1,758 research outputs found

    On stochastic sea of the standard map

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    Consider a generic one-parameter unfolding of a homoclinic tangency of an area preserving surface diffeomorphism. We show that for many parameters (residual subset in an open set approaching the critical value) the corresponding diffeomorphism has a transitive invariant set Ω\Omega of full Hausdorff dimension. The set Ω\Omega is a topological limit of hyperbolic sets and is accumulated by elliptic islands. As an application we prove that stochastic sea of the standard map has full Hausdorff dimension for sufficiently large topologically generic parameters.Comment: 36 pages, 5 figure

    Adaptação transcultural para o idioma português do método de triagem nutricional Determine your nutritional health (R) para idosos domiciliados / Cross-cultural adaptation to the Portuguese language of the Determine Your Nutritional Health (R) screening method for the elderly in assisted living accommodation

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    ABSTRACT IN PORTUGESE: O objetivo deste artigo é descrever o processo de adaptação transcultural do método de triagem nutricional, Determine Your Nutritional Health® (DNH), para utilização na população idosa brasileira. O DNH consiste de 10 questões com enunciados afirmativos, às quais são atribuídas pontuações específicas e cuja soma corresponde ao escore final, que classifica os indivíduos de acordo com a presença ou a ausência de risco nutricional. O processo de adaptação transcultural do método DNH envolveu as seguintes etapas: tradução; retrotradução; equivalência semântica; avaliação dos especialistas; pré-teste e versão final do método. Foram realizadas adaptações de palavras e expressões do método DNH, para a realidade brasileira. A versão final do método foi definida para o Brasil como “Verifique a condição nutricional do idoso”, apresentando as mesmas questões da versão original do DNH, contudo, em formato mais claro, por meio de perguntas, consideradas acessíveis e de fácil entendimento, segundo a avaliação de profissionais de saúde e de idosos. A versão brasileira do método de triagem nutricional, “Verifique a condição nutricional do idoso”, encontra-se traduzida e adaptada para uso em idosos brasileiros domiciliados. ABSTRACT IN ENGLISH: This article aims to describe the process of cross-cultural adaptation of the Determine Your Nutritional Health® (DNH) screening method for the elderly Brazilian population. The DNH consists of 10 questions with affirmative statements, to which specific scores are assigned and when added up correspond to the final score, which classifies individuals according to the presence or absence of nutritional risk. The process of cross-cultural adaptation of the DNH method involved the following stages: translation; back translation; semantic equivalence; evaluation by the experts; pre-test and final version of the method. Adjustments were made in words and expressions of the DNH method for the Brazilian reality. The final version of the method has been defined for Brazil as “Verify the nutritional conditions of the elderly,” presenting the same questions as in the original version of the DNH. It was in a clearer format, through questions, considered accessible and easy to understand, according to the assessment of health professionals and the elderly. The Brazilian version of the nutritional screening method, “Verify nutritional conditions of the elderly,” was translated and adapted, for use in Brazilian elderly in assisted living accommodation

    Integrated local control of active power and voltage support for three-phase three-wire converters

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    The derivation of a robust control algorithm is presented to provide decoupled active power regulation and local grid voltage support in three-phase three-wire grid-connected converters (GCCs). Unlike conventional control schemes, the proposed strategy is designed to be harmonic sequence asym-metric for the purpose of local voltage unbalance correction. A frequency-domain Norton equivalent model is derived to illustrate the working principle of the strategy. Accordingly, by following a frequency-domain decoupled method, the funda-mental positive-sequence, the harmonic symmetrical sequences and the fundamental negative-sequence components are regu-lated independently. Consistent to the model analysis, simulation results validate reduction of local voltage unbalance and total harmonic distortion. Since no external sensors are required for the implementation of the strategy, it is a local approach, applicable to already-existing GCC systems. Moreover, in view of the higher switching frequencies as attainable by devices from the next SiC generation, the accuracy and dynamic behavior of the control algorithms can be much enhanced, improving therefore the quality of the processed energy

    Beyond in-phase and anti-phase coordination in a model of joint action

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    In 1985, Haken, Kelso and Bunz proposed a system of coupled nonlinear oscillators as a model of rhythmic movement patterns in human bimanual coordination. Since then, the Haken–Kelso–Bunz (HKB) model has become a modelling paradigm applied extensively in all areas of movement science, including interpersonal motor coordination. However, all previous studies have followed a line of analysis based on slowly varying amplitudes and rotating wave approximations. These approximations lead to a reduced system, consisting of a single differential equation representing the evolution of the relative phase of the two coupled oscillators: the HKB model of the relative phase. Here we take a different approach and systematically investigate the behaviour of the HKB model in the full four-dimensional state space and for general coupling strengths. We perform detailed numerical bifurcation analyses and reveal that the HKB model supports previously unreported dynamical regimes as well as bistability between a variety of coordination patterns. Furthermore, we identify the stability boundaries of distinct coordination regimes in the model and discuss the applicability of our findings to interpersonal coordination and other joint action tasks

    Measurements of integrated and differential cross sections for isolated photon pair production in pp collisions at √s=8 TeV with the ATLAS detector

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    A measurement of the production cross section for two isolated photons in proton-proton collisions at a center-of-mass energy of √s=8 TeV is presented. The results are based on an integrated luminosity of 20.2 fb−1 recorded by the ATLAS detector at the Large Hadron Collider. The measurement considers photons with pseudorapidities satisfying |ηγ|40GeV and EγT,2>30 GeV for the two leading photons ordered in transverse energy produced in the interaction. The background due to hadronic jets and electrons is subtracted using data-driven techniques. The fiducial cross sections are corrected for detector effects and measured differentially as a function of six kinematic observables. The measured cross section integrated within the fiducial volume is 16.8 ± 0.8  pb . The data are compared to fixed-order QCD calculations at next-to-leading-order and next-to-next-to-leading-order accuracy as well as next-to-leading-order computations including resummation of initial-state gluon radiation at next-to-next-to-leading logarithm or matched to a parton shower, with relative uncertainties varying from 5% to 20%

    Search for supersymmetry in events with four or more leptons in √s =13 TeV pp collisions with ATLAS

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    Results from a search for supersymmetry in events with four or more charged leptons (electrons, muons and taus) are presented. The analysis uses a data sample corresponding to 36.1 fb −1 of proton-proton collisions delivered by the Large Hadron Collider at s √ =13 TeV and recorded by the ATLAS detector. Four-lepton signal regions with up to two hadronically decaying taus are designed to target a range of supersymmetric scenarios that can be either enriched in or depleted of events involving the production and decay of a Z boson. Data yields are consistent with Standard Model expectations and results are used to set upper limits on the event yields from processes beyond the Standard Model. Exclusion limits are set at the 95% confidence level in simplified models of General Gauge Mediated supersymmetry, where higgsino masses are excluded up to 295 GeV. In R -parity-violating simplified models with decays of the lightest supersymmetric particle to charged leptons, lower limits of 1.46 TeV, 1.06 TeV, and 2.25 TeV are placed on wino, slepton and gluino masses, respectively

    Search for High-Mass Resonances Decaying to τν in pp Collisions at √s=13 TeV with the ATLAS Detector

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    A search for high-mass resonances decaying to τν using proton-proton collisions at √s=13 TeV produced by the Large Hadron Collider is presented. Only τ-lepton decays with hadrons in the final state are considered. The data were recorded with the ATLAS detector and correspond to an integrated luminosity of 36.1 fb−1. No statistically significant excess above the standard model expectation is observed; model-independent upper limits are set on the visible τν production cross section. Heavy W′ bosons with masses less than 3.7 TeV in the sequential standard model and masses less than 2.2–3.8 TeV depending on the coupling in the nonuniversal G(221) model are excluded at the 95% credibility level

    Search for the direct production of charginos and neutralinos in final states with tau leptons in √s=13 TeV collisions with the ATLAS detector

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    A search for the direct production of charginos and neutralinos in final states with at least two hadronically decaying tau leptons is presented. The analysis uses a dataset of pp collisions corresponding to an integrated luminosity of 36.1 fb−1, recorded with the ATLAS detector at the Large Hadron Collider at a centre-of-mass energy of 13TeV.Nosignificant deviation from the expected Standard Model background is observed. Limits are derived in scenarios of ˜χ+1 ˜χ−1 pair production and of ˜χ±1 ˜χ02 and ˜χ+1 ˜χ−1 production in simplified models where the neutralinos and charginos decay solely via intermediate left-handed staus and tau sneutrinos, and the mass of the ˜ τL state is set to be halfway between the masses of the ˜χ±1 and the ˜χ01. Chargino masses up to 630 GeV are excluded at 95% confidence level in the scenario of direct production of ˜χ+1 ˜χ−1 for a massless ˜χ01. Common ˜χ±1 and ˜χ02 masses up to 760 GeV are excluded in the case of production of ˜χ±1 ˜χ02 and ˜χ+1 ˜χ−1 assuming a massless ˜χ01. Exclusion limits for additional benchmark scenarios with large and small mass-splitting between the ˜χ±1 and the ˜χ01 are also studied by varying the ˜ τL mass between the masses of the ˜χ±1 and the ˜χ01

    Charged-particle distributions at low transverse momentum in √s=13 13 TeV pp interactions measured with the ATLAS detector at the LHC

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    Measurements of distributions of charged particles produced in proton–proton collisions with a centre-of-mass energy of 13 TeV are presented. The data were recorded by the ATLAS detector at the LHC and correspond to an integrated luminosity of 151 μb −1 μb−1 . The particles are required to have a transverse momentum greater than 100 MeV and an absolute pseudorapidity less than 2.5. The charged-particle multiplicity, its dependence on transverse momentum and pseudorapidity and the dependence of the mean transverse momentum on multiplicity are measured in events containing at least two charged particles satisfying the above kinematic criteria. The results are corrected for detector effects and compared to the predictions from several Monte Carlo event generators
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