Bacterial diversity and ecosystem functioning (BEF) relationships have received considerable attention during the last three decades and tend to be positive in most cases. However, most studies were done in closed systems and largely ignored the importance of placing local communities into the metacommunity context, in which dispersal can be a crucial factor modifying community diversity and composition and ecosystem functioning. The aim of this study was to investigate the effects of both diversity and dispersal on the responses of bacterial community to a starvation perturbation. To achieve this, we implemented a batch culture experiment using the dilution-to-extinction approach to create a diversity gradient of local bacterial community richness. Different dispersal rates were manipulated by transferring cells in different quantities from a regional source to the cultures, and they were then exposed to a perturbation by transferring them into water from another lake which differed in organic carbon content and quality. We evaluated the BEF relationship by measuring the bacterial community composition using t-RFLP and multiple ecosystem functions. Generally, our results demonstrated that diversity and dispersal have an interactive and positive effect on ecosystem functioning. In particular, dispersal had a stronger and more pronounced effect on ecosystem functioning when bacterial diversity was low. When evaluating the responses of bacterial community respiration, no significant difference was observed among different treatments, however, there were clear differences in substrate utilization patterns, implying that specific functions, such as decomposing certain substrates, are more sensitive to a perturbation than general functions, such as respiration. Therefore it is important to include multiple functional parameters when studying BEF relationships and, in particular, when applying our knowledge to the conservation of natural environments.

This study investigated the mental health of high school students enrolled in the International Baccalaureate (IB) High School Diploma Program (n =139) in a large, southeastern high school. Mental health was assessed using both positive indicators (life satisfaction, academic achievement, academic self-efficacy) and negative indicators (psychopathology) indicators of adolescent social-emotional and school functioning. Findings from this study include that IB students perceive more stress than their general education peers, yet maintain mental health that is equivalent or superior to that of their general education peers. The role of coping in predicting mental health outcomes in IB students was also investigated. Findings indicate that specific coping styles are differentially related to mental health outcomes in this sub-population of adolescents. Furthermore, coping styles moderate the influence of stress on global life satisfaction and internalizing psychopathology. These findings suggest that participation in the academically rigorous and time-intensive IB program is not harmful to the mental health of high school students, and in fact may be beneficial, as evidenced by the superior academic functioning of students in the IB program.

Advances in cancer treatment have led to a significant increase in the number of pediatric oncology survivors. These survivors often have late effects in their cognitive, academic, executive, and psychological functioning subsequent to their chemotherapy and radiation treatment. In particular, executive functioning (EF), which is crucial for cognitive and academic functioning, has been recognized as an area that is impacted by treatment. Several studies have described cognitive remediation programs that seek to improve EF skills in pediatric oncology survivors. Although these programs have led to improvements in EF skills, they are often difficult to replicate due to the extensive time requirement. Many survivors also experience distress and anxiety and would likely benefit from cognitive behavioral therapy, which has been shown to be an effective intervention for children with internalizing disorders. Thus, a brief intervention that combines treatment for executive functioning and psychological distress is warranted. A mixed methods study was conducted to evaluate the impact of a nine-week blended cognitive remediation and cognitive behavior therapy group for pediatric oncology survivors and their parents. Participants were pediatric cancer survivors, age 9-14, and their parents who were referred through a local children's hospital that specialized in oncology treatment. Pre and post measures of EF, psychological functioning, and parental stress were examined. Semi-structured interviews with participants and their parents were completed and analyzed to learn more about the function of short-term group therapy for pediatric oncology survivors. Content analysis of the parent support group sessions was also conducted. Significant changes were found for youth internalizing symptoms, youth adaptive skills, youth executive functioning, and parental stress. There was also a positive correlation between parental stress and parent-rated youth internalizing problems as well as parent-rated youth behavioral symptoms and a negative correlation between parental stress and parent-rated youth adaptive behavior. Qualitative interviews indicated that participants felt that the intervention was helpful. Themes from the parent group included the challenge of managing late effects, balancing multiple roles, and coping with distress. Implications, limitations, and recommendations for further areas of research are presented. / text

The aim of this research was to establish what black adults' perceptions are of factors that contribute to healthy family functioning. Qualitative research was conducted. Random sampling was used to obtain eighteen black participants between the ages of 20 and 50. These participants responded in writing to the following open ended question: "What factors do you think contribute to healthy family functioning?" Semi-structured interviews were also conducted with the eight participants who presented with the richest data. Analysis of the data yielded 10 prevalent themes and eleven other themes. The 10 prevalent themes were: respect, love, communication, family time/spending time together, trust, understanding, discipline, availability for each other, boundaries and religion. The other eleven themes were: personal space, responsibility, hierarchy, family rules, conflict handling, morality, roles, maturity, intelligence, culture and forgiveness. The above mentioned 21 themes were grouped in seven broad categories, namely communication, conflict handling, affectionate involvement, family rules, boundaries, religion and other dimensions. All these themes were compared to existing research results. It appeared that themes of this study correspond with many dimensions of family functioning as indicated by family therapy models and existing research. Participants also indicated new dimensions not mentioned by the existing literature. Recommendations were made concerning future research. / Thesis (M.A. (Clinical Psychology))--North-West University, Potchefstroom Campus, 2005.

In response to public concern over fairness in testing, conducting a differential item functioning (DIF) analysis is now standard practice for many large-scale testing programs (e.g., Scholastic Aptitude Test, intelligence tests, licensing exams). As highlighted by the Standards for Educational and Psychological Testing manual, the legal and ethical need to avoid bias when measuring examinee abilities is essential to fair testing practices (AERA-APA-NCME, 1999). Likewise, the development of statistical and substantive methods of investigating DIF is crucial to the goal of designing fair and valid educational and psychological tests. Douglas, Roussos and Stout (1996) introduced the concept of item bundle DIF and the implications of differential bundle functioning (DBF) for identifying the underlying causes of DIF. Since then, several studies have demonstrated DIF/DBF analyses within the framework of “unintended” multidimensionality (Oshima & Miller, 1992; Russell, 2005). Russell (2005), in particular, examined the effect of secondary traits on DBF/DTF detection. Like Russell, this study created item bundles by including multidimensional items on a simulated test designed in theory to be unidimensional. Simulating reference group members to have a higher mean ability than the focal group on the nuisance secondary dimension, resulted in DIF for each of the multidimensional items, that when examined together produced differential bundle functioning. The purpose of this Monte Carlo simulation study was to assess the Type I error and power performance of SIBTEST (Simultaneous Item Bias Test; Shealy & Stout, 1993a) for DBF analysis under various conditions with simulated data. The variables of interest included sample size and ratios of reference to focal group sample sizes, correlation between primary and secondary dimensions, magnitude of DIF/DBF, and angular item direction. Results showed SIBTEST to be quite powerful in detecting DBF and controlling Type I error for almost all of the simulated conditions. Specifically, power rates were .80 or above for 84% of all conditions and the average Type I error rate was approximately .05. Furthermore, the combined effect of the studied variables on SIBTEST power and Type I error rates provided much needed information to guide further use of SIBTEST for identifying potential sources of differential item/bundle functioning.

The aim of this research was to establish what black adults' perceptions are of factors that contribute to healthy family functioning. Qualitative research was conducted. Random sampling was used to obtain eighteen black participants between the ages of 20 and 50. These participants responded in writing to the following open ended question: "What factors do you think contribute to healthy family functioning?" Semi-structured interviews were also conducted with the eight participants who presented with the richest data. Analysis of the data yielded 10 prevalent themes and eleven other themes. The 10 prevalent themes were: respect, love, communication, family time/spending time together, trust, understanding, discipline, availability for each other, boundaries and religion. The other eleven themes were: personal space, responsibility, hierarchy, family rules, conflict handling, morality, roles, maturity, intelligence, culture and forgiveness. The above mentioned 21 themes were grouped in seven broad categories, namely communication, conflict handling, affectionate involvement, family rules, boundaries, religion and other dimensions. All these themes were compared to existing research results. It appeared that themes of this study correspond with many dimensions of family functioning as indicated by family therapy models and existing research. Participants also indicated new dimensions not mentioned by the existing literature. Recommendations were made concerning future research. / Thesis (M.A. (Clinical Psychology))--North-West University, Potchefstroom Campus, 2005.

Cognitive functioning is disrupted during a depressive episode and cognitive dysfunction persists when depression is in remission. A subtype of depressed individuals who exhibit elevated inflammatory biomarkers may be at particular risk for cognitive dysfunction. We examined whether an elevated inflammatory biomarker (C-reactive protein: CRP) in acute and/or remitted depression was associated with specific deficits in executive functioning, episodic memory, and verbal fluency. Data were drawn from a population-based sample of Dutch adolescents (N = 1,066; 46% male) recruited at the age of 11 and followed over the course of eight years. We tested whether adolescents with either, (i) a history of depression (Wave 1 – 3) or (ii) current depression (Wave 4), and elevated levels of C-reactive protein measured in blood at Wave 3 performed worse on cognitive assessments at Wave 4. Eight measures of cognitive functioning were hypothesized to load on to one of three dimensions of cognitive functioning (executive functioning, episodic memory, and verbal fluency) within a structural equation model framework. Higher levels of CRP were associated with worse future executive functioning in adolescents with and without current/prior depression. A current depression diagnosis also was associated with worse future executive functioning. There was consistent evidence linking low socioeconomic status and health-related covariates (high body mass index/sedentary behavior) with worse performance across multiple measures of cognitive functioning and, importantly, the association of depression/CRP and executive functioning was no longer significant when controlling for these covariates. Future studies may benefit from investigating whether specific depressogenic behaviors (e.g., sedentary behavior/substance use) mediate a relationship between depression and worse executive functioning, potentially via a prospective pathway through elevated inflammation. / Psychology

No description available.

Objective: Grit is a noncognitive trait related to perseverance and consistent pursuit of long-term goals. Research on grit and aging provides evidence that grit increases with age and may be protective of cognitive and everyday functioning. However, no studies to date have examined relations between concurrently measured grit, cognitive abilities, and everyday functioning. This study tested two hypotheses: 1) that grit would predict cognitive performance and that this relation would be moderated by clinical diagnosis of cognitive status (i.e., healthy vs. mild cognitive impairment; MCI), and 2) that grit would predict everyday functioning and that this effect would be mediated by compensatory strategy use. Methods: Sixty-one older adults were recruited from the Penn Memory Center’s National Alzheimer’s Coordinating Center (NACC) cohort, including forty healthy controls with normal cognition and twenty-one individuals with mild cognitive impairment (MCI). Participants completed tests of verbal episodic memory, executive functioning, grit, compensatory strategy use, and everyday functioning. Results: Grit was not associated with cognitive functioning in either domain. Instead, memory performance was predicted only by clinical status (healthy vs. MCI), and executive functioning was predicted by clinical status, depressive symptoms, and years of education. Grit was negatively associated with everyday functional difficulties; however, there was no indirect effect of compensatory strategy use. Additionally, grit was moderately correlated with depression symptoms (r = -0.41). Conclusions: Grit is predictive of preserved everyday functioning, but not cognitive functioning, in a sample of healthy older adults and individuals with MCI. Mechanisms explaining the role of grit on everyday function remain elusive, though secondary analyses support that grit also influences affective well-being and may have a weaker role in the context of cognitive impairment. / Psychology

No description available.