Esta pesquisa teve por objetivo investigar empiricamente as decisões interpretativas quanto ao timing e dinâmica de quatro execuções do primeiro movimento da Sonata para piano n.1 de Francisco Mignone. Por meio da comparação de gravações, foram identificadas estratégias expressivas adotadas pelos intérpretes em relação ao timing, dinâmica e articulação, evidenciando assim o direcionamento expressivo do discurso musical em determinados trechos da obra. Tendo em vista os eventos musicais característicos de cada seção da Sonata, foi realizada uma análise da organização rítmica que apoiou a análise das gravações. / This research aimed at empirically investigating the interpretative decisions regarding timing and dynamics of four recorded performances of the first movement of Sonata n.1 for piano by Francisco Mignone. The comparison identified the expressive strategies adopted by the chosen interpreters in relation to articulation and dynamics thus bringing out the temporal profiles of predetermined spans. Issues such as background and organizational planning of the Sonata were taken into account in view of the musical events characteristic of each section. Theories of rhythmic organization supported the analyses of recordings.

Depuis quelques années, l’étude du code neuronal impliqué dans la perception des signaux de communication acoustique est devenue un domaine de recherche considérable. La littérature récente de ce domaine suggère que la discrimination entre ces signaux reposerait plutôt sur une organisation des décharges neuronales en motifs temporels que sur des variations globales de taux de décharge. Ma thèse a eu pour objectif de déterminer dans quelle mesure une régulation des inhibitions corticales peut (i) changer les motifs temporels déclenchés par des vocalisations conspécifiques et hétérospécifiques et (ii) modifier l’information portée par ces motifs sur l’identité des vocalisations. Nous avons enregistré l’activité neuronale dans le cortex auditif de cobayes anesthésiés en 16 sites corticaux lors de la présentation d’un jeu de vocalisations, et avons partiellement bloqué les inhibitions corticales par des applications de Gabazine (4minutes, 10µm). Dans ces conditions, les réponses évoquées sont plus fortes et les motifs temporels plus marqués. L’information mutuelle quantifiée au niveau de chaque site cortical est augmentée mais l’information populationnelle au niveau de l’ensemble des 16 sites enregistrés n’est pas modifiée, un effet qui peut s’expliquer par le fait que la redondance entre les sites corticaux est augmentée. Nous avons ensuite évalué dans quelle mesure une modulation noradrénergique était susceptible de mimer les effets d’un blocage partiel des inhibitions. Bien que les agonistes utilisés (α1, α2 et ) aient tous induit des modifications des réponses évoquées et de la reproductibilité des motifs temporels, aucun d’entre eux n’a induit de changements importants de l’information portée par les réponses neuronales aux vocalisations. En revanche, les effets induits par la phenylephrine, un agoniste α1, sont vraisemblablement sous-tendus par une action sur les inhibitions intra-corticales, ce qui rend plausible l’hypothèse d’une modulation noradrénergique des inhibitions corticales. Il est donc envisageable que l’action coordonnée de plusieurs systèmes neuromodulateurs puisse moduler les inhibitions corticales et ainsi changer la quantité d’information portée par les neurones corticaux sur l’identité des stimuli à discriminer. / Over the last 10 years, the neural code involved in the perception of acoustic communication signals has become a large area of researches. The recent literature suggests that the discrimination between these signals relies more on the temporal organization of neuronal discharges rather than on global changes of firing rate. My PhD thesis aimed at determining to what extent the regulation of cortical inhibition may (i) change the temporal patterns triggered by conspecific and heterospecific vocalizations and (ii) modify the information carried by these patterns on the vocalization identity. Neuronal activity was recorded in the auditory cortex of anesthetized guinea pigs in 16 cortical sites during presentation of a set of vocalizations, and a partial blockage of intra-cortical inhibition was performed by Gabazine application (4 minutes, 10μm). Under these conditions, evoked responses were stronger and the temporal patterns were reinforced. Mutual information quantified at each cortical site was increased but the information computed at the populationnal level did not change, an effect that could be explained by the fact that the redundancy between cortical sites was increased. We then assessed to which extent the noradrenergic modulation can mimic the effects of a partial blockage of inhibitions. Although all the tested drugs modulated both the evoked responses and the spike-timing reliability, none of the noradrenergic agonists used here (α1, α2 and ) induced significant changes in the information carried by neuronal responses. However, the effects induced by phenylephrine, an α1 agonist, seemed to involve an action on the intra-cortical inhibition, which suggests that a noradrenergic modulation of cortical inhibition can operate in the auditory cortex. It is therefore possible to envision that the coordinated action of several neuromodulatory systems modulates cortical inhibition and thus changes the information carried by cortical neurons on the stimuli identity.

Le neurone est une cellule polarisée qui se divise en deux compartiments spécialisés : le compartiment somato-dendritique et le compartiment axonal. Généralement, le premier reçoit l'information en provenance d'autres neurones et le second génère un message en sortie lorsque la somme des entrées dépasse une valeur seuil au segment initial de l'axone. Ce signal de nature discrète appelé potentiel d'action (PA) est propagé activement jusqu'à la terminaison synaptique où il déclenche la transmission chimique de l'information. Cependant, la fonction axonale ne se résume pas à la simple transmission des séquences de PA à l'image d'un câble de télégraphe. L'axone est également capable de transmettre des variations continues de signaux électriques infraliminaires dit analogues et les combiner avec l'information digitale véhiculée par le PA. J'ai consacré la majorité de mon travail de thèse à l'étude de ce nouvel aspect de la fonction axonale dans le cadre de la transmission synaptique entre les neurones pyramidaux au sein du réseau excitateur CA3 de l'hippocampe de rat. Les résultats obtenus à partir d'enregistrements de paires de neurones pendant ma thèse mettent en évidence deux sortes de signalisation analogue et digitale qui aboutissent à la facilitation de la transmission synaptique. La facilitation analogue-digitale (FAD) a été observée lors d'une dépolarisation prolongée, mais également à la suite d'une hyperpolarisation transitoire au niveau du corps cellulaire. Ce sont deux versants d'une même plasticité à court-terme qui découle de l'état biophysique des canaux ioniques sensibles au voltage étant à l'origine du PA. / The neuron is a polarised cell divided into two specialized compartments: the somato-dendritic and the axonal compartment. Generally, the first one receives information arriving from other neurones and the second generates an output message, when the sum of inputs exceeds a threshold value at the axon initial segment. This all-or-none signal, called the action potential (AP) is propagated actively to the synaptic terminal where it triggers chemical transmission of information. However, axonal function is not limited to transmission of AP sequences like a telegraph cable. The axon is also capable of transmitting continuously changing sub-threshold electric signals called analogue signals and to combine them with the digital information carried by the AP. I devoted the majority of my thesis work to the study of these novel aspects of axonal function in the framework of synaptic transmission between pyramidal neurons in the CA3 excitatory network of the rat hippocampus. The results obtained through paired recordings brought to light two kinds of analogue and digital signalling that lead to a facilitation of synaptic transmission. Analogue-digital facilitation (ADF) was observed during prolonged presynaptic depolarization and also after a transient hyperpolarization of the neuronal cell body. These are two sides of the same form of short-term synaptic plasticity depending on the biophysical state of voltage gated ion channels responsible for AP generation. The first variant of ADF induced by depolarization (ADFD) is due to AP broadening and involves Kv1 potassium channels.

In spreads pectrum (SS)watermarking of audio signals, since the watermark acts as an additive noise to the host audio signal, the most important challenge is to maintain perceptual transparency. Human perception is a very sensitive apparatus, yet can be exploited to hide some information, reliably. SS watermark embedding has been proposed, in which psycho-acoustically shaped pseudo-random sequences are embedded directly into the time domain audio signal. However, these watermarking schemes use informed detection, in which the original signal is assumed available to the watermark detector. Blind detection of psycho-acoustically shaped SS watermarking is not well addressed in the literature. The problem is still interesting, because, blind detection is more practical for audio signals and, psycho-acoustically shaped watermarks embedding offers the maximum possible watermark energy under requirements of perceptual transparency. In this thesis we study the blind detection of psycho-acoustically shaped SS watermarks in time domain audio signals. We focus on a class of watermark sequences known as random phase watermarks, where the watermark magnitude spectrum is defined by the perceptual criteria and the randomness of the sequence lies in their phase spectrum. Blind watermark detectors, which do not have access to the original host signal, may seem handicapped, because an approximate watermark has to be re-derived from the watermarked signal. Since the comparison of blind detection with fully informed detection is unfair, a hypothetical detection scheme, denoted as semi-blind detection, is used as a reference benchmark. In semi-blind detection, the host signal as such is not available for detection, but it is assumed that sufficient information is available for deriving the exact watermark, which could be embedded in the given signal. Some reduction in performance is anticipated in blind detection over the semi-blind detection. Our experiments revealed that the statistical performance of the blind detector is better than that of the semi-blind detector. We analyze the watermark-to-host correlation (WHC) of random phase watermarks, and the results indicate that WHC is higher when a legitimate watermark is present in the audio signal, which leads to better detection performance. Based on these findings, we attempt to harness this increased correlation in order to further improve the performance. The analysis shows that uniformly distributed phase difference (between the host signal and the watermark) provides maximum advantage. This property is verified through experimentation over a variety of audio signals. In the second part, the correlated nature of audio signals is identified as a potential threat to reliable blind watermark detection, and audio pre-whitening methods are suggested as a possible remedy. A direct deterministic whitening (DDW) scheme is derived, from the frequency domain analysis of the time domain correlation process. Our experimental studies reveal that, the Savitzky-Golay Whitening (SGW), which is otherwise inferior to DDW technique, performs better when the audio signal is predominantly low pass. The novelty of this work lies in exploiting the complementary nature of the two whitening techniques and combining them to obtain a hybrid whitening (HbW) scheme. In the hybrid scheme the DDW and SGW techniques are selectively applied, based on short time spectral characteristics of the audio signal. The hybrid scheme extends the reliability of watermark detection to a wider range of audio signals. We also discuss enhancements to the HbW technique for robustness to temporal offsets and filtering. Robustness of SS watermark blind detection, with hybrid whitening, is determined through a set of experiments and the results are presented. It is seen that the watermarking scheme is robust to common signal processing operations such as additive noise, filtering, lossy compression, etc.

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In the spring of 2010, I worked with four street youths from Durban to create a short fictional film based on their lives. There were two main components to this project: first, a series of drama workshops and second, the film-making process. The filmmaking process consisted of the participants improvising scenes based on their street lives that I captured on film. This project engaged with Theatre for Development and Participatory Video practices. The young man who initiated this project did so because he wanted to change people’s perceptions of youths who lived on the streets. Additionally, he wanted to change his own perceptions of himself. The film provided baseline data regarding how the participants viewed themselves and their lives on the streets. Analysis of interviews conducted after the completion of the project, when compared with the baseline data, demonstrated social impacts that occurred as a result of making the film. This data was coded and interpreted using François Matarasso’s (1997) positive criteria for the social impact of participating in arts projects as well as corresponding negative categories that I generated. The film, once coded, demonstrated that the participants felt negatively about their lives on the streets, with many examples emerging from the categories Lack of Social Cohesion and Lack of Agency. In contrast, the interviews revealed positive social impacts across all categories, but especially in relation to Personal Development, Local Image and Identity, and Community Empowerment and Self-Determination (Matarasso 1997). The participants reported that they felt differently about themselves as a result of the project. They also said that there had been a change in the way some people treated them. Findings revealed that the film project resulted in positive social impacts on the street youth participants. As a result of the film, they engaged in critical thinking and reflection related to Paulo Freire’s (1970) notion of praxis. They also wished for changes in their lives and in some cases enacted change. It was significant that social impacts and change extended to youths in difficult circumstances. In conclusion, this research proved that participating in the film project broadened and enriched the lives of the participants. Problems arose in terms of sustainability. Further projects and research are needed to establish the possible impacts from longterm and sustainable arts projects on youths from the streets. / Thesis (M.A.)-University of KwaZulu-Natal, Durban, 2011.

The aim of the thesis is to investigate and analyse students’ expressions of pleasure and displeasure and how these are manifested in actions in the teaching of textile sloyd in lower secondary education. The study’s focus is on students’ expressions of pleasure and displeasure in social action in the working processes of textile sloyd and on how these expressions can be related to learning. The empirical material consists of observations, video and audio recordings, individual interviews and focus group interviews, where video and audio recordings were used as stimulated recall. In all, 32 lessons in textile sloyd and 49 students aged 14-15 years were observed at four different schools. Theoretically, the thesis is based on Mead’s practical intersubjectivity and on Dewey’s theory of experience-based learning and dependence on emotions and actions. Pleasure and displeasure constitute valuating partial aspects of emotions. Based on a socio-cultural perspective, emotions are regarded as practices which arise from different predispositions’ dependence on the social context. The study’s analytical approach is hermeneutical. Critical incidents regarding students’ expressions of pleasure and displeasure in social action found in observations and video and audio recordings were analysed in terms of Mead’s concept of gestures. The events were combined with what the students describe as critical incidents of pleasure and displeasure in the interviews and focus group talks. The material was then thematised. Several situations were then subjected to deeper analysis based on sociality and a change in perspective and related to different concepts of learning. The result of the thesis shows a tripartite semantic structure where students’ pleasure and displeasure in textile sloyd are mainly based on textile sloyd’s specific educational community, students’ relationship to the sloyd object and their experience of the working process. Social interaction, humour and mutual acknowledgement proved to be of importance for the function of pleasure and displeasure in the students’ working processes. The students’ experience of pleasure and displeasure depended on their control of the work, the characteristics of different craft techniques and their awareness of time. Pleasure and displeasure in textile sloyd found an expression in four overarching emotional practices with decisive importance for the students’ opportunities for learning: the repudiating, insecure, accepting and incorporating emotional practice. The study also provides an insight into how different cultural factors enable a certain scope for pleasure and displeasure. In this connection, social changes in relation to objects are discussed, as are changes in sociality and emotionality. Based on the pair of concepts of authenticity and ephemerality and closeness and intensity, cultural changes are visualised that are conceivably important for the students’ experiences of pleasure and displeasure in textile sloyd.

Esta pesquisa teve por objetivo investigar empiricamente as decisões interpretativas quanto ao timing e dinâmica de quatro execuções do primeiro movimento da Sonata para piano n.1 de Francisco Mignone. Por meio da comparação de gravações, foram identificadas estratégias expressivas adotadas pelos intérpretes em relação ao timing, dinâmica e articulação, evidenciando assim o direcionamento expressivo do discurso musical em determinados trechos da obra. Tendo em vista os eventos musicais característicos de cada seção da Sonata, foi realizada uma análise da organização rítmica que apoiou a análise das gravações. / This research aimed at empirically investigating the interpretative decisions regarding timing and dynamics of four recorded performances of the first movement of Sonata n.1 for piano by Francisco Mignone. The comparison identified the expressive strategies adopted by the chosen interpreters in relation to articulation and dynamics thus bringing out the temporal profiles of predetermined spans. Issues such as background and organizational planning of the Sonata were taken into account in view of the musical events characteristic of each section. Theories of rhythmic organization supported the analyses of recordings.

Acompanha: O processo de produção de vídeos na construção de conceitos sociológicos na sala de aula a partir do protagonismo juvenil / Esta investigação tem por objetivo desenvolver um produto educacional tecnológico que possa contribuir no desenvolvimento de conceitos próprios da Sociologia, por meio da produção de vídeos em sala de aula e da promoção do protagonismo juvenil. Para tanto, partiu-se da pesquisa qualitativa que procurou promover a participação dos jovens aprendizes na produção de vídeos em sala de aula. Esses jovens, em colaboração com a professora investigadora, produziram vídeos de diferentes temas relacionados ao eixo Direitos Humanos. Para isso, foram consolidadas práticas pedagógicas relacionadas a didática Histórico-crítica de João Luiz Gasparin (2012). Nesse contexto, as propostas específicas do Ensino de Sociologia foram orientadoras para que os alunos aprendizes construíssem novas relações com os saberes, algo previsto na Educação em Direitos Humanos (EDH). Serviram como fundamentação teórica as concepções de Borba (1999), Rizinni (1999) e Oliveira & Oliveira (1999) quanto a pesquisa participante, Silva (2009a; 2009b), Moraes (2010), Paraná (2008) e Brasil (2006) a respeito do Ensino de Sociologia, Moran (2000), Borba (1999), Costa (2005) e Rojo (2012) para retratar a importância das TIC nos espaços escolares. Espera-se com essa dissertação, oferecer uma contribuição para novos estudos a respeito do Ensino de Sociologia e do protagonismo juvenil na construção de novos conceitos e conhecimentos sobre a vida em sociedade. / This investigation aims at developing a technological educational product that can contribute to the development of own concepts of sociology, through the production of videos in the classroom and the promotion of juvenile protagonism. Therefore, we started with the qualitative research which sought to promote the participation of young apprentices in the production of videos in the classroom. These young people, in collaboration with the researcher teacher, produced videos of different topics related to the axis Human Rights. For this, were consolidated pedagogical practices related to History-Critical didactic of João Luiz Gasparin (2012). In this context, the specific proposals of the Sociology Teaching were guiding in order that apprentices students build new relationships with knowledge, something provided in Human Rights Education (HRE). Served as theoretical basis the concepts of Borba (1999), Rizinni (1999) and Oliveira & Oliveira (1999) about the participatory research, Silva (2009a; 2009b), Moraes (2010), Parana (2008) and Brazil (2006) concerning the Sociology teaching, Moran (2000), Borba (1999), Costa (2005) and Rojo (2012) to portray the importance of ICT in school spaces. It is hoped with this dissertation, offer a contribution to further studies on the Sociology Teaching and youth protagonism in the construction of new concepts and knowledge about life in society.