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  • 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.
1

Vocaliza??es subaqu?ticas e fen?menos n?o lineares em focas ant?rticas

MACIEL, Israel de S? 02 February 2016 (has links)
Submitted by Jorge Silva (jorgelmsilva@ufrrj.br) on 2017-11-08T17:53:03Z No. of bitstreams: 1 2016 - Israel de S? Maciel.pdf: 3184590 bytes, checksum: 1d079e88bc7d2ff9256dc558436b7cd3 (MD5) / Made available in DSpace on 2017-11-08T17:53:03Z (GMT). No. of bitstreams: 1 2016 - Israel de S? Maciel.pdf: 3184590 bytes, checksum: 1d079e88bc7d2ff9256dc558436b7cd3 (MD5) Previous issue date: 2016-02-02 / CAPES / Pinnipeds produce a variety of underwater sounds that are often related to reproductive activities and social interactions. In addition, several species of seals provide evidence of vocalizations with geographical and individual variations. Most of bioacoustics researches with seals studied the terrestrial environment repertoire using linear analysis. However, some characteristics of vocalizations can not be explained with linear analysis only or taking into account only one part of the animal's life. The nonlinear phenomena (NLP) present in vocalizations (sideband, harmonic, sub-harmonic, biphonation, jump of frequency and deterministic chaos) are still poorly studied. Given the importance of this phenomena in vocalizations to individual recognition, especially in social mammals, was studied the underwater vocalizations of Antarctic seals in order to know their vocal repertoire and their NLP as well as discuss their possible function. In 2013, Brazilian Navy conducted acoustic recordings on Half Moon Island. In this collection were recorded 128GB of sound files between 12th and 30th of November. A total of 18 days of uninterrupted collections, producing 7,448 files of 3 minutes each. These recordings were taken at the presence of seals to Lobodontini Tribe. A total of 15 types of vocalizations were found in the period between days 12-16/November. A pattern in the vocalizations types L, K and E, arranged in sequence K, L and E, respectively, was observed in all seal recordings. All files presented biphonations, jumps of frequency, harmonics, sidebands and chaos in nine types of vocalizations (A, C, E, F, K, L, M, N and O). The nonlinearities were abundant on all files, being present in 75.56% (N = 1829) of vocalizations. Deterministic chaos was most common, present in 53.86% of non-linear features and 43.08% of vocalizations in general. Taking into account only the tonal vocalizations, 88.85% of vocalizations were nonlinear. The repetition of the KLE pattern also displays a recognition function. The NLP, mainly deterministic chaos, had high incidence in the studied vocalizations indicating that this type has an important role in communication. Furthermore, it seems to belong to the acoustic pattern of Antarctic?s Lobodontines. / Pin?pedes produzem uma variedade de sons subaqu?ticos que frequentemente s?o relacionados com atividades reprodutivas e intera??es sociais. Diversas esp?cies de focas apresentam evid?ncias de vocaliza??es com varia??es geogr?ficas e individuais. A maioria dos trabalhos com focas estudou o repert?rio em ambiente terrestre e com olhares para as an?lises lineares. Entretanto, algumas caracter?sticas das vocaliza??es n?o podem ser explicadas apenas com an?lises lineares ou levando em conta apenas uma parte da vida do animal. Os fen?menos n?o lineares (FNLs) presentes em vocaliza??es (banda lateral, harm?nico, sub-harm?nico, bifona??o, pulos de frequ?ncia e caos determin?stico) ainda s?o pouco estudados. Dada a import?ncia deste fen?meno nas vocaliza??es para o reconhecimento individual, principalmente em mam?feros sociais, este trabalho buscou estudar as vocaliza??es subaqu?ticas de focas ant?rticas, visando conhecer seu repert?rio vocal e seus FNLs, bem como discutir a poss?vel fun??o dos mesmos. Em 2013, a Marinha do Brasil realizou grava??es ac?sticas na Ilha Meia Lua na Ant?rtica. Nesta coleta foram registrados 128GB de arquivos de som nos dias entre 12 e 30 de novembro, totalizando 7.448 arquivos de 3 minutos cada. Nestas grava??es foi constatada a presen?a de focas pertencentes ? Tribo Lobodontini. Contatou-se tamb?m a presen?a de 15 tipos de vocaliza??es no per?odo entre os dias 12 a 16/novembro. Em todos os dias que houve grava??es de focas foi observado um padr?o nos tipos L, K e E, organizados na sequ?ncia K, L e E, respectivamente. Ap?s a inspe??o visual de todos os arquivos, foram encontrados pulos de frequ?ncia, bifona??es, harm?nicos, bandas laterais e caos determin?stico em nove tipos de vocaliza??es (A, C, E, F, K, L, M, N e O). As n?o linearidades foram abundantes em todos os arquivos, estando presentes em 75,56% (N=1829) das vocaliza??es. O caos determin?stico foi o mais comumente observado, estando presente em 53,86% das fei??es n?o lineares e 43,08% das vocaliza??es em geral. Levando em conta apenas as vocaliza??es tonais, 88,85% das vocaliza??es foram n?o lineares. A repeti??o do padr?o KLE parece apresentar uma fun??o de reconhecimento. Os FNLs, principalmente os do tipo caos determin?stico, estiveram muito presentes nas vocaliza??es estudadas, indicando que este tipo de emiss?o possui uma fun??o importante na comunica??o. Al?m disso, estes parecem pertencer ao repert?rio ac?stico padr?o de Lobodontines ant?rticos.

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