1,720,964 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
Acute Aortic Dissection - Personal-experience
No full textAortic dissection is a catastrophic event with a high mortality rate for untreated patients. One hundred and thirteen patients with acute aortic dissection were observed in the IInd Surgical Department of Milan University from 1974 to 1985; 55 had type I and II aortic dissection and 58 had type III aortic dissection. All patients with type I and II and about 50% of patients with type III aortic dissection underwent surgical correction. In the second type III group the aortic lesion was surgically corrected only when visceral ischaemia or ischaemia of the lower limb was recognized. In the other type III cases, medical treatment was preferred. The mortality rate was lower after medical treatment (15%) than after surgical treatment (37%). Follow-up was performed for the majority of patients and was recently completed with non-invasive techniques like Magnetic Resonance. It accurately shows the residual dissection and follows, the development of occlusion of the false lumen without any risk to the patients
Intracavitary Heart Fibroma - A Case of Successful Total Excision
No full textTumors of the heart are relatively rare events and fibromas represent no more than 5% of these. A central source of peripheral embolization suggests the possibility to kept in mind in the absence of other causes and is therefore worthy of closer investigation
Influenza di precedenti ricostruzioni dell'asse iliacofemorale sulla pervietà del by pass femorofemorale.
No full textA series of 40 femoro-femoral by-pass grafts (FFBG) is presented; these operations were performed from 1978 to 1987 and the follow-up ranged between 6 and 36 months. The subjects were divided retrospectively into two groups, to evaluate the effect of prior iliofemoral reconstructive operations on the long-term patency of the FFBGs. Thirty-four patients (group A) had no previous surgery and 15 (group B) had 23 previous femoral surgical reconstructions. At operation, 34 recipient deep femoral arteries underwent adjunctive TEA (24 out of group A; 10 out of group B) as well as 9 donor limb deep femoral arteries (all out of group A). No donor limb steal phenomenon was recorded in both groups. FFBG occlusion occurred without any statistically significant differences in the groups (A 12%, B 20%) and only in one case a thigh amputation was needed (group B)
Neoplastic Thrombosis of the Inferior Vena-cava and Right Atrium Due To Kidney Cancer - 3 Surgically Treated Cases
No full textExtension into vena cava and right atrium of tumor thrombus from a renal cell carcinoma presents a surgical challenge. The use of cardiopulmonary by-pass, hypothermia and cardiac arrest with temporary exsanguination has allowed the successful surgical excision of this tumor. During 1986 and 1987 3 patients with cancer of kidney invading the vena cava were operated on with this surgical technique. No deaths occurred. The possibility of curing this type of cancer with minimal operative risk and good results is 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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