1,720,980 research outputs found
Sabre dance pattern in mid-ventricular-apical hypertrophic cardiomyopathy: an unusual finding
No full textTransthoracic three-dimensional echocardiography visualization of functional anatomy of double-orifice mitral valve
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Left ventricular flow dynamics by cardiac imaging techniques in heart failure patients: state of the art
No full textBackground: The evaluation of left ventricular (LV) flow dynamics is a novel approach to assessing LV function that goes beyond traditional metrics. This approach has been applied to patients with heart failure (HF), providing valuable insights that are discussed in this review, with the aim of enhancing our understanding of LV function in the context of the HF syndrome. Methods: The analysis of LV flow dynamics is typically conducted using ultrasound and magnetic resonance imaging (MRI) techniques, primarily including particle image velocimetry echocardiography, Vector Flow Imaging, HyperDoppler, and four-dimensional flow MRI. A variety of parameters can be obtained that describe the geometry of the LV vortex, vorticity, kinetic energy, energy dispersion, as well as the amplitude and direction of the hemodynamic forces within the LV cavity. Results: In normal subjects, vortex formation plays a crucial role in optimizing LV filling, diastolic-systolic coupling, and energy transfer during systolic ejection. In patients with HF, alterations in vortex structure and dynamics have been associated with both systolic and diastolic LV dysfunction, demonstrating the potential to diagnose early LV dysfunction. Furthermore, these alterations have been linked to LV remodeling and thrombus formation. Several studies have also explored intracardiac flow metrics as biomarkers for guiding HF treatments, including pharmacological interventions, cardiac resynchronization therapy, and LV assist devices. Conclusions: Currently available data suggest that the evaluation of LV flow dynamics can have diagnostic and prognostic utility in HF. However, large-scale, multicenter, and prospective studies are needed, particularly to validate therapeutic implications
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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