University of Winnipeg

About: University of Winnipeg is a education organization based out in Winnipeg, Manitoba, Canada. It is known for research contribution in the topics: Population & Context (language use). The organization has 3235 authors who have published 6413 publications receiving 150564 citations. The organization is also known as: U of W.

Binocular Training Reduces Amblyopic Visual Acuity Impairment

Abstract: Amblyopia is the most common cause of monocular visual impairment. Patching, which is modestly effective, is the current treatment of amblyopia in children. There is no clinically approved treatment for adults. The present study is a clinical trial (non-sham controlled and non-randomized) that assessed the efficacy of binocular training for improvement of the visual acuity in children and adults with amblyopia. Twenty-two amblyopic subjects ranging in age from 5 to 73 (mean: 36.2) years for whom patching and/or surgical treatments did not correct their visual impairment completed an average of 14.5 sessions of binocular training over a period of 4 to 6 weeks. Random dot kinematograms were presented dichoptically to the two eyes and the participants' task was to identify the direction of motion of the targets. Mean visual acuity improvement was 0.34 LogMAR (range: 0.1-0.58 LogMAR) and was shown to persist 6 months following the cessation of binocular training. Our study provides results in a large number of patients that confirm the clinical effectiveness of binocular training as a treatment for amblyopia in improving visual acuity in both children and adults. Moreover, this study is the first to demonstrate that the improvements in visual function were maintained for 6 months in the absence of any additional treatment.

Size reduction of a microstrip antenna with dielectric superstrate using meta-materials: artificial magnetic conductors versus magneto-dielectrics

Abstract: Planar antenna gain can be enhanced using a high-permittivity cover as the superstrate (D.R. Jackson and N.G. Alexopolous, 1985). As well, partially reflecting sheets (PRSs) have been used as the superstrate layer for gain enhancement (T. Zhao et al., 2005). In addition, artificial magnetic conductors (AMCs) as the ground plane have been able to reduce the microstrip antenna size with a PRS cover (A. Fresidis et al., 2005). On the other hand, a class of novel materials called magneto-dielectrics has recently been introduced which can simulate both high permittivity and permeability, while being low-loss (H. Mosallaei and K. Sarabandi, 2004) (A. Buerkle and K. Sarabandi, 2005). Thus, these novel materials hold promise in antenna miniaturization (H. Mosallaei and K. Sarabandi, 2004) (A. Buerkle and K. Sarabandi, 2005). In this paper, initially a conventional microstrip antenna with the high-permittivity dielectric superstrate is designed. Then, using a periodic structure of metallic patches, acting as an AMC, the antenna size is reduced. Furthermore, another size reduction method for this class of high-gain antennas is proposed using magneto-dielectrics. The results are presented and discussed.