1,720,970 research outputs found
Transcatheter lithotripsy to facilitate post-dilatation of underexpanded aortic transcatheter heart valve
Full text linkTakotsubo Cardiomyopathy Following Pericardiocentesis After Aortic Valve Repair and Ascending Aorta Replacement
No full textTakotsubo cardiomyopathy is a reversible cardiomyopathy, which generally developes in menopausal women and is characterized by left ventricle dysfunction with apical ballooning in the absence of coronary artery disease. It is often triggered by a stressful event, and its clinical presentation resembles acute anterior myocardial infarction. This condition is a rare adverse event of cardiac operations, and only a few cases are described in the literature, especially after mitral valve operations. We report the case of a 69-year-old man who underwent aortic valve repair and ascending aorta replacement, followed by pericardial effusion 6 months later, requiring pericardiocentesis resulting in Takotsubo cardiomyopathy
Can Perceval sutureless valve reduce the rate of patient-prosthesis mismatch?
No full textOBJECTIVES: The aim of this study is to compare the theoretical incidence of patient-prosthesis mismatch (PPM) in patients undergoing a sutureless or a sutured aortic valve replacement using an exact statistical matching. METHODS: Between May 2012 and March 2016, 65 patients with severe symptomatic aortic stenosis underwent a sutureless aortic valve replacement with the Perceval bioprosthesis in 2 centres. Moreover, 177 aortic valve replacements with conventional sutured bioprosthesis were performed between August 2003 and September 2015. Perceval and sutured patients were 1:1 exactly matched for sex and body surface area (BSA), resulting in 62 couples (sutureless: BSA 1.77 ± 0.16 m2, female 62.9% vs sutured: BSA 1.77 ± 0.15 m2, female 62.9%). RESULTS: After matching, the indexed effective orifice area was 1.50 ± 0.18 cm2/m2 and 0.81 ± 0.19 cm2/m2 in the sutureless and the sutured group, respectively (P < 0.001). No PPM occurred in patients who received a Perceval bioprosthesis (n = 62). In the sutured group (n = 62), 38 patients (61.3%) developed a PPM, which was moderate in 41.9% (n = 26) and severe in 19.4% (n = 12) (P < 0.001). CONCLUSIONS: The indexed effective orifice area of the sutureless group was significantly larger than in the sutured one. The incidence of PPM with the conventional sutured biprosthesis was 61.3%, while it decreases to 0% in the sutureless group. No PPM was reported in the sutureless valve group. Therefore, the Perceval sutureless valve provides larger effective orifice areas compared to the sutured conventional bioprosthesis and could be considered as a good option to reduce the risk of a PPM
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
- …
