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Le sommeil s’avère crucial pour le bien-être de l’organisme. En particulier, le sommeil est une période privilégiée pour le maintien et la plasticité du cortex. En outre, de nombreuses études ont démontré son importance dans les processus de mise à l’échelle des synapses neuronales, la consolidation mnésique, la régularisation des émotions ainsi que la performance cognitive. La période et la structure du sommeil sont gouvernées par deux processus, soit la pression homéostatique et le rythme circadien. Le rythme circadien endogène, généré par le noyau suprachiasmatique de l’hypothalamus, se maintient synchronisé au rythme jour-nuit environnemental par l’information photique provenant des cellules ganglionnaires intrinsèquement photoréceptrices de la rétine. Par conséquent, la lumière et le fonctionnement de la rétine s’avèrent importants pour le maintien du rythme circadien et, en conséquence, le sommeil. De ce fait, il n’est pas surprenant que la cécité soit reliée à une plus grande fréquence de troubles du sommeil. Ceux-ci proviennent, du moins en partie, de rythmes circadiens non-synchronisés ou en libre cours causé par l’absence d’information photique. La cécité induit aussi une modulation anatomique et fonctionnelle du cortex, en particulier dans les aires visuelles. Cette réorganisation corticale peut, donc, aussi moduler l’activité corticale lors de l’état de sommeil. Les études, qui font l’objet de cette présente thèse, visent à investiguer les effets de la cécité sur la période et la structure du sommeil. En particulier, des données comportementales et physiologiques furent comparées entre un groupe de participants avec cécité, ne reportant aucune perception visuelle résiduelle, et un groupe contrôle de participants ayant une vision normale. La cécité était d’origine congénitale chez la moitié des participants et elle fut acquise plus tard dans la vie chez les autres participants aveugles. Les présentes études rapportent sur la qualité de leur sommeil, le rythme éveil-sommeil, la phase du rythme circadien, ainsi que la macro- et microstructure de leur sommeil. En lien avec les études antérieures, les aveugles démontrent une plus grande fréquence de phases anormales du rythme circadien, de troubles du sommeil et de déstabilisation du rythme éveil-sommeil. De plus, bien que la structure du sommeil demeure généralement présente en absence de vision, certaines modulations électrophysiologiques furent observées. En particulier, des différences dans l’activité corticale lors du sommeil NREM observées entre les aveugles congénitaux et les aveugles tardifs suggèrent que la réorganisation corticale, provenant de la perte de vision, peut être observée lors du sommeil. De plus, la modulation des aires corticales visuelles associée avec la cécité résulte en une absence de certaines composantes caractéristiques des différents stades du sommeil. Notamment, l’oscillation occipitale de fréquence alpha observée lors d’un état de repos et lors de l’endormissement se voit absente chez les aveugles. Les résultats démontrent que la modulation du rythme circadien ainsi que la réorganisation corticale associée avec la cécité agissent sur la période et la structure caractéristique du sommeil. / Sleep is a crucial state for the wellbeing of humans. More specifically, sleep is a privileged period for cortical maintenance and plasticity. Accordingly, numerous studies have demonstrated the importance of sleep in synaptic downscaling processes, memory consolidation, emotional regulation, as well as cognitive performance. The timing and structure of sleep is shown to be governed by two main processes: the homeostatic pressure and the circadian rhythm. In turn, the endogenous circadian rhythm, produced by the suprachiasmatic nucleus of the hypothalamus, is entrained to the day-night environmental cycle by photic input from the intrinsically photoreceptive retinal ganglion cells. Thus, light is necessary for the proper entrainment of the circadian rhythm, and consequently, for sleep. It is, therefore, not surprising that blindness is associated with a greater incidence of sleep disturbances. Specifically, these disturbances can be, in part, explained by abnormal or free-running circadian rhythms resulting from the absence of photic input. Further, absence of visual input also induces anatomical and functional changes throughout the brain, and specifically in the visual cortical areas. Such cortical reorganisation could, potentially, also modulate the cortical activity of sleep. The studies that compose the present thesis aim to expand upon the effects of blindness on the timing and structure of sleep. Specifically, both behavioural and physiological data were collected and compared between a group of blind participants, reporting no conscious light perception, and a control group of normal sighted participants. In the blind group, half of the participants were born blind, while the other half had acquired blindness later in life. The studies report on the various components of sleep, including its quality, the sleep-wake rhythm, the phase of the circadian rhythm, as well as its macro- and microstructure. In line with previous studies, a larger incidence of abnormal circadian phase, sleep disturbances, and reduced sleepiv wake stability were observed in the blind group. Further, although the macro- and microstructure of sleep remains generally present in the absence of vision, certain electrophysiological differences were, nevertheless, observed. Differences in NREM cortical activity observed between the congenitally and late blind participants suggest that the cortical reorganisation associated with the absence of vision may be detected through electrophysiological recordings of sleep. Further, modulations of cortical activity in blindness also resulted in the absence of certain characteristics of the different stages of sleep. Namely, occipital alpha oscillations, typically observed during a quiet resting state and in the transition from wake to sleep, are absent in blind individuals. These results, therefore, demonstrate that both the circadian rhythm abnormalities and the cortical reorganisation that is associated with the absence of vision can influence both the timing and the structure of sleep in blind individuals.

One of the biggest issues facing VR as a platform is the limitation of the user’s physical space. Not everyone has a lab, empty warehouse, or open space in their home or office, and even if they do, the hardware also limits the physical space the user can take advantage of. Fitting the entirety of the environment within few square meters is a strict limitation for many applications. A method of moving the user within a larger space is needed, but current methods come with drawbacks. Developing a new movement method that avoids these drawbacks will help ensure a better experience for the user.

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This design-based research provides design considerations for developing educational tools for teaching programming to blind primary schoolers, as an effort towards more inclusive classrooms, given that the tools available today are not accessible to these students. Existing tools were analyzed and tested, and co-design practices were applied in exploring ‘instructions’ as a main logic operation for computer programming, through experimenting with diverse types of interfaces, having visually impaired participants at the center of the process. Physical and mental patterns, relevant for improving the accessibility of such tools, are unveiled and further discussed in this study.

The licentiate thesis examines what spending time in a forest garden can offer children when this environment is used for teaching aimed at sustainability. What do the children remember from their visits to the forest garden? What do they find special or memorable? What can the children learn there? To answer such questions, walk-and-talk conversations were conducted with children who for a three-year period had regularly visited a forest garden during school hours. The overall purpose of the licentiate thesis is to deepen knowledge about what spending time in a forest garden in a school context can offer children, reflected from the children's perspectives. Furthermore, the thesis aims to deepen knowledge about walk-and-talk conversations as a data collection method when children are respondents. This leads to the research questions: 1. In what ways can walk-and-talk conversations as a data collection method reflect children's perspectives in an environment and in relation to places? What are the possibilities and limitations of the method? 2. What significance do forest garden visits in a pedagogical context aimed at learning for sustainability have from the children's perspective? The theoretical starting points of the licentiate thesis draw on social studies of childhood, ecological literacy and affordances. Another concept that emerged in the analysis process was plant blindness. Data consisted of audio-recorded walk-and-talk conversations, children's photographs and recorded informal, supplementary interviews. A total of 28 children (11 boys and 17 girls) participated in sub-studies II and III. The children were aged 7-9 years, but most were 9 years old. The licentiate thesis consists of three sub-studies: Sub-study I is a literature review that focuses on opportunities, limitations, and challenges in using walk-and-talk conversations as a data collection method with children and young people. Walk-and-talk conversations can increase opportunities to capture children's perspectives and help to reduce power imbalances between children and researchers. However, analysing data from child-led walks and conversations can be challenging, while awareness of the researcher's own position and assumptions becomes particularly important. Sub-study II deals with the forest garden from children’s perspective. The first category, ‘to appreciate the place the forest garden’, contained the following themes: physical work, relationships with animals and plants, aesthetic and edible aspects and food, and friends. Most of the children enjoyed staying in the forest garden with its natural features. They valued the care of living organisms and felt that spending time in the forest garden was fun and exciting. In the second category, ‘aspects of learning in the forest garden’, the following themes emerged; practical skills, coexistence and caring, and biological knowledge and ecological understanding. Sub-study III deals with the four most photographed phenomena in the forest garden. The first were the plants, including trees and shrubs, which provided sensual, aesthetic and emotional affordances. The second was the pond, which provided physical affordances and wishes, while the third, the barbecue area, provided social affordances. Finally, the tipi provided affordances for privacy and imagination. To conclude: children's forest garden visits, with learning and nature encounters, can contribute to sustainable development. The investigated forest garden was an outdoor environment designed for children with natural features and with a focus on organic farming, where the forest garden educators helped to create a framework for both learning and relational opportunities. Developing ecological literacy in the new generation is a crucial concern, and the results of the licentiate thesis suggest that establishing educational outdoor environments where children receive parts of their education can contribute to the development of such literacy. The creation of outdoor environments for children is thus an important sustainability issue. / Licentiatuppsatsen undersöker vad skogträdgårdsvistelser kan erbjuda barn när en sådan miljö används för undervisning riktad mot hållbarhet. Det övergripande syfte är att fördjupa kunskap om vad skogsträdgårdsvistelser i en skolkontext kan tillföra barn, speglat utifrån barnens perspektiv. Vidare syftar uppsatsen till att fördjupa kunskaper om samtalspromenader som datainsamlingsmetod när barn är respondenter. Licentiatuppsatsens teoretiska utgångspunkter tar avstamp i barndomssociologi (Social Studies of Childhood), ekologisk litteracitet och affordances. Ett annat begrepp som framkom efter analysprocessen var växtblindhet. Den undersökta skogsträdgården, var en natur- och utomhusmiljö med inriktning mot ekologisk odling designad för barn, där skogsträdgårdspedagogernas pedagogiska inramning bidrog till att skapa både pedagogiska och relationella möjligheter. Metodvalet har varit ljudupptagna samtalspromenader, barns fotografier samt inspelade informella, kompletterande intervjuer. Sammanfattningsvis visar resultaten att barns skogsträdgårdsvistelser, lärande och naturmöten bidra till hållbar utveckling. Utvecklandet av ekologisk litteracitet hos den uppväxande generationen måste betraktas som central, och licentiatuppsatsens resultat pekar mot att anläggandet av pedagogiska utomhusmiljöer där barn får delar av sin undervisning kan bidra till utvecklandet av sådan litteracitet. Tillskapandet av utomhusmiljöer för barn är därför en viktig hållbarhetsfråga.

D. Litt et Phil. (Literature and Philosophy) / Eye health promotion is an important aspect of VISION 2020 campaign that aims to eliminate unwarranted cases of avoidable blindness worldwide by the year 2020. Most developing countries, including South Africa, have a serious burden of eye diseases and unwarranted causes of visual impairment and blindness. The purpose of this research therefore was to highlight the lack of an integrated eye health promotion policy in the South African primary health care system which can play a major role in the elimination of this burden of disease and also to make proposals for eye health promotion policy development in South Africa. A combination of quantitative and qualitative research methods was used in this study. Questionnaires and interviews were conducted with all national and provincial health managers of portfolios relevant to eye care. Also, various health policy documents were requested from the National and Provincial Department of Health to ascertain claims of any existing guidelines on eye care. The policy documents and guidelines obtained had no specific reference to eye health promotion. Only 11 (23%) of the managers of provincial health directorates reported that they have integrated vision screening in their health promotion programmes as part of eye health promotion strategies. Eye care managers in the provinces reported that school visits accounted for 75% of eye health promotion programmes target areas. Also, apart from the Northern Cape Province which has no eye care manager and consequently no eye health promotion programmes, the Western Cape Province also does not have eye health promotion programmes and relies mostly on private sector for eye care services. The lack of an integrated eye health promotion policy and most probably the lack of a dedicated directorate that deals with eye health promotion issues may be a contributing factor to the overwhelming lack of integrated eye health promotion activities in South Africa. It is therefore recommended that an integrated eye health promotion model be developed and be part of the South African primary health care system. / Health Studies

One strategy to restore vision in retinitis pigmentosa and related retinal degenerations is by cell replacement. Typically, patients lose vision when the outer retinal photoreceptor layer is lost, and so the therapeutic ideal would be to restore vision at this stage of disease. It is not currently known if a degenerate retina lacking the outer nuclear layer of photoreceptor cells would allow the survival, maturation and reconnection of replacement photoreceptors, as prior studies used hosts with a pre-existing outer nuclear layer at the time of treatment. Here, using a murine model of severe human retinitis pigmentosa at a stage when no host rod cells remain, transplanted rod precursors are shown to reform an anatomically distinct and appropriately polarised outer nuclear layer. A trilaminar nuclear organisation is returned to the rd1 hosts that had only two retinal layers before treatment. The newly introduced rod precursor cells were able to resume their developmental programme in the degenerate host niche to become mature rods with light- sensitive outer segments, and reconnected with host neurons downstream. Visual function, assayed in the same animals before and after transplantation, was restored in animals with zero rod function at baseline. These observations suggest that a cell therapy approach may reconstitute a light-sensitive cell layer de novo and hence repair a structurally damaged visual circuit. Rather than placing discrete photoreceptors amongst pre-existing host outer retinal cells, total photoreceptor layer reconstruction may provide a clinically relevant model to investigate cell-based strategies for retinal repair.