1,721,155 research outputs found

    The risk of right ventricular failure with current continuous-flow left ventricular assist devices

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    Introduction: Right ventricular failure (RVF) still results as the major cause of morbidity and mortality after left ventricular assist device (LVAD) implantation. Despite overall improved outcomes and lower rates of RVF with the use of the newer, continuous-flow (CF) LVADs over pulsatile-flow devices, and development of clinical prediction scores to facilitate preoperative identification of patients at risk for RVF after implantation, RVF occurs in 13% to 40% of continuous-flow device. Areas covered: In this article, a review has been carried out on the current evidence for preoperative assessment of RV function and RVF risk for appropriate patient selection mainly focusing on current imaging and invasive assessment tools. Expert commentary: According to all findings, it is recommended that measurements of RV function should be included in all risk predictions models and that standardization of echocardiographic and hemodynamic evaluation protocols be adopted before and after device implantation across LVAD centers. The balance of well-accepted and fixed multiple variables might be able to better predict the outcomes in such a delicate clinical panorama

    Going Beyond Counting First Authors in Author Co-citation Analysis

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    The 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

    Questions and answers on the use of aspirin for primary prevention of cardiovascular disease in diabetes

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    Patients with diabetes have a prothrombotic state and a 2 to 4 times higher risk of cardiovascular events than those without diabetes. Aspirin is the cornerstone of treatment in patients withcardiovascular disease, irrespective of diabetes status, being able to confer a 19% relative risk reduction per year in serious vascular events compared with placebo at long-term follow-up (6.7% vs 8.2% per year, p < 0.0001). Data regarding the benefit-risk ratio of aspirin prescribed to patients with diabetes without established cardiovascular disease are less convincing, especially when compared to other preventive strategies. Of note, in primary prevention trials, aspirin allocation yielded a significant 12% proportional reduction in serious vascular events, irrespective of diabetes status, corresponding to a small annual absolute risk reduction (0.06% per year). However, in everyday clinical practice aspirin is still largely prescribed by both diabetologists and cardiologists. In this article, we provide eight questions and answers corroborated by available evidence on the use of aspirin for primary prevention of cardiovascular disease in diabetes

    Variations on the Author

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    “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

    Clinical use of doppler echocardiography in organic mitral regurgitation: From diagnosis to patients’ management

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    Knowledge of mitral regurgitation (MR) is essential for any care provider, and not only for those directly involved in the management of cardiovascular diseases. This happens because MR is the most frequent valvular lesion in North America and the second most common form of valve disease requiring surgery in Europe. Furthermore, due to the ageing of the general population and the reduced mortality from acute cardiovascular events, the prevalence of MR is expected to increase further. Doppler echocardiography is essential both for the diagnosis and the clinical management of MR. In the present article, we sought to provide a practical step-by-step approach to help either performing a Doppler echocardiography or interpreting its findings in light of contemporary knowledge on organic (but not only) MR

    Appropriate Similarity Measures for Author Cocitation Analysis

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    We 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

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    We 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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