286 research outputs found

    Decision-making accuracy of soccer referees in relation to markers of internal and external load

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    This study examined the relationships between the decision-making performances of soccer referees and markers of physiological load. Following baseline measurements and habituation procedures, 13 national-level male referees completed a novel Soccer Referee Simulation whilst simultaneously adjudicating on a series of video-based decision-making clips. The correctness of each decision was assessed in relation to the mean heart rate (HR), respiratory rate (RR), minute ventilation (VE), perceptions of breathlessness (RPE-B) and local muscular (RPE-M) exertion and running speeds recorded in the 10-s and 60-s preceding decisions. There was a significant association between decision-making accuracy and the mean HR (p = 0.042; VC = 0.272) and RR (p = 0.024, VC = 0.239) in the 10-s preceding decisions, with significantly more errors observed when HR ≄ 90% of HRmax (OR, 5.39) and RR ≄ 80% of RRpeak (OR, 3.34). Decision-making accuracy was also significantly associated with the mean running speeds performed in the 10-s (p = 0.003; VC = 0.320) and 60-s (p = 0.016; VC = 0.253) preceding decisions, with workloads of ≄250 m·min−1 associated with an increased occurrence of decisional errors (OR, 3.84). Finally, there was a significant association between decision-making accuracy and RPE-B (p = 0.021; VC = 0.287), with a disproportionate number of errors occurring when RPE-B was rated as “very strong” to “maximal” (OR, 7.19). Collectively, the current data offer novel insights into the detrimental effects that high workloads may have upon the decision-making performances of soccer referees. Such information may be useful in designing combined physical and decision-making training programmes that prepare soccer referees for the periods of match play that prove most problematic to their decision-making

    How experience influences infants’ recognition of male and female faces

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    Young infants with female primary caregivers are able to differentiate familiar female faces from novel female faces but not male faces. Experience processing faces may be important for being able to discriminate among similar-looking faces. Subsequently, increasing infants’ experience with less familiar faces should improve their ability to differentiate those types of faces. This study examined if infants’ experience with faces affected their recognition of new faces. Prior to testing, 2-3 month old infants were assigned to one of three conditions: a male video, a female video, and no video condition. Infants were familiarized to both male and female faces during test. For the male faces, infants who saw the male video showed a familiarity preference, infants who saw the female video showed a novelty preference, and infants who saw no video showed no preference. For female faces, infants showed no preference when assigned to the male video and no video condition, while infants assigned to the female video (n = 5) showed a familiarity preference. A follow up infant-controlled habituation study tested if infants processed faces featurally or holistically. During testing, infants saw one familiar face, one composite face, and one novel face. None of the infants in the male video, female video, or no video conditions were able to distinguish the familiar face from the composite face. Only infants in the female video condition showed an increase in looking time from the familiar face to the novel face

    Decision-making accuracy of soccer referees in relation to markers of internal and external load

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    Rosie Arthur - ORCID: 0000-0003-0651-4056 https://orcid.org/0000-0003-0651-4056Supplementary data for this paper is available at: https://eresearch.qmu.ac.uk/handle/20.500.12289/13683 .AM replaced with VoR 2024-03-18.This study examined the relationships between the decision-making performances of soccer referees and markers of physiological load. Following baseline measurements and habituation procedures, 13 national-level male referees completed a novel Soccer Referee Simulation (SRS) whilst simultaneously adjudicating on a series of video-based decision-making clips. The correctness of each decision was assessed in relation to the mean heart rate (HR), respiratory rate (RR), minute ventilation (V̇E), perceptions of breathlessness (RPE-B) and local muscular (RPE-M) exertion, and running speeds recorded in the 10-s and 60-s preceding decisions. There was a significant association between decision-making accuracy and the mean HR (P=0.042; VC=0.272) and RR (P=0.024, VC=0.239) in the 10-s preceding decisions, with significantly more errors observed when HR ≄90% of HRmax (OR, 5.39) and RR ≄80% of RRpeak (OR, 3.34). Decision-making accuracy was also significantly associated with the mean running speeds performed in the 10-s (P=0.003; VC=0.320) and 60-s (P=0.016; VC=0.253) preceding decisions, with workloads of ≄250 m·min-1 associated with an increased occurrence of decisional errors (OR, 3.84). Finally, there was a significant association between decision-making accuracy and RPE-B (P=0.021; VC=0.287), with a disproportionate number of errors occurring when RPE-B was rated as “very strong” to “maximal” (OR, 7.19). Collectively, the current data offer novel insights into the detrimental effects that high workloads may have upon the decision-making performances of soccer referees. Such information may be useful in designing combined physical and decision-making training programmes that prepare soccer referees for the periods of match play that prove most problematic to their decision-making.aheadofprintaheadofprin

    Micro-CT 3D imaging reveals the internal structure of three abyssal xenophyophore species (Protista, Foraminifera) from the eastern equatorial Pacific Ocean

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    Xenophyophores, giant foraminifera, are distinctive members of the deep-sea megafauna that accumulate large masses of waste material (‘stercomare’) within their agglutinated tests, and organise their cells as branching strands enclosed within an organic tube (the ‘granellare’ system). Using non-destructive, three-dimensional micro-CT imaging we explored these structures in three species from the abyssal eastern Pacific Clarion-Clipperton Zone (CCZ). In Psammina spp., the low-density stercomare occupied much of the test interior, while high-density granellare strands branched throughout the structure. In Galatheammina sp. the test comprised a mixture of stercomare and test particles, with the granellare forming a web-like system of filaments. The granellare occupied 2.8–5.1%, the stercomare 72.4–82.4%, and test particles 14.7–22.5%, of the ‘body’ volume in the two Psammina species. The corresponding proportions in Galatheammina sp. were 1.7% (granellare), 39.5% (stercomare) and 58.8% (test particles). These data provide a potential basis for estimating the contribution of xenophyophores to seafloor biomass in areas like the CCZ where they dominate the megafauna. As in most xenophyophore species, the granellare hosted huge numbers of tiny barite crystals. We speculate that these help to support the extensive granellare system, as well as reducing the cell volume and lightening the metabolic burden required to maintain it

    A Bare Molecular Cloud at z~0.45

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    Several neutral species (MgI, SiI, CaI, FeI) have been detected in a weak MgII absorption line system (W_r(2796)~0.15 Angstroms) at z~0.45 along the sightline toward HE0001-2340. These observations require extreme physical conditions, as noted in D'Odorico (2007). We place further constraints on the properties of this system by running a wide grid of photoionization models, determining that the absorbing cloud that produces the neutral absorption is extremely dense (~100-1000/cm^3), cold (<100 K), and has significant molecular content (~72-94%). Structures of this size and temperature have been detected in Milky Way CO surveys, and have been predicted in hydrodynamic simulations of turbulent gas. In order to explain the observed line profiles in all neutral and singly ionized chemical transitions, the lines must suffer from unresolved saturation and/or the absorber must partially cover the broad emission line region of the background quasar. In addition to this highly unusual cloud, three other ordinary weak MgII clouds (within densities of ~0.005/cm^3 and temperatures of ~10000K) lie within 500 km/s along the same sightline. We suggest that the "bare molecular cloud", which appears to reside outside of a galaxy disk, may have had in situ star formation and may evolve into an ordinary weak MgII absorbing cloud.Comment: 15 pages, 4 figures, 4 tables, ApJ accepte

    GRACKLE: a chemistry and cooling library for astrophysics

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    We present the Grackle chemistry and cooling library for astrophysical simulations and models. Grackle provides a treatment of non-equilibrium primordial chemistry and cooling for H, D, and He species, including H2 formation on dust grains; tabulated primordial and metal cooling; multiple UV background models; and support for radiation transfer and arbitrary heat sources. The library has an easily implementable interface for simulation codes written in C, C++, and Fortran as well as a Python interface with added convenience functions for semi-analytical models. As an open-source project, Grackle provides a community resource for accessing and disseminating astrochemical data and numerical methods. We present the full details of the core functionality, the simulation and Python interfaces, testing infrastructure, performance, and range of applicability. Grackle is a fully open-source project and new contributions are welcome.Comment: 20 pages, 8 figures, accepted for publication in MNRAS. For more info, visit grackle.readthedocs.i

    Markov Chain methods for the Bipartite Boolean Quadratic Programming Problem

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    We study the Bipartite Boolean Quadratic Programming Problem (BBQP) which is an extension of the well known Boolean Quadratic Programming Problem (BQP). Applications of the BBQP include mining discrete patterns from binary data, approximating matrices by rank-one binary matrices, computing the cut-norm of a matrix, and solving optimisation problems such as maximum weight biclique, bipartite maximum weight cut, maximum weight induced sub-graph of a bipartite graph, etc. For the BBQP, we first present several algorithmic components, specifically, hill climbers and mutations, and then show how to com- bine them in a high-performance metaheuristic. Instead of hand-tuning a standard metaheuristic to test the efficiency of the hybrid of the components, we chose to use an automated generation of a multi- component metaheuristic to save human time, and also improve objectivity in the analysis and compar- isons of components. For this we designed a new metaheuristic schema which we call Conditional Markov Chain Search (CMCS). We show that CMCS is flexible enough to model several standard metaheuristics; this flexibility is controlled by multiple numeric parameters, and so is convenient for automated genera- tion. We study the configurations revealed by our approach and show that the best of them outperforms the previous state-of-the-art BBQP algorithm by several orders of magnitude. In our experiments we use benchmark instances introduced in the preliminary version of this paper and described here, which have already become the de facto standard in the BBQP literature
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