A considerable number of Very Long Baseline Interferometry (VLBI) surveys have been conducted in the northern hemisphere and very few in the southern hemisphere mostly because of a lack of telescopes and therefore adequate baseline coverage. Thus there is a deficit of calibrator sources in the southern hemisphere. Further, some of the most interesting astronomical objects eg. the galactic centre and the nearest galaxies (the small and large Magellanic Clouds) lie in the southern hemisphere and these require high resolution studies. With a major expansion of radio astronomy observing capability on its way in the southern hemisphere (with the two SKA (Square Kilometre Array) precursors, meerKAT (Karoo Array Telescope) and ASKAP (Australian SKA Pathfinder), leading to the SKA itself) it is clear that interferometry and VLBI in the southern hemisphere need a dense network of calibration sources at different resolutions and a range of frequencies. This work seeks to help redress this problem by presenting an analysis of 31 southern sources to help fill the gaps in the southern hemisphere calibrator distribution. We have developed a multi-parameter method of classifying these sources as calibrators. From our sample of 31 sources, we have 2 class A sources (Excellent calibrators), 16 class B sources (Good calibrators), 9 class C sources (Poor calibrators) and 4 class D sources (Unsuitable calibrators).

The study of lateralisation has taken several forms ranging from investigating morphological asymmetries to research on lateralised motor and perceptual functions with many studies successfully evidencing lateralisation in a variety of species. This study, featuring three species (olive baboons, rhesus macaques, and spotted hyaenas) investigated visual field biases with the aim of determining whether emotional valence underpins these biases whilst also considering the influence of a number of other factors such as emotional intensity, age, sex, rank, and, for the first time, oestrus cycles (olive baboons only). This study aimed to establish whether Campbell’s (1982) Right Hemisphere Hypothesis or Silberman & Weingartner’s (1986) Valence Hypothesis offered the more valid theory for the lateralisation of emotion by considering interactions across the full spectrum of emotion – a question the almost exclusive investigation of negatively affective scenarios by previous studies has been unable to answer. Furthermore, this study provided a new methodology for investigating behavioural lateralisation by suggesting that separating the visual spectrum into five fields (extreme left, mid left, centre, mid right and extreme right) allows a more accurate insight into the lateralisation of visual perception than the traditional hemifield model. Finally, a more conservative method is proposed for analysing behavioural data in future studies from this field and suggests that these methods provide a more accurate representation of the lateralisation of emotion than those previously employed. A population-level left side bias was found for the spotted hyaenas, thus providing the first evidence of significantly lateralised behaviour in a large carnivore and, for this species at least, lending some support to Campbell’s (1982) Right Hemisphere hypothesis but as population-level biases were not found for either of the other species it may be premature to suggest this support is unequivocal. Significant age effects were found in two species as adult olive baboons and spotted hyaenas were both found to express significant left side biases. Spotted hyaenas were also found to express significant left side biases for females, dominant individuals, high intensity interactions, and sexual valence interactions whilst olive baboons expressed a significant left side bias during negative valence behaviours but no significant lateral biases were found in any context for rhesus macaques. In olive baboons behaviours performed by males and those of a low intensity were found to occur more frequently in the mid and central visual fields and neutral valence behaviours were less occurrent in the extreme visual fields whilst in spotted hyaenas sexual, positive and negative valence behaviours were significantly less centralised than neutral valence behaviours. Non-oestrus adult female olive baboons were significantly more strongly lateralised than in-oestrus females, thus suggesting an influence of sex hormones upon lateralisation that may also have been apparent from the hyaena data, particularly regarding the significant lateral biases observed for females and dominant individuals. Finally, this thesis discusses a number of methodological issues that were encountered during this study and provides recommendations for future research in this field. Namely, this thesis provides an updated method for calculating laterality bias that is much more suitable for species with binocular vision and details a novel method of assessing visual field preferences by considering central and peripheral visual fields as separate entities. Furthermore, this thesis suggests that the weighted method designed and implemented for this study provides a much more accurate methodological foundation for analyses which avoids the caveats that may have affected previous research and thus provides a considerably more robust template that should be encouraged for any similar subsequent studies.

! Title of thesis : Influence of laterality in somatognostic functions of floorball players Demarcation of the issue : This thesis is dedicated to the influence of laterality in somatognostic functions of floorball players and it rates relation between these two phenomenons. It is a first research in this branch and sport, also, it informs about the coherence of these two phenomenons, from the point of view as a cause of sports injuries and also as a prevention of sports injuries. Justification : Athletes get injured frequently in many different situations. Often, we are dealing with an injury as a consequence, but not the real cause. Physical therapist should get oriented in this problematics to be more effective in the healing process of the athlete. To avoid such problems in adulthood, we should be more focused on the prevention just at the beginning of a sports career of a small athlete. No matter what sports level the athlete had achieved, we are focusing especially in one-sided sport activities. Aim of the thesis : The aim of thesis is to find out any coherence of the effect of one-sided sports, as floorball, to somatognostic functions of players at the age between 6 - 14 years old. Methodology of the thesis : Research is created in a form of descriptive - associative academic method. It is...

Dans le contexte du réchauffement climatique, les enregistrements paléoclimatiques à différentes échelles temporelles et spatiales apparaissent essentiels pour comprendre les mécanismes du climat. La Patagonie Chilienne (41°S à 56°S) parcourue du Nord au Sud par les Andes représente une contrainte topographique majeure sur les circulations atmosphériques et océaniques. Cette région est la seule qui intercepte la totalité de la ceinture des vents d'ouest austraux et constitue donc une zone clé pour étudier les changements paléoenvironnementaux et comprendre les mécanismes océan-atmosphère et leurs interactions aux moyennes et hautes latitudes de l'hémisphère sud. Dans ce contexte, les objectifs de cette thèse sont : (1) de tester l’analyse pollinique dans les sédiments marins de cette région, (2) d’étudier les modifications des paléoenvironnements continentaux au cours des 20 000 dernières années à partir de deux carottes océaniques de la campagne "PACHIDERME" (MD07-3088 et MD07-3104) et (3) de déterminer leurs liens avec l’activité des vents d’ouest et avec l’influence de ces vents dans l’hémisphère sud et donc sur le climat à l’échelle globale. Les analyses polliniques dans les sédiments marins de surface à l’intérieur et à l’extérieur des fjords de la Patagonie reflètent fidèlement la végétation actuelle développée sur le continent le plus proche, ce qui prouve la validité de la palynologie marine dans cette région. Au niveau de la péninsule de Taitao (46°S), l’expansion des forêts nord patagoniennes après 17.6 ka marque le début de la déglaciation. Cette dernière est interrompue par un évènement froid et humide, l’Antarctic Cold Reversal (ACR) qui s’exprime ici par le développement des tourbières de Magellan et est lié à l’intensification des vents d’ouest. Le développement de taxons héliophiles à ~11 ka illustre le début de l’Holocène sous des conditions plus chaudes et plus sèches qui sont également enregistrées autour du Fjord de Reloncavi (41°S). Ces conditions persistent jusqu’à ~8-7 ka, puis les changements de végétation aux cours de l’Holocène montrent une variabilité climatique plus importante évoluant vers un climat plus froid et plus humide qui se renforce au nord de la Patagonie après ~6-5 ka puis pendant l’Holocène supérieur. La comparaison de nos résultats avec les données paléoclimatiques de la région souligne les déplacements de la ceinture des vents d’ouest. Après une descente rapide vers le sud au début de la déglaciation, cette ceinture des vents d’ouest remonte vers le nord pendant l’ACR avant de redescendre à nouveau vers le sud à l’Holocène proche de sa position actuelle. Ce phénomène appuie l’hypothèse d’un lien entre les variations du CO2 atmosphérique et la ceinture des vents d’ouest jusqu’au début de l’Holocène. A partir de l’Holocène moyen et supérieur, la ceinture des vents d’ouest s’élargit avec un léger retour vers le nord probablement lié à la mise en place d’El Niño au niveau de l’océan Pacifique tropical. / In the context of global warming, paleoclimate records at different time and spatial scales appear critical to understand climate mechanisms. Chilean Patagonia (41°S to 56°S), crossed by the Andes from north to south, represents a major topographic constraint on ocean and atmospheric circulation. It is the only region that intercepts the entire southern westerly wind belt. Thus it represents a key-area for the study of paleoenvironmental changes in the southern hemisphere and the understanding of ocean-atmosphere mechanisms and their interactions from the mid- to high-latitudes of the southern hemisphere. In this context, the purposes are: (1) to test the pollen analysis on marine surface sediments in this region, (2) to study the continental changes of paleoenvironments during the last 20,000 years from two oceanic cores of the "PACHIDERME" campaign (MD07-3088 and MD07-3104) and (3) to evaluate their links with southern westerly wind belt activity and with the influence of these winds on the southern hemisphere and with the climate at a global scale. The pollen analyses of marine surface sediments in fjords or offshore from Chilean Patagonia reflect the present-day vegetation from the nearby continental area. At the Peninsula of Taitao (46°S), the North Patagonian forest expansion after 17.6 kyr shows the beginning of the deglaciation. This last (period) is interrupted by a wet and cool event, the Antarctic Cold Reversal (ACR), that was expressed here by development of the Magellanic moorland linked to the southern westerly wind intensification. The expansion of heliophytic taxa at ~11 kyr illustrates the beginning of the Holocene under warmer and drier conditions that are also recorded around the fjord of Reloncavi (41°S). These conditions persisted until ~8-7 kyr, and then the vegetation changes during the Holocene show a larger climate variability toward a cooler and wetter climate that enhances in northern Patagonia later ~6-5 kyr during the Late Holocene. Our results compared with the regional paleoclimatic data highlight the shifts of the southern westerly wind belt. After a rapid southward shift at the beginning of the deglaciation, the southern westerly wind belt returns northward during the ACR before reaching southern latitudes near to their present-day position. This scheme strengthens the inference of the link between atmospheric CO2 variability and the southern westerly wind belt up to the Early Holocene. From the mid and late Holocene, the southern westerly wind belt was displaced northward with a slight return probably linked to the beginning of El Niño recorded in tropical Pacific Ocean.

This thesis provides a comparative analysis of vowel quality in South African English (SAE) using the following data: firstly, the existing impressionistic literature on SAE and other relevant accents of English, the former of which is subject to a critical review; secondly, acoustic data from a similar range of accents, including new SAE data, collected and instrumentally analyzed specifically for the purposes of this research. These various data are used to position, on both a descriptive and theoretical level, the SAE vowel system. In addition, and in the service of providing a careful reconstruction of the linguistic history of this variety, it offers a three-stage koin´eization model which helps, in many respects, to illuminate the respective roles played by endogenous and exogenous factors in SAE’s development. More generally, the analysis is focussed on rendering explicit the extent to which the synchronic status and diachronic development of SAE more generally, and SAE vowel quality more particularly, provides support for a number of descriptive and theoretical frameworks, including those provided in Labov (1994), Torgersen and Kerswill (2004), Trudgill (2004) and Schneider (2003; 2007). With respect to these frameworks, and based on the results of the analysis, it proposes an extension to Schneider’s (2007) Dynamic Model, shows Trudgill’s (2004) model of new-dialect formation to be inadequate in accounting for some of the SAE data, provides evidence that SAE is a possibly imminent but ‘conservative’ member of Torgersen and Kerswill’s (2004) SECS-Shift and uses SAE data to question the applicability of the SECS-Shift to FOOT-Fronting. Furthermore, this thesis provides evidence that SAE has undergone an indexicallydriven arrestment of the Diphthong and Southern Shifts and a subsequent and related diffusion of GenSAE values at the expense of BrSAE ones. Similarly, it shows that SAE’s possible participation in the SECS-Shift constitutes an effective chain-shift reversal ‘from above’. It stresses that, in order to understand such phenomena, recourse needs to be made to a theory of indexicality that takes into account the unique sociohistorical development of SAE and its speakers. Lastly, the adoption of the three-stage koin´eization model mentioned above highlights the merits of considering both endogenous and exogenous factors in the historical reconstruction of new-dialect formation and, for research into SAE in particular, strengthens the case for further investigation into the possible effects of 19th-century Afrikaans/Dutch, Yiddish and north-of-English dialects on the formation of modern SAE. / Thesis (Ph.D. (English))--North-West University, Potchefstroom Campus, 2009.

This thesis provides a comparative analysis of vowel quality in South African English (SAE) using the following data: firstly, the existing impressionistic literature on SAE and other relevant accents of English, the former of which is subject to a critical review; secondly, acoustic data from a similar range of accents, including new SAE data, collected and instrumentally analyzed specifically for the purposes of this research. These various data are used to position, on both a descriptive and theoretical level, the SAE vowel system. In addition, and in the service of providing a careful reconstruction of the linguistic history of this variety, it offers a three-stage koin´eization model which helps, in many respects, to illuminate the respective roles played by endogenous and exogenous factors in SAE’s development. More generally, the analysis is focussed on rendering explicit the extent to which the synchronic status and diachronic development of SAE more generally, and SAE vowel quality more particularly, provides support for a number of descriptive and theoretical frameworks, including those provided in Labov (1994), Torgersen and Kerswill (2004), Trudgill (2004) and Schneider (2003; 2007). With respect to these frameworks, and based on the results of the analysis, it proposes an extension to Schneider’s (2007) Dynamic Model, shows Trudgill’s (2004) model of new-dialect formation to be inadequate in accounting for some of the SAE data, provides evidence that SAE is a possibly imminent but ‘conservative’ member of Torgersen and Kerswill’s (2004) SECS-Shift and uses SAE data to question the applicability of the SECS-Shift to FOOT-Fronting. Furthermore, this thesis provides evidence that SAE has undergone an indexicallydriven arrestment of the Diphthong and Southern Shifts and a subsequent and related diffusion of GenSAE values at the expense of BrSAE ones. Similarly, it shows that SAE’s possible participation in the SECS-Shift constitutes an effective chain-shift reversal ‘from above’. It stresses that, in order to understand such phenomena, recourse needs to be made to a theory of indexicality that takes into account the unique sociohistorical development of SAE and its speakers. Lastly, the adoption of the three-stage koin´eization model mentioned above highlights the merits of considering both endogenous and exogenous factors in the historical reconstruction of new-dialect formation and, for research into SAE in particular, strengthens the case for further investigation into the possible effects of 19th-century Afrikaans/Dutch, Yiddish and north-of-English dialects on the formation of modern SAE. / Thesis (Ph.D. (English))--North-West University, Potchefstroom Campus, 2009.

Perceptual rivalry refers to visual phenomena that are characterised by alternations between different percepts, despite an unchanging sensory input. Two common types of perceptual rivalry are (i) reversible figures — two-dimensional stable images that when viewed, are perceived to switch between different interpretations, and (ii) binocular rivalry — the alternations in image dominance resulting from the presentation of conflicting stimuli, one to each eye. Several investigators have suggested that these rivalling phenomena are mediated by similar neural mechanisms. Such a view, however, has not only been inadequately substantiated, but has also yet to be assessed in the context of a directly testable neurophysiological model. Miller and Pettigrew have proposed a novel, high-level interhemispheric switch (IHS) explanatory model of binocular rivalry. This model conceptualises the perceptual alternations as being mediated by alternations between one hemisphere’s selected image and the other hemisphere’s selected (rival) image. To assess their hypothesis, caloric vestibular stimulation (CVS) was used. CVS is a simple, inexpensive, and non-invasive brain stimulation technique that unilaterally activates high-level attentional areas. In accordance with the IHS model, CVS was found to significantly affect predominance (the duration that one image is perceived relative to the other, within a given viewing period) during conventional binocular rivalry with horizontal/vertical gratings and with orthogonal oblique gratings. The present thesis therefore aims, through the use of CVS, to extend this IHS model of binocular rivalry to reversible-figure alternations and propose a general IHS model of perceptual rivalry. Chapter 1 provides a detailed literature review of the field within the context of comparing both perceptual rivalries. In Chapter 2, investigations are presented on two different reversible figures — the perspective-reversing Necker cube and the figure–ground reversing Rubin’s vase–faces illusion. In these experiments, CVS was found to significantly change observers’ predominance compared to their baseline predominance. These results demonstrate that interhemispheric switching also mediates the alternations of these visual phenomena, in addition to binocular rivalry, thereby extending the IHS model to one of perceptual rivalry in general. Moreover, the findings are interpreted in a cognitive neuroscience context, including a novel proposal of a forebrain framework for the IHS model. Chapter 3 presents CVS experiments that address the issue of percept–to–hemisphere selection and the reproducibility of CVS effects, following Miller’s initial work on two types of conventional binocular rivalry. In planned analyses, significant predominance changes were not found in horizontal/vertical rivalry, oblique rivalry and Necker-cube rivalry. In post-hoc analyses that accounted for study-design differences between Miller’s original experiments and the present experiment, CVS was again not shown to induce significant predominance changes in any of the rivalry types. Assessment of directional predominance changes following CVS appeared to suggest an arbitrary selection of percept–to–hemisphere in all rivalry types, although no firm conclusions could be drawn from the obtained data on this issue. Nevertheless, the experiments further extend upon Miller’s earlier work by examining the inter- and intra-individual reproducibility of CVS-induced effects on predominance. Such reproducibility was found to be low and potential reasons for this are discussed. The experiments in Chapter 4 examine a type of binocular rivalry in which dichoptic presentation of Díaz-Caneja stimuli yields rivalry among four different stable images: half-field rivalry between the images presented to the eyes, and coherence rivalry in which aspects of each eye’s presented image are perceptually regrouped into rivalling coherent images. Each of these rivalries was found to occur for about half the given viewing time. Furthermore, CVS significantly shifted the predominance of perceived coherent images (coherence rivalry) but not half-field images (eye rivalry). This finding suggests that coherence rivalry (like conventional rivalry according to previous experiments) is mediated by interhemispheric switching at a high level, while eye rivalry is mediated by intrahemispheric mechanisms, most likely at a low level. In addition, it is proposed that Díaz-Caneja stimuli induce ‘meta-rivalry’ whereby these discrete high- and low-level competitive processes themselves rival for visual consciousness. The current thesis thus presents a novel meta-rivalry model of multistable binocular rivalry. It also presents the first direct evidence that interhemispheric switching mediates reversible-figure alternations, thereby supporting a generalised IHS model of perceptual rivalry. It is argued that both models provide a parsimonious exploratory framework within which specific predictions can be made and readily tested. Finally, the findings of all experiments in the current thesis are summarised.

Perceptual rivalry refers to visual phenomena that are characterised by alternations between different percepts, despite an unchanging sensory input. Two common types of perceptual rivalry are (i) reversible figures — two-dimensional stable images that when viewed, are perceived to switch between different interpretations, and (ii) binocular rivalry — the alternations in image dominance resulting from the presentation of conflicting stimuli, one to each eye. Several investigators have suggested that these rivalling phenomena are mediated by similar neural mechanisms. Such a view, however, has not only been inadequately substantiated, but has also yet to be assessed in the context of a directly testable neurophysiological model. Miller and Pettigrew have proposed a novel, high-level interhemispheric switch (IHS) explanatory model of binocular rivalry. This model conceptualises the perceptual alternations as being mediated by alternations between one hemisphere’s selected image and the other hemisphere’s selected (rival) image. To assess their hypothesis, caloric vestibular stimulation (CVS) was used. CVS is a simple, inexpensive, and non-invasive brain stimulation technique that unilaterally activates high-level attentional areas. In accordance with the IHS model, CVS was found to significantly affect predominance (the duration that one image is perceived relative to the other, within a given viewing period) during conventional binocular rivalry with horizontal/vertical gratings and with orthogonal oblique gratings. The present thesis therefore aims, through the use of CVS, to extend this IHS model of binocular rivalry to reversible-figure alternations and propose a general IHS model of perceptual rivalry. Chapter 1 provides a detailed literature review of the field within the context of comparing both perceptual rivalries. In Chapter 2, investigations are presented on two different reversible figures — the perspective-reversing Necker cube and the figure–ground reversing Rubin’s vase–faces illusion. In these experiments, CVS was found to significantly change observers’ predominance compared to their baseline predominance. These results demonstrate that interhemispheric switching also mediates the alternations of these visual phenomena, in addition to binocular rivalry, thereby extending the IHS model to one of perceptual rivalry in general. Moreover, the findings are interpreted in a cognitive neuroscience context, including a novel proposal of a forebrain framework for the IHS model. Chapter 3 presents CVS experiments that address the issue of percept–to–hemisphere selection and the reproducibility of CVS effects, following Miller’s initial work on two types of conventional binocular rivalry. In planned analyses, significant predominance changes were not found in horizontal/vertical rivalry, oblique rivalry and Necker-cube rivalry. In post-hoc analyses that accounted for study-design differences between Miller’s original experiments and the present experiment, CVS was again not shown to induce significant predominance changes in any of the rivalry types. Assessment of directional predominance changes following CVS appeared to suggest an arbitrary selection of percept–to–hemisphere in all rivalry types, although no firm conclusions could be drawn from the obtained data on this issue. Nevertheless, the experiments further extend upon Miller’s earlier work by examining the inter- and intra-individual reproducibility of CVS-induced effects on predominance. Such reproducibility was found to be low and potential reasons for this are discussed. The experiments in Chapter 4 examine a type of binocular rivalry in which dichoptic presentation of Díaz-Caneja stimuli yields rivalry among four different stable images: half-field rivalry between the images presented to the eyes, and coherence rivalry in which aspects of each eye’s presented image are perceptually regrouped into rivalling coherent images. Each of these rivalries was found to occur for about half the given viewing time. Furthermore, CVS significantly shifted the predominance of perceived coherent images (coherence rivalry) but not half-field images (eye rivalry). This finding suggests that coherence rivalry (like conventional rivalry according to previous experiments) is mediated by interhemispheric switching at a high level, while eye rivalry is mediated by intrahemispheric mechanisms, most likely at a low level. In addition, it is proposed that Díaz-Caneja stimuli induce ‘meta-rivalry’ whereby these discrete high- and low-level competitive processes themselves rival for visual consciousness. The current thesis thus presents a novel meta-rivalry model of multistable binocular rivalry. It also presents the first direct evidence that interhemispheric switching mediates reversible-figure alternations, thereby supporting a generalised IHS model of perceptual rivalry. It is argued that both models provide a parsimonious exploratory framework within which specific predictions can be made and readily tested. Finally, the findings of all experiments in the current thesis are summarised.

Forças aplicadas no corpo humano são essenciais para o crescimento tecidual, a postura e a locomoção. Entretanto, na postura sentada, altos níveis de pressão por tempo prolongado podem ocasionar graves danos à pele e aos tecidos subjacentes, podendo levar o indivíduo à morte devido às complicações decorrentes das úlceras de pressão. Pessoas com deficiência que apresentam impossibilidade, temporária ou definitiva, de deslocar-se, adotam a postura sentada em sua cadeira de rodas. Cadeirantes que apresentam diminuição ou perda de funções sensitivas estão mais predispostos a serem acometidos por úlceras por não perceberem os incômodos dos altos níveis de pressão na posição sentada. A engenharia biomecânica tem estudado novas tecnologias em ergômetros e em equipamentos de monitoramento da pressão no assento da cadeira de rodas, com diferentes sensores de medição da pressão, considerando o custo e a constituição do equipamento. Diante disso, foi desenvolvido um novo dispositivo óptico de baixo custo e constituição simples para monitoramento da pressão, utilizando o processamento de imagens da intensidade luminosa gerada pela deformação de semiesferas de elastômeros contra uma superfície transparente rígida iluminada lateralmente sem o uso de líquidos sensores. Foi projetado e desenvolvido um programa de aquisição e processamento, de calibração, de análise das imagens e um módulo de sensores elásticos adaptado ao assento de um ergômetro para cadeirantes. Para entender o funcionamento do dispositivo e avaliar o projeto do novo sistema de monitoramento da pressão foi realizado uma modelagem numérica por elementos finitos, uma análise experimental, uma estimativa da pressão por meio de modelo analítico e um experimento que visa avaliar o efeito do apoio do pé na distribuição da pressão no assento em repouso e com propulsão manual. Por meio, do novo dispositivo de pressão no assento de ergômetro ajustável, foi desenvolvido um novo método de monitoramento da pressão no assento de ergômetro para cadeirantes utilizando um princípio óptico de captação da imagem processada da deformação de semiesferas de elastômeros utilizando aplicativos em ambiente LabVIEW. O dispositivo possibilitou a aquisição, a análise e o monitoramento da imagem do mapeamento dos níveis de pressão no assento de lesados medulares que realizam propulsão manual. Os resultados dos experimentos demonstraram que a elevação do apoio do pé aumenta significativamente (p<0,05) a pressão média e máxima na região isquiática em lesados medulares. O mapeamento óptico com semiesferas de elastômeros para monitoramento da pressão por imagem no assento do ergômetro, mostrou ser uma ferramenta importante na avaliação adequação postural e na ergonomia da configuração de uma cadeira de rodas com potencial para desenvolver novas pesquisas na área da pessoa com deficiência com usuários de cadeira de rodas. / Forces applied to the human body is essential for tissue growth, posture and locomotion. However, in the sitting position, high-pressure levels for long periods can cause serious damage to the skin and underlying tissues, may lead the individual to death due to complications of pressure ulcers. People with disabilities who have not possible, temporary or permanent, to move, adopt a sitting posture with the use of a wheelchair. Wheelchair presenting decrease or loss of sensory functions are more likely to be affected by ulcers do not realize the discomfort of high levels of pressure in the sitting position. Biomechanics Engineering has studied new technologies ergometers and pressure monitoring equipment on the seat of the wheelchair, with different pressure measuring sensors, considering the cost and the setting up of the equipment. Therefore, a new optical device of low cost and simple constitution for pressure monitoring was developed using image processing of the light intensity generated by the deformation of elastomeric hemispheres against a rigid surface transparent illuminated laterally without the use of liquid sensors. For this, it designed and developed an acquisition program, calibration, processing, image analysis and elastic sensor module that is adapted to seat an ergometer for wheelchair users. To understand the device operation and evaluate the design of the new pressure monitoring system was carried out a numerical modeling for finite element, an experimental analysis, an estimate of the pressure by means of analytical model and an experiment designed to assess the effect of support standing on the pressure distribution on the seat at rest and with manual propulsion. By means of the new pressure device on the seat adjustable ergometer it was developed a new pressure monitoring method in ergometer seat for wheelchair users using an optical principle processed image capture of elastomeric hemispheres deformation using applications in LabVIEW environment. The device enabled the acquisition, analysis and monitoring of pressure levels of mapping image on spinal cord injuries seat performing manual propulsion. The results of the experiments with spinal cord injury, demonstrated that the rise foot support increases significantly (p <0.05) and the average maximum pressure in the ischial region. The optical mapping elastomeric hemispheres for monitoring image by pressing the ergometer seat, was an important tool in assessing the ergonomics of the configuration of a wheelchair and postural adjustment with the potential to develop further research in the area of disabled wheelchair users. / Tese (Doutorado)

This study describes the diachronic development of modality in South African English (henceforth SAfE) from the early 19th century up to its contemporary state (1820s to 1990s) in the registers of letters, news, fiction/narrative and non-fiction, on the basis of the theoretical framework of socio historical linguistics and the empirical approach of corpus linguistics. Both quantitative and qualitative analyses are conducted for modal and quasi-modal verbs, by means of the newly compiled historical corpus of SAfE and ICE-SA (with the addition of Afrikaans corpora for comparison). The study explores general frequency changes, register-internal changes and macro- and micro semantic changes, with the focus of the main semantic analysis more strongly on the obligation and necessity cluster1. A set of parameters is compiled for analysing the strength of obligation in the modals must and should, and the quasi-modal HAVE to, and is applied in the micro semantic analyses. The findings are compared with the trends for modality in other native English’s, such as American, British and Australian English (cf. e.g. Mair & Leech, 2006; Collins, 2009a; Leech, 2011), in an attempt to present a complete and comprehensive description of SAfE modality, as opposed to the traditional approach of focusing on peculiar features. It is reported that the trends of modality in SAfE correspond to those of other native varieties in some cases, but do not correspond in others. The modals of SAfE for example have declined more and the quasi-modals have increased less over the 20th century than in other native varieties of English. One particular case, in which SAfE is reported to be unique among other varieties, is the quantitative and qualitative trends for must, which has some implications for the manifestation of the democratisation process. Must in SAfE has not declined significantly over the 20th century (as it has in other native varieties) and has become less face threatening, since uses with a median (weaker) degree of force are just as frequent as those with a higher degree of force by the 1990s (unlike in other native varieties, where must has become restricted to high-degree obligative contexts). Based on socio historical, as well as linguistic evidence (on both quantitative and qualitative levels), language contact with Afrikaans is posited as the main influence for the increased use of must in contexts that are not face threatening. Extrapolating from the semantic findings, some new insights are offered regarding the phase in which SAfE finds itself within Schneider’s (2003) model of the evolution of New English’s, and some support is offered for Bekker’s (2012:143) argument that “SAfE is ...the youngest of the colonial varieties of English”, especially in the Southern Hemisphere. Ultimately, this thesis offers a piece in the larger puzzle that is SAfE, both in terms of linguistic (textual) and socio historical (contextual) aspects. / PhD (English), North-West University, Vaal Triangle Campus, 2014