1,720,960 research outputs found
Bicuspid aortic valve disease and ascending aortic aneurysm: Should an aortic root replacement be mandatory?
No full textOBJECTIVES: The higher risk of adverse aortic events in patients with bicuspid aortic valve (BAV) disease and ascending aorta aneurysm is known, but the management of moderate aortic root dilatation in younger patients is a controversial issue. The aim of the study was to compare survival in patients with or without root replacement. METHODS: We reviewed 166 consecutive patients with BAV disease and concomitant ascending aorta aneurysm (mean ascending aorta diameter: 51.4 ± 7.2 mm) undergoing cardiac surgery from 1994 to 2010. A total of 77 patients underwent Bentall procedure (90.9% male, mean age: 55.7 ± 12.7 years, Bentall group), whereas the remaining 89 patients underwent aortic valve replacement with supracoronary ascending aorta replacement (SAAR 71.9% male, mean age: 60.5 ± 11.2 years, SAAR group, P = 0.002). The preoperative mean diameter of the root was 44.0 ± 7.2 mm in the Bentall, and 38.5 ± 4.8 mm in the SAAR group (P < 0.0001). RESULTS: In-hospital mortality was 2.6% in the Bentall, and 2.3% in the SAAR groups. Overall survival was 84 and 81% in the Bentall (median follow-up: 105 months) versus 89 and 88% in the SAAR (median follow-up: 73 months) groups at 10 and 15 years (P = 0.36), respectively. The mean cardiopulmonary bypass (CPB) time was 201 ± 56 min and 174 ± 58 min (P = 0.0016), the mean cross-clamp time 156 ± 42 min and 132 ± 38 min (P = 0.0008) in the Bentall and SAAR groups, respectively. Four sudden deaths have occurred in the Bentall group and in 2 in the SAAR group. Progressive dilatation of the aortic root in the SAAR group was not significat (postoperative mean diameter: 36.3 ± 4.4 mm). Neither subgroup of patients in the SAAR with preoperative moderate dilatation of aortic root had significat aortic dilatation at the mean follow-up of 73 ± 39 months (preoperative diameter: 43.5 ± 2.3 mm versus postoperative: 39.1 ± 4.2 mm). One patient in Bentall and 1 in the SAAR groups were reoperated for tubular graft infection. CONCLUSIONS: In patients with BAV disease, ascending aorta aneurysm and moderate dilatation of the root, the significat reduction of CPB and cross-clamp times, the stability of the residual root at long term and the low risk of adverse aortic events associated with SAAR compared with the Bentall procedure have led us to consider the isolated aortic valve replacement with supracoronary aorta replacement an alternative strategy to the Bentall procedure, especially in high-risk and older patients
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
Nella selezione di donatori e riceventi per trapianto cardiaco, esiste un limite oltre il quale il rischio è da considerarsi troppo elevato?
No full textkoamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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