7,997 research outputs found

    Market Orientation Within University Schools Of Business: Can A Dynamical Systems Viewpoint Applied To A Non-Temporal Data Set Yield Valuable Insights For University Managers?

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    This study investigates the use of using complexity theory – the study of nonlinear dynamical systems of which chaos and catastrophe theory are subsets – in the analysis of a non temporal data set to derive valuable insights into the functioning of university schools of business. The approach is unusual in that studies of nonlinearity in complex dynamical systems typically involve longitudinal data.  Challenges associated with such studies usually involve establishing nonlinearity, obtaining a data set with a sufficient number of entries, and robust mathematical and computational requirements for effective analysis.  The format of the paper is as follows: 1) a general description of complex systems is presented which identifies a number of generally accepted characteristics of complex systems, 2) a description of the data set and the research technique utilized, 3) a presentation of the data set as an “attractor” landscape as typically defined in complex systems analysis, 4) potential insights that may be derived from the analysis; and 5) conclusions and recommendations for further study.  The value of the study is to demonstrate that within the framework of complexity theory, non longitudinal data may be used to derive valuable managerial insights into the functioning of organizations such as university schools of business

    Socioeconomic status as a risk factor for dementia death:individual participant meta-analysis of 86 508 men and women from the UK

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    Background Life-course socioeconomic factors may have a role in dementia aetiology but there is a current paucity of studies. Meta-analyses of individual participant data would considerably strengthen this evidence base. Aims To examine the association between socioeconomic status in early life and adulthood with later dementia death. Method Individual participant meta-analysis of 11 prospective cohort studies (1994-2004, n = 86 508). Results Leaving full-time education at an earlier age was associated with an increased risk of dementia death in women (fully adjusted hazard ratio (HR) for age ⩽14 v. age ⩾16: HR = 1.76, 95% CI 1.23-2.53) but not men. Occupational social class was not statistically significantly associated with dementia death in men or women. Conclusions Lower educational attainment in women was associated with an increased risk of dementia-related death independently of common risk behaviours and comorbidities

    Orientation-dependent pinning and homoclinic snaking on a planar lattice

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    We study homoclinic snaking of one-dimensional, localized states on two-dimensional, bistable lattices via the method of exponential asymptotics. Within a narrow region of parameter space, fronts connecting the two stable states are pinned to the underlying lattice. Localized solutions are formed by matching two such stationary fronts back-to-back; depending on the orientation relative to the lattice, the solution branch may “snake” back and forth within the pinning region via successive saddle-node bifurcations. Standard continuum approximations in the weakly nonlinear limit (equivalently, the limit of small mesh size) do not exhibit this behavior, due to the resultant leading-order reaction-diffusion equation lacking a periodic spatial structure. By including exponentially small effects hidden beyond all algebraic orders in the asymptotic expansion, we find that exponentially small but exponentially growing terms are switched on via error function smoothing near Stokes lines. Eliminating these otherwise unbounded beyond-all-orders terms selects the origin (modulo the mesh size) of the front, and matching two fronts together yields a set of equations describing the snaking bifurcation diagram. This is possible only within an exponentially small region of parameter space—the pinning region. Moreover, by considering fronts orientated at an arbitrary angle ψ to the x-axis, we show that the width of the pinning region is nonzero only if tan ψ is rational or infinite. The asymptotic results are compared with numerical calculations, with good agreement

    Postfledging habitat selection and survival of Henslow’s Sparrow: management implications for a critical life stage

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    Conserving populations of species that rely on rare habitat requires that managers understand which habitat characteristics will best support population growth across multiple life stages. For songbirds, management is most often aimed at nesting adult habitat associations. However, habitat that meets adult requirements may not be similarly suited to requirements for other life stages. Henslow’s Sparrow (Centronyx henslowii) is a tallgrass prairie songbird listed as threatened or endangered in 13 states. We examined survival and habitat selection of Henslow’s Sparrow during the postfledging period. During the nesting seasons in 2015 and 2016, we attached radio transmitters to 46 nestlings in a tallgrass prairie and modeled their survival and habitat selection as a function of habitat characteristics. Thirty-five percent of fledglings survived until two weeks postfledge. Survival was negatively associated with areas of sumac (Rhus copallinum) cover, positively associated with years since last burn, and decreased as the breeding season progressed. Snakes were the most common predator of fledglings. Independent fledglings used habitat that was different than that used by adults and dependent fledglings, with habitat used during the independent period having lower litter cover and increased forb cover compared to points used during the dependent period. During the dependent period, points used by fledglings were a mean distance of 40 m (± 11 SD) from the natal nest. Following independence, points used by fledglings were 236 m (± 89 SD) from the natal nest. Henslow’s Sparrow populations may benefit from removal of encroaching sumac in tallgrass prairie, and from consideration of the varying habitats used by the species during different life stages
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