1,720,966 research outputs found
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Get PDFWe 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
Iatrogenic retinal breaks in ultra-high-speed 25 gauge vitrectomy: a prospective study of elective cases
No full textBackground/Aims To evaluate the incidence of intraoperative retinal breaks in the ultrahigh-speed (UHS) 25-gauge vitrectomy system in elective vitreous-retina surgery cases. Methods A prospective series of 1676 eyes of 1306 consecutive patients. All eyes underwent an UHS 25-gauge transconjunctival sutureless pars plana vitrectomy for elective cases such as idiopathic epiretinal membrane (586 cases), floaters (153), macular hole (385), vitreous macular traction syndrome (119), dropped nucleus or intraocular lens (84) and vitreous bleeding (82). Patients were followed up for a minimum of 6 months. Results There were 1409 eyes involved in this study. Iatrogenic retinal breaks were found in 25 eyes (1.8%) during surgery. The majority were detected in cases where posterior vitreous detachment was induced during surgery (21 eyes; 2.8% of the patients), and in only four eyes (0.6%) with an already detached vitreous. In nine cases, rhegmatogenous retinal detachment developed during the follow-up. Patients who showed intraoperative retinal breaks were not in this group. Other complications during the follow-up included two cases of vitreous haemorrhage (0.1%), two cases of dislocated intraocular lens (0.1%), and 23 eyes with hypotony without any further complications. Conclusions UHS 25-gauge transconjunctival sutureless vitrectomy is a safe procedure for treatment of elective vitreous-retina cases. The risk of developing iatrogenic breaks seems to be correlated with adhesion of the posterior vitreous hyaloid. Other complications, such as rhegmatogenous retinal detachment or hypotony, were similar to previous reports. No correlation was found between iatrogenic retina breaks and other complications
Inverted internal limiting membrane flap technique for macular hole surgery without extra manipulation of the flap
No full textPurpose:
To determine whether surgical manipulation steps of the internal limiting membrane (ILM) flap, such as ILM trimmed, ILM tuck inside the hole, ILM massage, are mandatory to obtain satisfactory outcomes for the repair of large stage IV idiopathic macular hole using the inverted ILM flap technique.
Methods:
In this interventional comparative prospective single-masked study, 81 eyes were randomized into 2 treatments groups. In Group 1 (41 eyes), the classic inverted ILM flap technique was performed. In Group 2 (40 eyes), a modified procedure was used: after ILM peeling, no extra flap manipulation was performed. The macular hole was covered by the inverted ILM flap because of the air pressure at the time of the fluid–air exchange.
Results:
At 12 months, macular hole closure was observed in 40 eyes (97.6%) in Group 1 and in 39 eyes in Group 2 (97.5%). U-shape closure rate, ellipsoid zone defects, and external limiting membrane defects were similar in both groups. The results indicate no statistical difference in anatomical and functional success between both groups.
Conclusion:
The macular hole closure rate, improved visual acuity, and no extra complications indicate noninferiority of the modified inverted ILM technique. Internal limiting membrane finishing, tucking, and massage may not be required to obtain surgical success
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