On an algorithm for solving Fredholm integrals of the first kind

Statistics and Computing - In this paper we use an iterative algorithm for solving Fredholm equations of the first kind. The basic algorithm and convergence properties are known under certain...     

Family Influences on College Students' Anticipated Work-Family Conflict,Social Self-Efficacy,and Self-Esteem

The authors sought to test work-family conflict (WFC) theory by examining how family relationships may influence WFC, social self-efficacy, and self-esteem. They developed and tested a structural model of the relationship between family career influence and self-esteem through the mediating variables of anticipated emotion-based WFC, behavior-based WFC, and the cognitive variable of social self-efficacy. Data were collected from 301 college students (208 women, 93 men) and analyzed using structural equation modeling. Results indicated that family career influence positively related to college students' self-esteem through the mediating variables of social self-efficacy and emotion-based WFC. Behavior-based WFC did not function as a mediating variable. When focusing on issues related to students' self-esteem, career counselors should address ways that family influences anticipated emotion-based WFC and use interventions designed to increase social self-efficacy. Future researchers should consider and test additional mediating factors that may help explain how the dimensions of WFC relate to self-esteem.     

Common Factors' Role in Accredited MFT Training Programs

Common factors proponents discuss the benefits and methods of including common factors in marriage and family therapy (MFT) training; yet there are no empirical investigations of how common factors are incorporated into MFT curricula. The purpose of this study was to obtain a baseline understanding of common factors' role in MFT training. Thirty‐one directors of COAMFTE‐ and CACREP‐accredited MFT training programs responded to a survey about the inclusion of common factors in their training program, as well as the benefits, challenges, and students' reactions to common factors training. Findings show that common factors are regularly included in MFT training programs and have garnered largely positive responses. Additional results are discussed regarding the implications of common factors in MFT training.     

Relationship based social work practice: the case for considering the centrality of humour in creating and maintaining relationships

Relationship based social work practice has received increasing attention in recent years. The use of humour has infrequently been considered in relation to social work, and humour use is a neglected aspect in examining relationships in social work. As humour conveys humanity, is grounded in our earliest attachments and in the management of emotions, the purpose of this paper is to consider how humour operates in social work relationships. Importantly humour can help facilitate relationships with service users, and become a tool to help service users, social workers and their colleagues establish relationships.     

Contrasting effects of urban habitat complexity on metabolic functional diversity and composition of litter and soil bacterial communities

Functional diversity and composition of soil bacterial communities affect important soil biogeochemical processes. In natural and semi-natural ecosystems, variations in habitat complexity have been shown to significantly impact both litter and soil bacterial communities. However, this remains largely untested in urban ecosystems, where human management can lead to habitat complexity combinations unobserved in rural ecosystems. We established 10 research plots in low-complexity park, high-complexity park, and high-complexity remnant habitat types (n = 30) in Melbourne, Australia. The use of organic carbon substrates by soil and litter bacteria was measured using EcoPlates to investigate the effects of habitat complexity upon metabolic functional diversity and functional composition of bacterial communities of i) soil and ii) one-year old litter. Direct and indirect effects of habitat complexity, microclimate and decomposition status upon litter microbial functional diversity and composition were also modelled using path analysis. Soil bacterial communities had significantly higher functional diversity compared to litter bacterial communities, but no significant effect of habitat complexity was apparent. The functional composition of soil bacterial communities was not affected by habitat complexity. In contrast, the functional composition of litter bacterial communities in high complexity parks and remnants was significantly different from that in low-complexity parks. The functional composition of litter bacterial communities, but not their diversity, was directly affected by habitat complexity and microclimate as well as their indirect effects upon the decomposition status of litter. Human management of urban habitat complexity can alter the functional composition of litter and soil bacterial communities without affecting their functional diversity. While this can have significant impacts on bacteria-regulated processes and ecosystem services, it also suggests that urban bacterial communities might be able to adjust to further environmental and climatic changes affecting urban ecosystems.     

A comparison of the Hosmer–Lemeshow,Pigeon–Heyse,and Tsiatis goodness-of-fit tests for binary logistic regression under two grouping methods

Algebraic relationships between Hosmer–Lemeshow (HL), Pigeon–Heyse (J²), and Tsiatis (T) goodness-of-fit statistics for binary logistic regression models with continuous covariates were investigated, and their distributional properties and performances studied using simulations. Groups were formed under deciles-of-risk (DOR) and partition-covariate-space (PCS) methods. Under DOR, HL and T followed reported null distributions, while J² did not. Under PCS, only T followed its reported null distribution, with HL and J² dependent on model covariate number and partitioning. Generally, all had similar power. Of the three, T performed best, maintaining Type-I error rates and having a distribution invariant to covariate characteristics, number, and partitioning.     

Estimating and contextualizing the attenuation of odds ratios due to non collapsibility

The odds ratio is a measure commonly used for expressing the association between an exposure and a binary outcome. A feature of the odds ratio is that its value depends on the choice of the distribution over which the probabilities in the odds ratio are evaluated. In particular, this means that an odds ratio conditional on a covariate may have a different value from an odds ratio marginal on the covariate, even if the covariate is not associated with the exposure (not a confounder). We define the individual odds ratio (IORs) and population odds ratios (PORs) as the ratio of the odds of the outcome for a unit increase in the exposure, respectively, for an individual in the population and for the whole population, in which case the odds are averaged across the population. The attenuation of conditional odds ratio, marginal odds ratio, and PORs from the IOR is demonstrated in a realistic simulation exercise. The degree of attenuation differs in the whole population and in a case–control sample, and the property of invariance to outcome-dependent sampling is only true for the IOR. The relevance of the non collapsibility of odds ratios in a range of methodological areas is discussed.     

Tabulations for value at risk and expected shortfall

Value at risk and expected shortfall are the two most popular measures of financial risk. Here, we tabulate expressions for both these measures for over 100 parametric distributions, including all commonly known distributions, and illustrate a data application. We expect that this collection of expressions could serve as a source of reference and encourage further research with respect to measures of financial risk.     

On-the-Job Search,Mismatch and Worker Heterogeneity

This paper empirically examines the search behavior of currently employed workers to understand changes in on-the-job search across different types of employed individuals and varying labor market conditions. Using data from the American Time Use Survey, we estimate the responsiveness of workers with varying levels of productivity and job-match quality to regional labor market conditions. We find that those workers who are less-productive, mismatched in their current position, and high-productivity, mismatched workers are more likely to engage in search than other workers. These results have implications for models built on job mismatch, as well as for models seeking to explain increasing inequality and wage dispersion.