236 research outputs found

    Natural maps between CAT(0) boundaries

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    It is shown that certain natural maps between the ideal, Gromov, and end boundaries of a complete CAT(0) space can fail to be either injective or surjective. Additionally the natural map from the Gromov boundary to the end boundary of a complete CAT(-1) space can fail to be either injective or surjective.Comment: 8 page

    Rough CAT(0) spaces

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    We investigate various notions of rough CAT(0). These conditions define classes of spaces that strictly include the union of all Gromov hyperbolic length spaces and all CAT(0) spaces.Comment: Corrected typos and updated Corollaries 3.22 and 3.2

    Constructing Restricted Patterson Measures for Geometrically Infinite Kleinian Groups

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    In this paper, we study exhaustions, referred to as ρ-restrictions, of arbitrary nonelementary Kleinian groups with at most finitely many bounded parabolic elements. Special emphasis is put on the geometrically infinite case, where we obtain that the limit set of each of these Kleinian groups contains an infinite family of closed subsets, referred to as ρ-restricted limit sets, such that there is a Poincaré series and hence an exponent of convergence δρ, canonically associated with every element in this family. Generalizing concepts which are well known in the geometrically finite case, we then introduce the notion of ρ-restricted Patterson measure, and show that these measures are non-atomic, δρ-harmonic, δρ-subconformal on special sets and δρ-conformal on very special sets. Furthermore, we obtain the results that each ρ-restriction of our Kleinian group is of δρ-divergence type and that the Hausdorff dimension of the ρ-restricted limit set is equal to δ

    The Public Service Motivated Volunteer: Devoting Time or Effort?

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    Non-profit organizations, corporate volunteer programs, and government workplace schemes are asking volunteers for their time and effort. But, with the changes in how people volunteer, such as episodic, micro, and cyber volunteering, those managing volunteers need to understand whether they should focus on encouraging volunteers to donate more time or effort. Using public service motivation to measure volunteer\u2019s propensity to engage in volunteering, we compare three outcomes: time spent volunteering, frequency of volunteering, and volunteering intensity. In a sample of 411 volunteers, we find public service motivation is associated with more time spent volunteering, increased frequency, and higher levels of volunteering intensity. However, volunteering intensity explains the most variance. These findings suggest that how the individual perceives they exert volunteering intensity may be useful among public service motivated volunteers

    Impact Forces on Five Common Running Surfaces

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    It is commonly believed among runners of all skill levels that the surface one runs on, impacts the risk of injury because of the peak force is greater because one surface is “harder” than the other [1 2]. While surface hardness does vary, this study will determine if the footwear of the athlete is enough protection to mitigate these differences. We hypothesize the measured peak force during a simulated shod heel strike will not be significantly different across several common synthetic running surfaces but may be different across alternate shoes
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