• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 55
  • 50
  • 13
  • 7
  • 7
  • 7
  • 7
  • 7
  • 7
  • 7
  • 4
  • 3
  • 1
  • 1
  • 1
  • Tagged with
  • 171
  • 43
  • 35
  • 33
  • 21
  • 15
  • 13
  • 12
  • 12
  • 12
  • 11
  • 11
  • 10
  • 9
  • 9
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
61

Comparative anatomy of the vocal system of pinnipeds with emphasis on the bearded seal (Erignathus barbatus)

Choquette, Catherine January 1993 (has links)
No description available.
62

A stochastic measure of similarity between dolphin signature whistles

Stuby, Richard George Jr. 04 March 2009 (has links)
Bottlenose dolprlin (Tursiops trunratus) whistles are currently studied by subjective visual comparison of whistle spectrograms. This thesis describes the novel use of stochastic modeling to automate the comparison of dolphin whistles and to yield an objective, quantitative measure of whistle similarity. The relationship of bottlenose dolphin whistle production to a model of human speech production is discussed, providing a basis for the use of human speech recognition techniques for creating whistle models. Discrete hidden Markov models based on vector quantization of linear prediction coefficients are used to create whistle models based on statistical information derived from a sample set of dolphin whistles. Whistle model comparison results are presented indicating that evaluation of bottlenose dolphin whistles via hidden Markov modeling provides an objective measure of similarity between whistles. The results also demonstrate that hidden Markov models provide robustness against the effects of temporal and frequency variance in the comparison of whistles. The extensibility of stochastic modeling techniques to other animal vocalizations is discussed and possibilities for further work in areas such as the determination of possible structural components, similar to phonemes in human speech, is provided. / Master of Science
63

Infant vocal imitation of music

Pereira da Cruz Benetti, Lucia 02 August 2017 (has links)
No description available.
64

The vocalisations and anti-predatory behaviour of wild white-handed gibbons (Hylobates lar) in Khao Yai National Park, Thailand

Clarke, Esther A. E. January 2010 (has links)
The loud songs of gibbons (Hylobatidae) usually consist of a duet by the mated pair delivered each morning. These songs can transmit over a kilometre through dense forest habitat and therefore presumably play a role in long-distance communication. There is some evidence to suggest that gibbons use song in contexts other than their daily duets, such as predation, but these songs have not been well studied. Close- range communication is also relevant for gibbons, but these quieter calls have completely escaped any detailed observation. The responses of wild white-handed gibbons (Hylobates lar) to simulated visual and acoustic predators (tiger, clouded leopard, reticulated python and crested serpent eagle) were studied in Khao Yai National Park, Thailand to address the lack of empirical data about these important events. Little is known about gibbons’ anti- predatory behaviour in general, and simulated predator encounters provided an opportunity to investigate these responses as well. Results showed that gibbons used song as part of their anti-predator strategy and that subtle combinatorial changes were meaningful to conspecifics. They also showed marked behavioural changes in the short-term, and some evidence of longer-term changes as well. Quiet calls were also part of the gibbons’ response repertoire with the hoo call being particularly relevant. Hoos were used as a prelude to singing both normal duets and predator songs, but there were consistent differences between each context. Hoos were also delivered independently in a number of other contexts outside predation. When analysed, these hoos showed consistent contextual differences in a number of spectral parameters. Within the duet context, important contextual subtleties were evident also revealing a remarkable vocal plasticity. In addition, gibbons voluntarily attended to specific vocal elements of other gibbon duets, indicating that certain sequences are more pertinent than others. Results suggest both gibbon song and gibbon hoos are powerful communication tools that reliably reference external objects and events; this ability is also a critical feature of human language.
65

Functional design and use of acoustic signals produced by killer whales (Orcinus orca)

Samarra, Filipa Isabel Pereira January 2011 (has links)
This study aimed to investigate possible functions of the sounds produced by herring-eating killer whales in the Northeast Atlantic. In this study, I investigated the whistle repertoire of killer whales, which had previously only been studied in British Columbia, where it appeared to be restricted to the audible range. However, I show that high frequency whistles (> 17 kHz) were detected in Northeast Atlantic populations but not in Northeast Pacific populations. These results indicated substantial intraspecific variation in whistle production in killer whales. Little variation was observed in high frequency whistles recorded from three different sites in the Northeast Atlantic, suggesting this signal has a similar function across locations. The estimated active space of high frequency whistles and burst-pulse calls suggested that these are short-range signals used for within-group communication. Source levels of burst-pulse calls were lower than what was previously described in British Columbia, which possibly reflected the fact that these sounds do not need to propagate far because distances between group members are generally short. Calls, high frequency whistles and herding calls produced at different depths did not appear to suffer effects due to increased pressure, such as changing frequency or duration characteristics. Feeding appeared to take place below 10 m of depth, as suggested by the localisation of depth of production of feeding-related sounds. These depths were consistent with those at which tailslaps were produced in Dtags attached to individual whales. Feeding periods were characterised by deep diving, increased sound production and highly non-directional movement. These findings suggested that killer whales in a herring spawning ground use a feeding strategy different from carousel feeding used in herring overwintering grounds. These findings showed that Northeast Atlantic killer whales have a different sound repertoire to other populations, and suggested that they may employ different feeding strategies depending on prey behaviour.
66

Le lien perception-production en voix chantée : place des représentations motrices

Lévêque, Yohana 14 December 2012 (has links)
Un nombre croissant d'études révèle combien les processus cérébraux de production et de perception de l'action sont intriqués. En particulier, on sait maintenant que la perception de la parole induit l'activation de représentations motrices articulatoires chez l'auditeur. Dans ce travail, nous explorons la perception de la voix chantée, une action vocale non-linguistique. L'écoute d'une voix chantée provoque-t-elle une activation du système moteur ? Cette activité motrice est-elle plus forte pour la voix que pour un son musical non-biologique ? Ces questions sont abordées en utilisant de façon complémentaire deux protocoles comportementaux, une technique de lésion virtuelle par stimulation magnétique transcrâniale, l'étude des oscillations en EEG et celle de la variabilité métabolique en IRMf. Nos résultats montrent que la perception d'une voix chantée est effectivement associée à une activité du cortex sensorimoteur dans des tâches de répétition et de discrimination. De façon intéressante, les plus mauvais chanteurs ont montré la plus forte résonance motrice. Le système moteur pourrait, par la génération de modèles internes, faciliter le traitement des stimuli ou la préparation de la réponse vocale quand le traitement acoustique seul est insuffisant. L'ensemble des résultats présentés ici suggère que les interactions audiomotrices en perception de la voix humaine sont modulées par la dimension biologique du son et par le niveau d'expertise vocale des auditeurs. / A growing body of research reveals that action production and action perception interact. In particular, it has been shown that speech perception entails articulatory motor representations in the listener. In the present work, we investigate the perception of a singing voice, a stimulus that is not primarily linked to articulatory processes. Does listening to a singing voice induce activity in the motor system? Is this motor activity stronger for a voice than for a non-biological musical sound? Two behavioral tasks, a og virtual lesionfg{} paradigm using TMS, the study of brain oscillations with EEG and an fMRI experiment carried out during my PhD have shed some light on these questions. Our results show that the perception of a singing voice is indeed associated with sensorimotor activity in repetition and discrimination tasks. Interestingly, the poorer singers displayed the stronger motor resonance. The motor system could facilitate the processing of sound or the preparation of the vocal response by internal model generation when the acoustic processing is not effective enough. The set of studies presented here thus suggests that audiomotor interactions in human voice perception are modulated by two factors: the biological dimension of sound and the listeners' vocal expertise. These results suggest new perspectives on our understanding of the auditory-vocal loop in speech and of sound perception in general.
67

Variação do canto de Thamnophilus Doliatus (Linnaeus, 1764) (Aves: Thamnophilidae) em diferentes regiões da América Latina /

Catalano, Ana Luiza Camargo. January 2015 (has links)
Orientador: Reginaldo José Donatelli / Banca: Manoel Dias Filho / Banca: Carolina Demetrio Ferreira / Resumo: Este trabalho teve como objetivo analisar e comparar as vocalizações entre indivíduos e subespécies de Thamnophilus doliatus de diferentes localizações da América Latina. Foram analisados 280 cantos de 140 indivíduos diferentes, e as variáveis levadas em consideração foram: número de notas, duração do trecho em sequência, taxa de notas por segundo, frequência de pico total do trecho, duração da nota terminal e frequência de pico da mesma. Os cantos também foram divididos em porções para se calcular a variação de velocidade e de tonalidade (frequência) ao longo dos trechos. As características do canto foram correlacionadas com dados geográficos como latitude, longitude e altitude a fim de se conferir se existe alguma padronização com a localização, e a amostra também foi agrupada em subespécies de acordo com suas localizações para comparações. As variáveis analisadas foram fortemente correlacionadas com a latitude, indicando que indivíduos de localização equatorial emitem cantos com mais notas, mais longos, mais rápidos e com uma nota terminal mais grave do que aqueles localizados ao sul da distribuição. As variáveis também foram correlacionadas com a longitude, incluindo também a frequência de pico. Foram identificadas sete subespécies de acordo com as localidades em que foram gravadas, porém apenas cinco foram utilizadas para comparações. Resultados mostraram uma separação das subespécies intermedius e radiatus pelas significativas diferenças no número de notas, duração do trecho, taxa de notas por segundo e frequência de pico. Também foram feitas comparações com a recém-separada espécie Thamnophilus capistratus, e só foram encontradas diferenças significativas na nota terminal e na variação de frequência ao longo do trecho. Devido às características do canto se mostrarem mais próximas entre diferentes espécies (T. doliatus e T. capistratus), que entre as subespécies de... / Abstract: The aim of this study was to analyze and to compare vocalizations of individuals of the species Thamnophilus doliatus from different locations of Latin America. 280 loudsongs from 140 individuals were analyzed and the variables taken into account were the following: number of notes, duration of the sequenced patch, note rate (notes per second), overall peak frequency, duration of the terminal note, and peak frequency of the terminal note. The loudsongs were also divided into portions in order to measure the variation of note rate (speed) and pitch (frequency) along the patch. The loudsong characteristics were correlated with geographic factors such as latitude, longitude and altitude to check if there is any acoustic pattern with the location. Also, the sample was clustered into subspecies for comparisons. The analyzed variables were strongly correlated with latitude, where individuals from equatorial locations had loudsongs with more notes, longer in duration, faster in note rate and a terminal note lower in peak frequency. The variables also appeared to be significantly correlated with longitude, including as well the overall peak frequency. Seven subspecies were identified according to their locations, however, only five of them were used for comparisons. Results showed a separation of the intermedius and radiatus subspecies due to their significant divergence in number of notes, patch duration, note rate and peak frequency. Comparisons with the recently separated species Thamnophilus capistratus were also made and no significant variation were found in the number of notes and total duration, but there were differences in note rate, overall peak frequency, peak frequency and duration of the terminal note. Because song characteristics between the different species (T. doliatus and T. capistratus) presented to be more similar than among the subspecies of T. doliatus, raises the question of the existence of more than one species within ... / Mestre
68

Relações entre comportamento vocal, imunidade e níveis plasmáticos de corticosterona e testosterona em sapos (Rhinella granulosa) / Relations among vocal behavior, immunity and plasmatic levels of testosterone and corticosterone in toad (Rhinella granulosa)

Cassettari, Bruna de Oliveira 18 February 2016 (has links)
A exibição do comportamento vocal em muitas espécies de anfíbios anuros é relacionada aos níveis de hormônios esteroides gonadais e interrenais. Esses hormônios poderiam mediar a relação entre intensidade de sinais e imunidade, pois estão envolvidos no desenvolvimento das características sexuais secundárias, comportamento de corte e mobilização de reservas energéticas durante a atividade reprodutiva, enquanto apresentam também efeitos imunomoduladores. Nesse sentido, o objetivo deste trabalho foi explorar as relações entre comportamento reprodutivo, imunidade e níveis plasmáticos de testosterona e corticosterona em machos do sapo do semiárido brasileiro, Rhinella granulosa, em atividade reprodutiva e após manipulação hormonal. A precipitação foi o principal determinante ambiental para o aumento dos níveis de testosterona e corticosterona circulantes em machos de R. granulosa, estimulando o comportamento de vocalização. As relações fisiológicas encontradas indicam que os altos níveis plasmáticos de testosterona nos primeiros dias após a chuva devem promover o início do turno vocal, porém a corticosterona deve modular o esforço de vocalização. De forma geral, a exacerbação do comportamento vocal de R. granulosa tem efeitos negativos sobre a imunocompetência, porém alguns indivíduos que apresentam maiores concentrações plasmáticas de corticosterona apresentam concomitantemente alto esforço vocal e alta imunidade. De acordo, a aplicação transdérmica de corticosterona promoveu elevação aguda dos níveis plasmáticos deste glicocorticoide, bem como um aumento da função imune. Assim, apesar de a atenção principal ser comumente colocada no papel da testosterona na mediação de sinais honestos, nossos resultados corroboram a importância da corticosterona na mediação da expressão do comportamento de corte e imunocompetência em machos R. granulosa / In most anuran species, vocal behavior is usually related to plasmatic levels of gonadal and interrenal steroid hormones. These hormones could mediate the relationship between signal intensity and immunocompetence, since they are involved in the development of sexual traits, courtship behavior and energetic mobilization during reproductive activity and also exert immunomodulatory effects. The aim of this study was to explore relations among vocal behavior, immunity and plasmatic levels of testosterone and corticosterone in males of a toad species from Brazilian semi-arid, Rhinella granulosa, during reproductive activity and after hormonal manipulation. Precipitation was the main environmental determinant to increase circulating levels of testosterone and corticosterone in R. granulosa males, stimulating vocal behavior. Physiological relations indicate that high circulating testosterone levels in the days right after rain may promote the initiation of vocal behavior, while corticosterone may modulate vocal effort. In general, exacerbation of vocal behavior in R. granulosa has negative effects on immunocompetence, however, some individuals with higher plasmatic levels of corticosterone can present both high vocal effort and good immunocompetence. Corroborating this interpretation, acute increase in glucocorticoid plasmatic levels after hormonal manipulation was accompanied by raised immune function. Despite the emphasis on androgens influence on sexual selected male traits, our results corroborate greater influence of corticosterone in the mediation of expression of courtship behavior and immunocompetence in R. granulosa
69

Córtex cingulado anterior e respostas nociceptivas em cobaias: modulação GABAérgica, colinérgica e opioidérgica / Anterior cingulate cortex and nociceptive responses in a subject: gabaergic modulation, cholinergic and opioidergic

Cavalcanti, João Zugaib 23 February 2012 (has links)
A dor é um fenômeno multidimensional, que geralmente desencadeia reações emocionais desconfortáveis quando identificada. Sua relação com injúria tecidual pode ser interpretado como um mecanismo adaptativo de defesa à integridade do organismo, tendo em vista sua preservação evolutiva. Porém, o substrato neurobiológico do organismo parece determinar a complexificação do repertório comportamental em diferentes espécies. Nesse sentido, o córtex cingulado anterior (CCA) tem sido amplamente descrito em mamíferos modulando diferentes aspectos da dor. O presente trabalho utilizou os testes algesimétricos de vocalização e da formalina em cobaias, para se avaliar o decurso temporal do efeito da microinjeção de agonistas e antagonistas GABAérgico (muscimol e bicuculina); colinérgico (carbacol e atropina) e opioidérgico (morfina e naloxona). A microinjeção de bicuculina (1 nmol / 0,2 µl) exacerbou as respostas nociceptivas em ambos os testes, porém diferentes doses de muscimol (0,5, 1 e 2 nmol / 0,2 µl), não modificaram as respostas. O efeito da bicuculina foi bloqueado em ambos os testes pela microinjeção prévia de muscimol (1 nmol/ 0,2 µl) no CCA. A microinjeção de carbacol (2,7 nmol /0,2 µl) neste substrato promoveu antinocicepção, evidenciada por meio da atenuação da amplitude das vocalizações, mas não pelo teste da formalina. Esse efeito foi bloqueado pela administração prévia de atropina (0,7 nmol /0,2 µl) e de naloxona (2,7 nmol /0,2 µl). A microinjeção de morfina (4,4 nmol /0,2 µl) promoveu antinocicepção em ambos os testes. Concluímos que a inibição do tônus GABAérgico no CCA exacerba os comportamentos nociceptivos e que a antinocicepção promovida por carbacol pode ter sido mediada pelo sistema de opióides endógenos, tendo em 9 vista o bloqueio do seu efeito com naloxona. Além disso, a estimulação opióide promove uma contundente antinocicepção. / Pain is a multidimensional phenomenon which usually triggers uncomfortable emotional reactions when identified. Its relation injury can be interpreted as an adaptive mechanism to defend the integrity of the body given its evolutionary conservation. However the neurobiological substrate of the body seems to determine the complexification of behavioral repertoire in different species. Thus, the anterior cingulated cortex (ACC) has been widely described in mammals by modulating different cognitive aspects of pain. This study used algesimetric tests of vocalization and formalin in guinea pigs to evaluate the time course of the effect of microinjection of GABA agonists and antagonists (bicuculline and muscimol) and cholinergic (carbachol and atropine) beyond the opioid antagonist naloxone. The microinjection of bicuculline (1 nmol / 0,2 µl) exacerbated the nociceptive behavior in both tests but different doses of muscimol (0,5; 1 e 2 nmol / 0,2 µl) did not change the responses. The effect of bicuculline was blocked in both tests by prior microinjection of muscimol (1 nmol / 0,2 µl) in the ACC. The microinjection of carbachol (2,7 nmol / 0,2 µl) on this substrate promoted antinociception as evidenced by attenuation of the amplitude of the vocalizations, but not by the formalin test. This effect was blocked by prior administration of atropine (0,7 / 0,2 µl) and naloxone (0,7 nmol / 0, 2 µl). The microinjection of morphine (4,4 nmol / 0,2 µl) promoted antinociception in both tests. We conclude that inhibition of GABAergic tone in the ACC exacerbates nociceptive behaviors and that the antinociception promoted by carbachol may 11 have been mediated by endogenous opioid system in order blocking its effect with naloxone. In addition opioid stimulation promotes a striking antinociception.
70

Uso da vocalização como indicador patológico em leitões na fase de maternidade / Vocalization as an indicator of piglet\'s disease in farrowing

Risi, Natalia 08 June 2010 (has links)
O estudo da vocalização em animais de produção tem sido uma metodologia amplamente utilizada para avaliar as condições de bem-estar às quais os animais são submetidos. Diante disto, é importante tentar estabelecer novos métodos de identificação do quadro sanitário dos animais, na tentativa de melhorar a qualidade de vida dos mesmos. O presente trabalho tem, como objetivo principal, comparar as características acústicas presentes na vocalização de leitões com artrite e sadios durante a fase de maternidade. Algumas observações mais específicas também foram avaliadas envolvendo a variação da vocalização frente diferentes níveis de lesões proporcionadas pela artrite; a relação de parâmetros inerentes aos animais, tais como peso, idade, gênero e a influência da temperatura do ambiente na vocalização dos mesmos. O experimento foi desenvolvido na fase de maternidade em uma granja comercial de suínos. Durante o processo de aquisição de dados foram utilizados 123 leitões com idades entre 5 e 21 dias de vida; dentre estes, 60 eram animais artríticos e 63 sadios. Todos os animais selecionados foram submetidos a uma análise clínica prévia e a um processo de apreensão manual capaz de estimular a emissão de vocalização. Um microfone digital diretivo foi utilizado para realizar o registro dos sons emitidos por animais diagnosticados positivos bem como o dos negativos. A medida da temperatura ambiental foi feito por um dattalogger posicionado no centro geométrico do galpão. Os níveis de lesões nos animais com artrite foram analisados clinicamente e separados em lesões leves, moderadas e intensas. As chamadas foram editadas pelo software Audacity® versão 1.3 Beta e analisadas pelo software PRAAT®, capaz de fornecer os parâmetros envolvidos no espectro sonoro dos sinais, tais como a duração (s), frequência fundamental (Hz), intensidade sonora (dB) e quatro níveis de formantes (Hz). Os dados foram submetidos à analise de variância (GLM) e teste de significância entre as médias (Tukey). A partir destas medidas do sinal sonoro foi possível verificar que as vocalizações emitidas por leitões com artrite diferiram das vocalizações emitidas por leitões sadios em fase de maternidade, principalmente pelos menores valores médios encontrados na duração das chamadas, intensidade sonora, primeira e segunda formantes presentes na vocalização de animais com artrite. Os resultados relacionados aos níveis de lesão revelaram que os valores médios da intensidade sonora, frequência fundamental, primeira e segunda formantes diminuiram à medida que o nível de lesão aumentou. Para os animais sadios envolvidos no estudo, encontraram-se diferenças significativas em muitas variáveis acústicas presentes na vocalização de animais apresentando diferentes idades, pesos (Kg), gênero e condições fisiológicas em função da temperatura do ar. / The vocalizations study in farm animals has been a methodology used to assess the conditions of welfare which animals are subjected. In front of this, it is important to try to establish new methods to identifying the health situation of animals in an attempt to improve the quality of life for them. The purpose of this study was to analyze the acoustic features of vocalizations piglets vocalization in two different conditions: arthritis and healthy animals during farrowing house. Some specific comments were also evaluated involving calls variation in front of different levels of injuries provided by arthritis; the relation of animals parameters such as weight, age, sex and the influence of environmental temperature. The experiment was conducted in farrowing stage in a commercial farm pigs. During the process of data acquisition, 123 piglets aged between 5 and 21 days of life were used. Sixty were with arthritis and 63 were healthy. All animals selected were submitted to a previous clinical examination and handled to stimulate the emission of vocalization. A steering digital microphone was used for recording the sounds. Measures of ambient temperature were done by a dattalogger positioned at the geometric center of the shed. The levels of lesions in animals with arthritis were clinically analyzed and separated into light, moderate and intense injuries. After sound record, they were quantified as body weight, sex and age. Calls were issued by Audacity® software version 1.3 Beta and analyzed by software PRAAT®, which can provide parameters involved in the sound spectrum of the signals, such as duration (s), fundamental frequency (Hz), loudness (dB) four levels of formants (Hz). The data were submitted to analysis of variance (GLM) and test of significance between means (Tukey). From these measures sound signal was also observed that the vocalizations emitted by piglets differed from arthritis vocalizations emitted by healthy piglets being motherhood, especially by low values found in the average call duration, loudness, first and second formants present in vocalization of animals with arthritis. The results related to the level of injury revealed that the mean values of sound intensity, fundamental frequency, first and second formants were reduced as the level of injury increased. For healthy animals in the study, we found significant differences in many variables present in the acoustic vocalizations of animals with different ages, weights (kg), gender and physiological conditions as a function of air temperature.

Page generated in 0.0884 seconds