A Risk-Based Approach to Setting Priorities in Protecting Bridges Against Terrorist Attacks

This article presents an approach to the problem of terrorism risk assessment and management by adapting the framework of the risk filtering, ranking, and management method. The assessment is conducted at two levels: (1) the system level, and (2) the asset-specific level. The system-level risk assessment attempts to identify and prioritize critical infrastructures from an inventory of system assets. The definition of critical infrastructures offered by Presidential Decision Directive 63 was used to determine the set of attributes to identify critical assets--categorized according to national, regional, and local impact. An example application is demonstrated using information from the Federal Highway Administration National Bridge Inventory for the State of Virginia. Conversely, the asset-specific risk assessment performs an in-depth analysis of the threats and vulnerabilities of a specific critical infrastructure. An illustration is presented to offer some insights in risk scenario identification and prioritization, multiobjective evaluation of management options, and extreme-event analysis for critical infrastructure protection.     

Estimating the Ozone Depletion Potential of Methyl Bromide

Ozone depletion potential (ODP) represents the cumulative ozone depletion induced by a particular halocarbon relative to a reference gas (usually trichlorofluoromethane, CFC-11). We focus on ODP estimation for methyl bromide. Previous attempts at its estimation have assumed that components of the ODP equation are lognormally distributed. By considering a wide range of modeling scenarios, we show that this restriction (which is based on computational convenience rather than experimental evidence) has obscured the true uncertainty in the ODP value. Moreover, when publishing point estimates for the ODP value, previous authors have given either mean or median values. We submit that a more appropriate choice for a point estimate is the mode since the distribution of ODP is skewed and since the mode is by definition, the most likely value. For each modeling scenario considered, modal values are given. In general, we find these ODP point estimates are considerably lower than those published elsewhere.     

MODES OF EXPRESSION IN FAMILY THERAPY: A PROCESS STUDY OF ROLES AND GENDER*

Twenty-two two-parent families with a referred adolescent were seen by 11 male and 11 female trainees in family therapy. Mothers, fathers, adolescents, and therapists were rated for verbal expression in affective, behavioral, and cognitive! attributional modes during the first session. Results clearly point to role and content difference in modes of expression. Of particular importance are differences by role which occured as a function of therapist gender. These differences suggest that therapist gender has an impact on family therapists' and family members' verbalizations in first sessions of family therapy.     

Co-creative Leadership: An Integrated Approach towards Transformational Leadership

The classical understanding of team leadership is extremely difficult to sustain in times when complexity and dynamics have risen to such high levels that very few individuals can assimilate them. The success of team leadership requires the ``participation of those already implicated'' in the development and implementation of a solution – and therefore in the leadership process. How can this be achieved practically? It requires a leadership approach that allows each relevant perspective to be included, in a practical way, in the development of a common position, which can then be implemented collectively. Co-creative leadership creates this possibility – a transformational leadership approach that allows an organisation as a whole to adapt to its environment.     

Factor Multivariate Stochastic Volatility via Wishart Processes

This paper proposes a high dimensional factor multivariate stochastic volatility (MSV) model in which factor covariance matrices are driven by Wishart random processes. The framework allows for unrestricted specification of intertemporal sensitivities, which can capture the persistence in volatilities, kurtosis in returns, and correlation breakdowns and contagion effects in volatilities. The factor structure allows addressing high dimensional setups used in portfolio analysis and risk management, as well as modeling conditional means and conditional variances within the model framework. Owing to the complexity of the model, we perform inference using Markov chain Monte Carlo simulation from the posterior distribution. A simulation study is carried out to demonstrate the efficiency of the estimation algorithm. We illustrate our model on a data set that includes 88 individual equity returns and the two Fama-French size and value factors. With this application, we demonstrate the ability of the model to address high dimensional applications suitable for asset allocation, risk management, and asset pricing.     

Clinical gait and stepping performance measures in older adults

Problems with ambulation and mobility are frequent problems in older adults. Each year, about one in 100 older adults develops new severe mobility disability. Assessment of abnormal gait constitutes a major component of clinical practice and may lead to fall reduction. Clinicians can benefit from simple gait and mobility assessment tools to be used in busy clinical settings. This review focuses on gait and stepping performance measures that can be used by the busy clinician to assess gait, mobility performance, balance, and falls risk in the older adult.     

Book reviews

Wojciech Gasparski (ed.) Projektoznawstwo (Elementy wiedzy o projektowaniu) (The discipline of projest making. The elements of knowledge). Warsaw, Wydawnictow Naukowo‐Techniczne, 1988.