1,721,005 research outputs found
Extensive coronary thrombus causing full thickness myocardial infarction
No full textA young male presented 22 h following onset of symptoms with an anterior ST-elevation myocardial infarction. He was transferred for rescue angioplasty after failing to reperfuse with thrombolytic therapy. On arrival, his symptoms had settled. Following administration of intracoronary abciximab and passage of an angioplasty wire into the distal LAD, extensive thrombus was demonstrated in the left anterior descending artery extending from the ostium to the distal vessel Figure 1(a). Further intervention with attempted thrombectomy was considered but it was postponed pending a viability study because of the risks of displacing thrombus down the circumflex. A cardiac MRI scan with delayed gadolinium hyper-enhancement demonstrated the classical appearance of full-thickness infarction in the LAD territory Figure 1(b). No further intervention was therefore indicated. At one-year follow-up, the patient remains free of angina with NYHA Class 1 symptoms of heart failure
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
Tissue motion annular displacement of the mitral valve using two-dimensional speckle tracking echocardiology predicts the left ventricular ejection fraction in normal children
No full textBACKGROUND: The gold standard for determining the left ventricular ejection fraction is cardiac magnetic resonance imaging. Other parameters for determining the ejection fraction such as M-mode echocardiography are operator-dependant and often inaccurate. Assessment of the displacement of the mitral valve annulus using two-dimensional speckle tracking echocardiography may provide an accurate and simple method of determining the left ventricular ejection fraction in children.METHOD: We retrospectively studied 70 healthy 9-year-old children with no history of cardiovascular disease who had been assessed using cardiac magnetic resonance imaging and two-dimensional transthoracic echocardiography. Mitral displacement was determined using the tissue motion annular displacement (TMAD) feature of Philips QLAB version 9. The midpoint displacement of the mitral valve was calculated, and the predicted left ventricular ejection fraction was compared with magnetic resonance imaging-derived and M-mode-derived ejection fractions.RESULTS: The mean ejection fraction derived from magnetic resonance imaging (64.5 (4.6)) was similar to that derived from the TMAD midpoint (60.9 (2.7), p = 0.001) and the M-mode (61.9 (7), p = 0.012). The TMAD midpoint correlated strongly with the magnetic resonance imaging-derived ejection fraction (r = 0.69, p < 0.001), as did the predicted fraction (r = 0.67, p < 0.001). The M-mode ejection fraction showed a poor linear correlation with both magnetic resonance imaging-derived and TMAD-derived fractions (r = 0.33 and 0.04, respectively).CONCLUSION: TMAD of the mitral valve is a simple, effective, and highly reproducible method of assessing the ejection fraction in normal children. It shows a strong linear correlation with magnetic resonance imaging-derived ejection fraction and is superior to M-mode-derived ejection fractions.<br/
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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