Made available in DSpace on 2014-06-11T19:22:54Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-12-09Bitstream added on 2014-06-13T20:49:31Z : No. of bitstreams: 1 vitorio_r_me_rcla.pdf: 738679 bytes, checksum: f6658463b86c0d4b2c523cc21a93e6bb (MD5) / Pouco é conhecido sobre o andar de pacientes com doença de Parkinson (DP) em terrenos irregulares. Ainda, nenhum estudo abordou o controle visual na tarefa de ultrapassar obstáculo em pacientes com DP. Assim, o objetivo do estudo foi analisar o papel da visão no controle locomotor durante a ultrapassagem de obstáculos de diferentes alturas em idosos com DP e idosos sadios. Participaram 12 idosos com DP, classificados entre os estágios 1 e 2,5 da escala de Hoehn & Yahr, e 12 idosos sadios com idade, gênero e características antropométricas semelhantes. Os participantes foram convidados a percorrer andando, em velocidade preferida, uma distância de 8 metros, em condições sem obstáculo (SO) e com obstáculo baixo (OB) ou alto (OA). As tentativas foram apresentadas combinando condições de visão (informação visual dinâmica, estática e autosselecionada) e de obstáculo (SO, OB e OA), em 3 tentativas por condição, totalizando 27 tentativas; realizadas em 3 blocos. A amostragem visual foi manipulada através do uso de óculos de lentes de cristal líquido. A análise cinemática foi realizada tridimensionalmente e a análise cinética através de duas plataformas de força. As variáveis dependentes selecionadas incluíram a quantidade e duração das amostragens visuais autosselecionadas, o número de contatos, os parâmetros espaciais e temporais e variáveis extraídas a partir das curvas força-tempo normalizadas nas fases de aproximação e ultrapassagem do obstáculo. O tratamento estatístico das variáveis incluiu a estatística descritiva, uma ANOVA e oito MANOVAs. Os resultados revelaram que as manipulações experimentais, do terreno e da amostragem visual, provocaram modificações no comportamento motor dos participantes, tanto nos parâmetros cinemáticos como nos cinéticos. As condições de obstáculo alto e de informação visual estática foram as que mais... / The Parkinson's disease (PD) patients' behavior during walking on uneven terrain is less known. Furthermore, we didn't find any paper that studied the visual control during obstacle avoidance task in people with PD. The aim of this study was to analyze the role of vision in locomotor control during obstacle avoidance of different heights in people with PD and healthy elderly. It has been collected data of 12 PD patients (from 1 to 2.5 stages in the Hoehn & Yahr Scale) and 12 healthy elderly matched by age, gender and anthropometric characteristics. Participants were invited to walk, at preferred velocity, on an 8m long pathway, under conditions without obstacle (WO), ankle height obstacle (AO) and mid shank height obstacle (MSO). Trials combined conditions of visual information (DVI = dynamic visual information; SVI = static visual information; SSVI = self-selected visual information) and obstacle (WO, AO, MSO); twenty-seven trials were realized; which were distributed into 3 blocks. The visual sample was manipulated by the use of liquid crystal display goggles. Kinematics and kinetic analysis were realized by digital camcorders and two force plates, respectively. The selected dependent variables refer to amount of self-selected visual information, obstacle contacts, spatial and temporal parameters during the approaching and crossing phases and variables extracted from normalized force-time curves. Variables were statistically treated in a descriptive way and by one ANOVA e eight MANOVAs. Results showed that experimental manipulations, terrain and visual sample, modified motor behavior of participants. Gait control was more disturbed by MSO and SVI conditions. The higher number of obstacle contacts was observed in PD patients at SVI condition. PD influenced, in approach phase, spatial kinematics variables and stride velocity and, in crossing phase, leading limb propulsion for gait... (Complete abstract click electronic access below)

Orientador: Lilian Teresa Bucken Gobbi / Banca: Florindo Stella / Banca: Renato de Moraes / Resumo: Pouco é conhecido sobre o andar de pacientes com doença de Parkinson (DP) em terrenos irregulares. Ainda, nenhum estudo abordou o controle visual na tarefa de ultrapassar obstáculo em pacientes com DP. Assim, o objetivo do estudo foi analisar o papel da visão no controle locomotor durante a ultrapassagem de obstáculos de diferentes alturas em idosos com DP e idosos sadios. Participaram 12 idosos com DP, classificados entre os estágios 1 e 2,5 da escala de Hoehn & Yahr, e 12 idosos sadios com idade, gênero e características antropométricas semelhantes. Os participantes foram convidados a percorrer andando, em velocidade preferida, uma distância de 8 metros, em condições sem obstáculo (SO) e com obstáculo baixo (OB) ou alto (OA). As tentativas foram apresentadas combinando condições de visão (informação visual dinâmica, estática e autosselecionada) e de obstáculo (SO, OB e OA), em 3 tentativas por condição, totalizando 27 tentativas; realizadas em 3 blocos. A amostragem visual foi manipulada através do uso de óculos de lentes de cristal líquido. A análise cinemática foi realizada tridimensionalmente e a análise cinética através de duas plataformas de força. As variáveis dependentes selecionadas incluíram a quantidade e duração das amostragens visuais autosselecionadas, o número de contatos, os parâmetros espaciais e temporais e variáveis extraídas a partir das curvas força-tempo normalizadas nas fases de aproximação e ultrapassagem do obstáculo. O tratamento estatístico das variáveis incluiu a estatística descritiva, uma ANOVA e oito MANOVAs. Os resultados revelaram que as manipulações experimentais, do terreno e da amostragem visual, provocaram modificações no comportamento motor dos participantes, tanto nos parâmetros cinemáticos como nos cinéticos. As condições de obstáculo alto e de informação visual estática foram as que mais... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The Parkinson's disease (PD) patients' behavior during walking on uneven terrain is less known. Furthermore, we didn't find any paper that studied the visual control during obstacle avoidance task in people with PD. The aim of this study was to analyze the role of vision in locomotor control during obstacle avoidance of different heights in people with PD and healthy elderly. It has been collected data of 12 PD patients (from 1 to 2.5 stages in the Hoehn & Yahr Scale) and 12 healthy elderly matched by age, gender and anthropometric characteristics. Participants were invited to walk, at preferred velocity, on an 8m long pathway, under conditions without obstacle (WO), ankle height obstacle (AO) and mid shank height obstacle (MSO). Trials combined conditions of visual information (DVI = dynamic visual information; SVI = static visual information; SSVI = self-selected visual information) and obstacle (WO, AO, MSO); twenty-seven trials were realized; which were distributed into 3 blocks. The visual sample was manipulated by the use of liquid crystal display goggles. Kinematics and kinetic analysis were realized by digital camcorders and two force plates, respectively. The selected dependent variables refer to amount of self-selected visual information, obstacle contacts, spatial and temporal parameters during the approaching and crossing phases and variables extracted from normalized force-time curves. Variables were statistically treated in a descriptive way and by one ANOVA e eight MANOVAs. Results showed that experimental manipulations, terrain and visual sample, modified motor behavior of participants. Gait control was more disturbed by MSO and SVI conditions. The higher number of obstacle contacts was observed in PD patients at SVI condition. PD influenced, in approach phase, spatial kinematics variables and stride velocity and, in crossing phase, leading limb propulsion for gait... (Complete abstract click electronic access below) / Mestre

Orientador: Tânia Regina de Luca / Banca: Antonio Celso Ferreira / Banca: Milton Carlos Costa / Banca: Ana Maria Mauad / Banca: Marcos Francisco Napolitano de Eugenio / Resumo: Os anos de 1959 a 1962 são considerados como período Bossa Nova, época em que o estilo musical floresceu e se afirmou como marca distintiva. Sabe-se, porém, que o termo Bossa Nova foi desde logo utilizado para rotular o mais variado leque de atividades, objetos e situações. Por sua força sugestiva, relacionada a dinamismo e novidade, a sigla BN integrou o imaginário e representações de uma época, para a qual o Brasil aparecia como país jovem, moderno e promissor. Esta pesquisa aborda justa-mente essa movimentação bossanovista em sua vertente não-musical. Para tanto, em-prega a revista O Cruzeiro como fonte de material e objeto de estudo em si, haja vista a quantidade substancial de menções e utilizações que fez do termo Bossa Nova. Ana-lisam-se, aqui, os vários sentidos conferidos ao neologismo da moda e a função da música como polarizadora dessas representações. Contudo, dá-se atenção especial a um tipo peculiar de design gráfico explorado pela revista nos anos de 1959 e 1960, intitulado "paginações Bossa Nova". As matérias assim configuradas se caracterizaram pela geometrização, economia de elementos e amplo uso de fotomontagens. Além disso, propuseram interessante mescla entre coluna social, biografia, humor, expe-rimentação e manifesto pela atualização da forma de acordo com as linhas constru-tivistas que vigoravam em São Paulo e Rio de Janeiro naquele momento. Esses no-vos formatos de reportagens são analisados com base na história do jornalismo ilus-trado e nos intercâmbios havidos entre a imprensa periódica e campos dedicados à pesquisa formal mais pura. Demonstra-se, por fim, como alguns artistas, intelectu-ais e jornalistas brasileiros situados na transição entre as décadas de 50 e 60 co-mungaram ideais de modernidade análogos e os difundiram como ferramentas para a construção de mentalidades e representações sociais. / Abstract: The years between 1959 and 1962 are considered as Bossa Nova period, an ep-och on which the musical style flourished and settled as a distinctive brand. It is known that the term Bossa Nova was used soon to label the most varied fan of activities, objects and situations. Due to its suggestive strength related to dynamism and novelty, the label BN integrated the imaginary and representations of a time to which Brazil came up as a young country, modern and promising. This research holds such "bossanovistic" move-ment in its non-musical expression. This way, the weekly magazine O Cruzeiro is used as source of material and object of study in itself, regarding the substantial quantity of references and uses on Bossa Nova term. Several senses referring to the neologism and the function of music polarizing such representations are analyzed hereby. Nevertheless, special attention is given to a peculiar type of graphic design explored by the magazine in 1959 and 1960, named "Bossa Nova pages". The issues thus configurated are charac-terized by the geometry, economy of elements and wide use of photomontage. In addi-tion, an interesting mingle among social article, biography, humor, experiment and manifestation for the updating of the graphic form was proposed according to the "con-structivists" thoughts which were coming out in São Paulo and Rio de Janeiro at the time. Such new formats of reports are both analyzed and based upon the history of the illustrative journalism as well as in the interchanges that there have been between the periodical press and fields dedicated to a purer formal research. Eventually, it is demon-strated how some artists, intellectuals and Brazilian reporters situated in the transition between fifties and sixties joined similar ideals of modernity, widespreading them as tools for the construction of mentalities and social representations. / Doutor

The problem of this experimental study is to determine to what extent visual information may dominate over audio information. Additionally, the experimental design addresses problems with previous research in this area and emphasizes simplified approaches to the study of channel condition effects. The study does not include investigations of learning theory or short-term memory, but processes of listening and long-term memory are incorporated into the design. A stimulus of sound effects and slides was utilized in one audio and two audio-visual channel conditions, and results showed a high recall among all subjects in all three conditions. The study concludes that channel condition has little effect at low levels of information.

This project examined the effects menstruation may have on visual attention in women. A recent study examined electroencephalographic (EEG) gender differences using a visual object recognition task. Results indicated certain EEG amplitudes (specifically, P300 and N400) are greater in women than men. This study extended the previous findings to determine if these increased EEG amplitudes vary across menstrual phases. Eighteen female participants participated in a series of 3 EEG recording sessions using the same visual object recognition task from the previous study; 18 male participants completed this task once. Analyses from 15 of the 18 female and 16 of the 18 male participants support the previous finding of larger P300 amplitudes in response to relevant stimuli for women compared with men. While there was no distinctive N400 component in this study, there was a late negative (LN) component which was found to vary significantly between men and women. In addition, multiple visual evoked potential (VEP) components varied significantly across the menstrual cycle. In particular, the N200 component appeared to provide greater differences between menstrual phases than either the P300 or LN components; however, the results varied greatly by head location. The differentiation found with VEP components in response to the pop-out task used in this study provide support for basic visual processing variation across the menstrual cycle and between genders.

The aim of this thesis was to investigate how visual information is organised in perceptual short term memory, with special interest in colour, spatial frequency and velocity. Previous studies of VSTM have indicated the existence of specific memory mechanisms for visual attributes such as orientation, spatial frequency, velocity, contrast and colour. The retention of information in visual short term memory for these basic visual attributes can be disrupted by the presentation of masking stimuli during inter-stimulus intervals (ISIs), which are outside the range of traditional sensory masking. We exploited this memory masking effect in order to examine the organisation of visual information in VSTM. Four groups of experiments were conducted in which participants carried out a delayed discrimination paradigm that employed a two-alternative forced choice (2-AFC) procedure in conjunction with a method of constant stimuli. The fidelity of VSTM was measured by performance markers such as discrimination thresholds and point of subjective equalities. We have found selective memory masking effects, which serve as further evidence in favour of the modular organisation in VSTM, namely, that human visual perceptual memory is based upon multiple, tuned channels in case of colour, spatial frequency and speed, similar to those found in the earliest stages of visual processing for spatial frequency. Moreover, each of these storage mechanisms are tuned to a relatively narrow range of stimulus parameters that are closely linked to visual discrimination mechanisms. These findings add further support to the view that low-level sensory processing mechanisms form the basis for the retention of colour, spatial frequency and velocity information in perceptual memory. We also found evidence for the broad range of transfer of memory masking effects across spatial location, which indicates more long range, long duration interactions between channels that are likely to rely upon contributions from neural processes located in higher visual areas. In conclusion, the experiments presented in this thesis provide significant insight into the organization of visual information in perceptual short term memory. / Federation of Ophthalmic and Dispensing Opticians

Examination of goal-directed aiming tasks has revealed that rapid, discrete human action is amendable to online control. This control affords humans a margin of error in movement planning and execution as well as a means of acquiring their goals when the body and/or the environment are extrinsically perturbed. For over a century, the models of online movement control that have best described the trajectories and outcomes of goal-directed reaches hold that these movements are composed of two distinct components. The first component moves the limb from its resting position towards the target. The second component is a corrective movement that is formed on the basis of a visual referencing of the moving limb and target positions. As such, the temporal and spatial characteristics of these discrete movement changes have been attributed to the limits of visual information processing. Furthermore, the absence of any discrete movement changes in the portions of movements outside of the temporal and spatial limits of vision led many investigators to conclude that first component impulses are ballistic and uncontrollable. However, recent studies involving environmental perturbation and within-subject trial-to-trial spatial variability analyses have evidenced that initial impulses are privy to online control. Because the corrections made early in movement impulses occur quicker than purely afferent visual information can be processed this form of control has been attributed to the use of forward anticipatory processes. The four studies presented here examine the nature of initial impulse control through kinematic analyses of reaches made to targets against various combinations of limb, target, and environment perturbations. This was done in order to evaluate anticipatory control's relationship with visually-regulated control and the relative influence the two processes have on the movement trajectory and performance outcome. The first study examined target-directed reaches made against illusory moving background and target relocation perturbations. The results showed the presence of early anticipatory and late visually-regulated control. Non-interactive main effects of the two perturbations on outcome accuracy revealed that the processes operate independently. The second study tested the applicability of an air discharging stylus as a tool for perturbing reach velocities. The results showed that the stylus effectively perturbed limb velocity and highlighted the presence of a limb forwarding response to either an advancing or hindering perturbation. The findings evidence the non-specific nature of anticipatory control responses. The third study examined reaches made against combinations of actual limb velocity and target position perturbations. The interactive effect of the two perturbations on reach trajectories and outcome accuracy indicated that the perturbations were salient enough to prompt parallel operation of the two control processes. Again, the control of initial movement portions was highlighted by non-specific responses to the perturbations. The fourth study examined reaches made against combinations of illusory and actual perturbations to both the anticipatory and visually-regulated control processes. Interestingly, performers withheld responses to the illusory perturbation unless they were also responding to an actual perturbation. This finding suggests that anticipatory control responses are biased during movement preparation. Furthermore, combined illusory and actual perturbations to target position had interactive effects on visually regulated control. Overall, the studies evidence that target-directed movements are mediated by two modes of control. There is an anticipatory mode of control that operates continuously and, given that reaches are made within the spatial and temporal limits of visual processing, there is also a feedback driven discrete mode of control that overlaps with the continuous mode. / Thesis / Doctor of Philosophy (PhD)

No description available.

The amount and variety of visual information presented on electronic displays is ever-increasing. Finding and acquiring relevant information in the most effective manner possible is of course desirable. While there are advantages to presenting a large number of information objects on a screen at the same time, it can also hinder fast detection of objects of interest. One way of addressing that problem is Voice Assisted Visual Search (VAVS). A user supported by VAVS calls out an object of interest and is immediately guided to the object by a highlighting cue. This thesis is an initial study of the VAVS user interface technique. The findings suggest that VAVS is a promising approach, supported by theory and practice. A working prototype shows that locating objects of interest can be sped up significantly, requiring only half the amount of time taken without the use of VAVS, on average. / Voice-Assisted Visual Search

Made available in DSpace on 2014-06-11T19:30:54Z (GMT). No. of bitstreams: 0 Previous issue date: 2007-08-06Bitstream added on 2014-06-13T19:19:36Z : No. of bitstreams: 1 zago_pfp_dr_rcla.pdf: 1617834 bytes, checksum: 193398c19868a245f447705bc0bf0861 (MD5) / Três experimentos foram propostos para investigar os ajustes dinâmicos nos pesos de múltiplas fontes de informação sensorial. O primeiro experimento investigou as respostas posturais de 18 bebês frente às mudanças abruptas na amplitude do estímulo visual. Eles permaneceram sentados dentro de uma sala móvel por 8 tentativas de 60 segundos cada. A sala ficou estacionária na primeira tentativa. Nas sete tentativas seguintes, a sala foi oscilada em 0,2 Hz com amplitude de 1,1 cm, com exceção da quinta tentativa, na qual a sala foi movimentada em amplitude mais alta (3,2 cm). Os resultados mostraram fraco acoplamento entre informação visual e oscilação corporal. Contudo, a variabilidade de oscilação foi maior em bebês experientes no sentar independente. Nós concluímos que bebês não foram capazes de se adaptar às pequenas alterações na amplitude do estímulo visual. O segundo experimento investigou como o controle postural de crianças se adapta às abruptas mudanças no ambiente visual. Trinta crianças de 4, 8 e 12 anos de idade e dez adultos, permaneceram em pé dentro de uma sala móvel. A situação experimental foi similar a do primeiro experimento exceto que a amplitude baixa da sala foi de 0,5 cm e a amplitude alta foi de 3,2 cm. As respostas posturais de crianças mais velhas e adultas diminuíram mais para o estímulo visual do que aquelas de crianças mais novas quando a amplitude da sala foi aumentada. A variabilidade de oscilação diminuiu com a idade e foi maior durante a tentativa de alta amplitude. Crianças tão novas quanto 4 anos de idade já têm desenvolvida a capacidade de rapidamente diminuir a influência do estimulo visual. Contudo, os mais altos valores de ganho e variabilidade residual para crianças de 4 e 8 anos de idade sugerem que elas não apresentam respostas totalmente calibradas ao nível adulto... / Three experiments were designed to investigate the dynamic adjustments in the weights of multiple sensory modalities. The first experiment investigated the postural responses of 18 infants to abrupt changes in the amplitude of visual stimulus. They seated inside of a moving room for eight trials of 60 sec apiece. The room was stationary in the first trial. In the following seven trials, the room oscillated at 0.2 Hz with amplitude of 1.1 cm, with the exception of the fifth trial, in which the room moved at higher amplitude (3.2 cm). The results showed weak coupling between visual stimulus and body sway. However, sway variability of experienced sitters was higher in the high-amplitude trial. We concluded that infants were not able to adapt to low range of visual stimulus amplitude. The second experiment investigated how children s postural control adapt to abrupt changes in the surrounding visual environment. Thirty children from 4-, 8- and 12-year olds and ten adults stood upright inside of a moving room. The experimental set-up was similar to the first experiment except that low-amplitude was 0.5 cm and high-amplitude was 3.2 cm. Body sway responses of old children and adults downweight more to the visual stimulus than young children when the amplitude of the room increased. Sway variability decreased with age and was largest during the high-amplitude trial. Children as young as four years of age have already developed the adaptive capability to quickly downweight visual information. However, the higher gain values and residual variability observed for the 4 and 8 year-old children suggest that they have not fully calibrated their response to the adult level. The third experiment investigated the postural responses of two sensory modalities measured simultaneously... (Complete abstract click electronic access below)