1,720,952 research outputs found
A high-order discontinuous Galerkin method for natural convection problems
No full textDiscontinuous Galerkin (DG) methods have proved to be very well suited for the construction of robust high-order numerical schemes on unstructured and possibly non conforming grids for a wide variety of problems. In this paper we consider natural convection flow problems and present a high-order DG method for their numerical solution. The governing equations are the incompressible Navier-Stokes (INS) with the Boussinesq approximation to represent buoyancy effects and the energy equation to describe the temperature field. The method here presented is an extension to natural convection flows of a novel high-order DG method for the numerical solution of the INS quations, recently proposed in [1]. The distinguishing feature of this method is the formulation of the inviscid interface flux which is based on the solution of local Riemann problems associated with the artificial compressibility perturbation of the incompressible Euler equations. The discretization of the viscous term follows the well established DG scheme named BR2 [2, 3]. The method is fully implicit and the solution is advanced in time using either a first order backward Euler or a second order Runge-Kutta scheme. To assess the capabilities of the DG method developed in this paper we computed second-, third-and fourth-order space-accurate solutions of several benchmark problems on natural convection in two-dimensional cavities
A HIGH-ORDER DISCONTINUOUS GALERKIN SOLVER FOR 3D AERODYNAMIC TURBULENT FLOWS
No full textThis paper deals with the evaluation and validation of a recently developed parallel discontinuous Galerkin code for the numerical solution of the RANS and k-omega turbulence model equations. The main features of the code can be summarized as follows: a) high-order spatial accuracy on hybrid grids, b) fully coupled, implicit time discretization, c) non-standard, realizable k-omega model implementation, d) efficient parallel execution using METIS package for grid partitioning and PETSc library for the linear algebra. The paper reports the numerical results of second- and third-order accurate computations of the subsonic turbulent flow in the Stanitz elbow and of the transonic turbulent flow around the ONERA M6 wing
Early palliative care in haematological patients: A systematic literature review
No full textBackground Early palliative care together with standard haematological care for advanced patients is needed worldwide. Little is known about its effect. The aim of the review is to synthesise the evidence on the impact of early palliative care on haematologic cancer patients' quality of life and resource use. Patients and methods A systematic review was conducted. The search terms were early palliative care or simultaneous or integrated or concurrent care and haematological or oncohaematological patients. The following databases were searched: PubMed, Embase, Cochrane, CINHAL and Scopus. Additional studies were identified through cross-checking the reference articles. Studies were in the English language, with no restriction for years. Two researchers independently reviewed the titles and abstracts, and one author assessed full articles for eligibility. Results A total of 296 studies titles were reviewed. Eight articles were included in the synthesis of the results, two controlled studies provided data on the comparative efficacy of PC interventions, and six one-arm studies were included. Since data pooling and meta-analysis were not possible, only a narrative synthesis of the study results was performed. The quality of the two included comparative studies was low overall. The quality of the six non-comparative studies was high overall, without the possibility of linking the observed results to the implemented interventions. Conclusions Studies on early palliative care and patients with haematological cancer are scarce and have not been prospectively designed. More research on the specific population target, type and timing of palliative care intervention and standardisation of collected outcomes is required. PROSPERO registration number CRD42020141322
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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