1,517 research outputs found

    Learning in doing: the social anthropology of innovation in a large UK organisation

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    In the face of increasingly dynamic market environments, firms are being urged to develop learning and innovation capabilities if they wish to secure competitive advantage and long-term growth. A bank of work written from numerous theoretical perspectives has converged on the view that knowledge underpins the formation of such capabilities. While much of this literature emphasises the importance of cognitive knowledge, a new approach grounded in techniques from social anthropology suggests that learning is a non-cognitive practice, drawing on embodied exploration, everyday sociality, and a communitarian infrastructure of human and non-human actants. This thesis aims to consolidate the current literature on 'possessed' knowledge by clarifying the relationship between cognition and learning, and to advance understanding of innovation practices within firms by examining the role of non-cognitive mechanisms in the development of organisational capabilities. Drawing on a nine-month period of ethnographic research, this thesis describes the on-the-ground processes of learning and innovation within the marketing department of a large UK organisation. This evidence is used to investigate critically the theoretical claims regarding the role of both cognitive and non-cognitive forms of knowledge. Based on the empirical findings, three interrelated arguments are proposed: the design and governance of strategic learning devices involve non-cognitive practices; informal mechanisms of learning underpin the formation of new capabilities; and communitarian theories of learning overemphasise the social construction of knowledge, while neglecting the agency of the materiality of context

    Survival of near-critical branching Brownian motion

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    Consider a system of particles performing branching Brownian motion with negative drift μ=2ϵ\mu = \sqrt{2 - \epsilon} and killed upon hitting zero. Initially there is one particle at x>0x>0. Kesten showed that the process survives with positive probability if and only if ϵ>0\epsilon>0. Here we are interested in the asymptotics as \eps\to 0 of the survival probability Qμ(x)Q_\mu(x). It is proved that if L=π/ϵL= \pi/\sqrt{\epsilon} then for all xRx \in \R, limϵ0Qμ(L+x)=θ(x)(0,1)\lim_{\epsilon \to 0} Q_\mu(L+x) = \theta(x) \in (0,1) exists and is a travelling wave solution of the Fisher-KPP equation. Furthermore, we obtain sharp asymptotics of the survival probability when x<Lx<L and LxL-x \to \infty. The proofs rely on probabilistic methods developed by the authors in a previous work. This completes earlier work by Harris, Harris and Kyprianou and confirms predictions made by Derrida and Simon, which were obtained using nonrigorous PDE methods

    Applied Studies of Raptor Sensory Ecology are Rare

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    Light and noise often act as pollutants, but can also be used as tools for managing wildlife (e.g., sensory deterrents). Given that raptors are among the most threatened groups of birds, we expected there to be a moderate amount of applied research on their sensory ecology. We searched Web of Science and Google Scholar to quantify and classify the research that has been conducted on the applied sensory ecology of raptors. Of 32 studies assessing the effects of sensory pollution on raptors, we found that 10 studies examined effects of light pollution and 24 studies examined effects of noise pollution. Most of the studies regarding sensory pollution were of owls (21 studies). The United States was the site of the most noise pollution studies (seven studies) whereas Spain and Poland (two studies each) were sites of the most studies of light pollution. We found only seven studies that directly collected data regarding sensory deterrents. With so few studies examining applied aspects of the sensory ecology of raptors, we argue that effects of sensory pollution are poorly understood and the efficacy of sensory deterrents is largely unknown. Light and noise pollution are spreading across much of the globe. Applied research on the sensory ecology of raptors must be made a priority if wildlife managers are to conserve this imperiled group of birds

    Selectivity and functional diversity in arbuscular mycorrhizas of co-occurring fungi and plants from a temperate deciduous woodland

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    1 The arbuscular mycorrhizal (AM) fungi colonizing plants at a woodland site in North Yorkshire (UK) have been characterized from the roots of five plant species (Rubus fruticosus agg. L., Epilobium angustifolium L., Acer pseudoplatanus L., Ajuga reptans L. and Glechoma hederacea L.), and identified using small-subunit rRNA (SSUrRNA) gene amplification and sequencing. 2 Interactions between five plant species from the site and four co-occurring glomalean fungi were investigated in artificial one-to-one AM symbioses. Three of the fungi were isolated from the site; the fourth was a culture genetically similar to a taxon found at the site. Phosphorus uptake and growth responses were compared with non-mycorrhizal controls. 3 Individual fungi colonized each plant with different spatial distribution and intensity. Some did not colonize at all, indicating incompatibility under the conditions used in the experiments. 4 Glomus hoi consistently occupied a large proportion of root systems and outperformed the other fungi, improving P uptake and enhancing the growth of four out of the five plant species. Only G. hoi colonized and increased P uptake in Acer pseudoplatanus, the host plant with which it associates almost exclusively under field conditions. Colonization of all plant species by Scutellospora dipurpurescens was sparse, and beneficial to only one of the host plants (Teucrium scorodonia). Archaeospora trappei and Glomus sp. UY1225 had variable effects on the host plants, conferring a range of P uptake and growth benefits on Lysimachia nummularia and T. scorodonia, increasing P uptake whilst not affecting biomass in Ajuga reptans and Glechoma hederacea, and failing to form mycorrhizas with A. pseudoplatanus. 5 These experimental mycorrhizas show that root colonization, symbiont compatibility and plant performance vary with each fungus-plant combination, even when the plants and fungi naturally co-exist. 6 We provide evidence of physical and functional selectivity in AM. The small number of described AM fungal species (154) has been ascribed to their supposed lack of host specificity, but if the selectivity we have observed is the general rule, then we may predict that many more, probably hard-to-culture glomalean species await discovery, or that members of species as currently perceived may be physiologically or functionally distinct

    The Momentum Constraints of General Relativity and Spatial Conformal Isometries

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    Transverse-tracefree (TT-) tensors on (R3,gab)({\bf R}^3,g_{ab}), with gabg_{ab} an asymptotically flat metric of fast decay at infinity, are studied. When the source tensor from which these TT tensors are constructed has fast fall-off at infinity, TT tensors allow a multipole-type expansion. When gabg_{ab} has no conformal Killing vectors (CKV's) it is proven that any finite but otherwise arbitrary set of moments can be realized by a suitable TT tensor. When CKV's exist there are obstructions -- certain (combinations of) moments have to vanish -- which we study.Comment: 16 page

    Observational Constraints on the Modified Gravity Model (MOG) Proposed by Moffat: Using the Magellanic System

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    A simple model for the dynamics of the Magellanic Stream (MS), in the framework of modified gravity models is investigated. We assume that the galaxy is made up of baryonic matter out of context of dark matter scenario. The model we used here is named Modified Gravity (MOG) proposed by Moffat (2005). In order to examine the compatibility of the overall properties of the MS under the MOG theory, the observational radial velocity profile of the MS is compared with the numerical results using the χ2\chi^2 fit method. In order to obtain the best model parameters, a maximum likelihood analysis is performed. We also compare the results of this model with the Cold Dark Matter (CDM) halo model and the other alternative gravity model that proposed by Bekenstein (2004), so called TeVeS. We show that by selecting the appropriate values for the free parameters, the MOG theory seems to be plausible to explain the dynamics of the MS as well as the CDM and the TeVeS models.Comment: 14 pages, 3 Figures, accepted in Int. J. Theor. Phy

    Generalized Farey trees, transfer Operators and phase transitions

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    We consider a family of Markov maps on the unit interval, interpolating between the tent map and the Farey map. The latter map is not uniformly expanding. Each map being composed of two fractional linear transformations, the family generalizes many particular properties which for the case of the Farey map have been successfully exploited in number theory. We analyze the dynamics through the spectral analysis of generalized transfer operators. Application of the thermodynamic formalism to the family reveals first and second order phase transitions and unusual properties like positivity of the interaction function.Comment: 39 pages, 10 figure

    Existence of weak solutions for the generalized Navier-Stokes equations with damping

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    In this work we consider the generalized Navier-Stokes equations with the presence of a damping term in the momentum equation. The problem studied here derives from the set of equations which govern isothermal flows of incompressible and homogeneous non-Newtonian fluids. For the generalized Navier-Stokes problem with damping, we prove the existence of weak solutions by using regularization techniques, the theory of monotone operators and compactness arguments together with the local decomposition of the pressure and the Lipschitz-truncation method. The existence result proved here holds for any and any sigma > 1, where q is the exponent of the diffusion term and sigma is the exponent which characterizes the damping term.MCTES, Portugal [SFRH/BSAB/1058/2010]; FCT, Portugal [PTDC/MAT/110613/2010]info:eu-repo/semantics/publishedVersio

    Novel low energy hydrogen–deuterium isotope breakthrough separation using a trapdoor zeolite

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    AbstractCs-chabazite, a type of zeolite with caesium counter-cations, possesses interesting gas separation properties due to a highly selective molecular “trapdoor” effect. Herein the use of this material for H2/D2 isotope separation is demonstrated. Isotope separation was achieved using breakthrough separation with a single pass through a packed bed at moderate temperatures (293K) and pressures (0.17MPa) when one species was in a sufficiently low concentration. The breakthrough separation curves were successfully modelled using the Thomas kinetic breakthrough model and the Yoon and Nelson kinetic breakthrough model, where working transferable kinetic rate constants were developed. Use of this material for hydrogen isotope separation would significantly lower the total energy demand compared with current hydrogen isotope separation techniques such as cryogenic distillation and is applicable to separating out low concentrations of D2 (0.0156%) present in standard grade H2
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