Estimation of Asymmetric Stochastic Volatility Models: Application to Daily Average Prices of Energy Products

Energy supply and demand, and as a consequence energy prices, are likely to represent one of the biggest challenges of the 21st century. Commodity markets exhibit increased volatility when there is little or no underutilized supply capability to meet natural fluctuations in demand. In the case of energy markets, the large capital requirements and significant lead times associated with energy production and delivery make them more susceptible to the imbalances in supply capability and demand. Energy price volatility has destructive impact on market agents, and this impact is intensified when the prices exhibit asymmetric volatility. This article pursues two aspects of the issue. First we consider general aspects, especially the asymmetric pattern of volatility of daily returns of different types of energy products. Then, we analyze the behaviour of daily returns by using traditional models of volatility that include AGARCH, TGARCH, EGARCH, and ARSV strategies, as well as a threshold asymmetric autoregressive stochastic volatility (TA-ARSV) model that we propose. The energy products considered in this analysis are probably the most relevant energy products for the economic activity of the nations and the economic relations between countries: Crude Oil (OPEC reference basket and London Brent index), Gasoline, Natural Gas, Butane, and Propane. We use spot prices and the time reference ranges from 1986–1993 to 2009 depending on the product.     

Whatever works: Uncertainty and technological hybrids in medical innovation

The persistent uncertainty that looms over the search for solutions to health problems offers important conceptual insights for the study of technological change. This paper explores the notion of hybridization, namely the embodiment of multiple competing operational principles within a single medical device, as strategy to deal with the practical shortcomings due to said uncertainty. The history of the development of the hybrid artificial disc affords the elaboration of an alternative view of hybridization and, at the same time, the articulation of a dualism between medical science as area of basic research (e.g. what disease is) and as practical knowledge (e.g. how disease can be tackled).     

通货膨胀实时预测及菲利普斯曲线的适用性

本文从实时分析的视角,基于多种退势方法的产出缺口最终估计、准最终估计和实时估计序列,分别构建了四类预测模型对我国通货膨胀率进行预测,分析了产出缺口修正效应和滞后阶数变化效应对通胀预测的影响,并进一步考察了产出缺口在通胀预测中的作用及菲利普斯曲线在通胀预测中的适用性。研究结论表明,通胀率的实时预测效果要明显比基于最终数据的差,其中滞后阶数变化效应对实时预测精度的影响大于产出缺口修正效应;尤为重要的是,尽管在最终数据的预测分析中,产出缺口的引入能够提高通胀率的预测精度,但是在实时预测中,产出缺口没有提供有价值的信息,因此"产出—通胀"型菲利普斯曲线在我国通胀实时预测中并不适用。     

上海民族茶商变迁与近代中国茶业组织的发展

上海是近代中国茶叶出口的主要口岸,其民族茶商演变在一定程度上反映了近代中国茶业组织的特点及其变迁历史。"分包"式结构是中国茶业组织的主要特征,它是对茶叶小生产种植方式路径依赖的结果。近代中国茶业竞争力提升有赖于产业组织从"分包"到整合的转变,但洋行对出口经营的垄断制约着这种变迁。     

中国知识服务业国际竞争力研究

中国知识服务业的发展还处于初步阶段,国际竞争力水平存在较大差异,中国要建立创新型社会,就要注重知识服务业的发展,要从战略高度制定知识服务业相应的发展规划,建立相应的支撑体系,发挥政府职能作用,培养和引进专业人才,发展壮大知识服务企业等。     

生物样品中毒品检测的研究进展

毒品滥用已经成为当今日益严峻的全球问题,它给人们和社会带来了各种各样的严重危害,因此对生物样品中毒品物质的检测就变成当务之急。本文主要介绍了几种较为新颖的毒品检测技术,以及它们的研究进展。     

系统思考理论在部队装备管理信息化建设中的应用

系统思考是一种有效地解决复杂性问题的崭新思维模式和科学方法。部队装备管理信息化建设是当前我军装备管理领域着力进行的一项系统工程,以系统思考理论为指导,对于科学认识和指导部队装备管理信息化建设具有重要意义。从系统思考的基本理论着手,分析了系统思考在部队装备管理信息化建设中的重要作用,并在系统思考理论的指导下提出了有助于部队装备管理信息化建设的建议,为科学推动部队装备管理信息化建设提供参考。     

数字资源长期保存的技术保障机制

合理采用相关技术,建立数字资源长期保存系统并使其具有可持续性和可扩展性,使数字文献资源达到长期保存的目标,需要文献机构从管理上建立相应的技术保障机制。文章提出数字资源长期保存的技术保障机制建设的基本原则并从保存策略、研究跟踪、研究开发、组织保障、人员培养等5个方面进行机制的研究与建设。     

基于生态视角下的城市交通生态规划探讨

针对现代城市的交通现状及所遇到的问题,并结合现代城市逐渐趋向建设生态城市的形势,探讨城市交通的生态规划,并对城市交通生态规划的原则与实施进行研究。     

Organising migrant workers: the living wage campaign at the University of East London

This critical case study looks at the campaign led by Citizens UK and Unison to get the University of East London (UEL) to sign up to the London living wage (LLW). UEL agreed to pay the LLW after a brief campaign in November 2010 and it was subsequently implemented in August 2011. The study charts the course of the campaign and draws on mobilisation theory and new primary research to account for its success. What our findings suggest is that community organisers and union activists were able to organise and mobilise a largely apolitical group of migrant workers. This, we suggest, can be explained by the successful mobilisation of the community and augurs well for future broad‐based campaigns.