Elephant-seal movements: Modelling migration

Elephant seals migrate over vast areas of the eastern North Pacific Ocean between rookeries in southern California and distant northern foraging areas. Several models of particle movement were evaluated and a model for great-circle motion found to give reasonable results for the movement of an adult female. This model takes specific account of the fact that the movement is on the surface of a sphere and that the animal is apparently heading toward a particular destination. The parameters of the motion were estimated. Such a great-circle path of migration may imply that these seals have the ability to assess their position with respect to some global or celestial cues, allowing them to continually adjust their course and achieve the most direct geodesic route between origin and destination of migration. But the navigational mechanism actually used by these seals to accomplish such feats is as yet unknown.     

90年代特大城市发展与流动人口关系探析

以上海为例，通过对流动人口的抽样调查分析，探讨人口流动与特大城市的经济结构及空间扩散效应之间的相关性，以期寻求人口流动与特大城市经济发展之间的内在规律性，为中国特大城市发展和制订人口政策提供参考。     

Bayesian analysis of single-molecule experimental data

Summary.  Recent advances in experimental technologies allow scientists to follow biochemical processes on a single-molecule basis, which provides much richer information about chemical dynamics than traditional ensemble-averaged experiments but also raises many new statistical challenges. The paper provides the first likelihood-based statistical analysis of the single-molecule fluorescence lifetime experiment designed to probe the conformational dynamics of a single deoxyribonucleic acid (DNA) hairpin molecule. The conformational change is initially treated as a continuous time two-state Markov chain, which is not observable and must be inferred from changes in photon emissions. This model is further complicated by unobserved molecular Brownian diffusions. Beyond the simple two-state model, a competing model that models the energy barrier between the two states of the DNA hairpin as an Ornstein–Uhlenbeck process has been suggested in the literature. We first derive the likelihood function of the simple two-state model and then generalize the method to handle complications such as unobserved molecular diffusions and the fluctuating energy barrier. The data augmentation technique and Markov chain Monte Carlo methods are developed to sample from the posterior distribution desired. The Bayes factor calculation and posterior estimates of relevant parameters indicate that the fluctuating barrier model fits the data better than the simple two-state model.     

Issues and place: the hyperlink network of homeowner forums and implications for collective action

This paper explores the structure and the mechanisms involved in the formation of a hyperlink network of Guangzhou city's 118 homeowner forums in the context of a collective action by the homeowners. It develops a contextual analytical framework contending that the structure of the hyperlink network is influenced by utility values and utilization capability, as well as the media and social environments that shape these values, respectively. The results of the exponential random graph models support this framework. Specifically, hyperlinks are more likely to be created among neighborhood homeowner forums when the neighborhoods are located in the same administrative district, built by the same developers, and managed by the same property management companies. Unfavorable contexts that are prone to violent confrontation hamper the creation of cross-forum hyperlinks, but media visibility increases the odds of other forums hyperlinking to homeowner forums. In addition, high levels of online engagement are positively correlated with hyperlink formation. These findings suggest that although online platforms, such as homeowner forums, play a contributory role in collective action, they have limited power in fostering cross-neighborhood coalitions in urban China.     

限制交易的不完全市场下的金融创新演进过程

金融创新的扩散引起金融创新市场交易结构的改变。根据物种演进理论,在限制交易的不完全市场框架下,本文通过数理推导的方法建立了金融创新的演进模型,该模型揭示了在交互作用的多工具的金融市场中,金融创新的演进依赖于市场经纪人的行为特性、套期保值机会的出现、足够的市场交易规模以及金融市场的完善程度。     

知识和思想传播视野中的贾谊《旱云赋》

用思想史的眼光来审视和解读《旱云赋》,是契合其时文学发展特质、汉赋的文体特征和作家创作个性的新视角,其中所包含的阴阳灾异思想有一定的历史渊源,也与时代潮流相呼应,其内涵与贾谊散文所反映的阴阳灾异思想一起,通过知识传播实现其独特的意义。     

Institutional Conditions of Economic Globalization: Effects of Antitrust and Merger Laws on the Global Integration of the Acquisition Market1

A central insight from institutional theory about markets is that they cannot operate without governing rules to guide interactions among actors. Because most of these rules are made and enforced within national borders, international economic transactions are said to suffer from an “institutional abyss,” the lack of institutional arrangements for economic exchanges. Scholars have found that the abyss can be filled by two factors: network connectedness, such as inter-governmental organizations, and intercountry economic agreements, such as the World Trade Organization or free trade. This article proposes a third factor: the global diffusion of governmental regulations. When countries adopt highly standardized regulations on a particular transaction, it provides legal familiarity for foreigners and reduces procedural uncertainty surrounding how the transaction should be executed. Using fixed-effects models on longitudinal data, I show that the adoption of antitrust and merger laws increases the volume of cross-border mergers—the transaction the laws are meant to regulate. This result stands in direct opposition to financial scholars’ predictions that antitrust and merger laws will reduce cross-border mergers because the laws are meant to restrain, not liberate, the transaction. This article theorizes how the diffusion of regulations, not the elimination of regulations, can facilitate global market integration.     

Pricing and hedging equity-indexed annuities via local risk-minimization

Lin et al. (2009) employed the Esscher transform method to price equity-indexed annuities (EIAs) when the dynamic of the market value of a reference asset was driven by a generalized geometric Brownian motion model with regime-switching. Some rare events (release of an unexpected economic figure, major political changes or even a natural disaster in a major economy) can lead to brusque variations in asset prices, and hence we sometimes need to consider jump models. This paper extends the model and analysis in Lin et al. (2009). Specifically, we assume that the financial market has a regime-switching jump-diffusion model, under which we price the point-to-point, the Asian-end, the high water mark and the annual reset EIAs by exploiting the local risk-minimization approach. The effects of the model parameters on the EIAs pricing are illustrated through numerical experiments. Meanwhile, we present the locally risk-minimizing hedging strategies for EIAs.     

André Dabrowski's work on limit theorems and weak dependence

André Robert Dabrowski, Professor of Mathematics and Dean of the Faculty of Sciences at the University of Ottawa, died October 7, 2006, after a short battle with cancer. The author of the present paper, a long‐term friend and collaborator of André Dabrowski, gives a survey of André's work on weak dependence and limit theorems in probability theory. The Canadian Journal of Statistics 37: 307–326; 2009 © 2009 Statistical Society of Canada