Bidirectional cross-sectional and prospective associations between physical activity and body composition in adolescence: birth cohort study

The aim of this study was to investigate the cross-sectional and prospective associations between physical activity and body composition in adolescence. This is a prospective study, including 4,103 adolescents belonging to the Pelotas (Brazil) 1993 birth cohort, who were followed up at the mean ages of 11.3 and 14.7 years. Subsample analyses included 511 individuals with accelerometry and deuterium dilution data at 13.3 years. Sum of skinfolds at age 11.3 years was highly correlated with skinfolds at age 14.7 years (rho = 0.74, P < 0.001). More than 85% of participants remained in the same quintile or changed by not more than one quintile during the 3.4 year period. Tracking of physical activity was considerably lower, although still significant; the correlation was 0.24 (P < 0.001) and 61.4% of the adolescents moved one or less quintiles. In fully-adjusted models, no significant cross-sectional or longitudinal associations were found between physical activity and body composition, neither in boys nor in girls. These null results were confirmed in the 511 individuals with accelerometry and deuterium data. We provide evidence of tracking of physical activity and particularly body composition during adolescence. Our results do not support the hypothesis that physical activity and fatness are strongly related in adolescents.     

The ABCs of private equity and venture capital data and information

ABSTRACT

In June 2017, the Business Reference & Services Section of the Reference & User Services Association organized and hosted an event known as the Publishers' Forum during the annual American Library Association Conference in Chicago, Illinois. The Publishers' Forum is a professional development event that brings together business librarians and publishers of business information to engage in a discussion about business information products. The theme of the 2017 Publishers' Forum was private equity and venture capital data and information, and three different publishers were invited to speak and showcase their information products. This article will provide an overview of the Publishers' Forum, discuss the selection of private equity and venture capital as the theme, and highlight the importance of private equity and venture capital to business librarianship. Finally, this article will include a discussion of each of the publishers who presented at the Publishers' Forum and the information products they showcased.     

Classification and Subject Indexing Issues at a Mexican Library Specializing in Law Research

Abstract

Subject indexing and classification of law resources is a complex issue due to several factors: specialized meanings of legal terms, meanings across different branches of law, terms in legal systems from diverse countries, and terms in different languages. These issues led to the development of a classification and subject indexing system which will help answer the major challenges of indexing and classifying law resources in the Research Institute Library at the National Autonomous University of Mexico. Adopting its own classification required interdisciplinary work between law and information organization specialists, constant updating by legal specialists and others beyond the Legal Research Institute; and the sharing of this classification system with other institutions. Now, this classification system is used by important institutions that specialize in law, such as the network of Libraries of the Supreme Court of Justice of the Nation of Mexico. The purpose of this article is to show why and how this law classification and subject system was developed and is continuously being updated by libarians and law scholars in order for it to meet their specific needs.     

Effect of a congested match schedule on immune-endocrine responses,technical performance and session-RPE in elite youth soccer players

ABSTRACT

This study investigated the effects of a congested match schedule (7 matches played in 7 days) on steroid hormone concentrations, mucosal immunity, session rating of perceived exertion (S-RPE) and technical performance in 16 elite youth soccer players (14.8 ± 0.4 years; 170.6 ± 9.4 cm; 64.9 ± 7 kg). No change was observed for salivary cortisol concentration across match time points (P = 0.33; effect size [ES] = 0.13–0.48). In contrast, there was a decrease in salivary testosterone and salivary IgA (SIgA) concentrations from the 1st compared with the last time point (P = 0.01 and 0.001, ES = 0.42 and 0.67, respectively). The SIgA concentration varied across time points (P < 0.001) with the highest value observed at the 3rd time point (rest day) (3rd vs all time point; ES = 0.47–0.73). No changes were observed for S-RPE across time points (P > 0.05). A higher number of tackles and interceptions were observed during the 4th match vs 1st and 7th matches (P < 0.001; ES = 2.25 and 1.90, respectively). The present data demonstrate that accumulated fatigue related to participation in a congested match schedule might induce a decrease in testosterone concentration in youth players and negatively affect their mucosal immunity and capacity to perform certain technical actions.     

A neurodevelopmental profile of the rural hearing‐impaired child in the QwaQwa region,South Africa

Being hearing impaired does not only affect a child's academic performance, but can also influence a child's overall development and ability to succeed academically. Children with hearing impairment often experience delays in other areas of their development and an understanding of the inter‐relatedness of these delays are important in order to address all these aspects, and thus minimise the impact on a child's overall development. The paper provides a neurodevelopmental profile of 4‐year‐old to 8‐year‐old rural hearing‐impaired children based on the result of a psychometric assessment. Eighteen children were selected from a special needs school in the rural QwaQwa Free State area of South Africa and underwent a psychometric assessment using two test batteries (Griffiths mental developmental scales – extended revised and a neurodevelopmental evaluation scale). The neurodevelopmental profile will contribute to knowledge of the nature of the challenges faced by the hearing‐impaired child in rural education and the neurodevelopmental origin of these challenges.     

Genetic and Environmental Influences on Developmental Milestones and Movement: Results From the Gemini Cohort Study

Purpose: Variability in the timing of infant developmental milestones is poorly understood. We used a twin analysis to estimate genetic and environmental influences on motor development and activity levels in infancy. Method: Data were from the Gemini Study, a twin birth cohort of 2,402 families with twins born in the United Kingdom in 2007. Parents reported motor activity level for each of the twins at age 3 months using the Revised Infant Behavior Rating Scale and reported the ages at which they first sat unsupported, crawled, and walked unaided. Results: Activity level at 3 months and ages when first sitting and crawling were about equally influenced by the shared family environment (45%–54%) and genes (45%–48%). Genetic influences dominated for age when children took their first independent steps (84%). Conclusion: Aspects of the shared family environment appear to be important influences on motor activity levels and early milestones, although the timing of walking may have a stronger genetic influence. Further research to identify the specific environmental and genetic factors that promote early activity may be important for longer-term health outcomes.     

Prediction of abandonment in Spanish fitness centres

Research question: The increase of physical exercise in fitness centres has turned these facilities in important active lifestyle promoters. However, only between 30% and 60% of subscribers still linked to the sports centre after a year. The aim of this study is to design a model to predict the drop out in fitness centres. Research methods: Monthly data corresponding to the actual behaviour of 14,522 members of three sport centres in Spain were recorded over the course of one year. In order to calculate the likelihood of drop out, logistic regressions were used to create predictive models for each centre. Results and findings: It was possible to predict abandonment of users of sport centres from their historical behaviour, although the predictive models obtained for each centre were not completely coincident. The effectiveness of the models was around 70%. Implications: The analysis of users’ behaviour in a fitness centre can allow to avoid the drop out and therefore the abandonment of physical activity. Segmenting the customers based on the likelihood of drop out may be useful for improving the effectiveness of the strategies of loyalty and for optimizing the organization of human and material resources.