1,722,413 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
Early identification of patients at increased risk of liver failure, postoperative complications and death after major hepatectomy
No full textIntroduction: Aim of this study was to identify early predictive markers of clinically significant liver failure (PHLF B/C), postoperative complications and mortality after major liver resections.
Materials and methods: 115 consecutive major hepatectomies (three or more segments) were carried out and retrospectively analyzed. Association beetween PHLF, major complications, in-hospital mortality, demographics, clinical-pathologic and perioperative factors was evaluated. Multivariate logistic regression analysis was used to develop a predictive model for PHLF B/C, Clavien-Dindo grades III-V complications and mortality. Sensitivity, specificity and the area under the receiver operating characteristic (AUROC) curve were assessed.
Results: PHLF B/C was observed in 25 of 115 (21.7%) patients. 41 (35.7%) developed major complications, in-hospital mortality was 3.5% (4 patients). Multivariate logistic regression analysis identified high serum bilirubin and increased prothrombin time (PT) ratio on postoperative day 3 (POD3) as indipendent predictive markers of PHLF B/C (P < 0.05). POD3 high serum bilirubin was the only early postoperative factor influencing the risk of major complications (P < 0.05) and in-hospital death (P < 0.001) on multivariate analysis. ROC curve analysis of PT ratio (AUC 0.775) and serum bilirubin (AUC 0.813) on POD3 showed respectively 73% and 83% sensivity and 27% and 28% specificity at a threshold of 1.35 and 1.75 mg/dL.
Conclusions: Rising of serum bilirubin and PT ratio early after hepatectomy appears strongly predictive of PHLF B/C. Compared to other studies, our threshold value of serum bilirubin was slightly lower with a higher sensitivity. POD3 high serum bilirubin was the only factor influencing in-hospital mortality and major complication rates
Salvage hepatectomy for HCC recurrence after failed RFA, TACE or PEI: an unlock gateway to think of
No full textIntroduction: Outcomes of salvage hepatectomy for local
recurrent hepatocellular carcinoma (HCC) after locoregional
or percutaneous treatments are still unclear.
Methods: We conducted a retrospective analysis of 92
consecutive patients with HCC who underwent either primary
liver resection (group 1, 65/92) or salvage hepatectomy
for recurrent HCC after failed percutaneous or locoregional
treatments (group 2, 27/92).
The two cohorts were compared in terms of perioperative
mortality and morbidity and long-term disease-free and
overall survival rates were analized.
Results: Group 2 patients were previously submitted to a
different range of treatments such as: RFA (17 cases), RFA
+ PEI (4 cases), TACE (4 cases), RFA + TACE (2 cases).
HCC average size was comparable between group 1 and 2
(27.6 mm vs. 27.5 mm, respectively). In 6/60 (group 1) and
11/27 (group 2) liver resections were performed laparoscopically.
Perioperative mortality rate was nihil in both
groups and morbidity rate was comparable. The median
progression-free survival was 16 months [CI 95% 12.3-
19.6] for group 1 and 43 months [CI 95% 22.5-63.4] for
group 2 (p=0.013). The median overall survival was 68
months [CI 95% 32.4-103.5] for group 1 and 81 months
[56-106.9] for group 2 (p=0.015).
Conclusions: Salvage hepatectomy for HCC recurrence in
patients not resected upfront, whose HCC relapsed after
failure of loco-regional or percutaneous procedures, appears
to be safe and effective. In our limited series, it
provided optimal outcomes in terms of disease-free and overall long term survival, being a reasonable option in
such patients
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
Positron timing and detection in the MEG experiment
No full textHere the high timing resolution positron detector designed to be used in the MEG experiment is described. Several technical challenges have been faced to obtain the unprecedented goal resolution of 100 ps FWHM for positrons to be detected in the MEG experiment. Also an overview on past experiments is proposed. The key role of the MEG experiment in unveiling New Physics phenomena is briefly stressed. © owned by the author
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