Innovative approaches towards an economic fusion reactor     

Houyang Guo  Francis Y C Thio  Michl W Binderbauer  Richard J Buttery  Thomas R Jarboe  Rajesh Maingi  John S Sarff  Peter C Stangeby  Derek A Sutherland  Mickey R Wade  Michael C Zarnstorff 《国家科学评论(英文版)》2020,7(2):245

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Reference power values for the jump squat exercise in elite athletes: A multicenter study     

Pedro L. Valenzuela  Michael McGuigan  Guillermo Sánchez-Martínez  Elaia Torrontegi  Javier Vázquez-Carrión  Zigor Montalvo 《Journal of sports sciences》2020,38(19):2273-2278

ABSTRACT

The present study aimed to provide reference values for lower-limb muscle power assessed during the incremental jump squat (JS) test in elite athletes (i.e., professional athletes competing at international level). We pooled data from all JS tests performed by elite athletes of different sports in two high-performance centres between 2015 and 2019, and computed reference values (i.e., terciles) for mean power (MP), mean propulsive power (MPP), and peak power (PP). Reference values were obtained from 684 elite athletes (458 male and 226 female) of 16 different sports (boxing, judo, karate, fencing, taekwondo, wrestling, basketball, soccer, futsal, handball, rugby union, badminton, tennis, long distance running, triathlon, and sprinting). Significant differences (p < 0.001) were found between male and female athletes for MP (7.47 ± 1.93 and 6.15 ± 1.68 W·Kg^?1, respectively), MPP (10.50 ± 2.75 and 8.63 ± 2.43 W·Kg^?1), and PP (23.64 ± 6.12 and 19.35 ± 5.49 W·Kg^?1). However, the velocity at which these power measures was attained seemed to be independent of sex (~0.95, 1.00 and 2.00 m·s^?1 for mean, mean propulsive, and peak velocity, respectively) and homogeneous across different sport disciplines (coefficient of variation <10%). These data can be used to classify athletes’ power capabilities, and the optimum velocity ranges provided here could be useful for training purposes.  相似文献   

The effect of smartphones and playing video games on decision-making in soccer players: A crossover and randomised study     

Leonardo S. Fortes  Dalton De Lima-Junior  Lenamar Fiorese  José R. A. Nascimento-Júnior  Arnaldo L. Mortatti  Maria E. C. Ferreira 《Journal of sports sciences》2020,38(5):552-558

ABSTRACT

The objective of this study was to analyse the effect of the use of social networks in smartphones or playing video games on the passing decision-making performance in professional soccer athletes. Participants were 25 male professional soccer athletes (mean ± SD: age 23.4 ± 2.8 years). The participants performed three randomised conditions divided into three groups: control (CON), smartphone (SMA), and video game (VID). Before and after each experimental condition, the Stroop Task assessed the level of induced mental fatigue. Then, the athletes performed a simulated soccer match. A CANON® camera recorded the matches for further analysis on passing decision-making performance. A group effect was identified (p < .01) with impairment on passing decision-making performance for the SMA (p = .01, ES = 0.5) and VID (p = .01, ES = 0.5) conditions. We concluded that the use of social networks on smartphones and/or playing video games right before official soccer matches might impair the passing decision-making performance in professional soccer athletes.  相似文献   

Artificial intelligence and African conceptions of personhood     

Wareham  C. S. 《Ethics and Information Technology》2021,23(2):127-136

Ethics and Information Technology - Under what circumstances if ever ought we to grant that Artificial Intelligences (AI) are persons? The question of whether AI could have the high degree of moral...  相似文献   

Outstanding performances during elite-standard short and middle-distance finals and the hyperandrogenism regulation—A detailed analysis of Caster Semenya’s results     

Jonathan Ospina-Betancurt  Maria S. Zakynthinaki 《Journal of sports sciences》2020,38(6):703-709

ABSTRACT

Recently, there has been much controversy over the International Association of Athletics Federation (IAAF) regulations regarding eligibility to compete and natural testosterone levels in female athletes. Much interest lies in the analysis of Caster Semenya's extraordinary performance. The objective of this work were, a) Complete an analysis of Caster Semenya's results during the 800m finals and b) search for existing similar performances by other female athletes. We analysed the results of the finals of all IAAF World Championships and Olympic Games from 1984–2016, including the 800m results of the Diamond Leagues 2016–2018. Exponential curves were fit to the data to characterise and predict performance for each event. Caster Semenya's finishing times before her ineligibility to compete and after the suspension of the IAAF hyperandrogenism regulation were found to be 1.24% and 1.49%, respectively, faster than the characteristic performance of the elite-standard in the women’s 800m final. Other female athletes, with finishing times faster than the ones predicted by the characteristic curves were also discovered. The percentage difference in performance between Caster Semenya and the other participants did not reach 3% in the 800m event. No conclusions can be drawn regarding extraordinary results ever performed during the 100m, 200m or 400m finals.  相似文献   

Does modality matter? A latent profile and transition analysis of sedentary behaviours among school-aged youth: The UP&DOWN study     

David Sánchez-Oliva  Rebecca M. Leech  Alberto Grao-Cruces  Irene Esteban-Cornejo  Carmen Padilla-Moledo  Oscar L. Veiga 《Journal of sports sciences》2020,38(9):1062-1069

ABSTRACT

The aims of this study were to identify profiles of sedentary behaviour (SB) patterns, based on leisure-time self-reported SB modalities (screen, educative, social, and relaxing) and to evaluate changes in these profiles over 2 years among Spanish youth aged 8–18 years. Latent profile analysis (LPA), a data-driven analytic approach, was used to identify groups of boys and girls (n = 1553; 48% girls; mean±SD age: 12.56 ± 2.49 y) with distinct SB profiles using the SB modalities (time/d) as input variables. Latent transition analysis, an extension of LPA that uses longitudinal data, was used to analyse 2-year changes in these profiles. At baseline, four and three SB profiles were found among boys (labelled: screen, educative, social, and relaxing) and girls (labelled: screen/social, educative, and relaxing), respectively. Overall, more girls (range: 48%-67%) had the same profile over time, than boys (40%-52%). Participants with a screen or relaxing SB profile at baseline were more likely to have an educative profile after 2 years. Youth with a social and an educative SB profile at baseline were more likely to transition to profiles characterized by higher screen and social SB, respectively. Using a novel and person-centered approach, this study identified gender-specific SB profiles that were moderately stable over time.  相似文献   

The Developmental Sequence and Relations Between Gesture and Spoken Language in Toddlers With Autism Spectrum Disorder     

Meagan R. Talbott  Gregory S. Young  Jeff Munson  Annette Estes  Laurie A. Vismara  Sally J. Rogers 《Child development》2020,91(3):743-753

In typical development, gestures precede and predict language development. This study examines the developmental sequence of expressive communication and relations between specific gestural and language milestones in toddlers with autism spectrum disorder (ASD), who demonstrate marked difficulty with gesture production and language. Communication skills across five stages (gestures, word approximations, first words, gesture-word combinations, and two-word combinations) were assessed monthly by blind raters for toddlers with ASD participating in an randomized control trial of parent-mediated treatment (N = 42, 12–30 months). Findings revealed that toddlers acquired skills following a reliable (vs. idiosyncratic) sequence and the majority of toddlers combined gestures with words before combining words in speech, but in contrast to the pattern observed in typical development, a significant subset acquired pointing after first words.  相似文献   

Teaching a blind student anatomy during the Covid-19 pandemic     

Georga J. Longhurst B.Sc. .  M.Sc.  P.G.Cert.H.B.E.  S.P.Cert.  F.H.E.A. 《Anatomical sciences education》2021,14(5):586-589

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Toward a Developmental Science of Politics     

Meagan M. Patterson  Rebecca S. Bigler  Erin Pahlke  Christia Spears Brown  Amy Roberson Hayes  M. Chantal Ramirez  Andrew Nelson 《Monographs of the Society for Research in Child Development》2019,84(3):7-185

In this monograph, we argue for the establishment of a developmental science of politics that describes, explains, and predicts the formation and change of individuals’ political knowledge, attitudes, and behavior beginning in childhood and continuing across the life course. Reflecting our goal of contributing both theoretical conceptualizations and empirical data, we have organized the monograph into two broad sections. In the first section, we outline theoretical contributions that the study of politics may make to developmental science and provide practical reasons that empirical research in the domain of politics is important (e.g., for identifying ways to improve civics education and for encouraging higher voting rates among young adults). We also review major historical approaches to the study of political development and provide an integrative theoretical framework to ground future work. Drawing on Bronfenbrenner's ecological systems model as an organizing scheme and emphasizing social justice issues, we describe how factors rooted in cultural contexts, families, and children themselves are likely to shape political development. In the second section of the monograph, we argue for the importance and utility of studying major political events, such as presidential elections, and introduce the major themes, rationales, and hypotheses for a study of U.S. children's views of the 2016 U.S. presidential election. In addition, we apply a social-justice lens to political thought and participation, addressing the role of gender/sex and race/ethnicity in children's political development broadly, and in their knowledge and views of the 2016 U.S. presidential election specifically. In interviews conducted within the month before and after the election, we examined two overarching categories of children's political attitudes: (a) knowledge, preferences, and expectations about the 2016 election, and (b) knowledge and attitudes concerning gender/sex and politics, particularly relevant for the 2016 election given Hillary Clinton's role as the first female major-party candidate for the presidency. Participants were 187 children (101 girls) between 5 and 11 years of age (M = 8.42 years, SD = 1.45 years). They were recruited from schools and youth organizations in five counties in four U.S. states (Kansas, Kentucky, Texas, and Washington) with varying voting patterns (e.g., Trump voters ranged from 27% to 71% of county voters). The sample was not a nationally representative one, but was racially diverse (35 African American, 50 Latinx, 81 White, and 21 multiracial, Asian American, Middle Eastern, or Native American children). In addition to several child characteristics (e.g., age, social dominance orientation [SDO]), we assessed several family and community characteristics (e.g., child-reported parental interest in the election and government-reported county-level voting patterns, respectively) hypothesized to predict outcome variables. Although our findings are shaped by the nature of our sample (e.g., our participants were less likely to support Trump than children in larger, nationwide samples were), they offer preliminary insights into children's political development. Overall, children in our sample were interested in and knowledgeable about the presidential election (e.g., a large majority identified the candidates correctly and reported some knowledge about their personal qualities or policy positions). They reported more information about Donald Trump's than Hillary Clinton's policies, largely accounted for by the substantial percentage of children (41%) who referred to Trump's immigration policies (e.g., building a wall between the United States and Mexico). Overall, children reported as many negative as positive personal qualities of the candidates, with negative qualities being reported more often for Trump than for Clinton (56% and 18% of children, respectively). Most children (88%) supported Clinton over Trump, a preference that did not vary by participants’ gender/sex or race/ethnicity. In their responses to an open-ended inquiry about their reactions to Trump's win, 63% of children reported negative and 18% reported positive emotions. Latinx children reacted more negatively to the election outcome than did White children. Girls’ and boys’ emotional responses to the election outcome did not differ. Children's personal interest in serving as U.S. president did not vary across gender/sex or racial/ethnic groups (overall, 42% were interested). Clinton's loss of the election did not appear to depress (or pique) girls’ interest in becoming U.S. president. With respect to the role of gender/sex in politics, many children (35%) were ignorant about women's absence from the U.S. presidency. Only a single child was able to name a historical individual who worked for women's civil rights or suffrage. Child characteristics predicted some outcome variables. For example, as expected, older children showed greater knowledge about the candidates than did younger children. Family and community characteristics also predicted some outcome variables. For example, as expected, participants were more likely to support Trump if they perceived that their parents supported him and if Trump received a greater percentage of votes in the children's county of residence. Our data suggest that civic education should be expanded and reformed. In addition to addressing societal problems requiring political solutions, civics lessons should include the histories of social groups’ political participation, including information about gender discrimination and the women's suffrage movement in U.S. political history. Providing children with environments that are rich in information related to the purpose and value of politics, and with opportunities and encouragement for political thought and action, is potentially beneficial for youth and their nations.  相似文献   

The effects of a calf pump device on second half performance of a simulated soccer match in competitive youth players     

S. Béliard  J. Cassirame  G. Ennequin  G. Coratella  N. Tordi 《Journal of sports sciences》2019,37(6):708-716

During soccer matches, performance decrements have been reported that relate to both physical abilities and technical skills. To investigate the effects of low-frequency electrical stimulation LFES (VeinoplusSport®, Ad Rem Technology, France) administered during half-time recovery on performance alterations during the second half. Twenty-two highly trained young players undertook a soccer-match simulation (SAFT⁹⁰). During half-time, they were randomly assigned to LFES group or Placebo group. Each half was split into 3 bouts of 12 minutes. Following each bout, maximal strike speed (MSS), sprint test (ST), maximal sprint accelerations (MA) and metabolic power (MP) were determined in both groups. Arterial (AF) and venous flows (VF) were measured at rest and at the end of half-time. LEFS group exhibited beneficial effects on performance compared to the Placebo group with a likely effect for MSS, ST, MA, and a possible effect for MP. AF and VF increased statistically more in LEFS group compared to Placebo group. The use of specific calf-pump LFES during half-time of a youth simulated soccer match attenuated the decrease in performance during the second half compared to Placebo group. This effect is most marked at the beginning of the second half with regards to explosive parameters.  相似文献