Integrating advanced visual information with ball projection technology constrains dynamic interceptive actions

The role of advanced visual information in ball catching was investigated by integrating video images of action and ball projection technology in four different conditions: Integrated video and ball projection (VBP), Video-Only (VO), Ball Projection-Only (BPO) and Misleading Ball projection (MBP). Hand kinematics and gaze behaviour data were collected from participants who attempted to catch balls one handed in all conditions. During VBP, catching performance was more successful, tracking of the ball occurred earlier and lasted longer, with maximum grip aperture emerging earlier with a slower maximum velocity than in BPO. During VO, movement emerged later than VBP, with larger maximum and minimum grip aperture compared to VBP and BPO. Results provided evidence that advance information, prior to ball release, and vision of a ball’s trajectory are essential for successful performance and integrated projection technology may provide a representative design for studying interceptive actions

Proximity-to-goal as a constraint on patterns of behaviour in attacker-defender dyads in team games

Abstract The aim of this study was to determine whether spatiotemporal interactions between footballers and the ball in 1 vs. 1 sub-phases are influenced by their proximity to the goal area. Twelve participants (age 15.3 +/- 0.5 years) performed as attackers and defenders in 1 vs. 1 dyads across three field positions: (a) attacking the goal, (b) in midfield, and (c) advancing away from the goal area. In each position, the dribbler was required to move beyond an immediate defender with the ball towards the opposition goal. Interactions of attacker-defender dyads were filmed with player and ball displacement trajectories digitized using manual tracking software. One-way repeated measures analysis of variance was used to examine differences in mean defender-to-ball distance after this value had stabilized. Maximum attacker-to-ball distance was also compared as a function of proximity-to-goal. Significant differences were observed for defender-to-ball distance between locations (a) and (c) at the moment when the defender-to-ball distance had stabilized (a: 1.69 +/- 0.64 m; c: 1.15 +/- 0.59 m; P < 0.05). Findings indicate that proximity-to-goal influenced the performance of players, particularly when attacking or advancing away from goal areas, providing implications for training design in football. In this study, the task constraints of football revealed subtly different player interactions than observed in previous studies of dyadic systems in basketball and rugby union

Hindrance of Heavy-ion Fusion at Extreme Sub-Barrier Energies in Open-shell Colliding Systems

The excitation function for the fusion-evaporation reaction 64Ni+100Mo has been measured down to a cross-section of ~5 nb. Extensive coupled-channels calculations have been performed, which cannot reproduce the steep fall-off of the excitation function at extreme sub-barrier energies. Thus, this system exhibits a hindrance for fusion, a phenomenon that has been discovered only recently. In the S-factor representation introduced to quantify the hindrance, a maximum is observed at E_s=120.6 MeV, which corresponds to 90% of the reference energy E_s^ref, a value expected from systematics of closed-shell systems. A systematic analysis of Ni-induced fusion reactions leading to compound nuclei with mass A=100-200 is presented in order to explore a possible dependence of the fusion hindrance on nuclear structure.Comment: 10 pages, 9 figures, Submitted to Phys. Rev.

Enzymatic detoxification of the fumonisin mycotoxins during dry milling of maize

Fumonisin esterase FumD (EC 3.1.1.87), FUMzyme® (BIOMIN, Austria), effectively detoxifies fumonisin B mycotoxins (FB) by hydrolysis and removal of the tricarballylic acid groups. The current study evaluated FumD detoxification of total FB (FBT) in commercial maize utilising an experimental dry milling plant by introducing the enzyme during the kernel conditioning stage. Total FB and the hydrolysed product of FB1, HFB1, in maize and milling products were determined by LC-MS/MS. During maize conditioning of 4 h 10 min substantial FB1 hydrolysis was achieved between 1 and 4 U FumD/100 g maize. Complete conversion into HFB1 was delayed and only achieved at the highest enzyme concentration (32 U/100 g maize) reaching a 1:1 M conversion ratio. Dry milling of maize containing 3.29 ± 0.20 μmole FBT/kg (2354 ± 140 μg/kg) in the absence of FumD, resulted in a 2.5-fold increase in the FBT concentration in total hominy feed (8.34 ± 0.22 μmol/kg) (5979 ± 158 μg/kg) compared to the levels that prevail in Super (0.52 ± 0.07 μmol/kg) (347 ± 48 μg/kg) and Special (1.70 ± 0.01 μmol/kg) (1213 ± 8 μg/kg) maize meal, and Semolina (1.07 ± 0.14 μmol/kg) (765 ± 100 μg/kg) milling products. Introduction of FumD (40 U/kg) mainly impacted the total hominy feed product (germ + hominy milling fractions), constituting up to 30% of the reconstituted whole maize

How players exploit variability and regularity of game actions in female volleyball teams

Variability analysis has been used to understand how competitive constraints shape different behaviours in team sports. In this study, we analysed and compared variability of tactical performance indices in players within complex I at two different competitive levels in volleyball. We also examined whether variability was influenced by set type and period. Eight matches from the 2012 Olympics competition and from the Portuguese national league in the 2014–2015 season were analysed (1496 rallies). Variability of setting conditions, attack zone, attack tempo and block opposition was assessed using Shannon entropy measures. Magnitude-based inferences were used to analyse the practical significance of compared values of selected variables. Results showed differences between elite and national teams for all variables, which were co-adapted to the competitive constraints of set type and set periods. Elite teams exploited system stability in setting conditions and block opposition, but greater unpredictability in zone and tempo of attack. These findings suggest that uncertainty in attacking actions was a key factor that could only be achieved with greater performance stability in other game actions. Data suggested how coaches could help setters develop the capacity to play at faster tempos, diversifying attack zones, especially at critical moments in competition

TEMPORAL AND SPATIAL OCCLUSION OF ADVANCED VISUAL INFORMATION CONSTRAIN EMERGENT COORDINATION OF ONE-HANDED CATCHING BEHAVIOURS

Introduction Dynamic interceptive actions, like catching, are performed under severe spatial and temporal constraints. Here, behavioral processes underpinning one-handed catching was examined using a novel spatial and temporal occlusion design which enabled precise control of pre-release visual information of an actor and a fully coupled action response. Methods An integrated video and ball projection machine was used to create four temporal occlusion and five spatial occlusion conditions of an actor throwing a ball towards participants. Twelve participants’ hand kinematics and gaze behaviors were recorded while attempting to catch a projected ball synchronized with the video footage. Results Temporal occlusion findings revealed that when footage was occluded at earlier time points, catching performance decreased. Movement onset of the catching hand and initiation of visual ball tracking emerged earlier when footage of the thrower was occluded at a later time point in the throwing action. Spatial occlusion did not affect catching success, although movement onset emerged later when increased visual information of the actor was occluded. Later movement onset was countered by greater maximum velocity of the catching hand. The final stages of action (e.g., grasping action of the hand) remained unchanged across both spatial and temporal conditions suggesting the later phases of the action were organised using ball flight information. Discussion Findings revealed how catching behaviors were continuously (re)organized and adapted as information became available in task performance, first by using kinematic information of a thrower's actions, and then by ball flight information. This highlighted the importance of maintaining information-movement coupling during performance of interceptive actions, with these behavioral adaptations having important implications for research that assesses interceptive skills based solely on pre-ball flight information, as in many current video-based simulation paradigms. Contact [email protected]

Specialist role coaching and skill training periodisation: A football goalkeeping case study

© The Author(s) 2020. In sports like association football, professional teams are increasingly devoting resources to the role-based development of individual athletes and sub-groups. By employing ‘specialist coaches’ into athlete-support structures, clubs aim to facilitate individualised athlete training programs to enhance performance preparation as well as skill learning and talent development. Here, we discuss how contemporary pedagogical training approaches, like Nonlinear Pedagogy and the Constraints-Led approach, can enhance effectiveness of specialist role-based athlete development programs to facilitate performance functionality. We argue the need for a model of specialist role-based coaching practice in high performance sports organisations, based on a unified theoretical rationale, such as ecological dynamics. To exemplify the nature of specialist role-based coaching, a case study addresses how Nonlinear Pedagogy and Constraints-Led approach are being used for training professional football goalkeepers in an U23 years age group. Integrating key concepts from ecological dynamics, allied to principles of Nonlinear Pedagogy and the Constraints-Led approach, common skill training principles for specialist role coaches are highlighted. These illustrate the use of the recently introduced ‘Periodization of Skill Training’ framework for specialist role coaching, practically exemplifying a way to harness opportunities for performance enhancement and individualised talent development in the football goalkeeping context

Electromagnetic Dissociation of 8B and the Rate of the 7Be(p,gamma)8B Reaction in the Sun

In an effort to better determine the 7Be(p,gamma)8B reaction rate, we have performed inclusive and exclusive measurements of the Coulomb dissociation of 8B. The former was a study of longitudinal momentum distributions of 7Be fragments emitted in the Coulomb breakup of intermediate energy 8B beams on Pb and Ag targets. Analysis of these data yielded the E2 contribution to the breakup cross section. In the exclusive measurement, we determined the cross section for the Coulomb breakup of 8B on Pb at low relative energies in order to infer the astrophysical S factor for the 7Be(p,gamma)8B reaction. Interpreting the measurements with 1st-order perturbation theory, we obtained SE2/SE1 = 4.7 (+ 2.0,- 1.3) times 10^-4 at Erel = 0.6 MeV, and S17(0) = 17.8 (+ 1.4,- 1.2) eV b. Semiclassical 1st-order perturbation theory and fully quantum mechanical continuum-discretized coupled channels analyses yield nearly identical results for the E1 strength relevant to solar neutrino flux calculations, suggesting that theoretical reaction mechanism uncertainties need not limit the precision of Coulomb breakup determinations of the 7Be(p,gamma)8B S factor. A recommended value of S17(0) based on a weighted average of this and other measurements is presented

Theory to Practice: Performance Preparation Models in Contemporary High-Level Sport Guided by an Ecological Dynamics Framework

Abstract: A fundamental challenge for practitioners in high-level sporting environments concerns how to support athletes in adapting behaviours to solve emergent problems during competitive performance. Guided by an ecological dynamics framework, the design and integration of competitive performance preparation models that place athlete-environment interactions at the heart of the learning process may address this challenge. This ecological conceptualisation of performance preparation signifies a shift in a coach’s role; evolving from a consistent solution provider to a learning environment designer who fosters local athlete-environment interactions. However, despite the past decades of research within the ecological dynamics framework developing an evidence-based, theoretical conceptualisation of skill acquisition, expertise and talent development, an ongoing challenge resides within its practical integration into sporting environments. This article provides two case examples in which high-level sports organisations have utilised an ecological dynamics framework for performance preparation in Australian football and Association Football. A unique perspective is offered on experiences of professional sport organisations attempting to challenge traditional ideologies for athlete performance preparation by progressing the theoretical application of ecological dynamics. These case examples intend to promote the sharing of methodological ideas to improve athlete development, affording opportunities for practitioners and applied scientists to accept, reject or adapt the approaches presented here to suit their specific ecosystems

Measurement of two-halo neutron transfer reaction p(11^{11}Li,9^{9}Li)t at 3AA MeV

The p(\nuc{11}{Li},\nuc{9}{Li})t reaction has been studied for the first time at an incident energy of 3$A$ MeV delivered by the new ISAC-2 facility at TRIUMF. An active target detector MAYA, build at GANIL, was used for the measurement. The differential cross sectionshave been determined for transitions to the \nuc{9}{Li} ground andthe first excited states in a wide range of scattering angles. Multistep transfer calculations using different \nuc{11}{Li} model wave functions, shows that wave functions with strong correlations between the halo neutrons are the most successful in reproducing the observation.Comment: 6 pages, 3 figures, submitted to Physical Review Letter