Conditional moving linear regression: Modeling the recruitment process for ALLHAT

Effective recruitment is a prerequisite for successful execution of a clinical trial. ALLHAT, a large hypertension treatment trial (N = 42,418), provided an opportunity to evaluate adaptive modeling of recruitment processes using conditional moving linear regression. Our statistical modeling of recruitment, comparing Brownian and fractional Brownian motion, indicates that fractional Brownian motion combined with moving linear regression is better than classic Brownian motion in terms of higher conditional probability of achieving a global recruitment goal in 4-week ahead projections. Further research is needed to evaluate how recruitment modeling can assist clinical trialists in planning and executing clinical trials.     

Double trouble: work–family conflict and well-being for second job holders

The purpose of this study was to provide an initial investigation into the work–family conflict (WFC) experiences of individuals who hold a second job. Specifically, we proposed two opposing theoretical arguments regarding the relationship between WFC and four measures of well-being: life satisfaction, physical health, emotional exhaustion, and exercise for individuals who hold two jobs. In a sample of individuals working two jobs, we tested whether the effects of WFC arising from the first job and from the second job exerted an additive or interactive effect on employee well-being. Our results indicated that for emotional exhaustion, physical symptoms, and life satisfaction, the effects of WFC from two jobs are interactive; but that for exercise, the effects of WFC from two jobs are additive. In both cases, the additional WFC experienced as a result of working a second job contributed to the prediction of employee well-being over and above WFC from the first job. Results are discussed within the context of relevant theory, and suggestions are made for future research.     

Different Effects of Acculturative Stress and Family Life Stress on Depressive Symptoms among Married Vietnamese Immigrant Women in South Korea

Married Vietnamese immigrant women often face multiple stressors related to sociocultural adaptation and new family lives in South Korea. The purpose of this paper is to identify the different influences of acculturative and family life stress on depressive symptoms among Vietnamese immigrant wives. Data were collected through a questionnaire survey of 301 married Vietnamese immigrant women residing in South Korea. The study utilized linear regression analysis to test the relationships between the variables. The findings show that both acculturative and family life stress are positively related to depressive symptoms. Family life stress influences depressive symptoms to a greater extent than acculturative stress. The study emphasizes the significance of family‐related stress on mental health among married Vietnamese immigrant women in Korea and provides some implications for research, clinical practice, and policy.     

Urban and agricultural soils: conflicts and trade-offs in the optimization of ecosystem services

On-going human population growth and changing patterns of resource consumption are increasing global demand for ecosystem services, many of which are provided by soils. Some of these ecosystem services are linearly related to the surface area of pervious soil, whereas others show non-linear relationships, making ecosystem service optimization a complex task. As limited land availability creates conflicting demands among various types of land use, a central challenge is how to weigh these conflicting interests and how to achieve the best solutions possible from a perspective of sustainable societal development. These conflicting interests become most apparent in soils that are the most heavily used by humans for specific purposes: urban soils used for green spaces, housing, and other infrastructure and agricultural soils for producing food, fibres and biofuels. We argue that, despite their seemingly divergent uses of land, agricultural and urban soils share common features with regards to interactions between ecosystem services, and that the trade-offs associated with decision-making, while scale- and context-dependent, can be surprisingly similar between the two systems. We propose that the trade-offs within land use types and their soil-related ecosystems services are often disproportional, and quantifying these will enable ecologists and soil scientists to help policy makers optimizing management decisions when confronted with demands for multiple services under limited land availability.     

The Pacific Rim Library: A Surprising Pearl

The Pacific Rim Library (PRL) is an initiative of the Pacific Rim Digital Library Association (PRDLA). The project began in 2006 using the OAI-PMH paradigm and now holds over 300,000 records harvested from OAI data provider libraries around the Pacific. PRL's goal is to enable the sharing of digital collections amongst PRDLA members and the world, but greater unexpected benefits have been discovered. Through mirroring their metadata, PRL increases the chance that their data will be discovered in Google and other general search engines. With its many disparate collections, PRL is not a repository for traditional information discovery and retrieval. Initially users will bounce from a Google hit to the PRL metadata record in Hong Kong and then begin an intensive search on the original site which hosts the full digital object, in Vancouver, Honolulu, Wuhan, Singapore, or other PRDLA member location.     

Leadership,information, and risk attitude: A game theoretic approach

This paper experimentally investigates how risk attitudes mitigate leadership effectiveness in a collective setting with projects that exhibit both free riding and coordination problems. We take two novel approaches: 1) the introduction of economic game theory to psychological studies of leadership, and 2) the application of the leadership ontology of Drath et al. (2008) as a cross-disciplinary integrative framework. Leadership here is focused on the presence or absence of direction, alignment, and commitment as well as antecedent beliefs and practices that are held within a collective (for us, our experimental participants). Our leadership context is stripped down to very minimal conditions: three group members, an investment decision, and the introduction of information regarding group members' attitudes toward risk. We find that the mere mention of risk attitude (whether risky or risk averse) undermines leadership effectiveness in mitigating free riding for our 420 experimental participants. Our study's primary implications lie in the application of game theory methodology to the psychological study of leadership, the introduction of relevant individual difference constructs to economic studies of leadership, and the advocation of the Drath et al. (2008) framework as a helpful integrative mechanism for interdisciplinary leadership research.     

On gart's test for interaction of second order

Gart (1972) ottered a Statistic on testing the hypothesis of no second-order interaction in a 2×s×t contingency table. The statistic was tn be used as an asymptotic chi-square with (s-1) (t-1) degrees of freedom. We show that this statistic suiters from the drawback that unless certain side conditions hold, the statistic would reject the null hypothesis with probability approaching one asymptotically even in the null case. Hence the statistic is not strictly valid for the hypothesis for which it was intended.     

Distributions of the ratios of independent beta variables and applications

We establish the exact expressions of X₁/X₂ and of X₁/(X₁+X₂), where X₁ and X₂ are independent beta random variables of the first type, and provide some of their applications, in reliability and availability.