1,721,034 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
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
Esophageal replacement with colon in children using either the intrathoracic or retrosternal route: An analysis of both surgical and long- term results
No full textA total of 28 colon esophageal replacements performed in children for long gap esophageal atresia (22 patients), and intractable caustic stricture (6 patients) were reviewed. Emphasis was placed on identifying the pros and cons of the different reconstruction techniques: intrathoracic route (ITR) (19 patients) and retrosternal route (RSR) (9 patients). No hospital mortality occurred, whereas a higher morbidity rate occurred among patients operated on using the ITR as opposed to the RSR (68% vs 55%; P not significant). Six patients developed an anastomotic fistula (21% with the ITR vs 22% with the RSR; P not significant), whereas an anastomotic stenosis occurred in 13 patients (67% with the RSR, and 37% with the ITR; P < 0.07); Overall, dysphagia was the most prevalent symptom at 3 months follow-up, but had significantly decreased at the final follow-up (54% vs 16%; P < 0.0027). Functional results improved significantly during the follow-up (score 1-2 vs score 3-4; Fisher test: P = 0.001). However, despite the higher morbidity rate, better functional results were achieved using the ITR as opposed to the RSR
A transdiaphragmatic retroperitoneal approach for lower esophageal and gastroesophageal junction carcinomas
No full textRadical surgery and a regional lymphadenectomy still appear to be the treatment of choice for lower esophageal and gastroesophageal carcinomas. However, in some instances, difficulties can be encountered both in assessing the resectability of tumors extending toward retroperitoneal structures and in performing a lymphadenectomy of the preaortic area extending between the hiatus and celiac axis. For these reasons, we developed a specific transdiaphragmatic retroperitoneal approach. After thoraco-phreno-laparotomy, and exploration of both the thorax and the abdomen to rule out any metastatized disease, an extraperitoneal, posterior phrenotomy is performed from the aortic hiatus and extending anteriorly for 5 cm. This creates an access to the retroperitoneal space and, by incising the arcuate ligament, a wide exposure of the aorta can be obtained at this level. In this way a more complete visualization of the transdiaphragmatic preaortic area and an easier and safer dissection of the preaortic lymphoid tissue is possible
Percentage of time versus surface above cut-off in the analysis of bile reflux monitoring in man.
No full textRecent studies, using ambulatory optical monitoring of esophageal bilirubin concentration (Bilitec), have suggested that reflux of both acid and duodenal contents frequently occurs in patients with gastro-esophageal reflux disease (GERD). In in vitro studies, it was observed that a linear correlation exists between fiberoptic absorbance and bilirubin concentration, and that bilirubin concentration is an adequate marker for quantifying duodenogastroesophageal
reflux. It seems logical, therefore, to assume that the surface
above the cut-off level for bilirubin absorbance would provide an adequate quantitative marker for reflux of duodenal contents. Aim; To study whether the surface above cut-off during Bilitec monitoring has a better correlation with esophageal lesions and pH measurement than % of time above cut-off level. Method~: In 84 patients (46 men, mean age 46 -+ 2 years) evaluated for suspected gastro-esophageal reflux disease, we performed an upper gastrointestinal endoscopy and an ambulatory 24 hours esophageal pH and Bilitec monitoring. All drugs potentially affecting gastrointestinal motility and acid secretion were discontinued at least one week prior to the study. We calculated both the % of time and the surface of bilirubin absorbance above cut-off level of 0.14. We also calculated the % of time of pH < 4 and the surface of acid reflux. Results (mean .+ SEM) were compared by Student's ttest.
Results: : The endoscopy revealed no esophagitis in 45 patients (54%), grade 1 or 2 esophagitis in 23 patients (27%) and grade 3 or 4 esophagitis in 16 patients (19%). The % of time that bilirubin absorbance was above 0.14 was 6.1 .+ 1.5 in patients without esophagitis, 8.5 -+2.6 in patients with esophagitis grade 1 or 2, and 16.1 _+ 4.2 in patients with esophagitis grade 3 or 4 (p=0.006 compared to no esophagitis). A pathological Bilitec monitoring (% of time above 0.14 > 4.6) was present in 34 patients (40%). A poor but significant correlation was present between the pH measurement (% of time pH 0.14 was 7.8-+ 2.3 abs*min in patients without esophagitis 12.1 ± 4.5 abs*min in patients with esophagitis grade 1 or 2, and 18.1 ± 4.6 abs*min in patients with esophagitis grade 3 or 4 (p=0.03 compared to no esophagitis). The correlation between the pH measurement (% of time pH < 4) and Bilitec monitoring was not improved by considering the surface of bilirubin absorbance above cut-off level (R=0.47, p < 0.005). Taking into account the surface of acid reflux also failed to improve the correlation with the surface of bilirubin absorbance above cut-off level (R=0.32, p=0.03).
Conclusions: Taking into account the surface rather than the % of time above the cut-off level for bilirubin absorbance does not improve the correlation of Bilitec with acid reflux and with esophageal lesions. Bilirubin concentraction, reflected as bilirubin absorbance, may not be directly proportional to the caustic factor in duodeno-gastro-esophageal reflu
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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