Coach rating combined with small-sided games provides further insight into mental toughness in sport

Literature indicates that mental toughness contributes to successful performance when faced with challenge. This study used an exemplar sport of Australian Rules football to investigate whether skilled performance thrived across increased challenge in small-sided games. Higher (n = 14) and lower (n = 17) skilled Australian footballers were recruited. First, coaches rated participants' mental toughness (MTC) using the Mental Toughness Index. Second, participants competed in small-sided games where challenge was manipulated by varying the attacker to defender ratio to create lower and higher pressure scenarios. Decision-making, motor skill execution, and a combined total were measured. MTC rating was higher for higher skilled players. Total score of higher skilled players was significantly superior to lower skilled players in higher and lower pressure scenarios (p = 0.003). A "pressure differential score," calculated to determine whether participants maintained performance across increased challenge, indicated a significant decrease in performance (total score) from lower to higher pressure scenarios for lower skilled (p = 0.011), but not for higher skilled (p = 0.060) players. Furthermore, MTC scores were predictive of high pressure scenario total scores (p = 0.011). Findings suggest higher levels of mental toughness may contribute to maintain performance across the increased challenge of pressure within small-sided games. Practitioners can subjectively rate athlete mental toughness and then structure small-sided games to objectively measure performance under pressure scenarios. This provides an interdisciplinary approach to assess and train psychomotor skill. © 2019 Piggott, Müller, Chivers, Burgin and Hoyne

Imputation of missing sub-hourly precipitation data in a large sensor network : a machine learning approach

This research was supported by a UKRI-NERC Constructing a Digital Environment Strategic Priority grant “Engineering Transformation for the Integration of Sensor Networks: A Feasibility Study” [NE/S016236/1 & NE/S016244/1].Peer reviewedPostprin

Living in a risky world: the onset and ontogeny of an integrated antipredator phenotype in a coral reef fish

Prey individuals with complex life-histories often cannot predict the type of risk environment to which they will be exposed at each of their life stages. Because the level of investment in defences should match local risk conditions, we predict that these individuals should have the ability to modulate the expression of an integrated defensive phenotype, but this switch in expression should occur at key life-history transitions. We manipulated background level of risk in juvenile damselfish for four days following settlement (a key life-history transition) or 10 days post-settlement, and measured a suite of physiological and behavioural variables over 2 weeks. We found that settlement-stage fish exposed to high-risk conditions displayed behavioural and physiological alterations consistent with high-risk phenotypes, which gave them a survival advantage when exposed to predators. These changes were maintained for at least 2 weeks. The same exposure in post-settlement fish failed to elicit a change in some traits, while the expression of other traits disappeared within a week. Our results are consistent with those expected from phenotypic resonance. Expression of antipredator traits may be masked if individuals are not exposed to certain conditions at key ontogenetic stages

Chamber music: an unusual Helmholtz resonator for song amplification in a Neotropical bush-cricket (Orthoptera, Tettigoniidae)

Animals use sound for communication, with high-amplitude signals being selected for attracting mates or deterring rivals. High amplitudes are attained by employing primary resonators in sound producing structures to amplify the signal (e.g., avian syrinx). Some species actively exploit acoustic properties of natural structures to enhance signal transmission by using these as secondary resonators (e.g., tree-hole frogs). Male bush-crickets produce sound by tegminal stridulation and often use specialised wing areas as primary resonators. Interestingly, Acanthacara acuta, a Neotropical bush-cricket, exhibits an unusual pronotal inflation, forming a chamber covering the wings. It has been suggested that such pronotal chambers enhance amplitude and tuning of the signal by constituting a (secondary) Helmholtz resonator. If true, the intact system – when stimulated sympathetically with broadband sound – should show clear resonance around the song carrier frequency which should be largely independent of pronotum material, and change when the system is destroyed. Using laser Doppler vibrometry on living and preserved specimens, micro computed tomography, 3D printed models, and finite element modelling, we show that the pronotal chamber not only functions as a Helmholtz resonator due to its intact morphology but also resonates at frequencies of the calling song on itself, making song production a three-resonator system

Growth rate and retention of learned predator cues by juvenile rainbow trout: faster-growing fish forget sooner

Under conditions of spatial and/or temporal variability in predation risk, prey organisms often rely on acquired predator recognition to balance the trade-offs between energy intake and risk avoidance. The question of ‘for how long’ should prey retain this learned information is poorly understood. Here, we test the hypothesis that the growth rate experienced by prey should influence the length of the ‘memory window’. In a series of laboratory experiments, we manipulated growth rate of juvenile rainbow trout and conditioned them to recognize a novel predator cue. We subsequently tested for learned recognition either 24 h or 8 days post-conditioning. Our results suggest that trout with high versus low growth rates did not differ in their response to learned predator cues when tested 24 h post-conditioning. However, trout on a high growth rate exhibited no response to the predator cues after 8 days (i.e. did not retain the recognition of the predator odour), whereas trout on a lower growth rate retained a strong recognition of the predator. Trout that differed in their growth rate only after conditioning did not differ in their patterns of retention, demonstrating growth rate after learning does not influence retention. Trout of different initial sizes fed a similar diet (percent body mass per day) showed no difference in retention of the predator cue. Together, these data suggest that growth rate at the time of conditioning determines the ‘memory window’ of trout. The implications for threat-sensitive predator avoidance models are described

Coral Reef Fish Rapidly Learn to Identify Multiple Unknown Predators upon Recruitment to the Reef

Organisms often undergo shifts in habitats as their requirements change with ontogeny

Childhood body mass index trajectories: modeling, characterizing, pairwise correlations and socio-demographic predictors of trajectory characteristics

Background: Modeling childhood body mass index (BMI) trajectories, versus estimating change in BMI between specific ages, may improve prediction of later body-size-related outcomes. Prior studies of BMI trajectories are limited by restricted age periods and insufficient use of trajectory information. Methods: Among 3,289 children seen at 81,550 pediatric well-child visits from infancy to 18 years between 1980 and 2008, we fit individual BMI trajectories using mixed effect models with fractional polynomial functions. From each child's fitted trajectory, we estimated age and BMI at infancy peak and adiposity rebound, and velocity and area under curve between 1 week, infancy peak, adiposity rebound, and 18 years. Results: Among boys, mean (SD) ages at infancy BMI peak and adiposity rebound were 7.2 (0.9) and 49.2 (11.9) months, respectively. Among girls, mean (SD) ages at infancy BMI peak and adiposity rebound were 7.4 (1.1) and 46.8 (11.0) months, respectively. Ages at infancy peak and adiposity rebound were weakly inversely correlated (r = -0.09). BMI at infancy peak and adiposity rebound were positively correlated (r = 0.76). Blacks had earlier adiposity rebound and greater velocity from adiposity rebound to 18 years of age than whites. Higher birth weight z-score predicted earlier adiposity rebound and higher BMI at infancy peak and adiposity rebound. BMI trajectories did not differ by birth year or type of health insurance, after adjusting for other socio-demographics and birth weight z-score. Conclusions: Childhood BMI trajectory characteristics are informative in describing childhood body mass changes and can be estimated conveniently. Future research should evaluate associations of these novel BMI trajectory characteristics with adult outcomes

Prenatal exposure to predation affects predator recognition learning via lateralization plasticity

Prey with cerebral lateralization often shows a bias in escape direction and asymmetrical use of eyes for scanning. Such asymmetries are likely to cause ecological disadvantages when, for example, predators attack from the side in which the prey is more susceptible. However, lateralized individuals are diffuse in many species and, paradoxically, their frequency increases via developmental plasticity in environments with high-predation risk. Using wood frog tadpoles, Lithobates sylvaticus, we tested the hypothesis that cerebral lateralization enhances predator recognition learning and thus overcomes the costs of behavioral asymmetries in high predation risk environments. In the first experiment, we found tadpoles exposed to risk as embryos developed more intense lateralization in a rotational test compared to predator-naive controls. Risk exposure led to the more frequent development of clockwise swimming preference. In the second experiment, we found that tadpoles exhibiting no behavioral lateralization and tadpoles with marked clockwise swimming preference learned to recognize the novel predator odor, with the latter showing a better performance as predicted. Tadpoles with anticlockwise swimming preference did not learn to associate the predator with risk. Exposure to a high-risk environment during early ontogeny appears to favor the development of either a lateralization phenotype with refined predator recognition learning skills, or, to a lesser extent, a lateralization phenotype with poor predator recognition learning skills. Such individuals likely cope with predation using mechanisms other than learning

Coach rating combined with small-sided games provides further insight into mental toughness in sport

Literature indicates that mental toughness contributes to successful performance when faced with challenge. This study used an exemplar sport of Australian Rules football to investigate whether skilled performance thrived across increased challenge in small-sided games. Higher (n = 14) and lower (n = 17) skilled Australian footballers were recruited. First, coaches rated participants’ mental toughness (MTC) using the Mental Toughness Index. Second, participants competed in small-sided games where challenge was manipulated by varying the attacker to defender ratio to create lower and higher pressure scenarios. Decision-making, motor skill execution, and a combined total were measured. MTC rating was higher for higher skilled players. Total score of higher skilled players was significantly superior to lower skilled players in higher and lower pressure scenarios (p = 0.003). A “pressure differential score,” calculated to determine whether participants maintained performance across increased challenge, indicated a significant decrease in performance (total score) from lower to higher pressure scenarios for lower skilled (p = 0.011), but not for higher skilled (p = 0.060) players. Furthermore, MTC scores were predictive of high pressure scenario total scores (p = 0.011). Findings suggest higher levels of mental toughness may contribute to maintain performance across the increased challenge of pressure within small-sided games. Practitioners can subjectively rate athlete mental toughness and then structure small-sided games to objectively measure performance under pressure scenarios. This provides an interdisciplinary approach to assess and train psychomotor skill