Muscle-power quality: does sex or race affect movement velocity in older adults?

To determine sex and race differences in muscle power per unit of muscle contraction, knee-extensor muscle power normalized for knee-extensor muscle volume was measured in 79 middle-aged and older adults (30 men and 49 women, age range 50-85 years). Results revealed that women displayed a 38% faster peak movement velocity than men and African Americans had a 14% lower peak movement velocity than Whites of a similar age when expressed per unit of involved muscle (p < .001). As expected, men exhibited greater knee-extensor strength and peak power per unit of muscle than women, but women had a faster knee- extension movement velocity per unit of muscle than men at the same relative strength level. Moreover, African Americans had greater knee-extensor muscle volume than Whites but exhibited lower knee-extensor strength and lower movement velocity per unit of muscle when tested at the same relative strength levels.     

Bayesian Forecasting With Stable Seasonal Patterns

A multiplicative seasonal forecasting model for cumulative events in which, conditional on end- of-season totals being given and seasonal shape being known, it is shown that events occurring within the season are multinomially distributed is presented. The model uses the information contained in the arrival of new events to obtain a posterior distribution for end-of-season totals. Bayesian forecasts are obtained recursively in two stages: first, by predicting the expected number and variance of event counts in future intervals within the remaining season, and then by predicting revised means and variances for end-of-season totals based on the most recent forecast error.     

‘I am studying in the US but’: observations and insights from Caribbean college students

This paper examines the experiences and views of 12 Caribbean students studying at four Liberal Arts colleges and one large university in the Northeast, USA. The purpose of the study was to ascertain how young educated potential immigrants to the US today are thinking about race, identity, and homeland. The data were gathered through a 12-item open-ended questionnaire electronically administered through Google Forms. Among other issues, the researcher wanted to learn about participants’: decision to study in the US, experiences with race, identity and attitudinal shifts, feelings about being assigned racial labels, and current thinking about returning to their home countries. The findings highlight the acceptance of racial labels except for ‘African American’, a dogged adherence to national identity, the challenge of adjusting to the US racialized space, the view of the US as an education and economic transitional point for migrants on their return journey to their home countries, the formulation of new understandings and attitudes regarding mixed ancestry, and the defining role of sexual orientation in the attitude towards home country versus the US.     

Electricity consumption changes following solar adoption: Testing for a solar rebound

We use household-level data to explore residential electricity use patterns following installation of solar panels. Solar adoption leads to an increase in total electricity consumption relative to a matched non-adopting control group. Our point estimate translates to a rebound effect of 28.5%, suggesting that nearly a third of the electricity produced by a customer's solar panels is used for increased energy services, rather than reduced grid electricity consumption. We explore several potential drivers of an increase in electricity consumption. These results have important implications for electricity planning and policy, suggesting that rooftop solar stimulates additional demand for electricity.     

The Development of Students' Mathematics Self‐Concept in Relation to Gender: Different Countries,Different Trajectories?

Gender differences in the development of children's and adolescents' academic self‐perceptions have received increasing attention in recent years. This study extends previous research by examining the development of mathematics self‐concept across grades 7–12 in three cultural settings: Australia (Sydney; N=1,333), the United States (Michigan; N=2,443), and Germany (four federal states; N=4,688). Results of latent growth curve models document very similar patterns of self‐concept development in males and females in the three settings. First, gender differences in favor of boys were observed at the beginning of the observation period (grade 7). Second, gender was not significantly related to self‐concept change in either group, meaning that initial differences persisted across time. Third, the results provided no evidence that the form of the longitudinal change trajectories for mathematics self‐concept differed across the cultural settings. This pattern of results is inconsistent with explanatory models that predict converging or diverging gender differences in mathematics self‐concept. Furthermore, the results indicate that self‐concept development may be highly similar across western cultural settings.     

What Narrows the Stepgap? Closeness Between Parents and Adult (Step)Children in Germany

Using data from the German Family Panel (pairfam) based on 11,746 intergenerational family relationships, the present study examined differences in parental closeness across relations with multiple, coresidential, and non‐coresidential adolescent and adult children. Replicating previous research in a multilevel analysis across families, the authors found a strong positive effect of biological descent on closeness in comparison to adoptive and steprelations; this parental favoritism toward biological offspring was partly explained by selection via parental resources and attitudes. Supplemental within‐parent fixed effect analyses suggested that the relative disadvantage of stepchildren was offset by longer duration of the stepparent–stepchild relationship, lower household income, fewer children in the household, and high parental affirmation of familism.