1,720,980 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
Endoscopic drainage of pancreatic pseudocysts: a long term follow up study of 49 patients
No full textBackground/Aims: Endoscopic drainage is one of the non-surgical treatment modalities for pancreatic pseudocysts. The aim of the current study was to assess the safety and the utility of endoscopic treatment of pancreatic pseudocysts. Prognostic factors for the outcome were evaluated in a prospective analysis. Methodology: Forty-nine consecutive symptomatic patients were included in the study. Transmural drainage was used in 30 patients and transpapillary drainage in 19 patients. Results: Successful drainage was achieved in 27/30 (90%) patients after transmural drainage and in 16/19 (84.2%) patients after transpapillary drainage. Twelve (24.5%) patients had complications: 2 patients had bleeding, 2 patients had mild pancreatitis, 8 patients had cyst infection, in relation to the presence of necrosis (5 patients) or clogging of the stent (3 patients). Nine patients (20.9%) had recurrence of pseudocysts. Endoscopic drainage was a definitive treatment in 37/49 (75.5%) patients (median follow up: 25.9 months) Conclusions: Endoscopic drainage provides a successful and safe minimally invasive approach to pancreatic pseudocyst management
Sulla possibilità di drenaggio endoscopico, sotto guida ecografica, senza controllo radiologico, in pazienti con stenosi neoplastiche della via biliare principale
No full textAim. Endoscopic stent insertion has become the preferred, method for palliation of malignant biliary obstruction. Currently, endoscopic stent placement involves the use of contrast media and radiological equipment to achieve direct opacification of the biliary duct systems, and to determine the location and the extension of biliary obstruction. This report proposes a new combination of ultrasonography and biliary endoscopy, with endoscopic stent placement entirely performed under US-guidance. Methods. US-guided stent placement was carried out in 8 patients. A guide-wire and a guiding-catheter were endoscopically introduced and identified, by US, the common bile duct across the stricture. Hydromer-coated polyurethane angled stents (10F) were finally inserted over the guide-wire/guiding-catheter by a pusher tube system. Results. Successful stent insertion was achieved in all patients. There were no complications. Successful drainage, with substantial reduction in bilirubin level, was achieved in all patients (14.2±9.5 vs 4.2±2.9 mg/dl at 1 week). Conclusion. Endoscopic stent placement performed under US-guidance, is safe and effective. Further studies in a larger series, including more proximal strictures are suggested
Fistole biliari post-colecistectomia laparoscopica. Risultati del trattamento endoscopico
No full textAbstract
Background. Significant postoperative bile leaks occur in approximately 0.8 to 1.1% of patients. The goal of endoscopic therapy is to eliminate the transpapillary pressure gradient, thereby permitting preferential transpapillary bile flow rather than extravasation at the site of leak. Methods. Sixty-four patients were retrospectively evaluated. Endoscopic treatment comprised endoscopic sphincterotomy followed by insertion of a naso-biliary drainage or a stent. Retained stones were extracted by standard procedures. Results. The cystic duct remnant was the site of bile extravasation in 50 cases, ducts of Luschka. were the source in 4 cases, common bile duct in 6 cases and common hepatic duct in 4 cases. Retained bile duct stones were detected in 21 cases and papillary stenosis in 4 cases. Endoscopic therapy involved sphincterotomy in 25 cases with stones extraction in 21 cases followed by nasobiliary drain insertion, and placement of stent in the remainder. Bile leaks resolved in 96.9% of patients, on average 3 days in cases of associated stones or papillary stenosis, and 6.5 days in the remainder. Two cases of mild pancreatitis were evidenced from endoscopic treatment. Conclusions. Endoscopic management is the treatment of choice for postcholecystectomy bile leaks
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
Distally migrated esophageal self-expanding metal stents: wait and see or remove?
No full textBackground: Extraction of a migrated esophageal stent
may be extremely difficult with a substantial risk of complications
including esophageal perforation and hemorrhage.
Methods: Retrospectively 242 patients were evaluated
who underwent implantation of self-expanding metal
stents (SEMS) and 13 (5.4%) were identified with distal
stent migration. In all cases of stent dislocation into the
stomach, extraction of the stent was not attempted and
a new stent was inserted.
Results: Twelve patients had dysphagia. One patient
underwent surgery because of stent impaction in the
colon, 3 had unrecognized passage of the stent per rectum,
and 9 had evidence of the stent into the stomach.
Further severe complications were not observed in any
patient and all stents remained into the stomach.
Conclusion: Complications arising from migrated
esophageal stents are uncommon. Further studies are
warranted to determine which patients with migrated
SEMS warrant stent retrieval
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