A review of factors affecting the acute exercise-cognition relationship in children and adolescents

It is well documented that an acute bout of exercise has a positive effect on subsequent cognitive function in children and adolescents. However, the effect of: the exercise characteristics (i.e. intensity, duration and modality), the cognitive domain assessed, and moderating variables (such as the participant's age, physical fitness and baseline cognitive abilities); all of which affect this relationship are poorly understood. Therefore, the purpose of this review is to examine the impact of these variables on the acute exercise-cognition relationship in children (aged 6-11 years) and adolescents (aged 12-18 years). Searching the published literature from 2008 to date yielded 22 relevant studies in children and 14 relevant studies in adolescents. This review examines the effects of exercise characteristics (section 2), the cognitive domain assessed (section 3), and the time course of the effects (section 4), alongside the moderating effects of participant characteristics (section 5). The findings indicate that moderate intensity of ~ 30 min duration has positive effects across cognitive domains in children, whilst moderate-high intensity exercise of 10-30 min duration appears most beneficial in adolescents. Findings also suggest that the beneficial effects last for ~ 45 min post-exercise and, tentatively, may be more pronounced in children and adolescents with higher physical fitness levels. Future research in this area should continue to explore the factors (e.g. exercise characteristics, cognitive domains assessed and moderating variables) affecting the acute exercise-cognition relationship in children and adolescents. Where possible these factors should be controlled (or at the very least measured and reported), to allow a more complete interpretation of the findings and extending our understanding of this complicated relationship

Effect of football activity and physical fitness on information processing, inhibitory control and working memory in adolescents

Background: Whilst an acute bout of exercise has been shown to enhance subsequent cognition, including in adolescents, the effects of team games (of which Football is the most popular) has received little attention. Therefore, this study examined: the effect of an acute bout of outdoor Football activity on information processing, inhibitory control, working memory and circulating brain-derived neurotrophic factor (BDNF) in adolescents; the effect of physical fitness on cognition and; the moderating effect of physical fitness on the acute exercise responses. Methods: Following familiarisation, 36 adolescents (16 girls) took part in two trials (60-min Football and 60-min seated rest) separated by 7-d in a counterbalanced, crossover design. Information processing and inhibitory control (Stroop Test), and working memory (Sternberg Paradigm) were assessed 30-min before exercise/rest and immediately, 45- and 90-min post-exercise/rest. Capillary blood samples were obtained before exercise/rest and up to 120-min post-exercise/rest. The median split of distance covered on the MSFT was used to divide the group into high- and low-fit groups. Results: Performance on the cognitive function tasks was similar between Football and seated rest (trial*time interactions; all p > .05). However, the high-fit group had overall quicker response times on both levels of the Stroop Task and all three levels of the Sternberg Paradigm (main effect of fitness; all p  .05). Conclusion: The present study shows that higher levels of physical fitness are beneficial for cognitive function and provides novel evidence that an ecologically valid, and popular, form of exercise is beneficial for working memory following exercise, in high-fit participants only

Measurement of the inclusive and dijet cross-sections of b-jets in pp collisions at sqrt(s) = 7 TeV with the ATLAS detector

The inclusive and dijet production cross-sections have been measured for jets containing b-hadrons (b-jets) in proton-proton collisions at a centre-of-mass energy of sqrt(s) = 7 TeV, using the ATLAS detector at the LHC. The measurements use data corresponding to an integrated luminosity of 34 pb^-1. The b-jets are identified using either a lifetime-based method, where secondary decay vertices of b-hadrons in jets are reconstructed using information from the tracking detectors, or a muon-based method where the presence of a muon is used to identify semileptonic decays of b-hadrons inside jets. The inclusive b-jet cross-section is measured as a function of transverse momentum in the range 20 < pT < 400 GeV and rapidity in the range |y| < 2.1. The bbbar-dijet cross-section is measured as a function of the dijet invariant mass in the range 110 < m_jj < 760 GeV, the azimuthal angle difference between the two jets and the angular variable chi in two dijet mass regions. The results are compared with next-to-leading-order QCD predictions. Good agreement is observed between the measured cross-sections and the predictions obtained using POWHEG + Pythia. MC@NLO + Herwig shows good agreement with the measured bbbar-dijet cross-section. However, it does not reproduce the measured inclusive cross-section well, particularly for central b-jets with large transverse momenta.Comment: 10 pages plus author list (21 pages total), 8 figures, 1 table, final version published in European Physical Journal

Effect of differing durations of high-intensity intermittent activity on cognitive function in adolescents

Exercise duration may influence the acute effects on cognition. However, only one study to date has explored the dose-response relationship between exercise duration and cognition in adolescents. Thus, the purpose of this study was to investigate the effect of differing durations of high-intensity intermittent running on cognition in adolescents. Thirty-eight adolescents (23 girls) completed three trials separated by 7 d: 30 min exercise, 60 min exercise, and rest; in a randomised crossover design. The exercise was a modified version of the Loughborough Intermittent Shuttle Test (LIST), which elicited high-intensity intermittent exercise. Cognitive function tests (Stroop test, Sternberg paradigm, Flanker task) were completed 30 min pre, immediately post, and 45 min post exercise. Response times on the incongruent level of the Flanker task improved to a greater extent 45 min following the 30 min LIST, compared to rest (p = 0.009). Moreover, response times improved to a greater extent on the three-item level of Sternberg paradigm 45 min following the 30 min LIST, compared to the 60 min LIST (p = 0.002) and rest (p = 0.013), as well as on the five-item level 45 min following the 30 min LIST, compared to the 60 min LIST (p = 0.002). In conclusion, acute exercise enhanced subsequent cognition in adolescents, but overall, 30 min of high-intensity intermittent running is more favourable to adolescents’ cognition, compared to 60 min

Bacteriophage-encoded depolymerases: their diversity and biotechnological applications

Bacteriophages (phages), natural enemies of bacteria, can encode enzymes able to degrade polymeric substances. These substances can be found in the bacterial cell surface, such as polysaccharides, or are produced by bacteria when they are living in biofilm communities, the most common bacterial lifestyle. Consequently, phages with depolymerase activity have a facilitated access to the host receptors, by degrading the capsular polysaccharides, and are believed to have a better performance against bacterial biofilms, since the degradation of extracellular polymeric substances by depolymerases might facilitate the access of phages to the cells within different biofilm layers. Since the diversity of phage depolymerases is not yet fully explored, this is the first review gathering information about all the depolymerases encoded by fully sequenced phages. Overall, in this study, 160 putative depolymerases, including sialidases, levanases, xylosidases, dextranases, hyaluronidases, peptidases as well as pectate/pectin lyases, were found in 143 phages (43 Myoviridae, 47 Siphoviridae, 37 Podoviridae, and 16 unclassified) infecting 24 genera of bacteria. We further provide information about the main applications of phage depolymerases, which can comprise areas as diverse as medical, chemical, or food-processing industry.DPP acknowledges the financial support from the Portuguese Foundation for Science and Technology (FCT) through the grant SFRH/BD/76440/2011. SS is an FCT investigator (IF/01413/2013). The authors also thank FCT for the Strategic Project of the UID/BIO/04469/2013 unit, FCT and European Union funds (FEDER/COMPETE) for the project RECI/BBB-EBI/0179/2012 (FCOMP-01-0124-FEDER027462)

Activity patterns of primary school children during participation in The Daily Mile

The Daily Mile is a popular physical activity initiative in primary schools, yet little is known regarding the activity patterns of children during The Daily Mile. Eighty children (10.4 ± 0.7 years) participated in The Daily Mile (20-min). Activity patterns were assessed using global positioning systems (total distance and age-specific speed zones), alongside heart rate. Cardiorespiratory fitness was assessed using the Multi-Stage Fitness Test. Participants covered a distance of 2511 ± 550 m during The Daily Mile, and heart rate was 163 ± 27 beats.min−1. Participants travelled the furthest distance, and were most intermittent, during the first 5 min (main effect of time, both p < 0.001). Boys ran further and their activity was more intermittent compared to girls (main effect of sex, both p < 0.001). Moreover, the highest fit children ran further than less fit children (main effect of fitness, p < 0.001). This study provides novel evidence of the nature of physical activity during The Daily Mile; demonstrating that children covered, on average, 1.5-miles and exercised at a moderate-to-vigorous intensity. Furthermore, boys covered a greater distance and were more intermittent than girls; whilst higher fit children ran further than lower fit children. In summary, The Daily Mile makes a valuable contribution to in-school physical activity targets in all children

The Daily Mile™: acute effects on children’s cognitive function and factors affecting their enjoyment

The Daily Mile™ is a widely implemented school-based physical activity initiative. However, only two studies have explored the acute effects of participation in The Daily Mile on children’s cognitive functioning, reporting conflicting findings. Moreover, enjoyment of exercise is a determining factor in children’s motivation for, and adherence to, initiatives. However, factors affecting children’s enjoyment of The Daily Mile are unknown. Therefore, this study examined the acute effects of The Daily Mile on cognition and explored children’s enjoyment of participation in the initiative. Following familiarisation, 104 children (10.4 ± 0.7 years) completed a Daily Mile and resting control trial in a randomised, counterbalanced order. Prior to, immediately following and 45 min following The Daily Mile and resting, children completed the Stroop test (inhibitory control), Sternberg paradigm (visual working memory) and Flanker task (inhibitory control and cognitive flexibility). Additionally, 87 children took part in focus groups to explore factors affecting enjoyment. Cognitive data were analysed using two-way (trial*time) and three-way (trial*time*sex; trial*time*fitness) repeated measures analysis of variance (ANOVA). Focus group data were analysed using qualitative content analysis. There were no statistically significant effects of The Daily Mile on cognition, compared to rest (all p > 0.05). However, accuracy on the one-item level of Sternberg paradigm (p = 0.073, ηp2 = 0.028) and complex level of the Stroop test (p = 0.057; ηp2 = 0.031) tended to improve immediately following The Daily Mile, compared to resting; though this did not reach statistical significance. Children enjoyed participating in The Daily Mile, particularly due to its outdoor location, social context, and self-paced nature. However, some children found The Daily Mile boring due to its repetitive nature. Findings suggest that The Daily Mile does not significantly influence children’s immediate or delayed (45 min) cognition. However, there was a tendency for improved accuracy in visual working memory and inhibitory control immediately following The Daily Mile. Moreover, the findings demonstrate that The Daily Mile promotes enjoyment, particularly through social relatedness and autonomy. However, future research could consider whether adding variety into the initiative may help to sustain engagement in the children experiencing boredom

Dengue virus neutralizing antibody levels associated with protection from infection in Thai cluster studies

BACKGROUND: Long-term homologous and temporary heterologous protection from dengue virus (DENV) infection may be mediated by neutralizing antibodies. However, neutralizing antibody titers (NTs) have not been clearly associated with protection from infection. METHODOLOGY/PRINCIPAL FINDINGS: Data from two geographic cluster studies conducted in Kamphaeng Phet, Thailand were used for this analysis. In the first study (2004-2007), cluster investigations of 100-meter radius were triggered by DENV-infected index cases from a concurrent prospective cohort. Subjects between 6 months and 15 years old were evaluated for DENV infection at days 0 and 15 by DENV PCR and IgM ELISA. In the second study (2009-2012), clusters of 200-meter radius were triggered by DENV-infected index cases admitted to the provincial hospital. Subjects of any age 6 months and older were evaluated for DENV infection at days 0 and 14. In both studies, subjects who were DENV PCR positive at day 14/15 were considered to have been susceptible on day 0. Comparison subjects from houses in which someone had documented DENV infection, but the subject remained DENV negative at days 0 and 14/15, were considered non-susceptible. Day 0 samples were presumed to be from just before virus exposure, and underwent plaque reduction neutralization testing (PRNT). Seventeen susceptible (six DENV-1, five DENV-2, and six DENV-4), and 32 non-susceptible (13 exposed to DENV-1, 10 DENV-2, and 9 DENV-4) subjects were evaluated. Comparing subjects exposed to the same serotype, receiver operating characteristic (ROC) curves identified homotypic PRNT titers of 11, 323 and 16 for DENV-1, -2 and -4, respectively, to differentiate susceptible from non-susceptible subjects. CONCLUSIONS/SIGNIFICANCE: PRNT titers were associated with protection from infection by DENV-1, -2 and -4. Protective NTs appeared to be serotype-dependent and may be higher for DENV-2 than other serotypes. These findings are relevant for both dengue epidemiology studies and vaccine development efforts

Subjective health legacy of the Chornobyl accident: a comparative study of 19-year olds in Kyiv

<p>Abstract</p> <p>Background</p> <p>Since the Chornobyl accident in 1986, the physical health of exposed children in Ukraine has been monitored, but their perceived health has not been studied. This study examines health perceptions of Ukrainian adolescents exposed to radioactive fallout <it>in utero </it>or as infants, and the epidemiologic and Chornobyl-related influences on self-reported health.</p> <p>Method</p> <p>We assessed three groups of 19-year olds in Kyiv: 262 evacuees from contaminated areas near the plant; 261 classmate controls; and 325 population-based controls. The evacuees and classmates were previously assessed at age 11. Structured interviews were conducted with the adolescents and their mothers (N = 766), followed by general physical examinations (N = 722) and blood tests (N = 707). Proportional odds logistic regression and multi-group path analysis were the major statistical tests.</p> <p>Results</p> <p>The examination and blood test results were similar across groups except for a significantly elevated rate of thyroid enlargement found by palpation in evacuees (17.8%) compared former classmates (8.7%) and population-based controls (8.0%). In addition, four evacuees and one population control had had a thyroidectomy. Compared to controls, the evacuees rated their health the least positively and reported more medically diagnosed illnesses during the 5 years preceding the interview, particularly thyroid disease, migraine headache, and vascular dystony. The consistent risk factors (p < 0.001) for these subjective health reports were evacuee status, female gender, multiple hospitalizations, and health risk perception regarding Chornobyl. All three groups of mothers rated their children's health more negatively than the adolescents themselves, and maternal ratings were uniquely associated with the adolescents' health reports in the adjusted models. In the longitudinal evacuee and classmate subsamples, path analysis showed that mothers' health ratings when the children were age 11 predicted their later evaluations which in turn were associated with the adolescent self-reports.</p> <p>Conclusion</p> <p>The more negative self-evaluations of the evacuees were linked to a number of risk factors, including multiple hospitalizations, health risk perceptions, and epidemiologic risk factors. The increased rate of thyroid cancer and other diagnoses no doubt contributed to the evacuees' less positive subjective health. The strong effect of the mothers' perceptions argues in favor of developing risk communication programs for families rather than for mothers or adolescents as separate target groups.</p

T Cell-Dependence of Lassa Fever Pathogenesis

Lassa virus (LASV), the causative agent of Lassa fever (LF), is endemic in West Africa, accounting for substantial morbidity and mortality. In spite of ongoing research efforts, LF pathogenesis and mechanisms of LASV immune control remain poorly understood. While normal laboratory mice are resistant to LASV, we report that mice expressing humanized instead of murine MHC class I (MHC-I) failed to control LASV infection and develop severe LF. Infection of MHC-I knockout mice confirmed a key role for MHC-I-restricted T cell responses in controlling LASV. Intriguingly we found that T cell depletion in LASV-infected HHD mice prevented disease, irrespective of high-level viremia. Widespread activation of monocyte/macrophage lineage cells, manifest through inducible NO synthase expression, and elevated IL-12p40 serum levels indicated a systemic inflammatory condition. The absence of extensive monocyte/macrophage activation in T cell-depleted mice suggested that T cell responses contribute to deleterious innate inflammatory reactions and LF pathogenesis. Our observations in mice indicate a dual role for T cells, not only protecting from LASV, but also enhancing LF pathogenesis. The possibility of T cell-driven enhancement and immunopathogenesis should be given consideration in future LF vaccine development