1,720,965 research outputs found
Endovascular Surgery of Descending Thoracic Aorta Involved in T4 Lung Tumor
No full textPurpose: Surgical treatment of primary lung T4 tumors is controversial especially when the cancer invades the mediastinal structures or the descending thoracic aorta. Conventional surgical treatment is associated with a high perioperative mortality and morbidity rate. Thoracic EndoVascular Aortic Repair has emerged as a valid off-label alternative to conventional surgery. We aimed to assess perioperative and midterm aortic-related outcome of patients who have undergone aortic stent-graft implantation, followed by en bloc surgical treatment of the involved aorta and lung cancer resection. Materials and methods: From July 2017 to May 2020, we treated 5 patients diagnosed with a T4 lung cancer by the involvement of the descending thoracic aorta. When only the descending thoracic aorta is involved, a 2-stage procedure was considered, with aortic stent-graft implantation performed before tumor resection. One-stage strategy, with stent-graft implantation carried out before thoracotomy, was preferred for patients with the involvement of cardiac and/or other vascular mediastinal structures. Results: The mean age was 58.4 ± 6.2 years. All patients were affected by non-small cell lung cancer. All 5 patients required a single stent-graft to completely cover the involved segment of aorta. Four patients underwent a 2-stage procedure. One patient, with the involvement of the left inferior pulmonary vein, required a 1-stage en bloc resection of the left lower lobe, aortic wall adventitia, left inferior pulmonary vein, and reconstruction of the left atrial wall. Primary procedural success was achieved in all. At follow-up, no patient developed aortic-related complications. One patient died 2 years after surgery, due to local recurrence of the tumor. Conclusion: T4 lung resection combined with aortic stent-graft implantation can be safely performed. Endovascular surgery, by avoiding the use of cardiopulmonary bypass, aortic cross-clamping, and graft replacement, can reduce significant morbidity and mortality rate. Postoperative and long-term outcome of these patients treated with endovascular surgery is mainly related to pulmonary disease, not to aortic treatment
Endovascular treatment of distal aortic arch aneurysm associated with coarctation of aorta in a Jehovahâs Witness
Full text linkLate aneurysm formation in the proximal aorta or distal aortic arch is a recognized sequela of untreated stenosis of the aortic isthmus and is associated with substantial risk of aortic rupture. We describe the case of a 44-year-old man with untreated coarctation of the aorta who presented with a prestenotic dissecting thoracic aortic aneurysm. He declined surgery because he was a Jehovah’s Witness. Instead, we performed emergency endovascular aortic repair in which 2 stent-grafts were placed in the descending aorta. Our experience suggests that this procedure is a useful and safe alternative to open surgery in patients who have aneurysms associated with coarctation of the aorta
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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