563 research outputs found

    Existence of solutions for a higher order non-local equation appearing in crack dynamics

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    In this paper, we prove the existence of non-negative solutions for a non-local higher order degenerate parabolic equation arising in the modeling of hydraulic fractures. The equation is similar to the well-known thin film equation, but the Laplace operator is replaced by a Dirichlet-to-Neumann operator, corresponding to the square root of the Laplace operator on a bounded domain with Neumann boundary conditions (which can also be defined using the periodic Hilbert transform). In our study, we have to deal with the usual difficulty associated to higher order equations (e.g. lack of maximum principle). However, there are important differences with, for instance, the thin film equation: First, our equation is nonlocal; Also the natural energy estimate is not as good as in the case of the thin film equation, and does not yields, for instance, boundedness and continuity of the solutions (our case is critical in dimension 11 in that respect)

    Regularização ambiental, novos caminhos para a recuperação de áreas degradadas.

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    Com a promulgação da Lei Florestal nº 12.651/2012 foram instituídos o Cadastro Ambiental Rural (CAR) e o Programa de Regularização Ambiental (PRA), que visam a regularização dos passivos ambientais em imóveis rurais, com a recuperação de áreas degradadas onde deveria ocorrer vegetação nativa. Alguns Estados, dentre eles o Rio de Janeiro (RJ), publicaram normas sobre o PRA, resta analisar a completude do Decreto Estadual do RJ, nº 44.512/2013, e outras regulamentações sobre o tema. O presente trabalho objetivou caracterizar o arcabouço legal relacionado ao PRA no RJ, destacando as regulamentações nacionais e estaduais, e indicar as principais consequências para os imóveis rurais relacionadas a regularização ambiental. Constatou-se que o Decreto nº 44.512/2013 não é específico para o PRA e carece em detalhes. O tema é tratado em outras normativas, mas não foi promulgada uma norma que descreva especificamente as ações e prazos dos agentes envolvidos na implementação do PRA no Estado. A Resolução INEA nº 143/2017 trata do PRA apenas para grandes imóveis, mas para estes não se espera os auxílios como são os casos de pequenos produtores. Além disso, apesar do prazo do PRA terminar em 2017, os governos, nacional e estadual, ainda têm priorizado o CAR

    Improvement in medication education in a pediatric subspecialty practice

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    <p>Abstract</p> <p>Background</p> <p>The purpose of this study was to measure the impact of an educational intervention on parents of children taking methotrexate (MTX) for juvenile idiopathic arthritis (JIA).</p> <p>Methods</p> <p>This study was conducted using a pre- and postsurvey design. The parents of 100 children with JIA taking MTX for at least 2 months were surveyed during a routine office visit. The parents completed an initial questionnaire regarding the safe use, adverse effects, and guidelines for monitoring the toxicity of MTX. An educational intervention was then administered, and an identical follow-up questionnaire was given during the next office visit. Statistical analysis using a paired <it>t</it>-test (critical <it>P </it>value < 0.05) was performed on individuals who answered both questionnaires.</p> <p>Results</p> <p>There were 100 responses to the initial questionnaire and 67 responses to the follow-up questionnaire. The mean length of time between surveys was 2.9 ± 0.9 months. In those who completed both questionnaires, the overall correct score increased significantly from 75.8% to 93.4%, respectively (<it>P </it>< 0.0001). Individuals scored the lowest (49%) on the question that addressed MTX's impact on pregnancy and fertility.</p> <p>Conclusions</p> <p>MTX knowledge may be less than expected in the parents of children with JIA. Brief educational interventions in the pediatric subspecialty practice can significantly affect a family's understanding of their child's medications.</p

    Growth of Long Range Forward-Backward Multiplicity Correlations with Centrality in Au+Au Collisions at sNN\sqrt{s_{NN}} = 200 GeV

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    Forward-backward multiplicity correlation strengths have been measured with the STAR detector for Au+Au and p+p\textit{p+p} collisions at sNN\sqrt{s_{NN}} = 200 GeV. Strong short and long range correlations (LRC) are seen in central Au+Au collisions. The magnitude of these correlations decrease with decreasing centrality until only short range correlations are observed in peripheral Au+Au collisions. Both the Dual Parton Model (DPM) and the Color Glass Condensate (CGC) predict the existence of the long range correlations. In the DPM the fluctuation in the number of elementary (parton) inelastic collisions produces the LRC. In the CGC longitudinal color flux tubes generate the LRC. The data is in qualitative agreement with the predictions from the DPM and indicates the presence of multiple parton interactions.Comment: 6 pages, 3 figures The abstract has been slightly modifie

    Longitudinal Spin Transfer to Λ\Lambda and Λˉ\bar{\Lambda} Hyperons in Polarized Proton-Proton Collisions at s\sqrt{s} = 200 GeV

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    The longitudinal spin transfer, DLLD_{LL}, from high energy polarized protons to Λ\Lambda and Λˉ\bar{\Lambda} hyperons has been measured for the first time in proton-proton collisions at s=200GeV\sqrt{s} = 200 \mathrm{GeV} with the STAR detector at RHIC. The measurements cover pseudorapidity, η\eta, in the range η<1.2|\eta| < 1.2 and transverse momenta, pTp_\mathrm{T}, up to 4GeV/c4 \mathrm{GeV}/c. The longitudinal spin transfer is found to be DLL=0.03±0.13(stat)±0.04(syst)D_{LL}= -0.03\pm 0.13(\mathrm{stat}) \pm 0.04(\mathrm{syst}) for inclusive Λ\Lambda and DLL=0.12±0.08(stat)±0.03(syst)D_{LL} = -0.12 \pm 0.08(\mathrm{stat}) \pm 0.03(\mathrm{syst}) for inclusive Λˉ\bar{\Lambda} hyperons with =0.5 = 0.5 and =3.7GeV/c = 3.7 \mathrm{GeV}/c. The dependence on η\eta and pTp_\mathrm{T} is presented.Comment: 5 pages, 4 figure

    K/pi Fluctuations at Relativistic Energies

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    We report results for K/πK/\pi fluctuations from Au+Au collisions at sNN\sqrt{s_{NN}} = 19.6, 62.4, 130, and 200 GeV using the STAR detector at the Relativistic Heavy Ion Collider. Our results for K/πK/\pi fluctuations in central collisions show little dependence on the incident energies studied and are on the same order as results observed by NA49 at the Super Proton Synchrotron in central Pb+Pb collisions at sNN\sqrt{s_{NN}} = 12.3 and 17.3 GeV. We also report results for the collision centrality dependence of K/πK/\pi fluctuations as well as results for K+/π+K^{+}/\pi^{+}, K/πK^{-}/\pi^{-}, K+/πK^{+}/\pi^{-}, and K/π+K^{-}/\pi^{+} fluctuations. We observe that the K/πK/\pi fluctuations scale with the multiplicity density, dN/dηdN/d\eta, rather than the number of participating nucleons.Comment: 6 pages, 4 figure
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