1,721,095 research outputs found

    Frozen elephant trunk and arch endografts for chronic thoracoabdominal aortic dissections

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    Chronic aortic dissecting aneurysms (TAAD) presenting after acute Stanford type A or B dissection includes both arch and/or thoracoabdominal aortic aneurysms (TAAA). Approximately 60% of patients who survive surgical treatment of acute type A aortic dissections will require another aortic procedure. Similarly, more than 70% of patients with chronic type B aortic dissections will experience false lumen dilation at 5-year follow- up, often requiring intervention. Open or hybrid aortic repairs of complex TAAD involving the arch and the TAAA are very demanding procedures for both patients and clinicians. Open surgery remains the first line therapy in fit patients. Recent development of branched arch devices has offered an alternative option for high-risk patients. Technical challenges associated with the endovascular management of these complex aneurysms include proximal sealing zone often located in the aortic arch or the ascending aorta, narrow true lumen working space, and aortic branch perfusion by either the true or false lumen, or both. Recent studies have reported encouraging results with endovascular treatment of these complex dissecting aneurysms, especially following open ascending aortic repair. The aim of this review was to describe the available strategies for arch repair in the setting of a chronic TAAD and to determine the subset of patients that can benefit from of a totally endovascular approach

    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

    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

    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

    Influence of as-built surface topography on the fatigue behavior of slm Inconel 718: Experiments and modeling

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    The fatigue behavior of ABS SLM Inconel 718 obtained by testing directionally-fabricated specimens is presented and discussed together with characterization of surface topography of the specimens using green light interferometry
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