The purpose was to examine the ball catching strategies of 15 children with developmental coordination disorder (DCD) compared to 15 of their peers without DCD, and 15 younger children matched on ball skills. A ball catching activity (catching 10 consecutive balls in five different positions) and the developmental sequences proposed by Haywood and Getchell (2005) were used to evaluate movement patterns. Children with DCD caught significantly fewer balls than their peers at the chest and above the head. Children with DCD demonstrated delayed arm action catching on the right and delayed body actions when balls were projected away from body compared to their peers. In addition, development of some body actions of children with DCD was different compared to younger children. Results suggested that children with DCD have not developed accurate and consistent movement patterns.

The present study tested the hypothesis that distractor-based facilitation of visual search occurs because familiar distractors are processed and rejected in groups. We recorded participants’ eye movements during a visual search task to determine if familiar distractors were associated with an increased average distance between fixations and distractors. The study provided convergent evidence of a strong relation between search efficiency and distractor familiarity, wherein the distance between fixations and distractors increases with the efficiency of search. Further examination of eye movements suggested that the grouping of familiar distractors resulted in an efficient scanning of the search display by increasing the area of the display effectively processed during each fixation and therefore reducing the need to fixate individual distractors.

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Coordinated gaze and hand movements predominate a number of our interactions in reachable space and yet few studies examine the potential contribution of tactile feedback in planning these actions. This thesis was designed to investigate eye and hand coordination during movement sequences when reaching out to interact with objects. We developed a virtual reality paradigm that allowed us to control visual, tactile, and in some cases, auditory feedback provided to participants. Participants reached and touched five objects in succession. We measured behaviour that resulted from removing one or more of the aforementioned sources of feedback – focusing on task accuracy, and the timing and dynamics of eye and hand movements. Our principle manipulations were to remove visual feedback of the hand, and/or to change the object response to contact. We also unexpectedly removed tactile feedback signaling contact. In Experiment 1, we examined gaze and hand movement timing relative to contact events. Gaze remained long enough to capture contact in central vision, but also followed a time course indicating that contact timing was predicted. In Experiment 2 we examined the influence of dynamic object consequences (i.e., motion). Gaze remained to monitor consequences that follow initial contact especially when the hand was invisible; with longer delays it became difficult to differentiate between predictive or reactive movements. In Experiment 3 we directly tested whether gaze would hold upon a site of action during prolonged manipulation. Here, gaze remained past contact time and instead its departure was associated with the completion of action. Our findings are congruent with the notion that visually guided reaches are controlled to facilitate directing the hand to viewed locations of action – without visual feedback of the hand accuracy diminished and hand approach changed across all experiments. However, we provide consistent evidence that gaze is also controlled to capture planned sensory consequences related to action at its viewed location. Monitoring these sites would facilitate comparing predicted sensory events with those that are actively measured and improve control throughout the movement sequence. Such a process also indicates the importance of considering tactile feedback when examining coordinated eye and hand movements. / Thesis (Ph.D, Neuroscience Studies) -- Queen's University, 2009-11-13 16:12:30.086

Background: The 22q11.2 deletion syndrome (22q11.2 DS) causes a wide variety of symptoms, but the central nervous system (CNS) dysfunction is the one most likely to affect the day-to-day life of those affected by this genetic disorder. In addition to affecting the educational needs of children with 22q11.2 DS, the neurological deficits in childhood and adolescence could be related to future psychosis and schizophrenia, which can affect 30% of these patients. Thus, the development of screening tools for CNS dysfunction could help identify children who are most at risk for developing later psychosis, allowing them to receive additional care. As saccadic eye movement behaviours reflect the integrity of multiple brain structures, a battery of oculomotor tasks could help identify neurological deficits. This study sought to test the hypothesis that children with 22q11.2 DS would have deficits in oculomotor performance compared to typically developing children. Methods: A cohort of 16 children with 22q11.2 DS, and 32 age- and sex-matched controls completed prosaccade, antisaccade, delayed memory-guided sequential (DMS) and predictive eye movement tasks. Results: Compared to controls, children with 22q11.2 DS exhibited increased direction errors in the antisaccade task, increased timing errors in the DMS task, as well as decreased predictive and increased regular saccades in the predictive task. The group of children with 22q11.2 DS also exhibited an increase in saccade amplitude in the prosaccade, antisaccade and predictive tasks, increased error in saccade trajectory in the prosaccade, antisaccade and DMS tasks and decreased saccade velocity in the predictive saccade tasks. Conclusion: This study showed that performance in the eye movement tasks could be used to assess injury to the frontostriatal circuitry and cerebellum in children with 22q11.2 DS. / Thesis (Master, Neuroscience Studies) -- Queen's University, 2011-04-29 15:16:39.848

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No description available.

This study explores the philosophical, linguistic and textual interplay of absence and presence in Margaret Atwood's novel Cat's Eye. The premise of the thesis is that the novel posits language as a problematic communicative medium; as such, language conveys that meanings of words are flexible, mutable and transient. It is through frameworks which both establish states of absence and presence as well as destroy binary oppositions between the two that Cat's Eye conveys its positions about language. Thus, textual and extra-textual discourses about the natures of language and linguistic meaning are situated within recurrent thematic and formal attention to relationships between absence and presence. By exploring the roles of absence and presence in various phenomenological and linguistic contexts, this study concludes that absence/presence is a paradigm in Cat's Eye for the way in which words are (alternately as well as simultaneously) spoken and silent, understood and misunderstood, opposed and united.

Age, sex, race, heredity, environment and nutrition have been found to influence ametropia. In this study, the distribution of refractive errors has been investigated in relation to age, sex, race, education and near work, and lighting conditions. Visual awareness and vision screening in pre-school and schoolchildren were also investigated. Data were collected using the Nikon auto-refractor, retinoscope, Snellen V.A chart, and subjective techniques. 777 people were refracted, whose ages ranged between four and eighty years. Measurements were made in different sections of Umlazi township, therefore people of different socio-economic sectors were refracted. Four year-old children were found to be hyperopic. Hyperopia decreased and refraction shifted towards emmetropia. Myopia started to appear at the age of ten. Myopia increased until the age of twenty, and thereafter decreased slowly until the age of thirty three, where the average refraction was emmetropia. From age forty onwards, hyperopia was predominant. The incidence of high astigmatism, high hyperopia and high myopia is low in this community. Most people fall in the spherical refractive error region of between -1.000 and +1.000. The curve is leptokurtotic with highest peak around +0.250. The cylindrical error is between -0.500 and -1.000. No significant difference between sexes was found except at the fourth age group (40-51), where females are more hyperopic than males. The other sex difference is at ages ten to twelve, where females develop myopia earlier than males. Illumination plays no important role in the development of refractive errors in this community. Education and near work seem to account very little to the development of myopia. The influence of heredity on the development of ametropia was not investigated in depth. However, there is no evidence of heredity influencing the development of ametropia. There is a lack of vision screening and visual awareness. / Thesis (M.Optom.)-University of Durban-Westville, 1988.

The work of this thesis is motivated by the bene t of real-time HDR image processing which helps constructing better seeing aid devices for day-to-day uses. The seeing aids with HDR can achieve dynamic range greater than human eyes to capture visuals under various light conditions. Further, it helps range sensing devices to read the light codes better. This requires realtime HDR image processing running at 24 FPS. In this thesis, we demonstrate implementation of several HDR image compositing and tone mapping methods in CUDA to achieve realtime performance. In addition, a new tone mapping method termed PPEM is introduced as a novel tone mapping method by adjusting per pixel exposure. Finally, we apply relevant HDR methods to range sensing devices for robust reading.