1,637 research outputs found

    Even triangulations of n-dimensional pseudo-manifolds

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    Occupants in manifolds

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    Let K be a subset of a smooth manifold M. In some cases functor calculus methods lead to a homotopical formula for M minus K in terms of the subspaces M minus S, where S runs through the finite subsets of K.Comment: There is a sequel to this paper: title "Configuration categories and homotopy automorphisms". v2: some typos corrected, v3: some errors in section 1 corrected. v4: more errors corrected and therefore number of authors increased from 1 to 2. v5: more errors corrected especially in section 3. v6: just a few typos corrected and pointers adde

    Degenerations of ideal hyperbolic triangulations

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    Let M be a cusped 3-manifold, and let T be an ideal triangulation of M. The deformation variety D(T), a subset of which parameterises (incomplete) hyperbolic structures obtained on M using T, is defined and compactified by adding certain projective classes of transversely measured singular codimension-one foliations of M. This leads to a combinatorial and geometric variant of well-known constructions by Culler, Morgan and Shalen concerning the character variety of a 3-manifold.Comment: 31 pages, 11 figures; minor changes; to appear in Mathematische Zeitschrif

    Framing the tax and health nexus: a neglected aspect of public health concern

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    Previous studies have described various associations between tax policy and health. Here we propose a unifying conceptual framework of ‘Five R’s’ to stimulate awareness about the importance of tax to health improvement. First, tax can improve representation and democratic accountability, and help make governments more responsive to the needs of its citizens. Second, tax can create a revenue stream for a universal pool of public finance for health care and other public services. Third, progressive taxation when combined with appropriate public spending can help redistribute wealth and income and mitigate social and health inequalities. Fourth, the re-pricing of harmful products (e.g. tobacco, alcohol and unhealthy food) can help reduce their consumption. Fifth, taxation provides a route by which certain harmful industries can be regulated. The paper also discusses the barriers that hinder the full potential for taxation to be used to improve health, including: weak tax administrations, large ‘shadow economies’, international trade liberalisation, tax avoidance, transfer pricing by transnational corporations and banking secrecy. We suggest that a greater awareness of the manifold associations between tax and health will encourage health practitioners to actively promote fairer and better taxation, thereby helping to improve health and reduce health inequalities

    Gestao de beneficios na etapa de projecto em empreendimentos hospitalares do reino unido [Managing benefits in the design of healthcare favilities in the UK]

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    Proposal: The healthcare system in the United kingdomis passing through transformation and change for improvement and innovation. Within this context, healthcare facilities are being developed in a complex multi-stakeholder environment, which usually have diverse and conflicting interests and no experience in design. This contributes for difficulties in managing their requirements, leading to low quality of design. Aiming to contribute for the management of these projects, a benefits management model is being developed and introduced in the sector by the University of Salford. This model intends to support the consideration of different stakeholders’ expectations in project development. In this sense, the aim of this paper was to bring discussions about how such approach could be adopted to support the design process within those projects. This research was developed through the participation on the model implementation, in addition to a literature review on benefits management and design approaches that are used in the UK and that could support benefits management in the design process. Main findings are related to a need for anticipating the participation of designers on project development and straightening the relationship between designers and decision makers. As a result, recommendations could be done to support benefits management throughout the design process. Keywords: Design process, project management, benefits realisatio

    Thermal sensitivity of cell metabolism of different Antarctic fish species mirrors organism temperature tolerance

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    Despite cold adaptation, Antarctic fish show lower growth than expected from the van’t Hoff’s Q10 rule. Protein synthesis is one of the main energy-consuming processes, which is downregulated under energy deficiency. Considering the effect of temperature on growth performance, we tested if temperature-dependent cellular energy allocation to protein synthesis correlates with temperature-dependent whole-animal growth and thus thermal tolerance. Cell respiration and energy expenditure for protein synthesis were determined in hepatocytes of the circumpolar-distributed Antarctic eelpout Pachycara brachycephalum after warm acclimation (0 °C vs 5 °C) and, of two notothenioids the sub-Antarctic Lepidonotothen squamifrons and the high-Antarctic icefish Chionodraco hamatus. We used intermittent-flow respirometry to analyse cellular response to acute warming from 5 to 10 °C (P. brachycephalum) and from 1 to 5 °C (L. squamifrons, C. hamatus). Warming-induced rise in respiration was similar between 0- and 5 °C-acclimated P. brachycephalum and between L. squamifrons and C. hamatus. Irrespective of acclimation, warming decreased energy expenditure for protein synthesis in P. brachycephalum, which corresponds to reduced whole-animal growth at temperatures > 5 °C. Warming doubled energy expenditure for protein synthesis in L. squamifrons but had no effect on C. hamatus indicating that L. squamifrons might benefit from warmer waters. The species-specific temperature effect on energy expenditure for protein synthesis is discussed to mirror thermal sensitivity of whole-animal growth performance, thereby paralleling the degree of cold adaptation. Clearly more data are necessary including measurements at narrower temperature steps particularly for C. hamatus and an increased species’ number per ecotype to reinforce presented link between cellular and whole-animal thermal sensitivity

    2-manifold recognition is in logspace

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    We prove that the homeomorphism problem for 2-manifolds can be decided in logspace. The proof relies on Reingold's logspace solution to the undirected s,ts,t-connectivity problem in graphs

    Lower Bounds for Ground States of Condensed Matter Systems

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    Standard variational methods tend to obtain upper bounds on the ground state energy of quantum many-body systems. Here we study a complementary method that determines lower bounds on the ground state energy in a systematic fashion, scales polynomially in the system size and gives direct access to correlation functions. This is achieved by relaxing the positivity constraint on the density matrix and replacing it by positivity constraints on moment matrices, thus yielding a semi-definite programme. Further, the number of free parameters in the optimization problem can be reduced dramatically under the assumption of translational invariance. A novel numerical approach, principally a combination of a projected gradient algorithm with Dykstra's algorithm, for solving the optimization problem in a memory-efficient manner is presented and a proof of convergence for this iterative method is given. Numerical experiments that determine lower bounds on the ground state energies for the Ising and Heisenberg Hamiltonians confirm that the approach can be applied to large systems, especially under the assumption of translational invariance.Comment: 16 pages, 4 figures, replaced with published versio
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