5,270 research outputs found
Physical literacy: Importance, assessment and future directions
Physical literacy (PL) has become a major focus of physical education, physical activity and sports promotion worldwide. PL is a multifaceted conceptualisation of the skills required to fully realise potentials through embodied experience. Substantial financial investments in PL education by governments are underpinned by a wide range of anticipated benefits, including expectations of significant future savings to healthcare, improved physical and psychological well-being of the population, increased work-force productivity and raised levels of expertise in sport and exercise participation. However, disappointingly, scientific evidence showing the efficacy of PL interventions to successfully meet such high expectation is limited. We suggest that contradictions in research findings are due largely to limitations in movement assessment batteries and consequent discrepancies between measurements used to assess the immediate outcomes of PL programmes. Notably, there is no robust empirical tool for evidencing skill learning in the physical movement component of PL, education and this presents a serious limitation to the design of, and claims that can be made for, such interventions. Considering the parameters of proficient PL skills and the limitations of current evaluation instruments, possible future directions for developing empirical measures of PL movement skills are presented
Lead extrusion analysis by finite volume method
Computational numerical simulation is nowadays largely applied in the design and analysis of metal forming process. Extrusion of metals is one main forming process largely applied in the manufacturing of metallic products or parts. Historically, the Finite Element Method has been applied for decades in metal extrusion analysis [4]. However, recently in the academy, there is a trend to use Finite Volume Method: literature suggests that metal flow by extrusion can be analyzed by the flow formulation [1, 2]. Thus, metal flow can be modelled such us an incompressible viscous fluid [2]. This hypothesis can be assumed because extrusion process is an isochoric process. The MacCormack Method is commonly used to simulate compressible fluid flow by the finite volume method [3]. However, metal extrusion and incompressible fluid flow do not present state equations for the evolution of pressure, and therefore, a velocity-pressure coupling method is necessary to obtain a consistent velocity and pressure fields [3]. Present work proposes a new numerical scheme to obtain information about metal flow in the extrusion process, in steady state. The governing equations were discretized by Finite Volume Method, using the Explicit MacCormack Method to structured and collocated mesh. The SIMPLE Method was applied to attain pressure-velocity coupling [3]. These new numerical scheme was applied to forward extrusion process of lead. The incompressible metal extrusion velocity fields achieved faster convergence and a good agreement with analytical and experimental results obtained from literature. The MacCormack Method applied for metals produced consistent results without the need of artificial viscosity as employed by the compressible flow simulation approaches. Furthermore, the present numerical results also suggest that MacCormack Method and SIMPLE can be applied in the solution of metal forming processes besides the traditional application for compressible fluid flow
The role of psychological characteristics in facilitating the pathway to elite performance. Part 1: Identifying mental skills and behaviours
Given the complexity of the talent development process, it seems likely that a range of psychological factors underpin an athlete’s ability to translate potential into top-class performance. Therefore, the purpose of part one of this two-part investigation was to explore the attributes that facilitate the successful development of athletes from initial involvement to achieving and maintaining world-class status. Seven elite athletes and a parent of each of these athletes were interviewed regarding their own (their son’s/ daughter’s) development in sport. Data were content analyzed using a grounded theory approach. Although sporting achievement was conceptualized as being multidimensional, psychological factors were highlighted as the key determinants of those who emerged as talented and maintained excellence. Accordingly, we suggest that talent identification and development programs should place greater emphasis on the advancement and application of psychological behaviors at an early stage to optimize both the development and performance of athletes
The role of psychological characteristics in facilitating the pathway to elite performance. Part 2: Examining environmental and stage-related differences in skills and behaviors
MacNamara, Button, & Collins (under review) proposed that if individuals are to fulfill their potential they must possess and systematically develop a specific set of skills (termed Psychological Characteristics of Developing Excellence or PCDEs) that allow them to interact effectively with the developmental opportunities they are afforded. Given the complexity of the developmental pathway, it may well be that different skills are needed at different stages of development and across different performance domains. Twenty-four elite participants from team sports, individual sports, and music were purposefully sampled from different domains and interviewed on their experiences of their own pathways to excellence. Results suggested that although PCDEs were important throughout development, the manner by which they were deployed depended on stage, domain, and the characteristics of the individual performer. These findings support proposals to systematically incorporate PCDEs into TID practices because these may be the key feature in maintaining progress toward excellence
Development of a second generation prototype reflectometer for reflectance measurement in space Final technical report
Prototype reflectometer development for reflection measurements in spac
forall x: Calgary. An Introduction to Formal Logic
forall x: Calgary is a full-featured textbook on formal logic. It covers key notions of logic such as consequence and validity of arguments, the syntax of truth-functional propositional logic TFL and truth-table semantics, the syntax of first-order (predicate) logic FOL with identity (first-order interpretations), translating (formalizing) English in TFL and FOL, and Fitch-style natural deduction proof systems for both TFL and FOL. It also deals with some advanced topics such as truth-functional completeness and modal logic. Exercises with solutions are available. It is provided in PDF (for screen reading, printing, and a special version for dyslexics) and in LaTeX source code
Veering triangulations admit strict angle structures
Agol recently introduced the concept of a veering taut triangulation, which
is a taut triangulation with some extra combinatorial structure. We define the
weaker notion of a "veering triangulation" and use it to show that all veering
triangulations admit strict angle structures. We also answer a question of
Agol, giving an example of a veering taut triangulation that is not layered.Comment: 15 pages, 9 figure
Groundwater reinjection and heat dissipation: lessons from the operation of a large groundwater cooling system in Central London
The performance of a large open-loop groundwater cooling scheme in a shallow alluvial aquifer at a prominent public building in Central London has been monitored closely over its first 2 years of operation. The installed system provided cooling to the site continuously for a period of 9 months between June 2012 and April 2013. During this period, c. 131300 m3 of groundwater was abstracted from a single pumping well and recharged into a single injection borehole. The amount of heat rejected in this period amounts to c. 1.37 GWh. A programme of hydraulic testing was subsequently undertaken over a 3 month period between July and October 2013 to evaluate the performance of the injection borehole. The data indicate no significant change in injection performance between commissioning trials undertaken in 2010 and the most recent period of testing, as evidenced by comparison of injection pressures for given flow rates in 2010 and 2013. Continuous temperature monitoring of the abstracted water, the discharge and a number of observation wells demonstrates the evolution of a heat plume in the aquifer in response to heat rejection and subsequent dissipation of this heat during the 18 month planned cessation
Polarization switching and induced birefringence in InGaAsP multiple quantum wells at 1.5 mu m
We analyze the 1.5mum wavelength operation of a room temperature polarization switch based on electron spin dynamics in InGaAsP multiple quantum wells. An unexpected difference in response for left and right circularly polarized pump light in pump-probe measurements was discovered and determined to be caused by an excess carrier induced birefringence. Transient polarization rotation and ellipticity were measured as a function of time delay. (C) 2002 American Institute of Physics.</p
Aluminium extrusion analysis by the finite volume method
Present work proposes a novel numerical scheme to calculate stress and velocity fields of metal flow in axisymmetric extrusion process in steady state. Extrusion of aluminium is one main metal forming process largely applied in manufacturing bars and products with complex cross section shape. The upper-bound, slab, slip-line methods and more recently the numerical methods such as the Finite Element Method have been commonly applied in aluminium extrusion analysis. However, recently in the academy, the Finite Volume Method has been developed for metal flow analysis: literature suggests that extrusion of metals can be modelled by the flow formulation. Hence, metal flow can be mathematically modelled such us an incompressible non linear viscous fluid, owing to volume constancy and varying viscosity in metal forming. The governing equations were discretized by the Finite Volume Method, using the Explicit MacCormack Method in structured and collocated mesh. The MacCormack Method is commonly used to simulate compressible fluid flow by the finite volume method. However, metal plastic flow and incompressible fluid flow do not present state equations for the evolution of pressure, and therefore, a velocity-pressure coupling method is necessary to obtain a consistent velocity and pressure fields. The SIMPLE Method was applied to attain pressure-velocity coupling. This new numerical scheme was applied to forward hot extrusion process of an aluminium alloy. The metal extrusion velocity fields achieved fast convergence and a good agreement with experimental results. The MacCormack Method applied to metal extrusion produced consistent results without the need of artificial viscosity as employed by the compressible flow simulation approaches. Therefore, present numerical results also suggest that MacCormack method together with SIMPLE method can be applied in the solution of metal forming processes in addition to the traditional application for compressible fluid flow
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