1,720,982 research outputs found
Complicated myocardial infarction in a 99-year-old lady in the era of COVID-19 pandemic: from the need to rule out coronavirus infection to emergency percutaneous coronary angioplasty
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Pulmonary arterial hypertension and right ventricular systolic dysfunction in COVID-19 survivors
Full text linkEffects of Ivabradine on Right Ventricular Systolic Function in Patients With Chronic Obstructive Pulmonary Disease and Cor Pulmonale
No full textCor pulmonale is a clinical syndrome associated with pulmonary hypertension, frequently complicated by congestive heart failure, commonly caused by chronic obstructive pulmonary disease (COPD). Most patients with cor pulmonale have tachycardia. However, heart rate (HR) reduction represents a primary treatment goal to improve the survival and quality of life in these patients. Ivabradine can selectively slow HR at rest and during exercise. In this prospective study, we tested the hemodynamic effects, invasively determined using right-sided cardiac catheterization, of reducing HR with ivabradine. We selected 18 patients (13 men [72.2%], mean age 67 ± 10 years) with COPD and cor pulmonale, presenting with sinus tachycardia. All patients performed clinical evaluation, electrocardiogram, spirometry, echocardiogram, 6-minute walking distance, and right-sided cardiac catheterization within 1 month of enrollment. All tests were repeated after 6 months of ivabradine treatment (median assumed dose 11.9 mg/die). We noticed a significant decrease of HR (from 98 ± 7 to 77 ± 8 beats/min, p = 0.0001), with a concomitant reduction of the congestion index (from 25.9 ± 5.1 to 19.4 ± 5.7 mm Hg, p = 0.001), and the consequent improvement of the right ventricular systolic performance (right ventricular stroke volume augmented from 56.7 ± 7.9 to 75.2 ± 8.6 ml/beat, p = 0.0001). This allows an improvement in clinical status and exercise tolerance (Borg scale score decreased from 5.2 ± 1.4 to 4.1 ± 1.3, p = 0.01 and the 6-minute walking distance increased to 252 ± 65 to 377 ± 59 m, p = 0.001). In conclusion, HR reduction significantly improves hemodynamic and clinical status of patients with tachycardia affected by COPD and cor pulmonale
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
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