97 research outputs found
Systematic Review of Sport Coaches’ and Teachers’ Perceptions and Application of Game-Based and Constraints-Led Pedagogy: A Qualitative MetaStudy
This study represents the first comprehensive qualitative systematic review on sport coaches’ and teachers’ perceptions and application of Game-Based Approaches (GBA) and Constraints-Led Approach (CLA). From searching 12 electronic academic databases from 1982 to 2020, 29 studies met the eligibility criteria and were included in the metastudy. Data revealed studies were conducted in several different countries, and case study design was the predominant methodology. The main data collection method reported was cross-sectional interviews. There were inconsistencies in the quality of reporting methodologies, sampling procedures, data analysis, and assessing quality. The metatheory analysis identified weaknesses in the methodological and conceptual approaches, and a low number of studies stated philosophical perspectives. The meta-synthesis identified assumptions about learning, pedagogical knowledge and skills, content knowledge, and support as the overarching themes reported to impact coaches’ and teachers’ perceptions and application of GBAs and CLA. Finally, some recommendations for future research and practice are provided
Why do bad balls get wickets? The role of congruent and incongruent information in anticipation.
Skilled anticipation is underpinned by the use of kinematic and contextual information. However, few researchers have examined what happens when contextual information suggests an outcome that is different from the event that follows. We aimed to bridge this gap by manipulating the relationship between contextual information and final ball location in a cricket-batting task. We predicted that when contextual information is congruent with the eventual outcome then anticipation would be facilitated. In contrast, when contextual information is incongruent, this would lead to a confirmation bias on kinematic information and result in decreased anticipation accuracy. We expected this effect to be larger in skilled performers who are more able to utilise context. Skilled and less-skilled cricket batters anticipated deliveries presented using a temporally occluded video-based task. We created conditions whereby contextual information and event outcome were either congruent or incongruent. There was a significant skill by condition interaction (p < 0.05). The skilled group anticipated significantly more accurately than the less-skilled group on the congruent trials. Both groups anticipated less accurately on incongruent trials, with the skilled participants being more negatively affected. Skilled performers prioritise contextual information and confirmation bias affects the use of kinematic information available later in the action
Capturing and testing perceptual-cognitive expertise: A comparison of stationary and movement response methods
Numerous methods have been used to study expertise and performance. In the present article, we compare the cognitive thought processes of skilled soccer players when responding to film-based simulations of defensive situations involving two different experimental conditions. Participants either remained stationary in a seated position (n = 10) or were allowed to move (n = 10) in response to life-size film sequences of 11 versus 11 open-play soccer situations viewed from a player’s perspective. Response accuracy and retrospective verbal reports of thinking were collected across the two task conditions. In the movement-based response group, participants generated a greater number of verbal report statements, including a higher proportion of evaluation, prediction, and action planning statements, than did participants in the stationary group. Findings suggest that the processing strategies employed during performance differ depending on the nature of the response required of participants. Implications for behavioral methods and experimental design are discussed
A case study of the use of verbal reports for talent identification purposes in soccer: A Messi affair!
Using a two-study approach, the main purpose of this case study was to explore the use of a verbal reporting methodology to better understand the thought processes of soccer talent scouts during an in-situ talent identification environment. Study 1 developed a standardized coding-scheme to examine verbal cognitions during a single soccer game. Study 2 then utilized this methodology to examine two full-time recruitment staff trained in the use of concurrent verbal reporting before undertaking a live, in-game task. Participants also participated in a debrief interview following the game. The findings of the two studies suggest that developing a verbal reporting protocol is viable, however when applied in a live-game environment it is problematic. Future research should therefore consider a modified version of this task to further explore the cognitions of scouts whilst observing and identifying potential talent
Promiscuous Expression of α-Tubulin II in Maturing Male and Female Plasmodium falciparum Gametocytes
BACKGROUND: Antimalarial interventions designed to impact on the transmissible sexual stages of Plasmodium falciparum are evaluated by measurement of peripheral gametocyte carriage in vivo and infectivity to mosquitoes. Drug or vaccine-elicited effects may differentially affect the relative abundance of mature male and female sexual forms, and this can be measured by estimation of sex ratios before and after intervention in vivo and in vitro. Measuring the impact of anti-gametocyte drugs on sexual commitment of immature gametocyte stages in vitro is not currently possible as male and female parasites cannot be distinguished by morphology alone prior to stage IV. METHODOLOGY/PRINCIPAL FINDINGS: We have modified an existing immunofluorescence-based approach for distinguishing male and female gametocytes during development in vitro, by using highly synchronised magnetically-enriched gametocyte preparations at different stages of maturity. Antibodies recognising α-tubulin II (males) and Pfg377 (females) were used to attempt to discriminate the sexes. Transcription of these two proteins was not coordinated during in vitro development, with pfg377 transcripts accumulating only late in development, immediately prior to immunofluorescent signals from the PfG377 protein appearing in stage IV gametocytes. Contrary to previous descriptions of this protein as male-specific in P. falciparum, α-tubulin II recognised both male and female gametocytes at stages I to IV, but evidence of differential expression levels of this protein in late stage male and female gametocytes was found. Using antibodies recognising PfG377 as the primary marker and α-tubulin II as a secondary marker, robust estimates of sex ratio in in vitro cultures were obtained for gametocytes at stage IV or later, and validated by light microscopic counts. However, sex ratio estimation was not possible for early stage gametocytes due to the promiscuity of α-tubulin II protein expression, and the relatively late accumulation of PfG377 during the development process. CONCLUSIONS/SIGNIFICANCE: This approach is a feasible method for the evaluation of drug impacts on late-stage gametocyte sex ratio in in vitro studies. Additional sex-specific antigens need to be evaluated for sex ratio estimation in early stage gametocyte preparations
Multi-campaign Ship and Aircraft Observations of Marine Cloud Condensation Nuclei and Droplet Concentrations
In-situ marine cloud droplet number concentrations (CDNCs), cloud condensation nuclei (CCN), and CCN proxies, based on particle sizes and optical properties, are accumulated from seven field campaigns: ACTIVATE; NAAMES; CAMP2EX; ORACLES; SOCRATES; MARCUS; and CAPRICORN2. Each campaign involves aircraft measurements, ship-based measurements, or both. Measurements collected over the North and Central Atlantic, Indo-Pacific, and Southern Oceans, represent a range of clean to polluted conditions in various climate regimes. With the extensive range of environmental conditions sampled, this data collection is ideal for testing satellite remote detection methods of CDNC and CCN in marine environments. Remote measurement methods are vital to expanding the available data in these difficult-to-reach regions of the Earth and improving our understanding of aerosol-cloud interactions. The data collection includes particle composition and continental tracers to identify potential contributing CCN sources. Several of these campaigns include High Spectral Resolution Lidar (HSRL) and polarimetric imaging measurements and retrievals that will be the basis for the next generation of space-based remote sensors and, thus, can be utilized as satellite surrogates
Ecological influences on the behaviour and fertility of malaria parasites
BACKGROUND: Sexual reproduction in the mosquito is essential for the transmission of malaria parasites and a major target for transmission-blocking interventions. Male gametes need to locate and fertilize females in the challenging environment of the mosquito blood meal, but remarkably little is known about the ecology and behaviour of male gametes. METHODS: Here, a series of experiments explores how some aspects of the chemical and physical environment experienced during mating impacts upon the production, motility, and fertility of male gametes. RESULTS AND CONCLUSIONS: Specifically, the data confirm that: (a) rates of male gametogenesis vary when induced by the family of compounds (tryptophan metabolites) thought to trigger gamete differentiation in nature; and (b) complex relationships between gametogenesis and mating success exist across parasite species. In addition, the data reveal that (c) microparticles of the same size as red blood cells negatively affect mating success; and (d) instead of swimming in random directions, male gametes may be attracted by female gametes. Understanding the mating ecology of malaria parasites, may offer novel approaches for blocking transmission and explain adaptation to different species of mosquito vectors
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