1,720,963 research outputs found
Occluding clamp technique during coronary artery bypass grafting: single or double – clamp technique?
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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
Intraoperative continuous venovenous hemofiltration during coronary surgery
No full textPostoperative continuous venovenous hemofiltration decreases acute renal failure in patients with moderate renal dysfunction undergoing coronary artery bypass grafting, but it prolongs intensive care unit stay. We developed a simple method to connect a hemofiltration machine to the cardiopulmonary bypass system. To evaluate the benefit of intraoperative hemofiltration, 124 consecutive patients (mean age, 67 ± 6 years) with moderate renal dysfunction were studied. Surgery was preformed between January 2005 and May 2007. On-pump coronary artery bypass with hemofiltration was carried out in 40 patients (group A), 44 had on-pump coronary artery bypass without hemofiltration (group B), and 40 had off-pump coronary artery bypass (group C). Postoperative acute renal failure was defined as either renal failure requiring dialysis or ≥50% decline from the baseline glomerular filtration rate but not requiring dialysis. The 3 groups had similar demographic data and preoperative renal function. After adjusting for covariates and propensity scores, multivariate analysis showed that intraoperative hemofiltration and off-pump surgery protected postoperative renal function. Independent risk factors for postoperative renal dysfunction were age>70 years, left ventricular ejection fraction <35%, and the preoperative glomerular filtration rate. © SAGE Publications 2009
Off-pump versus on-pump coronary artery bypass: Does number of grafts performed represent a selection bias in comparative studies? Results from a matched cohort comparison
No full textBackground: Several retrospective studies comparing off-pump and on-pump coronary surgery and the largest randomized studies published to date showed a lower number of grafts performed in patients submitted to off-pump coronary artery bypass surgery (OPCAB). These findings bring about the question of the general applicability of the results. We eliminated the selection bias correlated with the number of grafts per patient by comparing the short-term outcomes of patients undergoing OPCAB and standard coronary artery bypass grafting (CABG) matched for number of grafts. Methods: Eighty-seven consecutive patients undergoing OPCAB (group A) were selected from the database of our Institution during a 2-year period. Matching was performed by iterative selection prioritizing, in the following sequence: number of grafts, EuroSCORE, and age. A total of 87 patients operated upon with the on-pump technique represented the control group (group B). Results: There were no significant differences in preoperative characteristics between the two groups. The number of grafts per patient was 2.2 ± 0.5 in group A and 2.2 ± 0.5 in group B. Early mortality did not differ between the two groups and it was 2.2% (2 patients) in group A and 3.4% (3 patients) in group B (p = NS). The incidence of myocardial infarction did not differ between the two groups. No patient in either group had stroke or coma. Five (5.7%) patients in group A and 7 (8.0%) patients in group B had atrial fibrillation (p = NS). Conclusions: We were unable to demonstrate any significant differences in short-term mortality or morbidity outcome between OPCAB and standard CABG patients. Our findings suggest that excellent results can be obtained with both surgical approaches. © 2005 CEPI Srl
Confronto tra diversi volumi di reinfusione nella riduzione della “sindrome da circolazione extracorporea (CEC)” con CVVH intraoperatoria in corso di intervento cardiochirurgico con bypass cardiopolmonare
No full textDispelling 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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