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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
371

Image Classification using Pair-wise Registration and Machine Learning with Applications to Neuroimaging

Long, Xiaojing 10 December 2010 (has links)
Alzheimer's disease~(AD) is the most frequent neurodegenerative dementia and a growing health problem. Early and accurate diagnosis and prediction of AD is crucial because treatment may be most efficacious if introduced as early as possible. Neuropsychological testing, which is clinically used, sometimes fails to recognize probable dementia, especially to recognize the disease at an early time point such as the mild cognitive impairment~(MCI), which is the prodromal stage of AD. Recently, there has been a realization that magnetic resonance imaging~(MRI) may help diagnoses of AD and MCI. In this dissertation, we introduce an MRI-analysis based algorithm to help diagnose the illness before irreversible neuronal loss has set in, and to help detect brain changes between MCI patients who may convert and may not convert to AD. Given a set of brain MR images, the algorithm first calculates the distance between each pair of images via a registration process. Then images are projected from a high dimensional Euclidean space to a low dimensional Euclidean subspace based on the calculated distances, with a dimension reduction method. Finally classical supervised classification approaches are employed to assign images to appropriate groups in the low dimensional space. The classification accuracy rates we obtained in our experiments are higher than, or at least comparable to, those reported in recently published papers. Moreover, this algorithm can be extended to explore the pathology distribution of AD. Exploring the distribution of AD pathology is of great importance to reveal AD related regional atrophy at specific stages of the disease and provide insight into longitudinal sequence of disease progression. Calculating distances between different brain structures produces different classification accuracy. Those structures yielding higher classification accuracy are considered as pathological regions. Our experimental results on pathology localization are also compared with the reproduced results using other existing popular algorithms; the observations are consistent. / Ph. D.
372

School for Children who are Blind

Alan, Ilker 28 September 2017 (has links)
Architecturally, my thesis project is a new type of design for children who have visual impairments. Most of the children who have visual impairments need more attention to receive a full education. With a proper education they will be able to start living by themselves without any assistance. I decided to design a school which would support the needs of the children and the aspirations of their parents; a place of safety and ambition that would free instructors and inspire the children. Then, I began to seek an architectural site program where I could locate my design. Old town Alexandria is an excellent location for the planned education center. Old town has its own urban context with boundaries like  the Potomac River,  trees, old railroad ways,  a  tunnel,  and other landmarks  like churches,  libraries, museums,  etc.  The children  in  the education  center  have  an  opportunity  to  learn  more  and  show  their  life  skills  easily  in  the  old town.  Also the site selection and location was important due to the history of the town, easy transportation and connections with surroundings, being right next to the Potomac River and minutes away from the Washington DC. / Master of Architecture
373

Quality of experience: a discussion on experiential access to outdoor environments

Douglass, D. Kim 24 January 2009 (has links)
This study explores experiential access to outdoor environments. This qualitative thesis presents the results of open-ended interviews with four people who have severe visual impairment. The interviews gathered information about the participants leisure activities in outdoor settings. The purpose of the study was to discover the factors in the environment that contribute to a positive recreation experience for people with visual impairment. Experiential qualities of the environment for both people who are sighted and those who are blind were compared through the analysis of eight contemporary authors' writings related to environmental understanding and the transcripts of the four interviews. The overlap of experience in outdoor environments between these two user groups was explored. Two areas of significant influence on the participants' experience was discovered; (a) wayfinding and making sense, and (b) affective response. The specific factors in the environment that influenced the quality of experience for these participants, other than those that contribute to making sense, were found to include: (a) interaction with nature, (b) awareness of enclosure & openness of the setting, (c) intellectual and physical stimulation and challenge, and (d) direct physical interaction with the surrounding environment. This study provides some of the specific benefits and advantages of incorporation of multi-sensory stimulation in design for people of all abilities. / Master of Landscape Architecture
374

Autobiographical memory in Parkinson's disease: A retrieval deficit

Smith, Sarah J., Souchay, C. January 2013 (has links)
Yes / This study examined the effects of providing cues to facilitate autobiographical memory retrieval in Parkinson's disease. Previous findings have shown that individuals with Parkinson's disease retrieve fewer specific autobiographical memories than older adult controls. These findings are clinically significant since the quality of autobiographical memory is linked to identity and sense of self. In the current study, 16 older adults with Parkinson's disease without dementia and 16 matched older adult controls were given 3 min in which to recall autobiographical memories associated with five different time periods and to give each memory a short title. Participants were later asked to retrieve the memories in three phases: firstly in a free recall phase; secondly in response to general cues (time periods) and finally in response to specific cues (the short titles previously given). The number of memories and the quality of the memory (general or specific) was recorded in each condition. Compared with matched older adult controls, the Parkinson's disease group was impaired in retrieving the memories that they had previously given in the free recall phase and in response to general cues. The performance of the group with Parkinson's disease was only equivalent to the older adults when they retrieved memories in response to self-generated cues. The findings are discussed in relation to theories of autobiographical memory and the neuropsychology of Parkinson's disease.
375

Postural Stability Changes in the Elderly with Cataract Simulation and Refractive Blur

Anand, Vijay, Buckley, John, Scally, Andy J., Elliott, David B. January 2003 (has links)
PURPOSE. To determine the influence of cataractous and refractive blur on postural stability and limb-load asymmetry (LLA) and to establish how postural stability changes with the spatial frequency and contrast of the visual stimulus. METHODS. Thirteen elderly subjects (mean age, 70.76 ± 4.14 [SD] years) with no history of falls and normal vision were recruited. Postural stability was determined as the root mean square [RMS] of the center of pressure (COP) signal in the anterior¿posterior (A-P) and medial¿lateral directions and LLA was determined as the ratio of the average body weight placed on the more-loaded limb to the less-loaded limb, recorded during a 30-second period. Data were collected under normal standing conditions and with somatosensory system input disrupted. Measurements were repeated with four visual targets with high (8 cyc/deg) or low (2 cyc/deg) spatial frequency and high (Weber contrast, ¿95%) or low (Weber contrast, ¿25%) contrast. Postural stability was measured under conditions of binocular refractive blur of 0, 1, 2, 4, and 8 D and with cataract simulation. The data were analyzed in a population-averaged linear model. RESULTS. The cataract simulation caused significant increases in postural instability equivalent to that caused by 8-D blur conditions, and its effect was greater when the input from the somatosensory system was disrupted. High spatial frequency targets increased postural instability. Refractive blur, cataract simulation, or eye closure had no effect on LLA. CONCLUSIONS. Findings indicate that cataractous and refractive blur increase postural instability, and show why the elderly, many of whom have poor vision along with musculoskeletal and central nervous system degeneration, are at greater risk of falling. Findings also highlight that changes in contrast sensitivity rather than resolution changes are responsible for increasing postural instability. Providing low spatial frequency information in certain environments may be useful in maintaining postural stability. Correcting visual impairment caused by uncorrected refractive error and cataracts could be a useful intervention strategy to help prevent falls and fall-related injuries in the elderly.
376

Provision of outdoor nature-based activity for older people with cognitive impairment: A scoping review from the ENLIVEN project

Collins, R., Owen, S., Opdebeeck, C., Ledingham, K., Connell, J., Quinn, Catherine, Page, S., Davies Abbott, I. & Jones, A.,, Clare, L. 31 August 2023 (has links)
Yes / The health and well-being benefits of outdoor nature-based activity are increasingly recognised, but older people with cognitive impairment face significant barriers to access. The ENLIVEN project aims to promote access by gathering evidence and coproducing guidance for activity providers. As part of this project, we conducted a scoping review to characterise the types of outdoor nature-based activity for older people with dementia and other forms of cognitive impairment for which research evidence is available and the range of outcomes is examined. The protocol is available online. We systematically searched relevant databases from 1st January, 2009, to 20th October, 2022, and screened articles against the following criteria: participants were older people aged 65 and above with cognitive impairment arising from dementia or another health condition. The study described the formal provision of outdoor nature-based activity away from the person’s usual place of residence, and at least one outcome of participation in the activity was evaluated. Twenty-eight articles met inclusion criteria, all focused on people with dementia. In most cases, participants were attending day care or living in residential care, and sample sizes ranged from 4 to 136. Activities fell into three groups: green day care (fifteen articles), equine-assisted interventions (seven articles), and community nature-based activities (six articles). Outcome domains explored were connection with nature, activity engagement, impacts on clinical symptoms, functional ability, physical, psychological and social health,, and quality of life. Outdoor nature-based activity can be offered as an opportunity for meaningful occupation to enrich daily life, as a framework for day care provision, or as an intervention to address clinical needs. The evidence base for green day care is relatively established, but the potential for addressing specific clinical needs remains to be explored. The paucity of evidence regarding community provision, especially for those not attending formal care settings, suggests the need for effective knowledge exchange to stimulate initiatives in this area. / UK Research and Innovation (UKRI) Healthy Ageing Challenge and UKRI/Economic and Social Research Council (ESRC) through Grant ES/V016172/1.
377

Resilience among Older Adults with Cognitive Impairment and Informal Caregivers

Kim, Sujee 07 June 2017 (has links)
The concept of resilience, which indicates people's capability of using resources in difficult circumstances in order to reduce or prevent negative effects and achieve positive outcomes, has given a new perspective to the scientific literature on the experience of late-life memory loss and the experience of caring for persons with memory loss. The current research was guided by incorporation of resilience into the stress process model for assessing personal and caregiver burden associated with mild and more severe memory loss. I conducted two studies to investigate the association of protective factors with the well-being of people with dementia or mild cognitive impairment and their caregivers. The first study focused on the well-being of older persons with dementia (PwDs). I employed data from a large national sample of older adults to examine how the perceived social cohesion of neighborhoods affects quality of life among people with and without cognitive impairment in conjunction with their engagement in valued leisure activities. Findings revealed that, regardless of cognitive health status, all participants who perceived high neighborhood social cohesion reported better quality of life along with more participation in valued activities. However, PwDs reported significantly lower perceived neighborhood social cohesion, less involvement in valued activities, and poorer quality of life than persons without cognitive impairment. The second study focused on the well-being of caregivers for older persons with mild cognitive impairment (PwMCIs). I used dyadic data from families dealing with mild cognitive impairment to examine how well-being of caregivers for PwMCIs differed according to whether PwMCI-caregiver dyads had similar or different perceptions of the PwMCIs' cognitive impairment severity. Caregivers reported lower caregiving burden when they and PwMCIs had a similar cognitive impairment representation, or when caregivers rated the PwMCIs’ cognitive functioning more positively than the PwMCIs rated themselves. Also, PwMCIs’ and caregivers' perceptions, and their concordance or discrepancy in those perceptions, varied across the multiple domains related to MCI symptoms. These findings demonstrate that care dyads' perception of MCI-related deficits is not a unitary construct, and that the context of PwMCIs’ and caregivers’ dyadic illness appraisals is significantly associated with the caregivers' well-being. Taken together, the results of these two studies illustrate the value of considering resilience processes in people with cognitive impairment and their caregivers. Examining dimensions of resilience, in association with assessment of the intersecting effects of personal, interpersonal, and environmental factors, provides additional information about the effects of cognitive impairment on older adults’ well-being and the effects of assisting someone with cognitive impairment on caregiver well-being. / Ph. D.
378

Impairment effects as a career boundary: a case study of disabled academics

Williams, Jannine, Mavin, Sharon A. 2013 June 1924 (has links)
No / Within the academic career literature, disabled academics are under-researched, despite calls for career theory development through the exploration of marginalized groups' career experiences and the boundaries which shape these experiences. Here, boundaries refer to the symbolic resources which become reified to construct social boundaries shaping what is and is not possible in career contexts. This article contributes to the advancement of academic career theory by enabling insights into impairment effects as an embodied career boundary for disabled academics and outlining how experiences of impairment effects and disabled academics' agency are entangled with their career context and organizational members' responses. Impairment effects shape career choices and opportunities, by being negated, and/or influencing expectations of employers to provide inclusive contexts which acknowledge impairment effects as a legitimate organizing principle. However this recognition of impairment as a legitimate organizing principle is not always reciprocated, with implications for disabled academics' careers.
379

Association between polygenic risk score and risk of myopia

Ghorbani Mojarrad, Neema, Plotnikov, D., Williams, C., Guggenheim, J.A. 08 November 2019 (has links)
Yes / Importance: Myopia is a leading cause of untreatable visual impairment and is increasing in prevalence worldwide. Interventions for slowing childhood myopia progression have shown success in randomized clinical trials; hence, there is a need to identify which children would benefit most from treatment intervention. Objectives: To examine whether genetic information alone can identify children at risk of myopia development and whether including a child’s genetic predisposition to educational attainment is associated with improved genetic prediction of the risk of myopia. Design, Setting, and Participants: Meta-analysis of 3 genome-wide association studies (GWAS) including a total of 711 984 individuals. These were a published GWAS for educational attainment and 2 GWAS for refractive error in the UK Biobank, which is a multisite cohort study that recruited participants between January 2006 and October 2010. A polygenic risk score was applied in a population-based validation sample examined between September 1998 and September 2000 (Avon Longitudinal Study of Parents and Children [ALSPAC] mothers). Data analysis was performed from February 2018 to May 2019. Main Outcomes and Measures: The primary outcome was the area under the receiver operating characteristic curve (AUROC) in analyses for predicting myopia, using noncycloplegic autorefraction measurements for myopia severity levels of less than or equal to −0.75 diopter (D) (any), less than or equal to -3.00 D (moderate), or less than or equal to −5.00 D (high). The predictor variable was a polygenic risk score (PRS) derived from genome-wide association study data for refractive error (n = 95 619), age of onset of spectacle wear (n = 287 448), and educational attainment (n = 328 917). Results: A total of 383 067 adults aged 40 to 69 years from the UK Biobank were included in the new GWAS analyses. The PRS was evaluated in 1516 adults aged 24 to 51 years from the ALSPAC mothers cohort. The PRS had an AUROC of 0.67 (95% CI, 0.65-0.70) for myopia, 0.75 (95% CI, 0.70-0.79) for moderate myopia, and 0.73 (95% CI, 0.66-0.80) for high myopia. Inclusion in the PRS of information associated with genetic predisposition to educational attainment marginally improved the AUROC for myopia (AUROC, 0.674 vs 0.668; P = .02), but not those for moderate and high myopia. Individuals with a PRS in the top 10% were at 6.1-fold higher risk (95% CI, 3.4–10.9) of high myopia. Conclusions and Relevance: A personalized medicine approach may be feasible for detecting very young children at risk of myopia. However, accuracy must improve further to merit uptake in clinical practice; currently, cycloplegic autorefraction remains a better indicator of myopia risk (AUROC, 0.87). / PhD studentship grant from the College of Optometrists (Drs Guggenheim and Williams; supporting Mr Mojarrad) entitled Genetic prediction of individuals at-risk for myopia development) and National Institute for Health Research (NIHR) Senior Research Fellowship award SRF-2015-08-005 (Dr Williams). The UK Medical Research Council and Wellcome grant 102215/2/13/2 and the University of Bristol provide core support for the Avon Longitudinal Study of Parents and Children (ALSPAC). A comprehensive list of grants funding is available on the ALSPAC website (http://www.bristol.ac.uk/alspac/external/documents/grant-acknowledgements.pdf). This research was conducted using the UK Biobank Resource (application 17351). The UK Biobank was established by the Wellcome Trust, the UK Medical Research Council, the Department for Health (London, England), the Scottish government (Edinburgh, Scotland), and the Northwest Regional Development Agency (Warrington, England). It also received funding from the Welsh Assembly Government (Cardiff, Wales), the British Heart Foundation, and Diabetes UK.
380

Eyewear for rugby union: wearer characteristics and experience with rugby goggles

Little, J-A., Eckert, F., Douglas, M., Barrett, Brendan T. 27 January 2020 (has links)
Yes / Unlike many other sports, Rugby Union has not permitted players to wear spectacles or eye protection. With an industrial partner, World Rugby developed goggles suitable for use while playing rugby for the purposes of growing participation amongst those that need to wear corrective lenses. This study reports on the profile and experiences of goggle wearers. 387 players received the goggles. Data were obtained from 188 (49 %) using an online, 75-item questionnaire. 87 % “strongly agreed/agreed” that goggles are beneficial and 75 % are happy with goggle performance. Common problems reported by 49.7 and 32.6 % of respondents were issues with fogging-up and getting dirty. 15 (8 %) players stopped wearing the goggles because of fogging-up, limits to peripheral vision and poor comfort/fit. Injuries were reported in 3 % of respondents. In none of these cases did the player stop wearing the goggles. From the positive experience of players in the trial, the goggles were adopted into the Laws of the game on July 1, 2019. As the need to correct vision with spectacles is common, and contact lenses are not worn by 80 % + of spectacle wearers, the new Rugby goggles will widen participation for those that need to wear refractive correction, or have an existing/increased risk of uniocular visual impairment.

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