1,721,042 research outputs found
Le anomalie dell'arteria epatica in relazione alla chirurgia dell'ipertensione portale
No full textThis study was aimed at investigating the occurrence of hepatic artery variants, at comparing the diagnostic value of duplex Doppler US with that of angiography, and at correlating the results with the technical problems in portal hypertension surgery. All patients were studied with angiography, conventional and duplex Doppler US. In 162 patients with portal hypertension, 38 hepatic artery variants (23.4%) were observed and classified according to Michaels. The commonest variant recognized by angiography was right hepatic artery arising from superior mesenteric artery (type III according to Michaels). US demonstrated hepatic artery variants in 9/162 patients (5.5%). At surgery, variants were found in 3/162 subjects (1.8%) and caused surgical problems in 2 of them (1.2%) - i.e., right hepatic artery arising from superior mesenteric artery. Arteriography is still the best examination to depict hepatic artery variants, while duplex Doppler US demonstrates only a few types. Moreover, the number of variants detected by imaging techniques (23.4%) differs greatly from that observed at surgery (1.8%). Finally, hepatic artery variants are not correlated with surgical problems, nor can the latter be foreseen by imaging methods. US is useful but not essential to detect hepatic artery variants which are subsequently confirmed by angiography
Confronto tra porto-TC e Lipiodol-TC nella stadiazione del carcinoma epatocellulare.
No full textEighteen patients (13 men and 5 women) with uni- and multifocal hepatocellular carcinomas (HCC) were examined. Mean patients age was 63.3 years (range: 47-74 years). All patients had alcoholic or posthepatitis cirrhosis; they were submitted to both CT during arterial portography (APCT) and Lipiodol-CT. The diagnosis of HCC was confirmed by fine-needle biopsy (FNB) in all cases. APCT and Lipiodol-CT results were compared for number, size and site of lesions-32 lesions in all. APCT demonstrated all the lesions: 9 of them were smaller than 2 cm, 14 ranged 2-5 cm and 9 were bigger than 5 cm; moreover, APCT demonstrated other lesions in 3/18 patients (16.6%) which had been missed by US, CT and angiography. Also Lipiodol-CT demonstrated all the 32 lesions and showed smaller lesions in 4/18 patients (22.2%); these nodules were smaller than 2 cm. Based on APCT results 11/18 patients (61.1%) were considered operable, vs. 7/18 patients (38.8%) based on Lipiodol-CT results. To conclude, both APCT and Lipiodol-CT are useful in the preoperative staging of HCC; Lipiodol-CT is preferable to APCT in the study of lesions smaller than 2 cm
Estrusioni ortodontiche settoriali per la stabilizzazione post-riduttiva di un caso di lussazione temporo-mandibolare
No full text
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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