Validation of two accelerometers to determine mechanical loading of physical activities in children

The purpose of this study was to assess the validity of accelerometers using force plates (i.e., ground reaction force (GRF)) during the performance of different tasks of daily physical activity in children. Thirteen children (10.1 (range 5.4–15.7) years, 3 girls) wore two accelerometers (ActiGraph GT3X+ (ACT), GENEA (GEN)) at the hip that provide raw acceleration signals at 100 Hz. Participants completed different tasks (walking, jogging, running, landings from boxes of different height, rope skipping, dancing) on a force plate. GRF was collected for one step per trial (10 trials) for ambulatory movements and for all landings (10 trials), rope skips and dance procedures. Accelerometer outputs as peak loading (g) per activity were averaged. ANOVA, correlation analyses and Bland–Altman plots were computed to determine validity of accelerometers using GRF. There was a main effect of task with increasing acceleration values in tasks with increasing locomotion speed and landing height (P < 0.001). Data from ACT and GEN correlated with GRF (r = 0.90 and 0.89, respectively) and between each other (r = 0.98), but both accelerometers consistently overestimated GRF. The new generation of accelerometer models that allow raw signal detection are reasonably accurate to measure impact loading of bone in children, although they systematically overestimate GRF.     

The unacknowledged value of female academic labour power for male research careers

Academic work in Sweden's higher education system is changing character. Distinctly different career pathways are emerging, as facilities for developing research careers and capital have become both more restricted and more dependent on external funding. These developments are in focus in the present article. Based on ethnographic research and a series of semi-structured interviews with new academics and senior academic mentors in education faculties, the research suggests that several factors intercede in how careers are developed and experienced. The unacknowledged exploitation of female academic labour is perhaps amongst the more significant of these.     

Endorsing achievement goals exacerbates the big-fish-little-pond effect on academic self-concept

The big-fish-little-pond effect (BFLPE) model predicts students’ academic self-concept to be negatively predicted by the achievement level of their reference group, controlling for individual achievement. Despite an abundance of empirical evidence supporting the BFLPE, there have been relatively few studies searching for possible moderators. Integrating the BFLPE model with Achievement Goal Theory, the present study aims to determine whether the negative effect of class-average achievement on academic self-concept is moderated by individual and class-average achievement goals. Our sample comprised of 2987 students (50% boys) from Grade 6 in 112 elementary schools in the Flemish region of Belgium (174 classes). Applying multilevel modelling, we found a stronger BFLPE when students’ individual achievement goals were higher, regardless of the specific nature of these goals. The BFLPE was not moderated by class-average levels of achievement goals. Overall, our findings demonstrate that the BFLPE is moderated by individual goal-related factors.     

Preschoolers rely on rich speech representations to process variable speech

To learn language, children must map variable input to categories such as phones and words. How do children process variation and distinguish between variable pronunciations (“shoup” for soup) versus new words? The unique sensory experience of children with cochlear implants, who learn speech through their device's degraded signal, lends new insight into this question. In a mispronunciation sensitivity eyetracking task, children with implants (N = 33), and typical hearing (N = 24; 36–66 months; 36F, 19M; all non-Hispanic white), with larger vocabularies processed known words faster. But children with implants were less sensitive to mispronunciations than typical hearing controls. Thus, children of all hearing experiences use lexical knowledge to process familiar words but require detailed speech representations to process variable speech in real time.