1,720,970 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
Intravitreal bevacizumab for extrafoveal choroidal neovascularization after ocular trauma
No full textPurpose: To describe two cases of extrafoveal choroidal neovascularization (CNV) after ocular trauma successfully treated with intravitreal bevacizumab injection. Methods: A 41-year-old man presented for progressive visual impairment in the left eye (LE). The patient had a positive history for pseudoxanthoma elasticum and suffered a blunt trauma in the LE 1 year before. Best-corrected visual acuity (BCVA) in the affected eye was 20/100. Fundus examination of the LE revealed angioid streaks and a choroidal rupture with retinal hemorrhages. Fluorescein angiography (FA) revealed an extrafoveal CNV and optical coherence tomography (OCT) findings demonstrated the presence of intraretinal fluid extending to the fovea. The second patient was a 61-year-old man complaining of blurred vision in the LE. Fundus examination of the LE revealed retinal pigment epithelium (RPE) changes, while FA showed the presence of an extrafoveal CNV close to the area of RPE attenuation. Intraretinal fluid extending to the fovea was detectable on OCT examination. An intravitreal injection of bevacizumab was proposed in both cases. Results: In the first patient, treatment with one intravitreal bevacizumab injection was successful in contrasting CNV activity, as OCT findings showed a resolution of intraretinal fluid accumulation. BCVA remained unchanged (20/100) over the 12-month follow-up period, most probably due to permanent alteration of the photoreceptors. In the second case, BCVA improved from 20/40 to 20/20 with complete resolution of leakage on FA and fluid on OCT 1 month after a single intravitreal injection of bevacizumab. Visual function remained stable over the 14-month follow-up. Conclusions: Our results indicate that intravitreal bevacizumab is effective in the management of extrafoveal CNV secondary to ocular trauma
Spectral Domain Optical Coherence Tomography Findings in Patients with Retinitis Pigmentosa
No full textBackground: To report the morphological macular findings detected by spectral domain optical coherence tomography (SD-OCT) and to determine their prevalence in patients with retinitis pignnentosa (RP). Methods: SD-OCT scans of 176 eyes from 90 patients affected by RP were reviewed. A careful evaluation was carried out on photoreceptor inner/outer segment (IS/OS) junction, external limiting membrane (ELM), inner limiting membrane thickening (ILMT), epiretinal membranes (ERMs), retinal micropseudocysts (MPCs), cystoid macular edema (CME), macular holes (MHs) and choroidal neovascularization (CNV). Results: The photoreceptor IS/OS junction was absent in the foveal region of 24 eyes (13.6%) and disrupted in 84 eyes (47.7%). The ELM was absent in 24 eyes (13.6%), whereas the ILMT was found in 118 eyes (67%). The presence of an ERM was detected in 48 eyes (27.3%). Some sort of vitreomacular alteration (ILMT and/or ERM) was identifiable in a total of 94.3% of eyes with RP. The presence of MPCs was detected in 32 eyes (18.2%). An evident CME was found in 22 eyes (12.5%). We also found MHs in 8 eyes (4.5%) and CNV in 3 eyes (1.7%). Conclusions: Our data indicate that RP is associated with alterations of many retinal layers. In particular, the vitreoretinal interface is affected in 94% of patients, and MPC can be identified in 18% of eyes. SD-OCT may contribute to the understanding of the pathophysiological mechanism involved in RP. Copyright (C) 2013 S. Karger AG, Base
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
Simultaneous vitreous hemorrhage and branch retinal artery occlusion after prepapillary arterial loop rupture
No full textPrepapillary arterial loops are rare benign congenital vascular anomalies that may be complicated by vitreous hemorrhage and branch retinal artery occlusion (BRAO). We describe the first case in the literature of simultaneous occurrence of both these complications in the same eye of a patient with a bilateral prepapillary arterial loop, successfully treated with vitrectomy. (C) 2013 Elsevier Masson SAS. All rights reserved
Birdshot Retinochoroidopathy Masquerading as Intraocular Lymphoma
No full textWe present a case of a patient with bilateral posterior uveitis HLA-A29 positive, masquerading intraocular lymphoma. A 43 year-old woman presented with bilateral vitritis and chorioretinal lesions compatible with "birdshot lesions". The patient was initially diagnosed with birdshot retinochoroidopathy and later on, during follow up, the occurrence of neurologic involvement and the lack of response to systemic immunosuppression led us to re-evaluate the diagnosis. A definite diagnosis of intraocular lymphoma with central nervous system involvement was made. This case is presented to highlight the importance of careful follow-up of patients with chronic uveitis and re-evaluation of systemic symptoms and signs, in particular when ocular findings are highly suggestive for masquerade syndrome
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