247 research outputs found

    Competitiveness and the Process of Co-adaptation in Team Sport Performance.

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    An evolutionary psycho-biological perspective on competitiveness dynamics is presented, focusing on continuous behavioral co-adaptations to constraints that arise in performance environments. We suggest that an athlete’s behavioral dynamics are constrained by circumstances of competing for the availability of resources, which once obtained offer possibilities for performance success. This defines the influence of the athlete-environment relationship on competitiveness. Constraining factors in performance include proximity to target areas in team sports and the number of other competitors in a location. By pushing the athlete beyond existing limits, competitiveness enhances opportunities for co-adaptation, innovation and creativity, which can lead individuals toward different performance solutions to achieve the same performance goal. Underpinned by an ecological dynamics framework we examine whether competitiveness is a crucial feature to succeed in team sports. Our focus is on intra-team competitiveness, concerning the capacity of individuals within a team to become perceptually attuned to affordances in a given performance context which can increase their likelihood of success. This conceptualization implies a re-consideration of the concept of competitiveness, not as an inherited trait or entity to be acquired, but rather theorizing it as a functional performer-environment relationship that needs to be explored, developed, enhanced and maintained in team games training programs

    The TIGA technique for detecting gravitational waves with a spherical antenna

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    We report the results of a theoretical and experimental study of a spherical gravitational wave antenna. We show that it is possible to understand the data from a spherical antenna with 6 radial resonant transducers attached to the surface in the truncated icosahedral arrangement. We find that the errors associated with small deviations from the ideal case are small compared to other sources of error, such as a finite signal-to-noise ratio. An in situ measurement technique is developed along with a general algorithm that describes a procedure for determining the direction of an external force acting on the antenna, including the force from a gravitational wave, using a combination of the transducer responses. The practicality of these techniques was verified on a room-temperature prototype antenna.Comment: 15 pages, 14 figures, submitted to Physical Review

    Energy absorption in lattice structures in dynamics: Experiments

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    Lattice structures offer the potential to relatively easily engineer specific (meso-scale properties (cell level)), to produce desirable macro-scale material properties for a wide variety of engineering applications including wave filters, blast and impact protection systems, thermal insulation, structural aircraft and vehicle components, and body implants. The work presented here focuses on characterising the quasi-static and, in particular, the dynamic load-deformation behaviour of lattice samples. First, cubic, diamond and re-entrant cube lattice structures were tested under quasi-static conditions to investigate failure process and stress–strain response of such materials. Following the quasi-static tests, Hopkinson pressure bar (HPB) tests were carried out to evaluate the impact response of these materials under high deformation rates. The HPB tests show that the lattice structures are able to spread impact loading in time and to reduce the peak impact stress. A significant rate dependency of load-deformation characteristics was identified. This is believed to be the first published results of experimental load-deformation studies of additively manufactured lattice structures. The cubic and diamond lattices are, by a small margin, the most effective of those lattices investigated to achieve this

    Phase III Randomized Trial Comparing the Efficacy of Cediranib as Monotherapy and in Combination With Lomustine Versus Lomustine Alone in Patients With Recurrent Glioblastoma

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    Purpose: A randomized, phase III, placebo-controlled, partially blinded clinical trial (REGAL [Recentin in Glioblastoma Alone and With Lomustine]) was conducted to determine the efficacy of cediranib, an oral pan-vascular endothelial growth factor (VEGF) receptor tyrosine kinase inhibitor, either as monotherapy or in combination with lomustine versus lomustine in patients with recurrent glioblastoma. Patients and Methods: Patients (N = 325) with recurrent glioblastoma who previously received radiation and temozolomide were randomly assigned 2:2:1 to receive (1) cediranib (30 mg) monotherapy; (2) cediranib (20 mg) plus lomustine (110 mg/m2); (3) lomustine (110 mg/m2) plus a placebo. The primary end point was progression-free survival based on blinded, independent radiographic assessment of postcontrast T1-weighted and noncontrast T2-weighted magnetic resonance imaging (MRI) brain scans. Results: The primary end point of progression-free survival (PFS) was not significantly different for either cediranib alone (hazard ratio [HR] = 1.05; 95% CI, 0.74 to 1.50; two-sided P = .90) or cediranib in combination with lomustine (HR = 0.76; 95% CI, 0.53 to 1.08; two-sided P = .16) versus lomustine based on independent or local review of postcontrast T1-weighted MRI. Conclusion: This study did not meet its primary end point of PFS prolongation with cediranib either as monotherapy or in combination with lomustine versus lomustine in patients with recurrent glioblastoma, although cediranib showed evidence of clinical activity on some secondary end points including time to deterioration in neurologic status and corticosteroid-sparing effects

    Ancient origins determine global biogeography of hot and cold desert cyanobacteria

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    Factors governing large-scale spatio-temporal distribution of microorganisms remain unresolved, yet are pivotal to understanding ecosystem value and function. Molecular genetic analyses have focused on the influence of niche and neutral processes in determining spatial patterns without considering the temporal scale. Here, we use temporal phylogenetic analysis calibrated using microfossil data for a globally sampled desert cyanobacterium, Chroococcidiopsis, to investigate spatio-temporal patterns in microbial biogeography and evolution. Multilocus phylogenetic associations were dependent on contemporary climate with no evidence for distance-related patterns. Massively parallel pyrosequencing of environmental samples confirmed that Chroococcidiopsis variants were specific to either hot or cold deserts. Temporally scaled phylogenetic analyses showed no evidence of recent inter-regional gene flow, indicating populations have not shared common ancestry since before the formation of modern continents. These results indicate that global distribution of desert cyanobacteria has not resulted from widespread contemporary dispersal but is an ancient evolutionary legacy. This highlights the importance of considering temporal scales in microbial biogeography

    Plagioclase preferred orientation in layered mylonites : evaluation of flow laws for the lower crust

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    Submitted in partial fulfillment of the requirements for the degree of Master of Science at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution February 2008We evaluate the applicability of plagioclase and gabbro flow laws by comparing predicted and observed deformation mechanisms in gabbroic shear zones. Gabbros and layered gabbro mylonites were collected from the Southwest Indian Ridge (SWIR), ODP Hole 735B. Deformation temperatures are constrained by two-pyroxene thermometry, stress is estimated from grain size, and deformation mechanisms are analyzed by microstructure and the presence or absence of a lattice preferred orientation (LPO). Our analyses indicate that mylonite layers deformed at a strain rate in the range of 10-12 to 10- 11 s-1, while coarse-grained gabbro deformed at a strain rate of approximately 10-14 to 10- 13 s-1. Plagioclase in pure plagioclase mylonite layers exhibit strong LPOs indicating they deform by dislocation creep. Plagioclase grain size in mixed plagioclase-pyroxene mylonite layers is finer than in pure plagioclase layers, and depends on the size and proportion of pyroxenes. Progressive mixing of pyroxene and plagioclase within gabbro mylonite layers is accompanied by weakening of the LPO indicating that phase mixing promotes a transition to diffusion creep processes that involve grain boundary sliding. Our results indicate that experimental flow laws are accurate at geologic strain rates, although the strain rate for diffusion creep of fine-grained gabbro may be underestimated. At the conditions estimated for the SWIR crust, our calculations suggest that strain localization leads to a factor of two to four decrease in lower crustal viscosity. Even so, the viscosity of lower gabbroic crust is predicted to be similar to that of dry upper mantle

    Developing Creativity to Enhance Human Potential in Sport: A Wicked Transdisciplinary Challenge

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    © Copyright © 2019 Vaughan, Mallett, Davids, Potrac and López-Felip. The challenge of developing creativity to enhance human potential is conceptualized as a multifaceted wicked problem due to the countless interactions between people and environments that constitute human development, athletic skill, and creative moments. To better comprehend the inter-relatedness of ecologies and human behaviors, there have been increasing calls for transdisciplinary approaches and holistic ecological models. In this paper we explore an ecological dynamics rationale for creativity, highlighting the conceptual adjacency of key concepts from transdisciplinarity, dynamic systems theory, ecological psychology and social-cognitive psychology. Our aim is to extend the scope of ecological dynamics and contextualize the application of non-linear pedagogy in sport. Foregrounding the role of sociocultural constraints on creative behaviors, we characterize the athlete-environment system as an ecological niche that arises from, and simultaneously co-creates, a form of life. We elaborate the notion that creative moments, skill and more generally talent in sport, are not traits possessed by individuals alone, but rather can be conceived as properties of the athlete-environment system shaped by changing constraints. This re-conceptualization supports a pedagogical approach predicated on notions of athletes and sports teams as complex adaptive systems. In such systems, continuous non-linear interactions between system components support the exploration of fluent and flexibly creative performance solutions by athletes and sports teams. The implications for practice suggest that cultivating a constellation of constraints can facilitate adaptive exploration of novel affordances (opportunities/invitation for action), fostering creative moments and supporting creative development in athletes. Future models or frameworks for practice contend that pedagogies should emerge from, and evolve in, interaction with the sociocultural context in which practitioners and athletes are embedded

    Systematic review of methods used in meta-analyses where a primary outcome is an adverse or unintended event

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    addresses: Peninsula College of Medicine and Dentistry, St Luke's Campus, University of Exeter, Exeter, UK. [email protected]: PMCID: PMC3528446types: Journal Article; Research Support, Non-U.S. Gov't© 2012 Warren et al.; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License ( http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.Adverse consequences of medical interventions are a source of concern, but clinical trials may lack power to detect elevated rates of such events, while observational studies have inherent limitations. Meta-analysis allows the combination of individual studies, which can increase power and provide stronger evidence relating to adverse events. However, meta-analysis of adverse events has associated methodological challenges. The aim of this study was to systematically identify and review the methodology used in meta-analyses where a primary outcome is an adverse or unintended event, following a therapeutic intervention

    Cosmological Constraints from Sunyaev-Zel'dovich-Selected Clusters with X-ray Observations in the First 178 Square Degrees of the South Pole Telescope Survey

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    We use measurements from the South Pole Telescope (SPT) Sunyaev Zel'dovich (SZ) cluster survey in combination with X-ray measurements to constrain cosmological parameters. We present a statistical method that fits for the scaling relations of the SZ and X-ray cluster observables with mass while jointly fitting for cosmology. The method is generalizable to multiple cluster observables, and self-consistently accounts for the effects of the cluster selection and uncertainties in cluster mass calibration on the derived cosmological constraints. We apply this method to a data set consisting of an SZ-selected catalog of 18 galaxy clusters at z > 0.3 from the first 178 deg2 of the 2500 deg2 SPT-SZ survey, with 14 clusters having X-ray observations from either Chandra or XMM. Assuming a spatially flat LCDM cosmological model, we find the SPT cluster sample constrain sigma_8 (Omega_m/0.25)^0.30 = 0.785 +- 0.037. In combination with measurements of the CMB power spectrum from the SPT and the seven-year WMAP data, the SPT cluster sample constrain sigma_8 = 0.795 +- 0.016 and Omega_m = 0.255 +- 0.016, a factor of 1.5 improvement on each parameter over the CMB data alone. We consider several extensions beyond the LCDM model by including the following as free parameters: the dark energy equation of state (w), the sum of the neutrino masses (sum mnu), the effective number of relativistic species (Neff), and a primordial non-Gaussianity (fNL). We find that adding the SPT cluster data significantly improves the constraints on w and sum mnu beyond those found when using measurements of the CMB, supernovae, baryon acoustic oscillations, and the Hubble constant. Considering each extension independently, we best constrain w=-0.973 +- 0.063 and the sum of neutrino masses sum mnu < 0.28 eV at 95% confidence, a factor of 1.25 and 1.4 improvement, respectively, over the constraints without clusters. [abbrev.]Comment: 21 pages, 8 figures, submitted to Ap

    Beyond Gaussian Averages: Redirecting Management Research Toward Extreme Events and Power Laws

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