Nineteen elite (E) gymnasts (>15hours/week gymnastic training), 14 high recreation (HR) gymnasts (8-15hours/week), and 15 low recreation (LR) gymnasts (1-7. 9 hours/week) were investigated to determine the effects of varying volumes of gymnastic training on bone mineral density (BMD) in prepubescent girls. Two normoactive control groups were additionally investigated to determine whether there was a magnitude effect of mechanical loading on BMD: 16 controls (C) and 15 height-and weight-matched controls (M). The mother of each daughter was measured in order to control and investigate the familial component of bone mass. Areal bone mineral density at the left proximal femur, lumbar spine (LS), and whole body (WB) and % body fat were measured by dual energy x-ray absorptiometry (DXA), and volumetric BMD was measured at the distal radius by peripheral QCT (pQCT). DXA BMD measures were corrected for bone size and expressed as bone mineral apparent density (BMAD). The HR group was significantly younger (8.68 ± 0.844 y, mean± SD) than both the E (10.02 ± 0.776 y) and C (9.96 ± 0.898 y) groups. The C group was significantly heavier (38.88 ± 4.868 kg) than the E (27.15 ± 2.819 kg), HR. (25.44 ± 3.564 kg), LR (32.98 ± 5.786 kg), and M (26.95 ± 3.301 kg) groups. Additionally, the LR group was significantly heavier than all other groups, with the exception of the C group. Femoral neck (FN) BMD was only significantly different between the E (0.706 ± 0.051 g•cm⁻²) and LR (0.649 ± 0.069 g•cm⁻²) groups. FNBMAD was only greater in the E (0.232 ± 0.048 g•cm⁻³) group compared to the C (0.191 ± 0.052 g•cm⁻³) group. LSBMAD and WBBMAD were significantly greater in both E (0.233 ± 0.019 and 0.100 ± 0.008 g•cm⁻³) and HR (0.239 ± 0.038 and 0.100 ± 0.006 g•cm⁻³) groups when compared to the LR (0.212 ± 0.022 and 0.090 ± 0.008 g•cm⁻³) and C (0.219 ± 0.020 and 0.085 ± 0.004 g•cm⁻³) groups, respectively. Total radial and cortical radial BMD was greater in both E (360.50 ± 51.569 and 484.28 ± 70.179 mg•cm⁻³) and HR (373.10 ± 45.318 and 480.66 ± 46.720 mg•cm⁻³) groups compared to the C (296.61 ± 29.677 and 426.144 ± 37.652 mg•cm⁻³) and M (306.42 ± 24.430 and 414.571 ± 25.194 mg•cm⁻³) groups, respectively. Radial trabecular BMD was greater in both E (211. 19 ± 38. 202 mg•cm⁻³) and HR (212. 61 ± 44.299 mg•cm⁻³) groups compared to the LR (175.89 ± 29.191 mg•cm⁻³), C (162.68 ± 27.304 mg•cm⁻³), and M (171.05 ± 30.639 mg•cm⁻³) groups. There were no significant differences for any bone measure among the groups of mothers. Mother-daughter correlations were relatively weak, and often insignificant, for BMD measures (r = 0.10-0.37), but strong for radial morphometric measures (r = 0.43-0.55). Radial trabecular BMD (r = 0.37; p<0.01) was more significantly correlated with gymnastic training volume (hours/week) than radial cortical BMD (0.30; p<0.05). These results suggest that there is a volume of training effect on BMD and a magnitude effect of mechanical loading on BMD. It appears that trabecular bone at the distal radius may adapt more rapidly or be more sensitive than cortical BMD to the strains imposed by impact loading. Additionally, it appears that, during prepubescence in females, bone morphometric properties may be more genetically regulated than bone mineralization. / Thesis / Master of Science (MSc)

Virtual reality (VR) involves an attempt to create an illusion that the user of the VR system is actually present in a synthetic (usually computer-generated) environment. Little is known about how various system parameters affect the illusion of presence in a virtual environment (VE). In particular, there seem to be very little quantitative data on which to base VR system design decisions. Also, while presence (or immersion) in VEs is a primary goal of VR, not much is known about how this variable affects task performance. The goal of this research was to provide a ratio-scale measure of perceived presence in a VE, to explore the effects of a number of environmental parameters on this measure and construct empirical models of these effects, and to relate perceived presence to user performance. This was done by manipulating eleven independent variables in a series of three experiments. The independent variables manipulated were scene update rate, visual display resolution, field of view, sound, textures, head-tracking, stereopsis, virtual personal risk, number of possible interactions, presence of a second user, and environmental detail. Participants performed a set of five tasks in the VE and rated perceived presence at the end of each set using the technique of free-modulus magnitude estimation. The amount of time spent in the VE was also recorded. The results indicate that the VR system parameters manipulated and analyzed in this research did affect participants' subjective feeling of presence in the VE. Field of view, sound, and head-tracking showed the largest effects. Other significant effects found were those of visual display resolution, texture-mapping, stereopsis, and the presence of a second user. Free-modulus magnitude estimation worked well as a measure of perceived presence. A positive relationship was found between perceived presence and task performance, but this relationship was relatively weak. Second-order empirical models were constructed that predicted perceived presence with moderate success and, with less success, task performance. / Ph. D.

Magnitude Scaling Factors (MSF) account for the durational effects of strong ground shaking on the inducement of liquefaction within the simplified liquefaction evaluation procedure which is the most commonly used approach for assessing liquefaction potential worldwide. Within the context of the simplified procedure, the spatial variation in the seismic demand imposed on the soil traditionally has been assumed to be solely a function of the spatial variation of the peak amplitude of the ground motions and the characteristics of the soil profile. Conversely, MSF have been solely correlated to earthquake magnitude. This assumption fails to appreciate the inverse correlation between the peak amplitude of ground motions and strong ground motion duration, and thus MSF would seemingly vary spatially. The combination of well-documented liquefaction response during the Darfield and Christchurch, New Zealand, earthquakes, densely-recorded ground motions for the events, and detailed subsurface characterization provides an unprecedented opportunity to investigate the significance of the spatial variation of MSF on the inducement of liquefaction. Towards this end, MSF were computed at 15 strong motion recording station sites across Christchurch and its surroundings using two established approaches. Trends in the site and spatial variation of the MSF computed for both the Darfield and Christchurch earthquakes are scrutinized and their implications on liquefaction evaluations are discussed. / Master of Science

Submitted by Fernanda Weschenfelder (fernanda.weschenfelder@uniceub.br) on 2017-08-28T19:50:40Z No. of bitstreams: 1 61500027.pdf: 1641143 bytes, checksum: 257099ddfbd3a6ecf3b102e57d4a1a86 (MD5) / Approved for entry into archive by Fernanda Weschenfelder (fernanda.weschenfelder@uniceub.br) on 2017-08-28T20:37:54Z (GMT) No. of bitstreams: 1 61500027.pdf: 1641143 bytes, checksum: 257099ddfbd3a6ecf3b102e57d4a1a86 (MD5) / Made available in DSpace on 2017-08-28T20:37:54Z (GMT). No. of bitstreams: 1 61500027.pdf: 1641143 bytes, checksum: 257099ddfbd3a6ecf3b102e57d4a1a86 (MD5) Previous issue date: 2017-07 / O presente estudo teve o objetivo de verificar o efeito do ganho e da perda de pontos na correspondência verbal em um jogo de cartas no qual a distorção do relato dos valores das cartas poderia resultar em maior probabilidade de vitória nas partidas. Para isso, o procedimento experimental consistiu em um jogo de cartas de computador, que foi realizado em pares de oponentes, o computador foi o oponente para todos os participantes. Cada partida do jogo foi composta por rodadas, e o objetivo dos jogadores foi obter o maior número de pontos, os quais foram obtidos ou mantidos quando se relatou maior valor que o oponente nas rodadas em que não houve checagem, ou dependendo da precisão do relato verbal nas rodadas em que houve checagem do relato. Os pontos foram trocados por trabalhos na disciplina que os participantes estavam matriculados. Foram realizados dois experimentos, sendo que o Experimento 1, teve como objetivo verificar o efeito da perda de pontos sobre a frequência dos relatos distorcidos em cinco mestrandos. O experimento contou com três condições experimentais: Perda de Pontos Magnitude Alta (P Alta), Perda de Pontos Magnitude Baixa (P Baixa) e Sem Pontos (SP), que se diferenciavam quanto à quantidade de perda de pontos caso houvesse checagem do relato e o participante tivesse distorcido. Os participantes jogaram nas três condições experimentais em três dias diferente: Pré Treino, Dia 2 e 3. Os dados mostraram que, em geral, a condição experimental que mais apresentou distorções foi SP e P Baixa teve mais distorções do que P Alta, mostrando assim que a variável independente controlou a correspondência verbal. Já o Experimento 2, teve como objetivo verificar o efeito do ganho de pontos sobre a frequência dos relatos precisos em quatro mestrandos. O Experimento 2 também teve três condições experimentais: Ganho de Pontos Magnitude Alta (G Alta), G de Pontos Magnitude Baixa (G Baixa) e SP, que se diferenciavam quanto à quantidade de ganho de pontos em rodadas com checagem e o participante tivesse relatado com precisão. Os resultados mostraram que houve mais distorção em SP e G Baixa teve mais distorções do que G Alta. Como os desvios padrão foram baixos, as diferenças de frequências de distorções entre as condições, ainda que pequenas, deram indícios que as variáveis manipuladas tiveram efeito em ambos os experimentos. Em ambos os experimentos, variáveis como: a frequência de distorções do oponente; valor obtido na carta; e, o reforço do ganho do trabalho na disciplina afetaram a correspondência verbal dos participantes. Sugerese replicações do estudo com alterações metodológicas para produzir mais discrepâncias nos resultados das diferentes condições experimentais e também mais distorções nos experimentos, em geral.

Made available in DSpace on 2016-04-29T13:17:33Z (GMT). No. of bitstreams: 1 Ana Paula de Oliveira Silva.pdf: 5574963 bytes, checksum: e89c5f7d5d8c726d8e40e5d7586fb9ca (MD5) Previous issue date: 2010-11-11 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The present study sought to investigate whether the magnitude of reinforcement is a relevant variable in determining the conditioned response suppression of "clicks", produced by presenting a negative punisher stimulus, in humans. Thirty participants were recruited and had tasked assemble puzzles 24 pieces on a computer. The responses observed was "click, drag, and engaging" pieces of the puzzle. Each side of piece placed in the correct position worth a point and, at the end of the experiment, the accumulated points were exchanged for cash. Participants were divided into 2 groups (A and B) in function maximum amount of cash received (R$10,00 or R$20,00 reais respectively). Subsequently, on the results obtained with the groups A and B, a new group was created with 6 participants who received R$10.00 reais and were exposed to ten presentations of conditioned aversive stimuli scheduled with a duration of 15 seconds each (groups A and B were exposed to only 3 presentations of this type, with duration of 1 minute each). Each participant, regardless of the group to which it belonged, performed the Test Task, and obtaining success, started the baseline. It was use the free operant procedure and the reinforcement schema FR1, both Baseline and Experimental Phase. The consequences for hits and errors also were the same. The pilot was initiated so that occurred the stabilization of response rate and the rate of reinforcements obtained. For participants of group a and group B, a schema VT or variable time entered into force at that stage, overlaid on the existing line FR1 schema: in three moments of the game the computer screen was green for 60 seconds and after that time, a fixed number of points (four points which is equivalent to around 10.5% of the total number of points that can be obtained on a puzzle) was withdrawn from the amount of points obtained so far. Loss was flagged by computer through a light sound (similar to coins falling on the floor). For the Group C conditions were identical, except the number of exhibits to the stimuli conditioned. None of the participants presented clearly a performance that could be considered response suppression. The performances were quite varied, and not consistent. The curves of the Experimental Phase present similar variations observed on the Baseline ones and are not consistent and exclusively quotas (and contiguous) upon presentation of the green screen / O presente trabalho pretendeu investigar se a magnitude do reforço é uma variável relevante na determinação da supressão condicionada da resposta de clicar , produzida pela apresentação de um estímulo punidor negativo , em humanos. Trinta participantes foram recrutados e tinham como tarefa montar quebra-cabeças de 24 peças em um computador. A cadeia de respostas observada foi clicar, arrastar e acoplar peças dos quebra-cabeças. Cada lado da peça colocado na posição correta valia um ponto e, ao final do experimento, os pontos acumulados eram trocados por dinheiro. Os participantes foram distribuídos em 2 grupos (A e B) em função quantidade máxima de dinheiro recebida (R$ 10,00 ou R$ 20,00 reais respectivamente). Posteriormente, diante dos resultados obtidos com os grupos A e B, um novo grupo foi criado com 6 participantes que receberam R$ 10,00 reais e foram expostos a dez apresentações dos estímulos aversivos condicionados programados com duração de 15 segundos cada (em quanto os grupos A e B foram expostos a apenas 3 apresentações desse tipo, com duração de 1 minuto cada). Cada participante, independentemente do grupo a que pertencia, realizada o Teste de Tarefa e, obtendo êxito, iniciava a Linha de Base. Foram utilizados o procedimento de operante livre e o esquema de reforçamento FR1 tanto na Linha de Base quanto na Fase Experimental. As conseqüências para acertos e erros também eram as mesmas. A fase Experimental era iniciada assim que ocorresse a estabilização da taxa de respostas e da taxa de reforços obtidos. Para os participantes do Grupo A e do Grupo B, um esquema VT ou tempo variável entrava em vigor nessa fase, sobreposto ao esquema FR1 vigente: em três momentos do jogo a tela do computador ficava verde por 60 segundos e ao final desse período, um número fixo de pontos (quatro pontos que é equivalente a em torno de 10,5% do total de pontos possíveis de serem obtidos em um quebra-cabeça) era retirado do montante de pontos obtidos até o momento. A perda de pontos era sinalizada pelo computador através de um som ameno (semelhante ao de moedas caindo no chão). Para o Grupo C as condições eram idênticas, exceto o número de exposições aos estímulos condicionados. Nenhum dos participantes apresentou claramente um desempenho que poderia ser considerado supressão de resposta. Os desempenhos foram bastante variados, e não consistentes. As curvas da Fase Experimental apresentam variações semelhantes e às observadas na Linha de Base e não são consistentes e exclusivamente contingentes (e contíguas) à apresentação da tela verde

Recent large earthquakes put in evidence the need of improving and developing robust and rapid procedures to properly calculate the magnitude of an earthquake in a short time after its occurrence. The most famous example is the 26 December 2004 Sumatra earthquake, when the limitations of the standard procedures adopted at that time by many agencies failed to provide accurate magnitude estimates of this exceptional event in time to launch early enough warnings and appropriate response. Being related to the radiated seismic energy ES, the energy magnitude ME is a good estimator of the high frequency content radiated by the source which goes into the seismic waves. However, a procedure to rapidly determine ME (that is to say, within 15 minutes after the earthquake occurrence) was required. Here it is presented a procedure able to provide in a rapid way the energy magnitude ME for shallow earthquakes by analyzing teleseismic P‑waves in the distance range 20-98. To account for the energy loss experienced by the seismic waves from the source to the receivers, spectral amplitude decay functions obtained from numerical simulations of Greens functions based on the average global model AK135Q are used. The proposed method has been tested using a large global dataset (~1000 earthquakes) and the obtained rapid ME estimations have been compared to other magnitude scales from different agencies. Special emphasis is given to the comparison with the moment magnitude MW, since the latter is very popular and extensively used in common seismological practice. However, it is shown that MW alone provide only limited information about the seismic source properties, and that disaster management organizations would benefit from a combined use of MW and ME in the prompt evaluation of an earthquake’s tsunami and shaking potential. In addition, since the proposed approach for ME is intended to work without knowledge of the fault plane geometry (often available only hours after an earthquake occurrence), the suitability of this method is discussed by grouping the analyzed earthquakes according to their type of mechanism (strike-slip, normal faulting, thrust faulting, etc.). No clear trend is found from the rapid ME estimates with the different fault plane solution groups. This is not the case for the ME routinely determined by the U.S. Geological Survey, which uses specific radiation pattern corrections. Further studies are needed to verify the effect of such corrections on ME estimates. Finally, exploiting the redundancy of the information provided by the analyzed dataset, the components of variance on the single station ME estimates are investigated. The largest component of variance is due to the intra-station (record-to-record) error, although the inter-station (station-to-station) error is not negligible and is of several magnitude units for some stations. Moreover, it is shown that the intra-station component of error is not random but depends on the travel path from a source area to a given station. Consequently, empirical corrections may be used to account for the heterogeneities of the real Earth not considered in the theoretical calculations of the spectral amplitude decay functions used to correct the recorded data for the propagation effects. / Starke Erdbeben in letzter Zeit zeigten deutlich den steigenden Bedarf nach einer Verbesserung und Entwicklung von stabilen und schnellen Methoden, um die Magnitude eines Erdbebens korrekt innerhalb kürzester Zeit nach dessen Auftreten zu ermitteln. Das bisher bekannteste Fallbeispiel in diesem Zusammenhang stellt das Sumatra-Erdbeben vom 26 Dezember 2004 dar. Dieses außergewöhnliche Ereignis zeigte deutlich die Grenzen der bisher gängigen und von den meisten Behörden zu dieser Zeit verwendeten Methoden zur Ermittlung der Erdbebenmagnitude. So konnte für dieses Beben mit den gängigen Ansätzen zeitnah die Magnitude nicht korrekt bestimmt werden / um eine angemessene Frühwarnung und entsprechende Gegenmaßnahmen einzuleiten. Die Energiemagnitude ME steht in direkter Verbindung mit der abgestrahlten seismischen Energie ES und stellt somit eine guten Abschätzung für den Hochfrequenzanteil dar, der von der Quelle ausgestrahlt wird und in die seismischen Wellen einfließt. Eine Methode, welche eine schnelle Ermittlung von ME ermöglicht (d.h. innerhalb von maximal 15 Minuten nach dem Erdbeben) wäre in diesem Falle benötigt worden. Im Rahmen dieser Arbeit wird eine Methode vorgestellt, die eine solche schnelle Ermittlung der Energiemagnitude ME für oberflächennahe Erdbeben ermöglicht, indem teleseismische P-Wellen im Bereich von 20°-98° analysiert werden. Um den Energieverlust der seismischen Wellen von deren Quelle bis zu den Empfängern angemessen zu berücksichtigen, werden spektrale Amplituden-Abnahmefunktionen verwendet, welche aus numerischen Simulationen von Greenschen Funktionen basierend auf dem durchschnittlichen globalen Modell AK135Q abgeleitet werden. Die vorgestellte Methode wurde mit einem umfangreichen globalen Datensatz (ca. 1000 Erdbeben) getestet, und die zeitnah ermittelten ME-Abschätzungen wurden mit anderen Magnitudenskalen verschiedener Behörden verglichen. Ein Vergleich mit der Momentenmagnitude MW war hierbei von besonderem Interesse, da diese Skala heutzutage weitverbreitet ist und häufig zum Einsatz kommt. Es zeigt sich jedoch, dass MW alleine nur begrenzte Informationen über die seismischen Herdeigenschaften liefern kann, und dass Organisationen des Katastrophenmagements von einer kombinierten Nutzung von MW und ME gerade hinsichtlich der unmittelbaren Evaluierung des tsunamigenen Potentials und der Erschütterungswirkung eines Erdbebens profitieren könnten. Die verwendete Methode zur Ermittlung von ME kommt ohne Wissen über die geometrischen Eigenschaften der Verwerfungszone aus (diese sind meist erst Stunden nach einem Erbeben verfügbar). Entsprechend wird die Eignung dieser Methode durch Eingruppierungen der analysierten Erdbeben nach ihrem Wirkungsmechanismus (Scherbruch, Abschiebung, Aufschiebung, etc.) diskutiert. Für die schnelle Abschätzung von ME ist kein klarer Trend unter Verwendung der verschiedenen Herdflächenlösungen erkennbar. Für ME-Werte, welche standardmäßig vom U.S. Geological Survey mit speziellen Korrekturwerten für die Abstrahlungscharakteristika ermittelt werden, trifft dies jedoch nicht zu. Weitere Untersuchungen sind nötig, um die Auswirkungen solcher Korrekturen auf die ME-Abschätzungen zu verifizieren. Indem die Redundanz der Informationen des analysierten Datensatzes ausgenutzt wurde, konnte die Varianz bei den Einzelstations-ME-Abschätzungen untersucht werden. Die größte Abweichung zeigt sich aufgrund von Intra-Stations-Fehlern (record-to-record), wenngleich auch der Inter-Stations-Fehler (station-to-station) nicht vernachlässigbar ist; so nimmt er für einige Stationen mehrere Magnitudeneinheiten an. Des Weiteren konnte gezeigt werden, dass der Intra-Stations-Anteil des Gesamtfehlers nicht zufällig ist, sondern abhängig vom Wellenweg von einem Quellgebiet zu einer bestimmten Station. Folglich können empirische Korrekturen dazu benutzt werden, den Heterogenitäten der realen Erde gerecht zu werden, welche heutzutage nicht in den theoretischen Kalkulationen der spektralen Amplituden-Abnahmefunktionen zur Korrektur der aufgezeichneten Daten verwendet werden.

Submitted by Fernanda Weschenfelder (fernanda.weschenfelder@uniceub.br) on 2017-08-28T19:50:40Z No. of bitstreams: 1 61500027.pdf: 1641143 bytes, checksum: 257099ddfbd3a6ecf3b102e57d4a1a86 (MD5) / Approved for entry into archive by Fernanda Weschenfelder (fernanda.weschenfelder@uniceub.br) on 2017-08-28T20:37:54Z (GMT) No. of bitstreams: 1 61500027.pdf: 1641143 bytes, checksum: 257099ddfbd3a6ecf3b102e57d4a1a86 (MD5) / Made available in DSpace on 2017-08-28T20:37:54Z (GMT). No. of bitstreams: 1 61500027.pdf: 1641143 bytes, checksum: 257099ddfbd3a6ecf3b102e57d4a1a86 (MD5) Previous issue date: 2017-07 / O presente estudo teve o objetivo de verificar o efeito do ganho e da perda de pontos na correspondência verbal em um jogo de cartas no qual a distorção do relato dos valores das cartas poderia resultar em maior probabilidade de vitória nas partidas. Para isso, o procedimento experimental consistiu em um jogo de cartas de computador, que foi realizado em pares de oponentes, o computador foi o oponente para todos os participantes. Cada partida do jogo foi composta por rodadas, e o objetivo dos jogadores foi obter o maior número de pontos, os quais foram obtidos ou mantidos quando se relatou maior valor que o oponente nas rodadas em que não houve checagem, ou dependendo da precisão do relato verbal nas rodadas em que houve checagem do relato. Os pontos foram trocados por trabalhos na disciplina que os participantes estavam matriculados. Foram realizados dois experimentos, sendo que o Experimento 1, teve como objetivo verificar o efeito da perda de pontos sobre a frequência dos relatos distorcidos em cinco mestrandos. O experimento contou com três condições experimentais: Perda de Pontos Magnitude Alta (P Alta), Perda de Pontos Magnitude Baixa (P Baixa) e Sem Pontos (SP), que se diferenciavam quanto à quantidade de perda de pontos caso houvesse checagem do relato e o participante tivesse distorcido. Os participantes jogaram nas três condições experimentais em três dias diferente: Pré Treino, Dia 2 e 3. Os dados mostraram que, em geral, a condição experimental que mais apresentou distorções foi SP e P Baixa teve mais distorções do que P Alta, mostrando assim que a variável independente controlou a correspondência verbal. Já o Experimento 2, teve como objetivo verificar o efeito do ganho de pontos sobre a frequência dos relatos precisos em quatro mestrandos. O Experimento 2 também teve três condições experimentais: Ganho de Pontos Magnitude Alta (G Alta), G de Pontos Magnitude Baixa (G Baixa) e SP, que se diferenciavam quanto à quantidade de ganho de pontos em rodadas com checagem e o participante tivesse relatado com precisão. Os resultados mostraram que houve mais distorção em SP e G Baixa teve mais distorções do que G Alta. Como os desvios padrão foram baixos, as diferenças de frequências de distorções entre as condições, ainda que pequenas, deram indícios que as variáveis manipuladas tiveram efeito em ambos os experimentos. Em ambos os experimentos, variáveis como: a frequência de distorções do oponente; valor obtido na carta; e, o reforço do ganho do trabalho na disciplina afetaram a correspondência verbal dos participantes. Sugerese replicações do estudo com alterações metodológicas para produzir mais discrepâncias nos resultados das diferentes condições experimentais e também mais distorções nos experimentos, em geral.

ITC/USA 2011 Conference Proceedings / The Forty-Seventh Annual International Telemetering Conference and Technical Exhibition / October 24-27, 2011 / Bally's Las Vegas, Las Vegas, Nevada / Inspired by human auditory system, an improved direction of arrival (DOA) technique using only two antennas with a scatterer in between them to achieve additional magnitude cues is proposed. By exploiting the incident-angle-dependent magnitude and phase differences between the two monopole antennas and applying 2-D / 3-D multiple signal classification algorithms (MUSIC), the DOA of an incident microwave signal can be estimated. Genetic algorithm is applied to optimize the scatterer geometry for the 3-D DOA estimation. The simulated results of both the azimuth and three-dimensional DOA estimation have shown an encouraging accuracy and sensitivity by incorporating a lossy scatterer.

Analysis of phase-contrast MR images yields cardiac flow information which can be manipulated to produce accurate segmentations of the aorta. New phase contrast segmentation algorithms are proposed that use mean-based calculations and least mean squared curve fitting techniques. A GPU is used to accelerate these algorithms and it is shown that it is possible to achieve up to a 2760x speedup relative to the CPU computation times. Level sets are applied to a magnitude image, where initial conditions are given by the previous segmentation algorithms. A qualitative comparison of results shows that the algorithm parallelized on the GPU appears to produce the most accurate segmentation. After segmentation, particle trace simulations are run to visualize flow patterns in the aorta. A procedure for the definition of analysis planes is proposed from which virtual particles can be emitted/collected within the vessel, which is useful for future quantification of various flow parameters. / October 2014

L’utilisation d’outils est un trait définitoire du genre Homo. Il est donc fondamental de mieux connaître les bases cognitives et cérébrales nous permettant d’utiliser des outils. Les modèles cognitivistes actuels expliquent l’utilisation d’outils à travers l’hypothèse de l’activation d’une mémoire gestuelle (i.e., engrammes gestuels ou visuo-kinétiques, ou connaissances sensorimotrices sur la manipulation ; voir Rothi, Ochipa, & Heilman, 1991 ; Buxbaum, 2001) ? Cette hypothèse ne permet toutefois pas de comprendre l’utilisation d’outils nouveaux. Une hypothèse alternative a été établie, suggérant que toute situation d’utilisation d’outils (familiers et nouveaux) requière un raisonnement technique (e.g., Osiurak & Badets, 2016). Ce type de raisonnement, qui impliquerait le lobe pariétal inférieur gauche, nous permettrait de formuler l’action mécanique et d’évaluer les propriétés physiques des outils et des objets. Dans le cadre de cette hypothèse, l’une des finalités de cette thèse était de mieux comprendre les troubles d’utilisation d’outils chez des patients cérébro-lésés. Le présent travail s’est également porté sur l’investigation de la cognition numérique. Par ce terme, nous ne faisons pas uniquement référence au calcul mental ou à l’arithmétique. Nous englobons également ce que Dehaene et Cohen (1995) ont nommé code analogique dans leur Modèle du Triple Code. Ce code stockerait les représentations des quantités numériques au sein des lobes pariétaux. Autrement dit, il contiendrait le sens du nombre (Dehaene, 1997) permettant d’associer une étiquette symbolique (e.g., chiffre arabe) à la quantité correspondante. Au quotidien, ce serait grâce à ces représentations que nous pourrions comparer ou estimer la numérosité des ensembles d’objets. L’objectif principal de cette thèse était de rapprocher, tant au niveau cognitif que cérébral, ces deux domaines d’intérêt que sont l’utilisation d’outils et la cognition numérique. En effet, nous avons remarqué que ces deux capacités nécessitaient toutes deux un processus commun d’estimation de la magnitude (i.e., magnitude des propriétés physiques et magnitude des quantités numériques). En outre, au niveau cérébral, elles nécessitent l’activation de régions communes dans le lobe pariétal. Pour penser ce lien, nous nous sommes appuyés sur la théorie de la magnitude (ATOM) formulée par Walsh (2003). Celui-ci postule que toutes les magnitudes, c’est-à-dire toutes les dimensions qui peuvent être décrites par des relations « plus que/moins que », soient traitées au sein d’un système commun et unique dans le lobe pariétal droit (Bueti & Walsh, 2009). Nous avons supposé que la magnitude des propriétés physiques pourrait être traitée dans ce système au même titre que les magnitudes discrètes (e.g., numérosité) et continues (e.g., temps, espace). Nos résultats ont mis en évidence un trouble de l’utilisation d’outils nouveaux chez les patients LBD, sans difficultés apparentes pour estimer les propriétés physiques. Les patients RBD étaient déficitaires dans toutes les conditions évaluant la cognition numérique, contredisant les prédictions issues du TCM. Ces patients étaient également en difficulté pour estimer la longueur mais pas le poids. Comme des associations entre estimation de la longueur et du poids, et entre estimation de la longueur et cognition numérique ont été observées dans les différents groupes, nous suggérons que le système de magnitude soit divisé en sous-systèmes. Fait étonnant, nous avons trouvé une association entre utilisation d’outils et calcul approximatif chez les patients LBD supposant une tentative de compensation de l’utilisation par le calcul. Finalement, il semble que l’utilisation d’outils et la cognition numérique reposent sur des mécanismes neurocognitifs distincts, puisque les différents types de magnitudes ne paraissent pas être traités au sein d’un système commun et unique. / Tool use is a defining feature of the genus Homo. It is therefore fundamental to better understand the cognitive and cerebral bases that allow us to use tools. The current cognitivist models explain tool use through the hypothesis of an activation of gestural memories (i.e., gestural or visuo-kinetic engrams, or sensorimotor knowledge of manipulation; see Rothi, Ochipa, & Heilman, 1991; Buxbaum, 2001). This theory is unable to explain the use of novel tools. An alternative hypothesis suggests that any situation of tool use (familiar and new) requires technical reasoning (e.g., Osiurak & Badets, 2016). This reasoning, involving the left inferior parietal lobe, would enable to formulate the mechanical action and to evaluate the physical properties of tools and objects. One of the aims of this thesis was to better understand the tool use disorders in brain-damaged patients, within the framework of the technical reasoning hypothesis. This work has also focused on the investigation of numerical cognition. By this term we refer to mental arithmetic and math, but also to analogical code (see the Triple Code Model, Dehaene & Cohen, 1995). It corresponds to the representation of numerical quantities, stored in the parietal lobes. In other words, this code would contain the sense of number (Dehaene, 1997) to associate a symbolic label (e.g., Arabic digits) with the corresponding quantity. In everyday life, this representation would be critical to compare or estimate the numerosity of object sets.The main objective of this thesis was to explore, at cognitive and cerebral levels, whether links exist between both fields of interest that are tool use and numerical cognition. Indeed, we noticed that both capacities need a common process of magnitude estimation (i.e., physical properties and numerical quantity). In addition, at the cerebral level, they require the activation of common regions in the parietal lobe. We relied on the Theory Of Magnitude (ATOM) formulated by Walsh (2003). It postulates that all magnitudes, namely the dimensions described by “more than/less than” relationships (e.g., Is this stick long enough to reach a given place?), are processed within a common and unique system, in the right parietal lobe (Bueti & Walsh, 2009). We assumed that the magnitude of physical properties could be processed in this system as well as the discrete (e.g., numbers) and continuous (e.g., time, space) magnitudes. Our results highlighted a disorder of novel tool-use in LBD patients, who nevertheless had no difficulty in estimating physical properties. The RBD patients were impaired in all conditions assessing the numerical cognition, refuting the predictions derived from TCM. They were also impaired in the estimation of the length but not of the weight. As associations between estimation of length and of weight, and between estimation of length and numerical cognition have been observed in the different groups, we suggest that the magnitude system be divided into subsystems. Surprisingly, we found an association between tool use and approximate calculation in LBD patients assuming an attempt to compensate tool use by calculation. Finally, it seems that tool use and numerical cognition rely on distinct neurocognitive mechanisms since the different types of magnitudes might not be processed within a common and unique system of magnitude