Thesis (Ph. D.)--Biomedical Engineering, Georgia Institute of Technology, 2007. / DeWeerth, Stephen, Committee Chair ; Lee, Robert, Committee Member ; Ting, Lena, Committee Member ; Katz, Paul, Committee Member ; Butera, Robert, Committee Member.

Thesis (M.S.)--University of British Columbia, 2003. / Includes bibliographical references (leaves 76-81).

Thesis (M.S.)--University of Oregon, 2003. / Includes bibliographical references (leaves 75-81).

No description available.

No description available.

<p>The semicircular canals of the vestibular system detect angular head rotations and play a fundamental role in guiding motor reflexes during locomotor behaviors. While extensive research has documented the relationship between the semicircular canal shape (i.e. radius of curvature and canal length) and locomotor behaviors, levels of intraspecific variation in primates are relatively unknown. Predictive models using these metrics to reconstruct locomotion in extinct animals are generally based on one individual per species. Furthermore, the influence of body size and to a lesser degree brain size heavily influences overall canal morphology.</p><p>This study documents intraspecific variation in the size, shape and orientation of the semicircular canals in relation to changes in function, brain size, and body size via analysis of high resolution CT scans of large samples of extant primate species. I test the hypothesis that the extent of intraspecific variation differs across a sample of primates, reflecting the intensity of selective pressure on canal shape in species that require agility during locomotion. I also examine whether spatial constraints resulting from the size of the skull (reflected by the size of the brain) affect canal radii of curvature and canal orthogonality more strongly than observed agility during locomotion. </p><p>To this end, data was gathered from high-resolution CT images of museum specimens. For the comparative analysis, 14-matched pairs of adult extant primate species were selected that contrast in agility and brain size in closely related genera. CT images of these specimens were used to measure functional measures of canal sensitivity (e.g., canal radii of curvature, orthogonality). This data was used to test hypotheses concerning intraspecific and interspecific variation in semicircular canal functional morphology. This data was then combined with a larger mammalian dataset culled from the literature, to further test hypotheses relating to body-size and brain size dependent variation in individual canal metrics. </p><p>Evaluation of levels of intraspecific variation support the hypothesis put forth by Billet et al. (2012), that selection on canal morphology is relaxed in animals with slow locomotor behaviors, who are observed to have higher levels of intraspecific variation. Analyses of interspecific variation provides tentative support for the use of canal orthogonality in reconstructive models, most especially in canal angles that seem least effected by other constraints—brain size, etc. However, locomotor signals are complex and brain/skull interactions can potentially produce misleading results when reconstructing locomotor behaviors. This work highlights the importance of critically assessing comparative groups used for inferring behaviors in both extinct and extant animals.</p> / Dissertation

O Brasil é o maior exportador e o terceiro maior produtor mundial de carne de aves, com 11,42 milhões de toneladas em 2010 e 12,86 milhões de toneladas em 2011. Com relação à produção e exportação de carne de peru em 2011, as exportações totalizaram 141,2 mil toneladas. , com uma redução de 10,5%, quando comparada com o ano anterior. O mercado de produtos à base de carne de peru tem se mostrado bastante promissor não só no Brasil como em vários outros países, representando 6,9% da produção mundial. Aliado ao desenvolvimento da produção animal, principalmente nos últimos anos, o bem-estar animal tem constituído tema de discussão e pesquisa, estando entre os assuntos mais discutidos atualmente na produção animal. É crescente a convicção dos consumidores de que os animais utilizados para produção de alimentos devem ser bem tratados. Problemas locomotores impedem que a ave se movimente livremente e, com isso, acessem os equipamentos necessários para sua sobrevivência: comedouros e bebedouros. Cerca de 10 a 40% do lucro bruto por lote é perdido devido a problemas locomotores nas aves, as quais podem ter a carcaça condenada completa ou parcialmente no abatedouro. Existem diversas formas de avaliar os problemas locomotores em aves de corte. No campo, as metodologias mais empregadas para avaliar problemas locomotores são exames visuais da capacidade de locomoção das aves, denominados de Gait Score (avaliação do caminhar). Entretanto essas metodologias são consideradas subjetivas, pois não utilizam nenhum equipamento e, sim,planilhas que orientam o usuário a observar o comportamento das aves ou medir com régua o tamanho das lesões. Isto quer dizer, que dependendo do avaliador e de sua interpretação um escore de injúrias será concluído. Desta forma, o objetivo deste trabalho é validar uma nova tecnologia para mensuração de problemas locomotores em aves de corte (frangos e perus), que seja objetiva, de fácil manuseio, confiável (independente do avaliador) e de uso universal.Para tal, essa nova tecnologia foi desenvolvida e avaliada comparativamente com seis metodologias de mensuração de problemas locomotores, previamente estabelecidas pelas amplas citações na literatura, buscando ajustá-la e validá-la. / Brazil is the largest exporter and third largest producer of poultry meat, with 11.42 million tons in 2010 and 12.86 million tons in 2011. With this relation to the production and export of turkey meat in 2011, exports totaling 141,200 tons, with reduction of 10.5% when compared with the previous year. The market for products made from turkey meat has been shown very promising not only in Brazil and in several other countries, accounting 6.9% of global production. Allied with development of animal production, especially in recent years, animal welfare has been a subject of discussion and research, being among the most discussed subjects currently in production animal. There is growing certainty of consumers that animals used for food production should to be treated well. The locomotor problems hinder the fowl from moving freely and with it accessing the equipment necessary for their survival: feeders and drinkers. About 10-40% of gross profit per lot is lost due to locomotor problems in birds, of which can be completely or partly condemned carcass the slaughterhouse. There are different ways of evaluating the locomotor problems in broiler chickens. In the field, the methodologies used to evaluate locomotor problems are visual examinations of walking ability of the birds, called Gait Score (evaluation of walking). Meanwhile these methods are considered subjective because does not use any equipment and, yeah, worksheets that guide the user to observe the bird behavior with a ruler or measuring the size of the lesions. This means that depending the evaluator and their interpretation a score of injuries will be concluded. In this way, the purpose of this work is to validate a new technology for measurement of locomotors problems in broiler chickens (chickens and turkeys) that be objective, with easily managed and confidante, independent the evaluator and with universal use. To this the new technology was developed and evaluated in comparison with six methodologies to measure locomotors problems, previously established by extensive citations in the literature, look for adjust it and validate it.

Human locomotor economy and efficiency are highly variable. This study investigated the role that stature plays in this variation, by evaluating metabolic and respiratory responses to walking and running at speeds set relative to one's stature. Four groups of subjects: male, high V0₂ max (n = 11); male, average V0₂ max (n = 10); female, high V0₂ max (n = 10); and female, average V0₂ max (n = 11) were habituated to treadmill locomotion prior to the measurement of maximal oxygen consumption (V0₂ max). The V0₂ max test entailed 1 km.h⁻¹ increases per min from 3 to 6 km.h⁻¹ walking, and 7 - 17 km.h⁻¹ running then 1% grade increments per min until exhaustion. On each of four other occasions, the subject walked or ran at 6 of a variety of relative speeds - walking at 0.5, 0.7, 0.9, 1.1, 1.3; running at 1.5, 1.7, 1.9 and for selected subjects 2.1, 2.3 and 2.5 statures.s⁻¹ ,and grades - 0%, +3%, -3%. Steady-state respiratory and metabolic responses, and treadmill speed were monitored by an on-line computer system developed for this study. Cadence and RPE were also monitored. All subjects demonstrated an exponential relationship between V0₂ and walking relative speed (st.s⁻¹) (RS) . V0₂ (ml.kg⁻¹.min⁻¹ ) = 4.747 * e(1.371*RS) During running this relationship was essentially linear . The variability of economy at relative speed (9.08%) and absolute speed (9. 01%) did not differ. Male and female subjects did not differ in response to absolute speed but females were more economical at relative speeds (p<0.05). Those with high and average aerobic capacity did not differ in locomotor economy at relative speed. Higher freely-chosen stride length was associated with a higher V0₂ response as velocity increased. The V0₂ of uphill walking was 1.4 times greater than that for downhill walking (running: 1.28 times) . Stride length decreased with increasing speed in uphill locomotion but the reverse was the case for downhill. The economy and efficiency of walking was greater than that of running. Walking economy was maximal between 0.7 and 0.9 st. s⁻¹. Running economy remained essentially unaffected by increased velocity. The setting of locomotor velocity relative to stature does not minimize inter-subject variability in metabolic and respiratory response .

L’appareillage permet à aux personnes amputées de membre inférieur de retrouver une autonomie de déplacement. Actuellement, cette autonomie est limitée dans certaines situations de la vie courante comme la marche en pente ou en escalier. Des capteurs dits embarqués sont de plus en plus souvent intégrés dans les prothèses et permettent d’enregistrer des informations cinématiques et dynamiques au cours de la locomotion. Dans ce contexte, l’objectif de la thèse est de contribuer au développement de méthodes de traitement des données issues de ces technologies pour quantifier et améliorer l’adaptation de la prothèse à l’environnement. Ces méthodes ont été mises en œuvre et évaluées dans le cadre de l’utilisation d’un nouveau système prothétique contrôlé par microprocesseur de genou-cheville (SPCM), développé par la société Proteor et visant à faciliter la locomotion des personnes amputées au-dessus du genou dans les situations de pente ou de descente d’escalier. La première partie de cette thèse a été consacrée à la quantification des adaptations permises par le SPCM au cours de la locomotion dans différentes situations de la vie courante (plat, pente, escalier). La deuxième partie de la thèse s’est intéressée à développer des estimations de paramètres de la marche (vitesse de marche et inclinaison de la pente) et à la classification de 4 situations de la vie courante (plat, montée et descente de pente, descente d’escalier) à l’aide d’algorithmes d’apprentissage automatique pouvant être calculé par le SPCM en temps réel. L’ensemble de ces travaux permettra de mieux quantifier l’activité réelle de l’utilisateur. Cette quantification pourrait aider l’utilisateur ou l’équipe médicale pour le suivi d’activité mais aussi le constructeur pour améliorer l’adaptation des éléments prothétiques à l’environnement rencontré et pour vérifier l’utilisation réelle du SPCM. / Prosthetic devices allow people with lower limb amputation to recover their autonomy. Currently, this autonomy is limited in several everyday life situations such as walking on a slope or in stairs. Embedded sensors, frequently integrated inside the prostheses, record kinematic and dynamic data during locomotion. In this context, this PhD thesis aims to contribute to the development of methods for the processing of data provided by these technologies to quantify and improve the adaptation of the prosthesis to the environment. These methods were applied and evaluated in the context of the use of a new prosthetic knee-ankle system controlled by microprocessor (SPCM) developed by Proteor to facilitate the locomotion in situations such as slope or downstairs walking for people with above knee amputation. The first part of the work was devoted to the quantification of the adaptations allowed by the SPCM in different situations of daily life (flat, slope, staircase). The second part of the thesis focused on the estimation of gait parameters (walking speed and slope inclination) and the classification of 4 everyday life situations (flat, slope ascent and descent, stair descent) using machine learning algorithms that can be computed by the SPCM in real time. The body of this work will make it possible to better quantify the user real life activity. This quantification could help the user or the medical team in the activity monitoring but also the manufacturer to improve the adaptation of the prosthetic components to the environment and to verify the SPCM actual use.

abstract: Spinal cord injury (SCI) disrupts the communication between supraspinal circuits and spinal circuits distal to the injury. This disruption causes changes in the motor abilities of the affected individual, but it can also be used as an opportunity to study motor control in the absence or limited presence of control from the brain. In the case of incomplete paraplegia, locomotion is impaired and often results in increased incidence of foot drag and decreased postural stability after injury. The overall goal of this work is to understand how changes in kinematics of movement and neural control of muscles effect locomotor coordination following SCI. Toward this end, we examined musculoskeletal parameters and kinematics of gait in rats with and without incomplete SCI (iSCI) and used an empirically developed computational model to test related hypotheses. The first study tested the hypothesis that iSCI causes a decrease in locomotor and joint angle movement complexity. A rat model was used to measure musculoskeletal properties and gait kinematics following mild iSCI. The data indicated joint-specific changes in kinematics in the absence of measurable muscle atrophy, particularly at the ankle as a result of the injury. Kinematic changes manifested as a decrease in complexity of ankle motion as indicated by measures of permutation entropy. In the second study, a new 2-dimensional computational model of the rat ankle combining forward and inverse dynamics was developed using the previously collected data. This model was used to test the hypothesis that altered coordination of flexor and extensor muscles (specifically alteration in burst shape and timing) acting at the ankle joint could be responsible for increases in incidence of foot drag following injury. Simulation results suggest a time course for changes in neural control following injury that begins with foot drag and decreased delay between antagonistic muscle activations. Following this, beneficial adaptations in muscle activation profile and ankle kinematics counteract the decreased delay to allow foot swing. In both studies, small changes in neural control caused large changes in behavior, particularly at the ankle. Future work will further examine the role of neural control of hindlimb in rat locomotion following iSCI. / Dissertation/Thesis / Ph.D. Bioengineering 2012