1,720,974 research outputs found
Steady-state pattern electroretinogram and frequency doubling technology in anisometropic amblyopia
Full text linkBackground: Steady-state pattern electroretinogram (PERG) and frequency doubling technology (FDT) perimetry can be used to selectively investigate the activity of the M-Y ganglion cells in adult anisometropic amblyopes.
Methods: Fifteen normal subjects (mean 27.8±4.1 years) and 15 adults with anisometropic amblyopia (mean 28.7±5.9 years) were analyzed using steady-state PERG and FDT.
Results: The amplitude of steady-state PERG was significantly different not only among the control group and both the amblyopic eye (P=0.0001) and the sound eye group (P=0.0001), but also between the latter two groups (P=0.006). The difference in FDT mean deviation was statistically significant not only between the control group and amblyopic eye group (P=0.0002), but also between the control group and the sound eye group (P=0.0009). The FDT pattern standard deviation was significantly higher in the control group rather than in the amblyopic eye (P=0.0001) or the sound eye group (P=0.0001). A correlation was found between the reduction in PERG amplitude and the increase in FDT-pattern standard deviation index not only in amblyopic (P=0.0025) and sound (P=0.0023) eyes, but also in the healthy control group (P=0.0001).
Conclusion: These data demonstrate that in anisometropic amblyopia, there is an abnormal functionality of a subgroup of the magnocellular ganglion cells (M-Y), and the involvement of these cells, together with the parvocellular pathway, may play a key role in the clinical expression of the disease
ET-1 plasma levels, choroidal thickness and multifocal electroretinogram in retinitis pigmentosa
No full textAbstractAimTo assess the relationship between both photoreceptor function and choroidal thickness and endothelin-1 (ET-1) plasma levels in patients with early stage retinitis pigmentosa (RP).Main methodsWe compared 24 RP patients (14 males and 10 females), 25 to 42years of age (mean age: 34±7years) with 24 healthy controls (12 males and 12 females) aged between 28 and 45years (mean 36±6.8years). All patients underwent visual field test, electroretinogram and multifocal-electroretinogram and choroidal thickness measurement by using spectral domain optical coherence tomography.Key findingsRP patients had a visual acuity of 0.95, a mean defect of the visual field of −7.90±1.75dB, a pattern standard deviation index of 6.09±4.22dB and a b-wave ERG amplitude of 45.08±8.24μV. Notably RP subjects showed significantly increased ET-1 plasma levels and reduced choroidal thickness compared with controls: respectively, 2.143±0.258pg/ml vs. 1.219±0.236pg/ml; p<0.002 and 226.75±76.37μm vs. 303.9±39.87μm; p<0.03. Spearman's correlation test highlighted that the increase of ET-1 plasma levels was related with the decrease of choroidal thickness (r=−0.702; p<0.023) and the increase of implicit time in both ring 2 (r=−0.669; p<0.034) and ring 3 (r=−0.883; p<0.007) of mfERG.SignificanceIncreased ET-1 plasma levels may play a key role in the impairment of retinal and choroidal blood flow due to the vasoconstriction induced by ET-1. This could lead to worsening of the abiotrophic process of the macular photoreceptors
ET-1 Plasma Levels, Aqueous Flare, and Choroidal Thickness in Patients with Retinitis Pigmentosa
Full text linkPurpose. To assess endothelin-1 (ET-1) plasma levels, choroidal thickness, and aqueous flare in patients with early stage retinitis pigmentosa (RP) and to search for possible correlations. Methods. We compared 24 RP patients with 24 healthy controls. Choroidal thickness and aqueous flare were measured, respectively, by using a spectral domain optical coherence tomography and a laser flare-cell meter, whereas plasma samples were obtained from each patient to evaluate ET-1 plasma levels. Results. Notably, RP subjects showed significantly increased ET-1 plasma levels and reduced choroidal thickness compared with controls: 2.143±0.258 versus 1.219±0.236 pg/mL, P<0.002, and 226.75±76.37 versus 303.9±39.87 μm, P<0.03, respectively. Higher aqueous flare values were also demonstrated in RP compared to controls: in detail, 10.51±3.97 versus 5.66±1.29 photon counts/ms, P<0.0001. Spearman’s correlation test highlighted that the increase of ET-1 plasma levels was related with the decrease of choroidal thickness (r=-0.702; P<0.023) and the increase of aqueous flare (r=0.580; P<0.007). Conclusions. Early stage RP patients show a breakdown of blood-ocular barrier and increased ET-1 plasma levels and these findings may contribute to the reduction of choroidal thickness
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
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