Physical activity and motor skills in children: A differentiated approach

Being physically active plays an essential role in a child's physical development. While there is ample evidence for a positive association between physical activity (PA) and motor skills in children, the question of how PA should be implemented to optimally foster motor skill proficiency is less clear. To address this gap, the current longitudinal study compared four groups of children with different patterns of leisure-time PA engagement—namely children engaging in either structured PA, unstructured PA, a combination of structured and unstructured PA, or no PA at all—with respect to their gross and fine motor skill development. Results of repeated measures mixed modeling procedures revealed that engaging in structured PA—either exclusively or in combination with unstructured PA—is beneficial for children's gross motor development, whereas engaging in unstructured PA lacks such effectiveness. As to fine motor skills, a beneficial tendency of structured PA was observed as well. Hence, PA seems to be beneficial for motor skill development particularly when implemented in a formal setting with guided opportunities for practice. In conclusion, regularly engaging in structured PA constitutes a promising way to promote motor skills and support motor development over the long term

The effect of video games, exergames and board games on executive functions in kindergarten and 2nd grade: An explorative longitudinal study

We examined the relation between different kinds of play behavior (video games, exergames, board games) in kindergarten (T1) and components of executive function (EF; inhibition, switching, verbal and visuospatial updating) in kindergarten and second grade (T1 and T2). Ninety-seven children participated in this longitudinal study. Parents were asked to complete a questionnaire regarding children's play behavior, reporting frequency, duration, and game type. The results indicate that play behavior is associated with EF development in children; however, only exergames, electronic puzzle games, and board games predicted EF at T2. Additionally, the time spent on electronic games was negatively related to visuospatial updating at T1 but did not predict EF at T2. The results support further investigation of a potential link between board game and exergame play behavior and EF development

The mediating role of self-concept between sports-related physical activity and mathematical achievement in fourth graders

Being physically active has many benefits for children and adolescents. It is essential for various aspects of physical and mental health, and also positively influences academic performance and school achievement. In addressing the still incomplete understanding of the link between physical activity (PA) and academic achievement, the present study scrutinized the open issues regarding different roles of PA type and PA duration within the relation between self-reported PA and objectively measured mathematical achievement in fourth graders. As to the type of PA, the current study distinguished between structured and unstructured sports activities children perform in their leisure time. Moreover, the current study investigated the indirect effect of PA on mathematical achievement by controlling for the mathematical self-concept as a mediating variable. Results showed PA to be positively related to mathematical outcomes if implemented in a structured setting and pursued for at least two hours per week. As to the mediation, the results revealed a full mediation, indicating PA to improve mathematical self-concept, which, in turn, positively affected mathematical achievement. Thus, engaging in structured PA for two hours or more a week may have additional benefits for children’s and adolescents’ self-concept in a way that is favorable and encouraging for promoting their academic achievement

Patterns and rates of viral evolution in HIV-1 subtype B infected females and males.

Biological sex differences affect the course of HIV infection, with untreated women having lower viral loads compared to their male counterparts but, for a given viral load, women have a higher rate of progression to AIDS. However, the vast majority of data on viral evolution, a process that is clearly impacted by host immunity and could be impacted by sex differences, has been derived from men. We conducted an intensive analysis of HIV-1 gag and env-gp120 evolution taken over the first 6-11 years of infection from 8 Women's Interagency HIV Study (WIHS) participants who had not received combination antiretroviral therapy (ART). This was compared to similar data previously collected from men, with both groups infected with HIV-1 subtype B. Early virus populations in men and women were generally homogenous with no differences in diversity between sexes. No differences in ensuing nucleotide substitution rates were found between the female and male cohorts studied herein. As previously reported for men, time to peak diversity in env-gp120 in women was positively associated with time to CD4+ cell count below 200 (P = 0.017), and the number of predicted N-linked glycosylation sites generally increased over time, followed by a plateau or decline, with the majority of changes localized to the V1-V2 region. These findings strongly suggest that the sex differences in HIV-1 disease progression attributed to immune system composition and sensitivities are not revealed by, nor do they impact, global patterns of viral evolution, the latter of which proceeds similarly in women and men

Modelling the spinning dust emission from dense interstellar clouds

Electric dipole emission arising from PAHs is often invoked to explain the anomalous microwave emission (AME). This assignation is based on an observed tight correlation between the mid-IR emission of PAHs and the AME; and a good agreement between models of spinning dust and the broadband AME spectrum. So far often detected at large scale in the diffuse interstellar medium, the AME has recently been studied in detail in well-known dense molecular clouds with the help of Planck data. While much attention has been given to the physics of spinning dust emission, the impact of varying local physical conditions has not yet been considered in detail. Our aim is to study the emerging spinning dust emission from interstellar clouds with realistic physical conditions and radiative transfer. We use the DustEM code from Compiegne et al. to describe the extinction and IR emission of all dust populations. The spinning dust emission is obtained with SpDust, as described by Silsbee et al., that we have coupled to DustEM. We carry out full radiative transfer simulations and carefully estimate the local gas state as a function of position within interstellar clouds. We show that the spinning dust emission is sensitive to the abundances of the major ions and we propose a simple scheme to estimate these abundances. We also investigate the effect of changing the cosmic-ray rate. In dense media, where radiative transfer is mandatory, we show that the relationship between the spinning and mid-IR emissivities of PAHs is no longer linear and that the spinning dust emission may actually be strong at the centre of clouds where the mid-IR PAH emission is weak. These results provide new ways to trace grain growth from diffuse to dense medium and will be useful for the analysis of AME at the scale of interstellar clouds.Comment: 7 pages, 10 figures, accepted by A&

Protostellar disk formation and transport of angular momentum during magnetized core collapse

Theoretical studies of collapsing clouds have found that even a relatively weak magnetic field (B) may prevent the formation of disks and their fragmentation. However, most previous studies have been limited to cases where B and the rotation axis of the cloud are aligned. We study the transport of angular momentum, and its effects on disk formation, for non-aligned initial configurations and a range magnetic intensities. We perform 3D AMR MHD simulations of magnetically supercritical collapsing dense cores using the code Ramses. We compute the contributions of the processes transporting angular momentum (J), in the envelope and the region of the disk. We clearly define what could be defined as centrifugally supported disks and study their properties. At variance with earlier analyses, we show that the transport of J acts less efficiently in collapsing cores with non-aligned rotation axis and B. Analytically, this result can be understood by taking into account the bending of field lines occurring during the gravitational collapse. For the transport of J, we conclude that magnetic braking in the mean direction of B tends to dominate over both the gravitational and outflow transport of J. We find that massive disks, containing at least 10% of the initial core mass, can form during the earliest stages of star formation even for mass-to-flux ratios as small as 3 to 5 times the critical value. At higher field intensities, the early formation of massive disks is prevented. Given the ubiquity of Class I disks, and because the early formation of massive disks can take place at moderate magnetic intensities, we speculate that for stronger fields, disks will form later, when most of the envelope will have been accreted. In addition, we speculate that some observed early massive disks may actually be outflow cavities, mistaken for disks by projection effects. (Abridged version of the abstract.)Comment: 23 pages, 23 figures, to be published in A&

A Randomized Trial of Effects of Health Risk Appraisal Combined With Group Sessions or Home Visits on Preventive Behaviors in Older Adults

Background. To explore effects of a health risk appraisal for older people (HRA-O) program with reinforcement, we conducted a randomized controlled trial in 21 general practices in Hamburg, Germany. Methods. Overall, 2,580 older patients of 14 general practitioners trained in reinforcing recommendations related to HRA-O-identified risk factors were randomized into intervention (n = 878) and control (n = 1,702) groups. Patients (n = 746) of seven additional matched general practitioners who did not receive this training served as a comparison group. Patients allocated to the intervention group, and their general practitioners, received computer-tailored written recommendations, and patients were offered the choice between interdisciplinary group sessions (geriatrician, physiotherapist, social worker, and nutritionist) and home visits (nurse). Results. Among the intervention group, 580 (66%) persons made use of personal reinforcement (group sessions: 503 [87%], home visits: 77 [13%]). At 1-year follow-up, persons in the intervention group had higher use of preventive services (eg, influenza vaccinations, adjusted odds ratio 1.7; 95% confidence interval 1.4-2.1) and more favorable health behavior (eg, high fruit/fiber intake, odds ratio 2.0; 95% confidence interval 1.6-2.6), as compared with controls. Comparisons between intervention and comparison group data revealed similar effects, suggesting that physician training alone had no effect. Subgroup analyses indicated favorable effects for HRA-O with personal reinforcement, but not for HRA-O without reinforcement. Conclusions. HRA-O combined with physician training and personal reinforcement had favorable effects on preventive care use and health behavio