The effect of beetroot juice supplementation on repeat-sprint performance in hypoxia     

Georgina L. Kent  Brian Dawson  Lars R. McNaughton  Gregory R. Cox  Louise M. Burke  Peter Peeling 《Journal of sports sciences》2019,37(3):339-346

This investigation assessed the effect of dietary nitrate (NO₃^?) supplementation, in the form of beetroot juice (BR), on repeat-sprint performance in normoxia and normobaric hypoxia. 12 male team-sport athletes (age 22.3 ± 2.6 y, VO_2peak 53.1 ± 8.7 mL.kg^?1.min^?1) completed three exercise trials involving a 10 min submaximal warm-up and 4 sets of cycling repeat-sprint efforts (RSE; 9 × 4 s) at sea level (CON), or at 3000 m simulated altitude following acute supplementation (140 mL) with BR (HYP_BR; 13 mmol NO₃^?) or NO₃^–depleted BR placebo (HYP_PLA). Peak (PPO) and mean (MPO) power output, plus work decrement were recorded during the RSE task, while oxygen consumption (VO₂) was measured during the warm-up. There were no significant differences observed between HYP_BR and HYP_PLA for PPO or MPO; however, work decrement was reduced in the first RSE set in HYP_BR compared with HYP_PLA. There was a moderate effect for VO₂ to be lower following BR at the end of the 10 min warm-up (ES = 0.50 ± 0.51). Dietary NO₃^? may not improve repeat-sprint performance in hypoxia but may reduce VO₂ during submaximal exercise. Therefore, BR supplementation may be more effective for performance improvement during predominantly aerobic exercise.  相似文献   

Digital Module 09: Sociocognitive Assessment for Diverse Populations https://ncme.elevate.commpartners.com     

Robert J. Mislevy  Maria Elena Oliveri 《Educational Measurement》2019,38(4):110-111

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Hero or Anti-Hero? Journalists and their Stories*     

Scott A. Eldridge II 《Journalism Practice》2019,13(8):890-894

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Frenemies: How Social Media Polarizes America by Jaime E. Settle     

Reviewed by Martin J. Riedl 《Mass Communication and Society》2019,22(4):562-564

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Inferno: an anatomy of American punishment     

Daniel P. Mears 《Journal of Criminal Justice Education》2018,29(2):318-320

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The Socio-Cultural Image of Childhood (Based on an Analysis of Soviet and Russian Feature Films about Children)     

K.N. Polivanova  M.A. Shakarova 《Russian Education & Society》2018,60(4):348-369

The current state of childhood research is grounded in classical psychological theories, and Russian psychology is tied to cultural and historical theory in particular. These theories were invented to generalize and make sense of the realities of childhood as they existed at the time when these theories were created. Rapid social changes, especially during recent decades, have led to the emergence of a wide range of sources that bear witness to how the day-to-day life of childhood has changed. The understanding of childhood has continued to transform from one era to another. A metaphor was even coined to describe it, and at some point there was even a specific metaphor coined, “the disappearance of childhood.” This article seeks to explore how the image of childhood has changed in relation to the image of adulthood. As material for analysis, we chose Soviet and Russian movies from the 1940s to 2000s. The study is based on the assumption that a sequential analysis based on Yuri Lotman’s theory of the structure of the text demonstrates how the image of childhood changes over time. If in the 1940s and 1950s the child was presented as immature and not quite grown up, the adult was portrayed as the embodiment of the ideal form of the individual, and the main conflict was structured around childish immaturity, then gradually over the decades more and more main characters who were children and adults were portrayed as different kinds of individuals, and the child (or teenager) sometimes came to embody obviously negative features. The child–adult dichotomy itself lost its significance.  相似文献   

Examining the influence of grip type on wrist and club head kinematics during the golf swing: Benefits of a local co-ordinate system     

Howie J. Carson  Jim Richards  Bruno Mazuquin 《European Journal of Sport Science》2019,19(3):327-335

Wrist movements have been identified as an important factor in producing a successful golf swing, with their complex motion influencing both club head velocity and orientation. However, a detailed analysis of wrist angles is lacking in the literature. The purpose of this study was to determine kinematics across wrists and club head characteristics during the golf swing under weak, neutral and strong grip conditions. Twelve professional male golfers executed 24 shots using a driver under three grip conditions. A six degrees of freedom analysis of the hand with respect to the distal forearm was performed using a 10-camera three-dimensional motion capture system. Differences in joint angles were explored using repeated measures ANOVAs at key swing events (onset, top of backswing and impact), in addition club head velocity and clubface angle at impact were also explored. Main findings revealed significant differences in flexion/extension and internal/external rotation for both wrists at all swing events, whereas fewer significant interactions were found in ulnar/radial deviation across grips for both wrists at all events. Clubface angle only differed significantly between the weak and the strong and neural grips, presenting a more ‘open’ clubface to the intended hitting direction. This study is the first to explore tri-planar wrist movement and the effect of different grips, such analysis has implications for coaching knowledge and practice and should inform future research into different aspects of skill, technique analysis and may inform injury mechanisms/prevention.  相似文献   

Kindergarten Children's Executive Functions Predict Their Second-Grade Academic Achievement and Behavior     

Paul L. Morgan  George Farkas  Marianne M. Hillemeier  Wik Hung Pun  Steve Maczuga 《Child development》2019,90(5):1802-1816

Whether and to what extent kindergarten children's executive functions (EF) constitute promising targets of early intervention is currently unclear. This study examined whether kindergarten children's EF predicted their second-grade academic achievement and behavior. This was done using (a) a longitudinal and nationally representative sample (N = 8,920, M_age = 97.6 months), (b) multiple measures of EF, academic achievement, and behavior, and (c) extensive statistical control including for domain-specific and domain-general lagged dependent variables. All three measures of EF—working memory, cognitive flexibility, and inhibitory control—positively and significantly predicted reading, mathematics, and science achievement. In addition, inhibitory control negatively predicted both externalizing and internalizing problem behaviors. Children's EF constitute promising targets of experimentally evaluated interventions for increasing academic and behavioral functioning.  相似文献   

Understanding Early Inhibitory Development: Distinguishing Two Ways That Children Use Inhibitory Control     

Andrew Simpson  Daniel J. Carroll 《Child development》2019,90(5):1459-1473

Inhibitory control is the capacity to suppress inappropriate responses. It is central to many aspects of development, most notably executive function and effortful control. Despite its importance, however, there are significant gaps in our understanding of inhibitory control’s early development, and several findings that remain hard to explain. Here, a new account of inhibitory control is presented, explaining previous findings by distinguishing between two distinct ways that inhibitory control is used. According to this “Strength/Endurance” account, inappropriate responses which are highly prepotent tax inhibitory strength; whereas inappropriate responses which remain active for a long time tax inhibitory endurance. The developmental trajectories of these two aspects of inhibitory control, and their separate impacts on broader development, are discussed.  相似文献   

Fighters,girls and other identities: sociolinguistics in a martial arts club     

Elaine W. Vine 《Sport in Society》2018,21(3):576-578

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