3,437 research outputs found

    Guidance and maneuver analyzer Patent

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    Guidance analyzer having suspended spacecraft simulating sphere for astronavigatio

    Semiclassical Limits of Extended Racah Coefficients

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    We explore the geometry and asymptotics of extended Racah coeffecients. The extension is shown to have a simple relationship to the Racah coefficients for the positive discrete unitary representation series of SU(1,1) which is explicitly defined. Moreover, it is found that this extension may be geometrically identified with two types of Lorentzian tetrahedra for which all the faces are timelike. The asymptotic formulae derived for the extension are found to have a similar form to the standard Ponzano-Regge asymptotic formulae for the SU(2) 6j symbol and so should be viable for use in a state sum for three dimensional Lorentzian quantum gravity.Comment: Latex2e - 26 pages, 6 figures. Uses AMS-fonts, AMS-LaTeX, epsf.tex and texdraw. Revised version with improved clarity and additional result

    Convexity Properties of the Diestel-Leader Group Γ_3(2)

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    The Diestel-Leader groups are a family of groups first introduced in 2001 by Diestel and Leader in [7]. In this paper, we demonstrate that the Diestel-Leader group Γ3(2) is not almost convex with respect to a particular generating set S. Almost convexity is a geometric property that has been shown by Cannon [3] to guarantee a solvable word problem (that is, in any almost convex group there is a finite-step algorithm to determine if two strings of generators, or “words”, represent the same group element). Our proof relies on the word length formula given by Stein and Taback in [10], and we construct a family of group elements X that contradicts the almost convexity condition. We then go on to show that Γ3(2) is minimally almost convex with respect to S

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

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    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

    Seven Dimensions of Wellness in Athletes with Upper Extremity Orthopedic Injuries: A Manual for Occupational Therapists

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    Increased attention has been placed on sports and athletes within the United States cultural. The latest reports of the noted sports economist Andrew Zimbalist estimated that the annual revenue of only 4 North American sports amounts to approximately $15 billion (Markovits, 2010). Athletes with upper extremity orthopedic injuries have traditionally been treated by occupational hand therapists (Hanson, Nabavi, & Yuen, 2000) however; research does not adequately address their needs outside of physical injury and musculoskeletal gain. Evidence is lacking within the profession of occupational therapy that encompasses the athlete as an occupational being. An occupational being is a person who participates in everyday occupations as an essential aspect of life. The physical dimension of wellness has traditionally been at the forefront of occupational hand therapy neglecting all other areas of wellness (social, spiritual, environmental, occupational, emotional, and intellectual dimensions of wellness). The Seven Dimensions of Wellness with Upper Extremity Orthopedic Injuries: A Manual for Occupational Therapists will provide occupational hand therapists with a resource to achieve successful outcomes with a client-centered Occupational Adaptation approach within a hand therapy facility. The manual was developed to guide intended to be used as a guide for therapists to implement at the beginning (initial evaluation), during (intervention), and at the end of therapy (discharge planning) to direct the client and therapist through a process of adaptation (rehabilitation) involving the Seven Dimensions of Wellness. The manual includes case studies, activities, and possible interventions associated with each dimension of wellness. The step-by-step instructions enable the therapist and the athlete to collaborate the treatment direction based on a combination of the athlete\u27s concerns paired with the occupational therapists‟ professional knowledge. It is hypothesized that athlete satisfaction and wellness recovery will be increased in treatment of athletes through guidance from this manual

    The Role of Council Committees in Promoting Financial Accountability

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    Financial accountability in municipalities is a critical aspect of municipal fiscal governance. It constitutes one of the fundamental roles exercised by the municipal council to ensure effective and efficient utilization of financial resources. Non-executive councilors organised through council committees are expected to shoulder the responsibility of exercising financial accountability. The Audit Committee is one of the committees established by municipal council to assist in holding the executive accountable for the manner in which municipal financial resources are managed.  These committees are created through various legislative regimes and municipal council Rules of Order.  The oversight committees had different outcomes with regard to financial accountability in different municipalities. The results of this research suggest that these committees they have not been very effective in exercising their responsibilities. The factors that contribute to accountability, transparency and regularity to ensure the effective functioning of these committees were explored.  Therefore, the following research question was posed to guide this research. What are the major underlying causes that contribute to financial accountability at the local level? What are the strengths and weaknesses of council committees and how they could contribute towards the strengthening of financial accountability? The Stellenbosch Municipality was used as a case study to explore the role of council committees in exercising financial accountability. The research findings revealed that there is need to establish a culture of openness, transparency and accountability.  Equally, the council committees must be empowered with the necessary authority and capacity to enable them to discharge their accountability function. Key Words: Municipal Council Committees, Financial accountability, Legislative Authority, Executive Authority, Budget process and Municipal Administration. DOI: 10.7176/PPAR/10-8-08 Publication date:August 31st 202

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

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    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.

    Evaluating weaknesses of "perceptual-cognitive training" and "brain training" methods in sport: An ecological dynamics critique

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    The recent upsurge in "brain training and perceptual-cognitive training," proposing to improve isolated processes, such as brain function, visual perception, and decision-making, has created significant interest in elite sports practitioners, seeking to create an "edge" for athletes. The claims of these related "performance-enhancing industries" can be considered together as part of a process training approach proposing enhanced cognitive and perceptual skills and brain capacity to support performance in everyday life activities, including sport. For example, the "process training industry" promotes the idea that playing games not only makes you a better player but also makes you smarter, more alert, and a faster learner. In this position paper, we critically evaluate the effectiveness of both types of process training programmes in generalizing transfer to sport performance. These issues are addressed in three stages. First, we evaluate empirical evidence in support of perceptual-cognitive process training and its application to enhancing sport performance. Second, we critically review putative modularized mechanisms underpinning this kind of training, addressing limitations and subsequent problems. Specifically, we consider merits of this highly specific form of training, which focuses on training of isolated processes such as cognitive processes (attention, memory, thinking) and visual perception processes, separately from performance behaviors and actions. We conclude that these approaches may, at best, provide some "general transfer" of underlying processes to specific sport environments, but lack "specificity of transfer" to contextualize actual performance behaviors. A major weakness of process training methods is their focus on enhancing the performance in body "modules" (e.g., eye, brain, memory, anticipatory sub-systems). What is lacking is evidence on how these isolated components are modified and subsequently interact with other process "modules," which are considered to underlie sport performance. Finally, we propose how an ecological dynamics approach, aligned with an embodied framework of cognition undermines the rationale that modularized processes can enhance performance in competitive sport. An ecological dynamics perspective proposes that the body is a complex adaptive system, interacting with performance environments in a functionally integrated manner, emphasizing that the inter-relation between motor processes, cognitive and perceptual functions, and the constraints of a sport task is best understood at the performer-environment scale of analysis
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