Sampling Returns for Realized Variance Calculations: Tick Time or Transaction Time?

This article introduces a new model for transaction prices in the presence of market microstructure noise in order to study the properties of the price process on two different time scales, namely, transaction time where prices are sampled with every transaction and tick time where prices are sampled with every price change. Both sampling schemes have been used in the literature on realized variance, but a formal investigation into their properties has been lacking. Our empirical and theoretical results indicate that the return dynamics in transaction time are very different from those in tick time and the choice of sampling scheme can therefore have an important impact on the properties of realized variance. For RV we find that tick time sampling is superior to transaction time sampling in terms of mean-squared-error, especially when the level of noise, number of ticks, or the arrival frequency of efficient price moves is low. Importantly, we show that while the microstructure noise may appear close to IID in transaction time, in tick time it is highly dependent. As a result, bias correction procedures that rely on the noise being independent, can fail in tick time and are better implemented in transaction time.     

Lung Cancer Risk from Radon in Marcellus Shale Gas in Northeast U.S. Homes

The amount of radon in natural gas varies with its source. Little has been published about the radon from shale gas to date, making estimates of its impact on radon‐induced lung cancer speculative. We measured radon in natural gas pipelines carrying gas from the Marcellus Shale in Pennsylvania and West Virginia. Radon concentrations ranged from 1,520 to 2,750 Bq/m³ (41–74 pCi/L), and the throughput‐weighted average was 1,983 Bq/m³ (54 pCi/L). Potential radon exposure due to the use of Marcellus Shale gas for cooking and space heating using vent‐free heaters or gas ranges in northeastern U.S. homes and apartments was assessed. Though the measured radon concentrations are higher than what has been previously reported, it is unlikely that exposure from natural gas cooking would exceed 1.2 Bq/m³ (<1% of the U.S. Environmental Protection Agency's action level). Using worst‐case assumptions, we estimate the excess lifetime (70 years) lung cancer risk associated with cooking to be 1.8×10^?4 (interval spanning 95% of simulation results: 8.5×10^?5, 3.4×10^?4). The risk profile for supplemental heating with unvented gas appliances is similar. Individuals using unvented gas appliances to provide primary heating may face lifetime risks as high as 3.9×10^?3. Under current housing stock and gas consumption assumptions, expected levels of residential radon exposure due to unvented combustion of Marcellus Shale natural gas in the Northeast United States do not result in a detectable change in the lung cancer death rates.     

State of the Art in Risk Analysis of Workforce Criticality Influencing Disaster Preparedness for Interdependent Systems

The objective of this article is to discuss a needed paradigm shift in disaster risk analysis to emphasize the role of the workforce in managing the recovery of interdependent infrastructure and economic systems. Much of the work that has been done on disaster risk analysis has focused primarily on preparedness and recovery strategies for disrupted infrastructure systems. The reliability of systems such as transportation, electric power, and telecommunications is crucial in sustaining business processes, supply chains, and regional livelihoods, as well as ensuring the availability of vital services in the aftermath of disasters. There has been a growing momentum in recognizing workforce criticality in the aftermath of disasters; nevertheless, significant gaps still remain in modeling, assessing, and managing workforce disruptions and their associated ripple effects to other interdependent systems. The workforce plays a pivotal role in ensuring that a disrupted region continues to function and subsequently recover from the adverse effects of disasters. With this in mind, this article presents a review of recent studies that have underscored the criticality of workforce sectors in formulating synergistic preparedness and recovery policies for interdependent infrastructure and regional economic systems.     

Discussion of “Nonparametric Bayesian Inference in Applications”: Bayesian nonparametric methods in econometrics

The use of Bayesian nonparametrics models has increased rapidly over the last few decades driven by increasing computational power and the development of efficient Markov chain Monte Carlo algorithms. We review some applications of these models in economic applications including: volatility modelling (using both stochastic volatility models and GARCH-type models) with Dirichlet process mixture models, uses in portfolio allocation problems, long memory models with flexible forms of time-dependence, flexible extension of the dynamic Nelson-Siegel model for interest rate yields and multivariate time series models used in macroeconometrics.     

Organizational Commitment over the Gendered Life Course at a Mexican Company

Mexican workplaces have changed significantly in response to the global marketplace by restructuring, downsizing, and implementing new production and administrative processes. This case study analyzes organizational commitment at a Mexican‐owned multinational corporation within the context of workplace transformation. Based on in‐depth interviews with 83 women and men, I identify two sources of commitment—family‐friendly and career‐friendly employment practices. Using the framework of the gendered life course, I show commitment fluctuated given the employees' stage in the life course. This study builds on the gender and work research by exploring how individual attributes of gender and parental status contribute to organizational commitment, but are underscored by the complexity of workplace context.     

The Dilemmas of Internationalization: Corporate Social Responsibility in the Multinational Corporation

We add to the global–local debate by highlighting concerns with the empirical and conceptual validity of the construct ‘integrated’ as it operates within corporate social responsibility (CSR). We do so by investigating the extent to which foreign national culture and related local issues are incorporated into the CSR policy of 37 multinational corporations, examining strategy development and implementation across global locations. This research suggests that integrated internationalization strategies do not resolve global and local CSR issues. In fact, they reinforce outcomes similar to global strategies, where core issues identified by headquarters are legitimated and local issues are marginalized, an outcome that appears somewhat at odds with the spirit of local responsiveness embedded in CSR thinking.     

Staying safe while consuming alcohol: a qualitative study of the protective strategies and informational needs of college freshmen

OBJECTIVE: In this qualitative study, the authors examined how students attempt to minimize harm to themselves and others when drinking. PARTICIPANTS: The authors recruited freshmen at a large, mid-Atlantic US public university during the fall semester of 2005 to participate in 8 focus groups. METHODS: The moderator's guide was developed through an iterative process that included input from experts and pilot testing. The researchers audiotaped focus group conversations, transcribed them, and subjected them to an interrater reliability check. Analysis was based on the framework of Information-Motivation-Behavioral Skills Model and a phenomenological approach. RESULTS: College students have a repertoire of coping strategies they use in an attempt to safeguard themselves and their friends from harm when drinking. Strategies encompass planning a safe context for drinking, using safety measures to minimize harm when drinking, and taking care of someone who has consumed too much alcohol. CONCLUSIONS: A harm-reduction focus that acknowledges and builds on existing protective strategies may be a promising avenue for alcohol interventions.     

Using Qualitative Methods with Poor Children in Urban Ethiopia: Opportunities &; Challenges

This paper discusses the advantages and challenges of using qualitative methods to elicit poor children’s perspectives about threats and positive influences on their wellbeing. It draws on research carried out by the author on the subjective experiences of poor children in Addis Ababa, the capital of Ethiopia in terms of their understandings of wellbeing, threats to their wellbeing, coping strategies, and positive or resilient outcomes. After a brief introduction reviewing previous approaches to child poverty in general and research on Ethiopian children in particular, the second section describes the research setting and the ethical approach to the study, which influenced how consent was obtained and the data analysed. The paper then describes the use of qualitative methods such as semi-structured interviews, draw-and-tell, and diaries, the kinds of data they produced and the methodological and ethical dilemmas and tensions encountered in using them. It concludes that despite the challenges qualitative methods are invaluable in order to understand what poor children see as threats and positive influences on their wellbeing.