1,721,322 research outputs found
Doppler and echocardiographic diagnosis of a free-floating left atrial thrombus
No full textWe report a case of a free-floating left atrial thrombus in a patient with severe mitral stenosis diagnosed by cross-sectional echocardiography. The Doppler technique was very useful in explaining some peculiar auscultatory and clinical aspects present in this rare complication of mitral valvar stenosis
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
Aortic atherosclerosis as an embolic source
No full textStroke is the third leading cause of death in several industrial countries and cardiogenic embolism accounts for 15–30 % of ischaemic strokes [1–5]. The diagnosis of a cardioembolic source of stroke is frequently uncertain and relies on the identification of a potential cardiac source of embolism in the absence of significant autochthonous cerebrovascular occlusive disease. In this regard, echocardiography (either transthoracic – TTE or Transoesophageal – TEE) serves as a cornerstone in the evaluation and diagnosis of these patients [6, 7]
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
Postoperative dissecting ventricular haematoma: a conservative strategy with a cardiac magnetic resonance imaging follow-up
No full textAppropriate 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
Diastolic ventricular interaction in normal and dilated heart during head-up tilting
No full textBackground: The normal human heart behaves as a single functional unit during preload reduction; adaptations of the left ventricle to head-up tilting is mediated through ventricular interdependence and biventricular-lung interaction. Hypothesis: We hypothesized that reduction of venous return in dilated cardiomyopathy is likely to have a great effect on ventricular chamber geometry and filling. The aim of this study was to evaluate the effects of gradual head-up tilting in normal subjects and in patients with dilated cardiomyopathy, addressing special attention to right (RV) and left ventricular (LV) dimensions, geometry, and filling, and to biventricular-lung interaction. Methods: Twenty normal subjects and 23 patients with moderate heart failure due to dilated cardiomyopathy were studied with two-dimensional and Doppler echocardiography in supine position and after 20°, 40°, and 60°tilting. Right ventricular and LV dimensions, LV geometry, and tricuspid, mitral, and pulmonary venous flow patterns were recorded at each step of the study. Geometric changes of the LV were evaluated by measurements of volumes and diameters in the apical four-chamber view (which identifies the interventricular septum and lateral wall) and apical two-chamber view (which identifies the inferior and anterior wall of the LV). Results: In the two groups, tilting was associated with reduction of RV area and LV diameter and volumes; percent variations in LV diameter and volumes recorded in four-chamber view were lower at each step of tilting than with those derived from the two-chamber view in controls and in patients. In normal subjects, mitral and tricuspid peak early flow velocities were decreased at any tilting level; peak late velocities were unchanged; peak velocity of systolic forward flow of the pulmonary vein was reduced, diastolic forward flow was unchanged, and the difference in duration between reverse pulmonary flow and forward mitral A wave was reduced. Doppler findings were qualitatively similar in patients, but tilting induced a more marked redistribution of LV filling to late diastole because of a significant increase in atrial contribution. Conclusions: Preload reduction by tilting induces profound effects on left and right dimensions, geometry, and filling in normal and dilated heart; reduction of RV dimensions are associated with changes in LV ventricular geometry (minimal reduction in septal-lateral diameter, marked reduction in anterior-posterior diameter), redistribution of right and left diastolic filling to late diastole, and redistribution of pulmonary venous flow to early diastole. These mechanisms are probably due to a favorable interaction between heart and lungs, which increases compliance within the pericardial space and facilitates redistribution of flow from the lungs. Even a minimal amount of preload reduction causes more marked effects in LV filling patterns in dilated cardiomyopathy than in normal hearts, confirming that ventricular interaction and pericardial constraint are increased when heart volume enlarges
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