkage to trust in the institutions. This type of study may represent a key step for understanding the social, economic and scientific components underlying the choices of citizens, communities and society about GMOs.     

中国省际劳均收入的收敛研究——基于核密度函数和Markov随机过程理论的分析

采用核密度函数和Markov随机过程理论研究了我国省区劳均收入分布的动态演变和发展趋势。研究发现,改革前我国省区劳均收入为多峰分布,其遍历分布为偏向低收入的双峰分布;改革后,劳均收入分布经历了从多峰到单峰再到双峰的演变过程,其遍历分布为偏向高收入的双峰分布。从长期发展趋势看,改革后我国多数地区将会收敛于高收入区间。     

Litteraturanmeldelse

This article examines the notion of distortion of copulas, a natural extension of distortion within the univariate framework. We study three approaches to this extension: (1) distortion of the margins alone while keeping the original copula structure; (2) distortion of the margins while simultaneously altering the copula structure; and (3) synchronized distortion of the copula and its margins. When applying distortion within the multivariate framework, it is important to preserve the properties of a copula function. For the first two approaches, this is a rather straightforward result; however, for the third approach, the proof has been exquisitely constructed in Morillas (2005). These three approaches unify the different types of multivariate distortion that have scarcely scattered in the literature. Our contribution in this paper is to further consider this unifying framework: we give numerous examples to illustrate and we examine their properties particularly with some aspects of ordering multivariate risks. The extension of multivariate distortion can be practically implemented in risk management where there is a need to perform aggregation and attribution of portfolios of correlated risks. Furthermore, ancillary to the results discussed in this article, we are able to generalize the formula developed by Genest &; Rivest (2001) for computing the distribution of the probability integral transformation of a random vector and extend it to the case within the distortion framework. For purposes of illustration, we applied the distortion concept to value excess of loss reinsurance for an insurance policy where the loss amount could vary by type of loss.