1,720,974 research outputs found
Manipulation of Ocular Aberrations in Myopes
No full textMyopia is a major cause of vision loss throughout the world. High myopia is associated with severe eye diseases like maculopathy, retinal detachment and glaucoma. The prevalence of myopia is increasing, and varies by country and by ethnic group. In some Asian populations the prevalence is 70%-80%. This thesis includes five experiments. In experiment I we investigated the effects of added positive and negative spherical aberration on accommodative response accuracy. We found that the accommodative response can be altered by modulating the spherical aberration of the eye with soft contact lenses. There was an improvement in the accommodative response slopes and a decrease in the lag of accommodation with the negative spherical aberration lenses compared to positive spherical aberration lenses. In experiment II we investigated whether the negative spherical aberration in contact lenses could be tolerated visually in terms of wearability and comfort. We found that all the subjects were satisfied with the contact lens comfort, distance and near vision and the stability of the vision with the lenses. The accommodative response was stable through out the treatment period. In experiment III we investigated the efficacy of a novel dual treatment for the improvement of accommodative accuracy and dynamics in myopes. The spherical aberration of the eye was effectively altered to negative in the treatment group as predicted. In the control group as expected there was no significant change in the spherical aberration of the eye with and without contact lenses. The treatment lenses decreased the lag of accommodation and increased the accommodative response slope at 3 months. In the experiment IV we investigated the effect of the treatment lenses used in the previous experiment on high and low contrast visual acuities after a one year treatment period. The results showed a significant improvement in both high and low contrast visual acuities after the one year period in the treatment group compared to the control group, even though it was not clinically significant. In experiment V we investigated the intrasession repeatability of peripheral aberrations using COAS-HD VR aberrometer and also reported the distribution of higher order aberrations in a group of young emmetropes. There was no significant difference in the variance of total higher-order RMS between on- and off-axis measurements. There was a significant change in the horizontal coma, spherical aberration and higher-order RMS with off-axis angle along the horizontal visual field. We demonstrated that fast, repeatable and valid peripheral aberration measurements can be obtained with this instrument. This thesis contributes new results in this field of myopia, aberration and accommodation
Manipulation of Ocular Aberrations in Myopes
No full textMyopia is a major cause of vision loss throughout the world. High myopia is associated with severe eye diseases like maculopathy, retinal detachment and glaucoma. The prevalence of myopia is increasing, and varies by country and by ethnic group. In some Asian populations the prevalence is 70%-80%. This thesis includes five experiments. In experiment I we investigated the effects of added positive and negative spherical aberration on accommodative response accuracy. We found that the accommodative response can be altered by modulating the spherical aberration of the eye with soft contact lenses. There was an improvement in the accommodative response slopes and a decrease in the lag of accommodation with the negative spherical aberration lenses compared to positive spherical aberration lenses. In experiment II we investigated whether the negative spherical aberration in contact lenses could be tolerated visually in terms of wearability and comfort. We found that all the subjects were satisfied with the contact lens comfort, distance and near vision and the stability of the vision with the lenses. The accommodative response was stable through out the treatment period. In experiment III we investigated the efficacy of a novel dual treatment for the improvement of accommodative accuracy and dynamics in myopes. The spherical aberration of the eye was effectively altered to negative in the treatment group as predicted. In the control group as expected there was no significant change in the spherical aberration of the eye with and without contact lenses. The treatment lenses decreased the lag of accommodation and increased the accommodative response slope at 3 months. In the experiment IV we investigated the effect of the treatment lenses used in the previous experiment on high and low contrast visual acuities after a one year treatment period. The results showed a significant improvement in both high and low contrast visual acuities after the one year period in the treatment group compared to the control group, even though it was not clinically significant. In experiment V we investigated the intrasession repeatability of peripheral aberrations using COAS-HD VR aberrometer and also reported the distribution of higher order aberrations in a group of young emmetropes. There was no significant difference in the variance of total higher-order RMS between on- and off-axis measurements. There was a significant change in the horizontal coma, spherical aberration and higher-order RMS with off-axis angle along the horizontal visual field. We demonstrated that fast, repeatable and valid peripheral aberration measurements can be obtained with this instrument. This thesis contributes new results in this field of myopia, aberration and accommodation
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
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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