The effect of chalk on the finger–hold friction coefficient in rock climbing

The main purpose of this study was to examine the effect of chalk on the friction coefficient between climber's fingers and two different rock types (sandstone and limestone). The secondary purpose was to investigate the effects of humidity and temperature on the friction coefficient and on the influence of chalk. Eleven experienced climbers took part in this study and 42 test sessions were performed. Participants hung from holds which were fixed on a specially designed hang board. The inclination of the hang board was progressively increased until the climber's hand slipped from the holds. The angle of the hang board was simultaneously recorded by using a gyroscopic sensor and the friction coefficient was calculated at the moment of slip. The results showed that there was a significant positive effect of chalk on the coefficient of friction (+18.7% on limestone and +21.6% on sandstone). Moreover sandstone had a higher coefficient of friction than limestone (+15.6% without chalk, +18.4% with chalk). These results confirmed climbers' belief that chalk enhances friction. However, no correlation with humidity/temperature and friction coefficient was noted which suggested that additional parameters should be considered in order to understand the effects of climate on finger friction in rock climbing.     

A Two-Year Longitudinal Study of Stressful Life Events, Social Support, and Social Problem-Solving Skills: Contributions to Children''s Behavioral and Academic Adjustment

We investigated the contributions of stressful life events and resources (social support and social problem-solving skills) to predicting changes in children's adjustment. At Time 1, 361 third through fifth graders completed measures of social support and social problem-solving skills. Their parents completed a stressful life events scale and a child behavior rating measure. The children's teachers provided ratings of behavioral and academic adjustment. 2-year follow-up data (Time 2) were obtained for approximately half of the sample on the same measures. Time 1 stressful life events and resources showed some significant but modest zero-order correlations with the Time 2 adjustment indices. Hierarchical multiple regressions revealed prospective effects for Time 1 social support on later teacher-rated competencies and grade-point average. In addition, increases over time in social support and social problem-solving skills (a composite score) were significantly related to improvement in behavioral and academic adjustment, whereas stressful life events were not predictive of adjustment.     

Motivational climates: assessing and testing how science classroom environments contribute to undergraduates’ self-determined and achievement-based science goals

The current research examined the psychometric properties and utility of a measure of college classroom environment in predicting goal-related outcomes rooted in goal contents and achievement goal theories. Exploratory and confirmatory factor analyses in Studies 1 and 2, respectively, yielded support for two distinct and gender-invariant classroom environment constructs—professorial concern and affiliation. Results of multilevel regression analyses in Study 3 indicated that both constructs were positive predictors of intrinsic and self-approach goals. Additionally, professorial concern was a significant positive predictor of extrinsic goal adoption. Contrary to expectation, perceptions of affiliation in the science classroom were unrelated to task-approach goals. These findings illustrate the important role that socially dynamic classroom contexts play in fostering motivation and satisfying basic needs for autonomy, competence, and relatedness.     

The effects of early sexual abuse on adult risky sexual behaviors among persons with severe mental illness

OBJECTIVE: There were two aims: first, to examine the relationship between prior sexual abuse and three types of adult risky sexual behaviors [(1) ever traded sex for drugs or money, (2) had unprotected sex in the past 6 months, and (3) frequency of unprotected sex in the past 6 months] among persons with severe mental illness (SMI), and second, to examine the potential mediating effects of adult rape, substance use, and PTSD. METHOD: Using a pooled sample of individuals with SMI (N=609), logistic and negative binomial regression analyses were used to investigate the impact of prior sexual abuse on these adult risky sexual behaviors. RESULTS: Childhood sexual abuse was associated with having ever traded sex for money and having engaged in unprotected sex in the past 6 months. However, childhood sexual abuse was inversely associated with the number of times males had unprotected sex in the past 6 months. Results differed between males and females and the impact of potential mediators also varied by gender and type of outcome studied. CONCLUSION: These findings suggest a complex link between childhood sexual abuse and adult risky sexual behaviors in persons with SMI. Clinical assessments of child abuse sequelae should include a variety of indicators and parameters of adult risky sexual behavior, as persons with SMI are at an increased risk of engaging in high-risk sexual behaviors and tend to have a higher exposure to childhood sexual abuse than does the general population.     

Constructing views of science tied to issues of equity and diversity: A study of beginning science teachers

In this study, we examined the discursive and social practices of a teacher educator (the first author) and her eight beginning science teachers in a course on the nature of science and issues of equity and diversity. We focused our investigation on beginning science teachers' views of science and science teaching, as well as the grounds they offered for their views. We organized our discussion of the nature of science, teacher learning, and grounds for views along three dimensions: personal, social, and political. We found that beginning teachers routinely drew from only one of these three dimensions to support their views of the nature of science and ways to represent science to all students. In our implications, we recommend that teacher educators encourage teacher learners to examine personal, social, and political grounds carefully and critically in the process of constructing or revising their views. We argue that attention to these three dimensions of grounds for views will assist beginning teachers in adopting nature of science positions that are broad and complex, that more clearly reflect the goals of equity and excellence, and thus, that hold greater promise for achieving a science education inclusive of all students. © 2003 Wiley Periodicals, Inc. J Res Sci Teach 40: 53–76, 2003     

The University and Purposeful Ethics

Written with the intent to argue for the purposeful place of ethics in the curriculum, this paper examines the role of the university in the knowledge society, the moral challenges that arise from this, and the importance of developing a pragmatic ethics.     

Family contexts of television

Educational technology research and development -