1,721,131 research outputs found
Is unilateral antegrade cerebral perfusion equivalent to bilateral cerebral perfusion for patients undergoing aortic arch surgery?
No full textA best evidence topic in cardiothoracic surgery was written according to a structured protocol. The question addressed was whether unilateral antegrade cerebral perfusion is equivalent to bilateral cerebral plegia for cerebral protection during aortic arch surgery. Altogether 233 papers were found using the reported search, of which 17 presented the best evidence to answer the clinical question. The author, journal, date and country of publication, patient group studied, study type, relevant outcomes, results, and study weaknesses of these papers are tabulated. These papers documented antegrade selective cerebral perfusion in a total of 3548 patients: bilateral cerebral perfusion in 2949 patients and unilateral perfusion in 599 patients. Both methods of cerebral perfusion resulted in neurological injury rates of <5%, but the period of antegrade cerebral perfusion allowed by bilateral perfusion was significantly higher. While unilateral perfusion allowed around 30-50 min, bilateral perfusion allowed 86 to over 164 min of ASCP with an acceptably low CVA rate. Therefore, we conclude that while both methods are acceptable, once the ASCP time is expected to rise over 40-50 min, bilateral cerebral perfusion is the technique that is best documented to be safe
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
LETTERS TO THE EDITOR: ANTICOAGULATION FOR PROSTHETIC HEART VALVES DURING PREGNANCY: THE IMPORTANCE OF WARFARIN DAILY DOSE
No full textFor which patients with left main stem disease is percutaneous intervention rather than coronary artery bypass grafting the better option?
No full textA best evidence topic in cardiac surgery was written according to a structured protocol. The topic addressed was to identify the patients with left main stem disease for which percutaneous intervention would be a better option than coronary artery bypass grafting. Altogether 665 papers were found using the reported search, of which 15 presented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers were tabulated. We conclude that if a bare metal stent is used for left main stenting the mortality at one year may be from 3% to over 28% in reported series. The restenosis rate of the bare metal stent in the left main position is around 20% at one year. There are some early series and randomized studies of drug eluting stents for left main stem lesions and the restenosis rate is reported to be around 10%. The European Society of Cardiology in their 2005 percutaneous intervention guidelines state that coronary bypass grafting is the procedure of choice for left main stem disease and only patients with a prohibitively high surgical risk should be considered. We consider that with such high restenosis rates, and with short-term follow-up in such low numbers and short periods compared to coronary artery bypass grafting, left main stenting should only be used as a last resort in patients turned down for coronary artery bypass grafting after full assessment by a cardiac surgeon due to prohibitive co-morbidities. © 2008 Published by European Association for Cardio-Thoracic Surgery. All rights reserved
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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