2,632 research outputs found

    A Clinical Practice Guideline to Improve Education in the Heart Failure Population

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    Managing heart failure patients in the outpatient setting can pose a challenge for nurses and health care staff due to the need to educate patients on self-care skills and management of disease. Several factors, including health literacy and numeracy, need to be considered when developing an education program for heart failure patients to promote self-care management. The purpose of this project was to provide nursing staff with a clinical practice guideline (CPG) that incorporated health and numeracy literacy assessment into an individualized education program. The Johns Hopkins nursing evidence-based practice (EBP) model, the situation-specific theory of heart failure (HF) self-care, and Wagner\u27s chronic care model guided the development and implementation of this project. The practice-focused question for this project asked whether evidence informs a CPG intended to assess health literacy and numeracy assessment and promote an enhanced individualized education intervention in an outpatient HF population. A literature review using 20 articles from 2006-2018 was completed. Five articles were selected to review levels of evidence, and three articles were chosen to support the development of the CPG. The CPG was reviewed, refined, and validated by an expert panel of HF nurses and physicians. The CPG might support a positive social change in the practice setting by improving the tools for nurses to assess health literacy in the HF patient population and provide individualized education to influence self-care interventions

    Ensemble model output statistics for wind vectors

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    A bivariate ensemble model output statistics (EMOS) technique for the postprocessing of ensemble forecasts of two-dimensional wind vectors is proposed, where the postprocessed probabilistic forecast takes the form of a bivariate normal probability density function. The postprocessed means and variances of the wind vector components are linearly bias-corrected versions of the ensemble means and ensemble variances, respectively, and the conditional correlation between the wind components is represented by a trigonometric function of the ensemble mean wind direction. In a case study on 48-hour forecasts of wind vectors over the North American Pacific Northwest with the University of Washington Mesoscale Ensemble, the bivariate EMOS density forecasts were calibrated and sharp, and showed considerable improvement over the raw ensemble and reference forecasts, including ensemble copula coupling

    Apollonian Circle Packings: Geometry and Group Theory II. Super-Apollonian Group and Integral Packings

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    Apollonian circle packings arise by repeatedly filling the interstices between four mutually tangent circles with further tangent circles. Such packings can be described in terms of the Descartes configurations they contain. It observed there exist infinitely many types of integral Apollonian packings in which all circles had integer curvatures, with the integral structure being related to the integral nature of the Apollonian group. Here we consider the action of a larger discrete group, the super-Apollonian group, also having an integral structure, whose orbits describe the Descartes quadruples of a geometric object we call a super-packing. The circles in a super-packing never cross each other but are nested to an arbitrary depth. Certain Apollonian packings and super-packings are strongly integral in the sense that the curvatures of all circles are integral and the curvature×\timescenters of all circles are integral. We show that (up to scale) there are exactly 8 different (geometric) strongly integral super-packings, and that each contains a copy of every integral Apollonian circle packing (also up to scale). We show that the super-Apollonian group has finite volume in the group of all automorphisms of the parameter space of Descartes configurations, which is isomorphic to the Lorentz group O(3,1)O(3, 1).Comment: 37 Pages, 11 figures. The second in a series on Apollonian circle packings beginning with math.MG/0010298. Extensively revised in June, 2004. More integral properties are discussed. More revision in July, 2004: interchange sections 7 and 8, revised sections 1 and 2 to match, and added matrix formulations for super-Apollonian group and its Lorentz version. Slight revision in March 10, 200

    Trial factors for the look elsewhere effect in high energy physics

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    When searching for a new resonance somewhere in a possible mass range, the significance of observing a local excess of events must take into account the probability of observing such an excess anywhere in the range. This is the so called "look elsewhere effect". The effect can be quantified in terms of a trial factor, which is the ratio between the probability of observing the excess at some fixed mass point, to the probability of observing it anywhere in the range. We propose a simple and fast procedure for estimating the trial factor, based on earlier results by Davies. We show that asymptotically, the trial factor grows linearly with the (fixed mass) significance

    Apollonian Circle Packings: Geometry and Group Theory III. Higher Dimensions

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    This paper gives nn-dimensional analogues of the Apollonian circle packings in parts I and II. We work in the space \sM_{\dd}^n of all nn-dimensional oriented Descartes configurations parametrized in a coordinate system, ACC-coordinates, as those (n+2)×(n+2)(n+2) \times (n+2) real matrices \bW with \bW^T \bQ_{D,n} \bW = \bQ_{W,n} where QD,n=x12+...+xn+221n(x1+...+xn+2)2Q_{D,n} = x_1^2 +... + x_{n+2}^2 - \frac{1}{n}(x_1 +... + x_{n+2})^2 is the nn-dimensional Descartes quadratic form, QW,n=8x1x2+2x32+...+2xn+22Q_{W,n} = -8x_1x_2 + 2x_3^2 + ... + 2x_{n+2}^2, and \bQ_{D,n} and \bQ_{W,n} are their corresponding symmetric matrices. There are natural actions on the parameter space \sM_{\dd}^n. We introduce nn-dimensional analogues of the Apollonian group, the dual Apollonian group and the super-Apollonian group. These are finitely generated groups with the following integrality properties: the dual Apollonian group consists of integral matrices in all dimensions, while the other two consist of rational matrices, with denominators having prime divisors drawn from a finite set SS depending on the dimension. We show that the the Apollonian group and the dual Apollonian group are finitely presented, and are Coxeter groups. We define an Apollonian cluster ensemble to be any orbit under the Apollonian group, with similar notions for the other two groups. We determine in which dimensions one can find rational Apollonian cluster ensembles (all curvatures rational) and strongly rational Apollonian sphere ensembles (all ACC-coordinates rational).Comment: 37 pages. The third in a series on Apollonian circle packings beginning with math.MG/0010298. Revised and extended. Added: Apollonian groups and Apollonian Cluster Ensembles (Section 4),and Presentation for n-dimensional Apollonian Group (Section 5). Slight revision on March 10, 200

    Apollonian Circle Packings: Geometry and Group Theory I. The Apollonian Group

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    Apollonian circle packings arise by repeatedly filling the interstices between four mutually tangent circles with further tangent circles. We observe that there exist Apollonian packings which have strong integrality properties, in which all circles in the packing have integer curvatures and rational centers such that (curvature)×\times(center) is an integer vector. This series of papers explain such properties. A {\em Descartes configuration} is a set of four mutually tangent circles with disjoint interiors. We describe the space of all Descartes configurations using a coordinate system \sM_\DD consisting of those 4×44 \times 4 real matrices \bW with \bW^T \bQ_{D} \bW = \bQ_{W} where \bQ_D is the matrix of the Descartes quadratic form QD=x12+x22+x32+x421/2(x1+x2+x3+x4)2Q_D= x_1^2 + x_2^2+ x_3^2 + x_4^2 -{1/2}(x_1 +x_2 +x_3 + x_4)^2 and \bQ_W of the quadratic form QW=8x1x2+2x32+2x42Q_W = -8x_1x_2 + 2x_3^2 + 2x_4^2. There are natural group actions on the parameter space \sM_\DD. We observe that the Descartes configurations in each Apollonian packing form an orbit under a certain finitely generated discrete group, the {\em Apollonian group}. This group consists of 4×44 \times 4 integer matrices, and its integrality properties lead to the integrality properties observed in some Apollonian circle packings. We introduce two more related finitely generated groups, the dual Apollonian group and the super-Apollonian group, which have nice geometrically interpretations. We show these groups are hyperbolic Coxeter groups.Comment: 42 pages, 11 figures. Extensively revised version on June 14, 2004. Revised Appendix B and a few changes on July, 2004. Slight revision on March 10, 200
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