OPTIONS AND EFFICIENCY IN MULTIDATE SECURITY MARKETS

This paper extends the work of Ross (1976; Q. J. Econ. (90)1, 75–89) to multidate security markets. First, we show that if a primitive security separates states at the terminal date, then there exist multiperiod European options on that security generating dynamically complete markets. Second, we show that if a primitive security conditionally separates states at the terminal date, then there exist multiperiod European options on that security generating generically dynamically complete markets provided that certain conditions hold. Third, we show that there are economies for which the minimum number of multiperiod European options on a primitive security generating generically dynamically complete markets is relatively large. Finally, we show that in these economies, a relatively small number of multiperiod European options on possibly different portfolio strategies of primitive securities generates generically dynamically complete markets.     

The evolution of world trade from 1995 to 2014: A network approach

This paper employs network analysis to study world trade from 1995 to 2014. We focus on the main connective features of the world trade network (WTN) and their dynamics. Results suggest that countries’ efforts to attain the benefits of trade have resulted in an intertwined network that is increasingly dense, reciprocal, and clustered. However, these features do not correspond to a linear aggregation of the characteristics of its constituents (trade sectors). Trade linkages are distributed homogeneously among countries, but their intensity (i.e. their value) is highly concentrated in a small set of countries. The main connective features of the WTN were not affected by the 2007–2008 international financial crisis. However, we find that the crisis marks a turning point in the evolution of the WTN from a two-group (led by the US and Germany) to a three-group (led by the US, Germany, and China) hierarchical structure.     

Uncovering the global network of economic policy uncertainty

This study uncovers the static and dynamic network of economic policy uncertainty (EPU) across 17 developed and emerging economies. We build a centrality network using the minimal spanning tree (MST) as well as a dependency network using partial correlations. Results from the MST show that EPU exhibits some degree of geographical connections with EPUs in seven countries in the sample directly linked to the US EPU. Evidence from dynamic time-varying MST reveals that the nature and dominance of the EPU network have changed significantly over time. Further, the US and German EPUs dominate a close-knit global policy uncertainty network with the highest net (To and From) transmitter of information flow in the dependency network. Greece, Russia, and Brazil are the top three net receivers of information in the global network of EPU. The policy implication of these results relates to the renewed and ongoing international debate on policy coordination.     

基于系统观视角的团队边界工作研究评介

有关团队边界的研究表明团队有效性是团队内外部因素共同作用的结果,识别团队边界所承担的多种角色,采取系统观,强调团队边界工作的内部导向与外部导向维度有助于整合团队过程研究与团队开放观研究。团队边界工作是团队所从事的旨在建立和维持团队边界,以及管理跨团队边界的互动行为。本文在对团队边界研究内部观与外部观分析基础上,提出了基于系统观指导下团队边界工作的研究同时重视内部导向与外部导向团队边界工作的发展趋势;梳理团队边界工作的内涵与分类,考察了团队边界工作的影响效应及其背景影响因素,进一步提出了团队边界工作的综合影响模型,指出内部导向与外部导向协调发展的团队边界工作对于组织管理实践的启迪以及未来的研究方向。     

长沙“四小龙”县域经济跨越发展的启示

县域经济在国民经济中处于十分重要的地位。本文研究长沙"四小龙"县域经济发展的特点、思路、战略、路径和方法,总结其取得成果的因素。长沙"四小龙"县域经济发展的实践证明,地方政府只要战略明确,抢抓机遇,大胆创新,立足本地特色,统筹城乡发展,勇于竞争,善于合作,坚持走新型工业化道路;切实转变观念,优化环境,就一定能取得县域经济超常规跨越式的发展。同处于中西部其他地区县市既要善于走出去到沿海发达地区学习先进的经验,更要两眼向内,注意学习地理位置相近、经济结构相似的本地"领头羊"的高招,因为来自后者的经验,更契合中西部地区的实际,更有说服力,中西部地区在实现县域经济跨越发展上一定大有可为。     

跨既有线70.52m钢结构桁架天桥整体吊装施工技术

本文以新建凌海南站天桥整体吊装工程为实例,详尽的论述了在既有线施工大吨位、大跨度钢结构桁架天桥的技术特点、施工工艺流程、现场构件拼装制作关键技术、钢结构构件的运输方式、拼装场地选取、400t履带吊拼装场地、场地布置、吊装顺序及走行线路等内容.     

Outsourcing and role stress: An empirical study of hotel spa managers

Hotel owners and managers are increasingly outsourcing their spas to specialist firms that oversee the spa's operations and personnel. In such spas the assume the role of boundary spanners as they are responsible for overseeing the operational relationship between the hotel and spa companies. In this role, they are responsible for trying to satisfy the hotel and spa companies’ often contradictory expectations while also often adhering to two sets of operating guidelines. As a result, they may experience different levels of role conflict and role ambiguity than spa managers who oversee spas managed by the hotel. The results of a questionnaire completed by 166 hotel spa managers from spas managed by hotels and those managed by third parties found greater levels of these role stressors in managers of outsourced hotel spas. Based on these findings, research suggestions and managerial implications are discussed.     

Descriptive statistics of large data sets by scatter plots, an exploratory approach

In the analysis of large tables of M variables on N observations one is interested in the relations between the variables and it is usual to inspect the M(M-1)/2 scatter plots of N points. Clearly, the scatter plot approach relies on visual inspection and is to be preferred in so far as applicable to detect simple relations, namely when M is small. Other approaches are needed for large values of M .
We consider that only the relatively few scatter plots that present a 'structure' are of interest for an exploratory analysis and, by 'structure', we mean a domain of specially high local density in the plot. Based on this concept, we propose a method constructed around two steps: the selection of the possibly interesting pairs of variables and the validation of the corresponding scatter plots. The selection of the pairs results from an algorithm based on a binary partitioning tree. The validation of the corresponding scatter plots enables the production of only those where a structure is found the recognition of a structure is derived from a statistic based on the length of the Minimum Spanning Tree constructed on the N points of the candidate scatter plot.
For illustration, we report on an industrial application where the method is routinely applied for exploratory purposes.     

基于余弦相似度(CS)和最小生成树(MST)的基金市场复杂网络研究

以中国基金市场中123家基金公司持有的投资组合为样本,综合运用余弦相似度(CS)和最小生成树(MST)方法,考量基金市场复杂网络。结果显示：各家基金公司持有股票组合的相似程度比持有债券组合的相似程度更高,表明他们持有的债券组合较之股票组合更加多元化,基金公司持有的股票相对集中于市值大、成长性高的公司。同时,全部资产投资组合、股票投资组合和债券投资组合等三类基金MST网络的节点度均服从幂律分布,表明大多数基金公司以少数强影响力基金公司为中心聚集起来,彼此之间具有较强的业务关联。此种网络结构特征可能导致市场风险向基金聚集团体集中,其抵御系统性风险的能力偏弱,也不利于满足投资者的理财多元化需求。