1,721,544 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
Immediate intraocular pressure response to selective laser trabeculoplasty
No full textBackground/aims-Selective laser trabeculoplasty targets the pigmented trabecular meshwork cells without damage to the trabecular meshwork architecture in vitro. A study was conducted in vivo of eight eyes with uncontrolled open angle glaucoma to ascertain the immediate intraocular response to selective laser trabeculoplasty. Methods-The trabecular meshwork of each eye was treated 360 degrees with a frequency doubled Q-switched Nd:YAG laser. Intraocular pressure was measured 1, 2, 24 hours and 1, 4, 6 weeks after treatment. Results-The average preoperative intraocular pressure was 26.6 (SD 7) mm Hg (range 18-37). Two hours and 6 weeks respectively after selective trabeculoplasty intraocular pressure was reduced in all the eyes treated with an average fall of 10.6 (5.2) mm Hg or 39.9%. A pressure spike of 10 mm Hg verified in one eye 1 hour after treatment. Conclusions-Selective laser trabeculoplasty decreased intraocular pressure by an amount similar to that achieved with standard trabeculoplasty. Additional study is needed to determine whether the beneficial effect is sustained over a longer period of follow up
Diode laser photocoagulation of choroidal neovascular membranes
No full textBackground. Krypton or argon laser treatment of choroidal neovascularization (CNV) has been shown to be effective in reducing the incidence of severe visual loss. The usefulness of diode laser in the treatment of many chorioretinal disorders is currently under evaluation. Methods. Our study involved 42 eyes of 41 patients affected with CNV which were treated with a near infrared diode laser. Results. The mean follow-up was 10.12 months. Visual acuity improved in 12 eyes (28.6%), did not change in 17 eyes (40.5%) and worsened in 13 eyes (30.2%). Mean visual acuity before treatment was 0.23 and 0.21 after treatment. Recurrent CNV was seen in 13 eyes. In a subgroup of 24 well-defined juxtafoveal or extrafoveal CNVs which underwent direct photocoagulation visual acuity improved in 8 eyes (33.3%), was unchanged in 11 (45.8%) and worsened in 5 (20.9%). Five eyes showed recurrent CNV. Conclusions. Our results appear to support the use of diode laser in the treatment of CNVs. The deeper penetration into the choriocapillaris of the diode wavelength could be effective in blocking CNV by inducing a more extensive chorioretinal atrophy
Antiangiogenic therapy with anti-vascular endothelial growth factor modalities for diabetic macular oedema
No full textBackground Diabetic macular oedema (DMO) is a common complication of diabetic retinopathy. The retina at the macula thickens and this can cause gradual loss of central vision. Although grid or focal laser photocoagulation has been shown to reduce the risk of visual loss in DMO or clinically significant macular oedema (CSMO), vision is rarely improved. Antiangiogenic therapy with anti-vascular endothelial growth factor (anti-VEGF) modalities has recently been proposed for improving vision in people with DMO. Anti-VEGF drugs are delivered by an injection in the vitreous cavity of the eye. Objectives This review aims to assess the effectiveness of anti-VEGF therapy for preserving or improving vision in people with DMO. Search strategy We searched the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library, MEDLINE, EMBASE and Caribbean Literature on Health Sciences (LILACS). There were no language or date restrictions in the search for trials. The electronic databases were last searched on 16 April 2009. Selection criteria We included randomised controlled trials (RCTs) comparing any antiangiogenic drugs with an anti-VEGF mechanism of action compared to another treatment, sham treatment, or no treatment. Data collection and analysis Two authors independently extracted the data. The risk ratio (RR) of visual loss and visual gain of 3 or more lines was estimated at least six months after treatment. Main results We found four small studies that collected only short-term outcomes (24 to 36 weeks); three of which had more than two randomisation groups generating five types of comparisons overall. Only one comparison included more than one trial in the analysis. The short-term outcome was the mean change in LogMAR visual acuity. One study on 172 patients compared three doses of pegaptanib versus sham (about 5 injections on average) and another compared bevacizumab or bevacizumab plus triamcinolone with sham (multiple bevacizumab injections and a single triamcinolone injection in 101 patients, 115 eyes overall) in patients with CSMO that was refractory to photocoagulation. Bevacizumab or bevacizumab plus triamcinolone were also compared to photocoagulation in 129 patients with untreated CSMO(150 eyes, multiple injections needed in 24 patients). Although comparisons tended to favour antiangiogenic therapy, estimates did not reach statistical significance or, if they did, they were not robust to sensitivity analysis regarding missing data and potential bias related to single trial estimates. No difference could be demonstrated in one study on 26 patients comparing bevacizumab to triamcinolone (both administered with a single injection) and between bevacizumab and bevacizumab plus triamcinolone in two studies on 182 patients. All the studies in this review, except for the study on pegaptanib, were at risk of bias based on the assessment of six methodological quality items. There were no serious adverse effects in these short-term studies, except for one case of severe anterior uveitis in one eye treated with bevacizumab. No included study examined long-term adverse effects of antiangiogenic therapy. Authors' conclusions There is not sufficient high quality evidence from large RCTs supporting the use of either single or multiple anti-VEGF intravitreal injections to treat DMO. Results from ongoing studies on several compounds should assess not only treatment efficacy but also, if a benefit is found, the number of injections needed for maintenance and long-term safety
Is a near infrared diode laser effective in inducing the closure of retinal macroaneurysms?
No full textIndocyanine green angiography in vitelliform macular lesions
No full textMany vitelliform macular diseases have been described through the years. Some arguments still exist about the appropriate terminology, the classification criteria and the etiopathogenesis. The alterations of the retinal pigment epithelium, the lipofuscin storage and the role of the choriocapillaris are being investigated. The aim of our study was to describe indocyanine angiographic features in Best's disease and pattern distrophies. Twenty-one eyes of 14 patients underwent indocyanine and fluorescein angiography. The indocyanine angiogram showed hypofluorescent and hyperfluorescent areas. The possible etiopathogenesis of the lesions includes a role of the retinal pigment epithelium
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
Chirurgia della cataratta: ruolo dell'iridografia a fluorescenza nella prevenzione delle complicanze
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