Characterizing the Risk of Infection from Mycobacterium tuberculosis in Commercial Passenger Aircraft Using Quantitative Microbial Risk Assessment

Quantitative microbial risk assessment was used to predict the likelihood and spatial organization of Mycobacterium tuberculosis ( Mtb ) transmission in a commercial aircraft. Passenger exposure was predicted via a multizone Markov model in four scenarios: seated or moving infectious passengers and with or without filtration of recirculated cabin air. The traditional exponential ( k  = 1) and a new exponential ( k  = 0.0218) dose-response function were used to compute infection risk. Emission variability was included by Monte Carlo simulation. Infection risks were higher nearer and aft of the source; steady state airborne concentration levels were not attained. Expected incidence was low to moderate, with the central 95% ranging from 10⁻⁶ to 10⁻¹ per 169 passengers in the four scenarios. Emission rates used were low compared to measurements from active TB patients in wards, thus a "superspreader" emitting 44 quanta/h could produce 6.2 cases or more under these scenarios. Use of respiratory protection by the infectious source and/or susceptible passengers reduced infection incidence up to one order of magnitude.     

Fraction of design space plots for generalized linear models

The use of graphical methods for comparing the quality of prediction throughout the design space of an experiment has been explored extensively for responses modeled with standard linear models. In this paper, fraction of design space (FDS) plots are adapted to evaluate designs for generalized linear models (GLMs). Since the quality of designs for GLMs depends on the model parameters, initial parameter estimates need to be provided by the experimenter. Consequently, an important question to consider is the design's robustness to user misspecification of the initial parameter estimates. FDS plots provide a graphical way of assessing the relative merits of different designs under a variety of types of parameter misspecification. Examples using logistic and Poisson regression models with their canonical links are used to demonstrate the benefits of the FDS plots.     

The bright and dark sides of leader traits: A review and theoretical extension of the leader trait paradigm

The leader trait perspective is perhaps the most venerable intellectual tradition in leadership research. Despite its early prominence in leadership research, it quickly fell out of favor among leadership scholars. Thus, despite recent empirical support for the perspective, conceptual work in the area lags behind other theoretical perspectives. Accordingly, the present review attempts to place the leader trait perspective in the context of supporting intellectual traditions, including evolutionary psychology and behavioral genetics. We present a conceptual model that considers the source of leader traits, mediators and moderators of their effects on leader emergence and leadership effectiveness, and distinguish between perceived and actual leadership effectiveness. We consider both the positive and negative effects of specific “bright side” personality traits: the Big Five traits, core self-evaluations, intelligence, and charisma. We also consider the positive and negative effects of “dark side” leader traits: Narcissism, hubris, dominance, and Machiavellianism.     

Do leaders reap what they sow? Leader and employee outcomes of leader organizational cynicism about change

Despite increased attention given to the attitude of organizational cynicism, few studies have examined the impact of leader cynicism in organizations. The present study sought to investigate relationships between leader cynicism about organizational change (CAOC) and outcomes relevant to both the leader (performance and organizational citizenship behavior ratings) and his/her employees (employee organizational commitment and CAOC). Using data from 106 manufacturing managers, leader CAOC was found to negatively influence both leader and employee outcomes. Of particular importance, transformational leader behavior was found to fully mediate these relationships and thus served as an important explanatory mechanism. A discussion concerning the potential consequences of these findings for organizations is provided.     

Longitudinal Image Analysis of Tumor/Healthy Brain Change in Contrast Uptake Induced by Radiation

This work is motivated by a quantitative Magnetic Resonance Imaging study of the differential tumor/healthy tissue change in contrast uptake induced by radiation. The goal is to determine the time in which there is maximal contrast uptake (a surrogate for permeability) in the tumor relative to healthy tissue. A notable feature of the data is its spatial heterogeneity. Zhang, Johnson, Little, and Cao (2008a and 2008b) discuss two parallel approaches to "denoise" a single image of change in contrast uptake from baseline to one follow-up visit of interest. In this work we extend the image model to explore the longitudinal profile of the tumor/healthy tissue contrast uptake in multiple images over time. We fit a two-stage model. First, we propose a longitudinal image model for each subject. This model simultaneously accounts for the spatial and temporal correlation and denoises the observed images by borrowing strength both across neighboring pixels and over time. We propose to use the Mann-Whitney U statistic to summarize the tumor contrast uptake relative to healthy tissue. In the second stage, we fit a population model to the U statistic and estimate when it achieves its maximum. Our initial findings suggest that the maximal contrast uptake of the tumor core relative to healthy tissue peaks around three weeks after initiation of radiotherapy, though this warrants further investigation.     

Death preparation and anxiety: a survey in Hong Kong

This study reports the results of a survey on death preparation, death-related beliefs, and death anxiety in a Hong Kong sample. Respondents (N = 285) recruited from the community were asked if they have prepared for themselves a life insurance, a will, and a resting place (e.g. burial site, columbarium, etc.). Questions about their death-related cultural beliefs and anxiety were also asked. Results indicated that respondents who have thought of preparing for their own deaths but not yet acted out (contemplators) held stronger traditional cultural beliefs about death than respondents who have either done the preparations (planners) or never thought of the idea (non-contemplators). Contemplators also reported higher death anxiety. Despite limitations of the study's design, the current results suggest the beliefs in cultural taboo may play a role in the preparation for one's death.     

Parents of adults with developmental disabilities: Age and reasons for reluctance to use another caregiver

Parents of individuals with developmental disabilities differ in their expressed reluctance to use another caregiver depending on their age. Older parents, more than younger parents, reported a reluctance to use another caregiver because of financial reasons and the unavailability of qualified caregivers. The results suggest that elderly parents may be willing to leave their developmentally disabled child with someone else but they require financial assistance and education regarding program quality and availability.Jean L. Engelhardt is a Research Associate of the Family and Child Studies Center, Department of Home Economics and Consumer Sciences, at Miami University in Oxford, Ohio. Her current research is in the area of older parents of developmentally disabled children. Dr. Engelhardt received her Ph.D. in Psychology from Notre Dame.Dr. Lutzer is Assistant Professor of Educational Psychology and an Associate of the Family and Child Studies Center at Miami University in Oxford, Ohio. She is currently involved in research on the older parents of developmentally disabled children.Timothy H. Brubaker is Professor and Director of the Family and Child Studies Center, Department of Home Economics and Consumer Sciences, at Miami University in Oxford, Ohio. Dr. Brubaker holds a Ph.D. from Iowa State University and is currently conducting research on the older parents of developmentally disabled children.We express our gratitude to the Family Resource Services Program of the Butler County (Ohio) Board of Mental Retardation and Developmental Disabilities for their help, and to the Jacob G. Schmidlapp Trust of Cincinnati for financial support during the writing of this article.