1,720,984 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
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Off-the-shelf total endovascular aortic arch aneurysm repair
No full textWe report the challenging case of a total endovascular repair of persistent type Ia endoleak in a 85 years-old patient who had previously undergone emergent thoracic endovascular aortic repair (TEVAR) and subsequent placement of Amplatzer Plug in the left subclavian artery for a huge symptomatic left hemiarch aneurysm.
The patient was at high surgical risk for history of chronic obstructive pulmonary disease, hypertension and coronary artery disease with previous percutaneous revascularization. Surgical debranching of the supra-aortic trunks was considered to be demanding because of the presence of a tracheostomy due to the removal of a laryngeal cancer with subsequent neck irradiation.
A total endovascular approach was then chosen, using the modular endograft NexusTM (Endospan). The device is equipped with a fixed branch to maintain the perfusion of the brachio-cephalic trunk and an optional fenestration for the left common carotid artery (LCCA). Under general anesthesia and through bilateral femoral surgical approach, the endograft was placed with proximal landing in the ascending aorta (zone 0). Through a surgical retrograde right humeral access, two Viabahn covered stent 8-100 mm were placed with the “chimney technique” throughout the graft fenestration to keep patent the LCCA. The final angiography showed the absence of any endoleaks with good patency of both the brachiocephalic trunk and left carotid artery. The computed tomography angiography scan at 2 months showed a good result
Endovascular aortic repair with aneurysm sealing system and parallel grafts: is it the solution for type I endoleaks and target vessels’ thrombosis?
No full textBACKGROUND Type I endoleaks (EL) from “gutters” and stent-graft compression represent the two main issues of the endovascular aortic repair (EVAR) using the chimney/snorkel technique. The potential impact of these complications would probably be reduced in presence of a sealing polymer, which could fill the “gutters” and can conform more precisely around the grafts without any adjunctive radial force.
Aim of the study was to assess the reported rate of type I EL and target vessels’ thrombosis occurring after chimney/snorkel EVAR using traditional endografts (Ch-EVAR) and those reported after EVAR with chimney using an Endovascular Aneurysm Sealing system (Ch-EVAS).
METHODS Analysis of the literature on Pubmed and Medline with the terms “Chimney” and “Parallel grafts” was performed. Case series of either Ch-EVAR or Ch-EVAS of juxtarenal/pararenal aneurysms, pseudoaneurysms and type Ia EL following EVAR were considered. Only papers with full text available in English and reporting complete data about the occurrence of endoleaks and stent-graft thrombosis with at least 1 month of follow-up were included in the analysis.
Exclusion criteria were papers with incomplete data, inadequate follow-up or reporting less than 5 cases. For both Ch-EVAR and Ch-EVAS, the total proportion of type I EL and target vessels’ thrombosis occurring during the follow-up was calculated, along with the respective 95% confidence intervals (CI). The R program (http://CRAR.R-project.org) with “Metaprop” package was used.
RESULTS The search on Pubmed retrieved 173 papers. Of these, only 24 papers were included in the analysis (20 in the Ch-EVAR group and 4 in the Ch-EVAS group). Data about 563 Ch-EVAR and 61 Ch-EVAS performed from January 2008 to December 2016 were analyzed. During the follow-up, a type I EL occurred in 10% of patients submitted to Ch-EVAR (95% CI: 8%-13%) and in 8% of patients submitted to Ch-EVAS (95% CI: 4%-19%). Target vessels thrombosis occurred in 9% of cases after Ch-EVAR (95% CI: 7%-12%) and in 6% of cases after Ch-EVAS (95% CI: 2%-17%). The nature of the reported studies did not allow the assessment of any statistically significant difference between the outcomes of both techniques.
CONCLUSIONS The reported rate of type I EL and target vessels’ thrombosis occurring after Ch-EVAR tended to be slightly higher than those reported after Ch-EVAS, however it was not possible to assess if these data differed significantly. A randomized controlled trial comparing the outcomes of Ch-EVAR and Ch-EVAS is then needed to improve the knowledge about this topic
Anatomic patterns of the supra-aortic vessels from the aortic arch in the era of total endovascular arch repair
No full textAIM To characterize the anatomic pattern of the aortic arch and the supra-aortic trunks (SAT: brachio-cephalic trunk, BCT; left common carotid artery, LCCA; left subclavian artery, LSA) in terms of mutual distances starting from the aortic valve (AV), clockface orientation from the sagittal aortic axis and aortic diameters.
METHODS Measurements of Computed Tomography Angiograms (CTAs) in three groups of patients (without any pathology of the aortic arch, group A; with dilatation of the aortic arch, B; with dilatation of the descending thoracic aorta below the LSA, C) were retrospectively collected and analyzed.
RESULTS A total of 230 CTAs were analyzed (80 in group A, 71 in B, 79 in C). Significant differences were recorded among the three groups in terms of mutual distances (being AV-BCT and BCT-LCCA significantly lower in patients of group A if compared to both group B and C, both P<.0001) and take-off angles (being BCT the lowest in group A and LCCA the lowest in group C). In group A, all SAT mutual distances showed a positive correlation with increasing aortic diameters. In group B and C, both the distances VAP-BCT and BCT-LCCA showed a positive correlation with increasing aortic diameters (R=0.22 and 0.24 respectively for group B; R=0.46 and 0.38 respectively for group C). In group B, the take-off angles of both LCCA and LSA showed a negative correlation with increasing aortic diameters (R= -0.26 and -0.23 respectively).
CONCLUSION The anatomic pattern of the aortic arch and the SAT varied significantly among the three groups
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