1,721,071 research outputs found
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
Abdominal aortic aneurysm in chronic thoracic dissection. Report of two cases
No full textTwo cases of lower abdominal aortic aneurysm in association with chronic thoracic dissections are reported. These infra-renal aortic aneurysms, superimposed on an abdominal extension of the dissection, always require surgical treatment because of their well known tendency to enlarge and rupture. The authors report their experience and discuss the management of this complication in chronic dissections treated surgically
Aneurysms of the coronary arteries: one case report
No full textTrue aneurysms of the coronary arteries are very uncommon. In our institution, from December 1982 to April 1987, in more than 2500 coronarographies, we observed only one case whose angiographic findings revealed a real fusiform aneurysm (at least 3 times the diameter of the original vessel) of the right coronary artery. The same patient exhibited a left anterior descending artery ectasia too, as we already noted in other cases not included in the present report. The other coronary arteries showed no associated lesions. Clinical findings included a previous myocardial inferior infarction and typical precordial effort pain with a basal and stress ECG showing non specific ST-T wave abnormalities. The patient underwent right coronary endoaneurysmectomy with interposition of a saphenous vein graft. Postoperative course was uneventful and 8 months after surgery the patient was asymptomatic, and basal and effort ECG showed no ischemic modification. Control angiogram revealed an optimal anatomical reconstruction with no further evolution of the left anterior descending artery dilatation. The distinction between vessel dilation and an aneurysm is discussed
Aneurismi infiammatori dell'aorta addominale
No full textThe authors present a review of the literature on inflammatory abdominal aortic aneurysms. These aneurysms represent from 3 to 10% of all abdominal aortic aneurysms. Progress has occurred in the technical approach to these aneurysms, and operative morbidity and mortality have been remarkably reduced. However, the pathogenesis remains poorly understood. Early reports have considered the inflammatory aneurysm as a distinct clinical and pathological entity, whereas recent evidences suggest a common etiopathogenetic mechanism for both atherosclerotic and inflammatory aneurysms. Finally, genetic and environmental factors, such as tobacco use, may predispose certain persons to the development of non-inflammatory aneurysms and others to a wide spectrum of inflammatory reactions until inflammatory aneurysms development. The most common clinical features of these aneurysms are represented by symptoms, such as abdominal or back pain, obstructive uropathy and by an elevated erythrocyte sedimentation rate. Computed tomography (CT) allows a specific diagnosis by the typical image of soft tissue surrounding the aortic wall enhancing with contrast administration. Ultrasonography is less sensitive whereas nuclear magnetic resonance (RNM) is a promising technique. Excretory urography may suggest the diagnosis by demonstration of ureter entrapment. Surgical therapy, by a technique of limited dissection represents the definitive treatment. Evolution of fibrosis after surgery is still debated because some studies have reported complete regression of inflammation and other partial regression or persistence of fibrotic process. At present, endovascular treatment of these aneurysms is occasionally reported, although preliminary results appear satisfactory
Gravi deformità in esito di frattura femorale: problemi nella terapia protesica. Presentazione di un caso
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
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