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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.
31

Revisão taxonômica de Gymnorhamphichthys (Gymnotiformes, Rhamphichthyidae) com descrição de duas novas espécies

RAMOS, Cristiane do Socorro January 2010 (has links)
Submitted by Edisangela Bastos (edisangela@ufpa.br) on 2013-03-06T22:12:11Z No. of bitstreams: 2 license_rdf: 23898 bytes, checksum: e363e809996cf46ada20da1accfcd9c7 (MD5) Dissertacao_RevisaoTaxonomicaGymnorhamphichthys.pdf: 868348 bytes, checksum: e3db7a24a27492dbd2c11245bff10530 (MD5) / Approved for entry into archive by Ana Rosa Silva(arosa@ufpa.br) on 2013-03-11T16:27:40Z (GMT) No. of bitstreams: 2 license_rdf: 23898 bytes, checksum: e363e809996cf46ada20da1accfcd9c7 (MD5) Dissertacao_RevisaoTaxonomicaGymnorhamphichthys.pdf: 868348 bytes, checksum: e3db7a24a27492dbd2c11245bff10530 (MD5) / Made available in DSpace on 2013-03-11T16:27:40Z (GMT). No. of bitstreams: 2 license_rdf: 23898 bytes, checksum: e363e809996cf46ada20da1accfcd9c7 (MD5) Dissertacao_RevisaoTaxonomicaGymnorhamphichthys.pdf: 868348 bytes, checksum: e3db7a24a27492dbd2c11245bff10530 (MD5) Previous issue date: 2010 / A revisão taxonômica do gênero Gymnorhamphichthys é apresentada, a diagnose para o gênero é ampliada, cinco espécies nominais são reconhecidas e duas espécies novas são descritas: Gymnorhamphichthys sp. n. 1, de rios da bacia do Paraguai, é diagnosticada pelas barras longas delgadas dorsais do corpo alcançando ou ultrapassando a linha lateral, número de barras 6-19 e baixo número de raios da anal 141-177 entre outros caracteres; Gymnorhamphichthys sp. n. 2, da bacia Amazônica, é diagnosticada pela presença de uma mascara escura na cabeça, barras largas com 26 m forma retangular e pelo elevado número de raios da anal 185-260 entre outros caracteres. Uma chave dicotômica para espécies é fornecida. / A taxonomic revision of the genus Gymnorhamphichthys is presented, a diagnosis for the genus is modified and expanded, five nominal species are recognized, and two new species are described: Gymnorhamphichthys sp. n. 1, from rivers of Paraguay basin, is diagnosed by thin bars on the dorsal region of its body, bars long slender reaching or exceeding below the lateral line, number of bars 6-19, and by the low number of anal rays (141-177), among other characters; Gymnorhamphichthys sp. n. 2, from Amazon basin, is diagnosed by the presence of a dark mask on the head, wide rectangular-shaped bars, and by the high number of anal rays (185-260), among other characters. A dichotomous key to species is provided.
32

Composição e biogeografia da avifauna das ilhas Caviana e Mexiana, foz do Rio Amazonas

HENRIQUES, Luiza Magalli Pinto 14 January 1994 (has links)
Submitted by Edisangela Bastos (edisangela@ufpa.br) on 2013-08-02T20:47:20Z No. of bitstreams: 2 Dissertacao_ComposicaoBiogeografiaAvifauna.pdf: 3876317 bytes, checksum: 5dc9196ab33ea380d24761f723deb625 (MD5) license_rdf: 23898 bytes, checksum: e363e809996cf46ada20da1accfcd9c7 (MD5) / Approved for entry into archive by Ana Rosa Silva(arosa@ufpa.br) on 2013-08-14T12:25:22Z (GMT) No. of bitstreams: 2 Dissertacao_ComposicaoBiogeografiaAvifauna.pdf: 3876317 bytes, checksum: 5dc9196ab33ea380d24761f723deb625 (MD5) license_rdf: 23898 bytes, checksum: e363e809996cf46ada20da1accfcd9c7 (MD5) / Made available in DSpace on 2013-08-14T12:25:22Z (GMT). No. of bitstreams: 2 Dissertacao_ComposicaoBiogeografiaAvifauna.pdf: 3876317 bytes, checksum: 5dc9196ab33ea380d24761f723deb625 (MD5) license_rdf: 23898 bytes, checksum: e363e809996cf46ada20da1accfcd9c7 (MD5) Previous issue date: 1993 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / CNPq - Conselho Nacional de Desenvolvimento Científico e Tecnológico / As ilhas Caviana e Mexiana, localizadas na foz do rio Amazonas, são ilhas construídas por sedimentos fluviais e por terrenos bem consolidados que datam do Terciário e que foram separados tectonicamente do continente no início do Holoceno. A composição da avifauna dessas ilhas é analisada tanto do ponto de vista biogeográfico como do ecológico. Registramos 148 espécies de aves para a ilha caviana e 183 para a ilha Mexiana. A discrepância entre o tamanho da área, Caviana é maior que Mexiana, e o número de espécies observado deve-se a uma sub-amostragem de Caviana. Entretanto, a análise da composição demonstrou que Caviana é mais rica em espécies florestais do que Mexiana. Em contrapartida, Mexiana apresentou uma maior riqueza de aves de habitats abertos. Essas diferenças sugerem que a elevação do nível do mar no início do Holoceno provocou a extinção de grande parte da avifauna de sub-bosque de mata na ilha Mexiana. As porções de teso na ilha mexiana não foram submersas, permanecendo a avifauna característica, que também é representada na ilha de Marajó. A análise da distribuição de 157 espécies subdividiu a avifauna em sete categorias: ampla distribuição sul-americana (77), ampla distribuição amazônica (25), distribuição restrita a Amazônia Oriental (07), distribuição restrita ao sul do rio Amazonas e ao leste do rio Tapajós (03), distribuição restrita a várzea (19), ampla distribuição ao norte da Amazônia e ausentes no interflúvio Tocantins-Xingú (05), ampla distribuição no Brasil Central (21). Não reconhecemos elementos restritos ao interflúvio Tocantins-Xingú. Esse fato relaciona-se com fatores ecológicos e não históricos. O padrão relacionado ao norte da Amazônia pode ser interpretado como sendo dispersão recente, através do sistema de ilhas da foz do rio Amazonas, ou pela formação dos arcos Purús e Gurupá, estabelecendo conexão entre a margem direita e esquerda do rio Amazonas, associados ao abaixamento do nível do mar no Pleistoceno. A dispersão ocorreu nos dois sentidos, explicando a existência de um grande número de espécies e subespécies cuja distribuição se restringe a Amazônia Oriental e a dispersão de elementos do Planalto Central para o norte da Amazônia. A última também está relacionada com a expansão das vegetações abertas, características do Planalto Central, nos períodos glaciais. / The islands of Caviana and Mexiana, located in the mouth of the Amazon River, are composed of fluvial sediments and well consolidated lands that date from the Terciary and that were separated from the continent by tectonic action at the beginning of the Holocene. The composition of the avifauna of these islands is analized both from the biogeographical and the ecological points of view. I registered 148 bird species for Caviana Island and 183 for Mexiana Island. The discrepancy between the size of the two islands (Caviana is larger than Mexiana) and the number of species observed is due to undersampling of Caviana. However, the analysis of faunal composition demonstrated that Caviana is richer in forest species than is Mexiana. In contrast, Mexiana showed a greater richness of birds of open habitats. These differences suggest that the rising of sea level at the beginning of the Holocene caused the extinction of greater part of the fauna of the understory ou Mexiana. The portions of Mexiana Island with "teso" vegetation were not submerged, maintaining their characteristic avifauna, which is also represented on Marajó Island. To analyse of the distribuitions of 157 species I subdivided the avifauna into seven categorias: widespread distribution in South America (77 species); widespread Amazonian distribution (25); distribution restricted to eastern Amazonia (7); distribution restricted to south of the Amazon River and east of the Tapajós River (3); distribution restricted to várzea (19); widespread distribution in northern Amazonia and absent from the Tocantins-Xingu interfluvium (5); and widespread distribution in Central Brasil (21). I did not find elements restricted to the Tocantins-Xingu interfluvium. This fact is related to ecological rather than historical factors. The pattern related to northern Amazonia can be interpreted as the result of recent dispersal, the system of islands at the mouth of the Amazon, or by the formation of the Purás and Gurupá Arches, which, associated with the lowering of sea level during Pleistocene, established a connection between lhe right and left banks of the Amazon River. The dispersal occurred in both directions, explaining lhe existence of a large number of species and subspecies with distributions restricted to eastern Amazonia, as well as the dispersal of Central Brasilian elements to north of the Amazon River. This last component of the avifauna is a1so related to the expansion of open vegetations, characteristic of Central Brazil, during glacial periods.
33

Observação do transporte de sedimentos em suspensão ao longo do Canal Norte do rio Amazonas durante condições de baixa descarga (outubro 2008) / Observation of suspended sediment transport along North Channel of Amazon river during low discharge (October 2008)

Edgard Villarinho Garcia Neto 21 October 2011 (has links)
Fundação Carlos Chagas Filho de Amparo a Pesquisa do Estado do Rio de Janeiro / The Amazon river, located in northernBrazil, discharges between 80,000 and 250,000 m3s-1 of water onto the adjacent shelf, creating a plume of brackish water that extends hundreds of kilometers away from the river mouth. This river also carries a large amount of fine sediments to the ocean where fluid mud has been found in the topset and upper foreset layers of the subaqueous delta formed on the mid-shelf. One of the main goals of this dissertation is to describe how turbulence and suspended sediment concentration vary along the Northern Channel of the Amazon river. Water column measurements were carried out in October 2008 at six anchor stations (P1, P3, P5, P6, P8 e P9) located seaward of the river mouth; P1 and P9 were 125 km apart. Each station was occupied during 13 hours during which current speed and direction were continuously sampled with a 600 kHz Teledyne-RDI ADCP; hourly profiles of temperature, salinity, turbidity and depth were also obtained. Water samples were collected for determination of Suspended Particulate Matter (SPM) concentration and calibration of the turbidity sensor. Current speed reached values above 1.5 m s1 in the along-channel direction (NE-SW); a remarkable ebb-flood asymmetry was observed and flows were strongly ebb-dominated. Throughout the water column, SPM concentration at stations P1 and P3 varied between 100 and 300 mg L1 in association with the presence of freshwater. In contrast, a strong salinity gradient was observed between stations P6 and P9, coinciding with the occurrence of concentrations of SPM above 10 g L-1 (fluid mud). At stations P3, P5 and P6, interface between freshwater from the Amazon river and salt water from the continental shelf, shear stresses wereestimated through four diferents methods: Reynolds, Turbulent Kinetic Energy (TKE), modified TKE and Quadratic Law; in the nearbed region (3 mab) the computed values varied between 0 and 3 Pa. At the three stations (P3, P5 and P6) the lowest and the highest shear stress values were obtained through, respectively, the Reynolds and the TKE methods. Over the whole water column turbulence intensity was estimated through the standard deviation of the turbulent component of the along-channel current velocity (root-mean square of u); from these values, it was estimated the turbulent dissipation of energy (G), whose values at 3 mab varied between zero and 20 s1.
34

Observação do transporte de sedimentos em suspensão ao longo do Canal Norte do rio Amazonas durante condições de baixa descarga (outubro 2008) / Observation of suspended sediment transport along North Channel of Amazon river during low discharge (October 2008)

Edgard Villarinho Garcia Neto 21 October 2011 (has links)
Fundação Carlos Chagas Filho de Amparo a Pesquisa do Estado do Rio de Janeiro / The Amazon river, located in northernBrazil, discharges between 80,000 and 250,000 m3s-1 of water onto the adjacent shelf, creating a plume of brackish water that extends hundreds of kilometers away from the river mouth. This river also carries a large amount of fine sediments to the ocean where fluid mud has been found in the topset and upper foreset layers of the subaqueous delta formed on the mid-shelf. One of the main goals of this dissertation is to describe how turbulence and suspended sediment concentration vary along the Northern Channel of the Amazon river. Water column measurements were carried out in October 2008 at six anchor stations (P1, P3, P5, P6, P8 e P9) located seaward of the river mouth; P1 and P9 were 125 km apart. Each station was occupied during 13 hours during which current speed and direction were continuously sampled with a 600 kHz Teledyne-RDI ADCP; hourly profiles of temperature, salinity, turbidity and depth were also obtained. Water samples were collected for determination of Suspended Particulate Matter (SPM) concentration and calibration of the turbidity sensor. Current speed reached values above 1.5 m s1 in the along-channel direction (NE-SW); a remarkable ebb-flood asymmetry was observed and flows were strongly ebb-dominated. Throughout the water column, SPM concentration at stations P1 and P3 varied between 100 and 300 mg L1 in association with the presence of freshwater. In contrast, a strong salinity gradient was observed between stations P6 and P9, coinciding with the occurrence of concentrations of SPM above 10 g L-1 (fluid mud). At stations P3, P5 and P6, interface between freshwater from the Amazon river and salt water from the continental shelf, shear stresses wereestimated through four diferents methods: Reynolds, Turbulent Kinetic Energy (TKE), modified TKE and Quadratic Law; in the nearbed region (3 mab) the computed values varied between 0 and 3 Pa. At the three stations (P3, P5 and P6) the lowest and the highest shear stress values were obtained through, respectively, the Reynolds and the TKE methods. Over the whole water column turbulence intensity was estimated through the standard deviation of the turbulent component of the along-channel current velocity (root-mean square of u); from these values, it was estimated the turbulent dissipation of energy (G), whose values at 3 mab varied between zero and 20 s1.
35

Contribuição das queimadas na América do Sul para o derretimento das geleiras andinas : estudo de caso sobre o impacto do aerossol "black carbon" na geleira Zongo-Bolívia

Magalhães Neto, Newton de 07 November 2017 (has links)
Submitted by Biblioteca de Pós-Graduação em Geoquímica BGQ (bgq@ndc.uff.br) on 2017-11-07T16:12:29Z No. of bitstreams: 1 Tese - Contribuição das queimadas na América do Sul para o derretimento das geleiras Andinas.pdf: 12013598 bytes, checksum: b9ec5b579fb35328075809a39c2dbffb (MD5) / Made available in DSpace on 2017-11-07T16:12:29Z (GMT). No. of bitstreams: 1 Tese - Contribuição das queimadas na América do Sul para o derretimento das geleiras Andinas.pdf: 12013598 bytes, checksum: b9ec5b579fb35328075809a39c2dbffb (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Universidade Federal Fluminense. Instituto de Química. Programa de Pós-Graduação em Geoquímica, Niterói, RJ / O período de maior ocorrência das queimadas na América do Sul, de agosto à outubro, coincide com mudanças sazonais na circulação atmosférica que tornam favoráveis o transporte e a deposição de black carbon sobre as geleiras Andinas. Com o intuito de avaliar o potencial impacto do black carbon emitido pelas queimadas na bacia Amazônica sobre a massa de gelo dessas geleiras, foram modeladas a emissão de BC, o seu transporte e deposição sobre a geleira Zongo, as mudanças no albedo e a perda de massa de gelo/neve em 2 anos críticos, 2007 e 2010. Os valores de emissão para estes anos na bacia Amazônica foram de 34 e 26 Gg para os picos em setembro, e 51 e 76 Gg anuais. Estes valores foram utilizados para a modelagem da emissão, transporte, deposição e perda de massa de gelo devido ao black carbon. A redução no albedo devido as queimadas foi de 2,5-5%, o que resultou em uma perda de massa de gelo/neve de 3,0-6,5 kg/m² ao ano, equivalente a um incremento de 2-4,5% na perda de massa de gelo/neve anual. Esta perda de massa de gelo devido as queimadas pode ser observada na descarga da geleira nos meses de agosto e setembro. O recuo da frente da geleira apresentou uma relação direta com o desmatamento e o número de queimadas na América do sul. Períodos com maiores taxas de recuo coincidiram com os anos de maiores eventos de queimada e desmatamento. / The period of greatest occurrence of fires in South America, from August to October, coincides with seasonal changes in atmospheric circulation that favor the transportation and deposition of black carbon on the Andean glaciers. In order to evaluate the potential impact of the black carbon emitted by the fires in the Amazon over these glaciers, we modeled the emission of BC, its transport and deposition on the Zongo glacier, the change in glacier albedo and the resulting Ice / snow mass loss, during 2 critical years, 2007 and 2010. The emission values for these years in the Amazon basin were 34 and 26 Gg for the peaks in September, and 51 and 76 Gg annual. These values were used for modeling the emission, transport, deposition and loss of ice/snow due to black carbon. The estimated albedo reduction were 2.5-5%, which resulted in a loss of ice / snow mass of 3.0-6.5 kg / m² per year, equivalent to an increase of 2-4,5% annual ice / snow mass loss. The estimated ice/snow loss due to Amazon fire emission can be observed in the Zongo's discharge during august and september. The retreat of the front of the glacier presented a direct relation with the deforestation and the number of fires events in South America. Periods with the highest retreat rates coincided with the years of major events of burning and deforestation.
36

Diversidade de espécies no complexo Monodelphis brevicaudata (Didelphimorphia:Didelphidae), inferida por dados moleculares e morfológicos

PAVAN, Silvia Eliza D´Oliveira January 2009 (has links)
Submitted by Edisangela Bastos (edisangela@ufpa.br) on 2013-03-05T21:17:38Z No. of bitstreams: 1 Dissertacao_DiversidadeEspeciesComplexo.pdf: 1354054 bytes, checksum: 488a49ce72ef48a66321024a1866b930 (MD5) / Approved for entry into archive by Ana Rosa Silva(arosa@ufpa.br) on 2013-03-11T14:42:32Z (GMT) No. of bitstreams: 1 Dissertacao_DiversidadeEspeciesComplexo.pdf: 1354054 bytes, checksum: 488a49ce72ef48a66321024a1866b930 (MD5) / Made available in DSpace on 2013-03-11T14:42:32Z (GMT). No. of bitstreams: 1 Dissertacao_DiversidadeEspeciesComplexo.pdf: 1354054 bytes, checksum: 488a49ce72ef48a66321024a1866b930 (MD5) Previous issue date: 2009 / O complexo de espécies M. brevicaudata possui distribuição reconhecida para o Norte da América do sul e compreende três espécies descritas ‐ M. brevicaudata, M. glirina, e M. palliolata ‐ e duas não descritas, reconhecidas em estudos prévios. A delimitação de espécies baseada somente em caracteres morfológicos é complicada, de forma que diversos táxons nominais já foram associados ao grupo e diversos arranjos taxonômicos foram propostos. Os poucos estudos baseados em dados moleculares que incluíram espécimes do complexo brevicaudata revelaram altas taxas de divergência genética. Este trabalho buscou elucidar a sistemática do complexo de espécies M. brevicaudata através do estudo dos padrões de variação morfológica e genética. Para tal, desenvolvemos análises filogenéticas baseadas em dois genes mitocondriais: citocromo b e 16 S rDNA. Adicionalmente, estudamos a morfologia externa e craniana dos espécimes, investigando a existência de congruência entre a variação genética e morfológica. As análises morfológicas foram, em geral, congruentes com as moleculares, as quais indicaram os mesmos clados em todas as análises filogenéticas. Foram formalmente reconhecidas nove espécies para o complexo. Monodelphis brevicaudata, M. palliolata e M. glirina são consideradas espécies válidas; M. touan é revalidado da sinonímia de M. brevicaudata e duas espécies novas são descritas e nomeadas; a espécie M. domestica provou ser intimamente relacionada a espécimes do grupo brevicaudata, sendo aqui considerada como integrante do referido grupo; duas espécies reconhecidas como distintas permanecem sem uma descrição formal; M. maraxina é sinonimizada com M. glirina. Foi observado dimorfismo sexual para as espécies estudadas, sendo que para as duas espécies estatisticamente testadas (teste T de student), M. glirina e M. sp. nov. “Trombetas”, os machos apresentaram crânios significativamente maiores que as fêmeas. Rios de grande porte parecem ter participado na diferenciação genética e estruturação filogeográfica das espécies. O padrão filogeográfico encontrado sugere ao menos dois centros de diversificação para o grupo, um no escudo das Guianas, envolvendo as espécies ao norte do rio Amazonas, e outro no escudo brasileiro, envolvendo M. glirina e M. domestica. / Short‐tailed opossums of the Monodelphis revicaudata complex inhabit northern South America, and comprise three described species ‐ M. brevicaudata, M. glirina, and M. palliolata ‐ and two undescribed forms already recognized in prior studies. Species delimitation based solely on morphological features is difficult, and because of that many nominal taxa have been associated with this species complex, and several taxonomic arrangements have been proposed. Previous molecular phylogenetic studies using specimens of this species complex revealed substantial genetic divergence rates. The present study aims to elucidate the systematics of the M. brevicaudata species complex through the analyses of molecular and morphological characters. We performed phylogenetic analyses on two mitochondrial genes (cyt b and 16S), studied the external and cranial morphology, and investigated whether observed genetic variation is congruent with morphological differences. Our morphological results were generally concordant with the molecular results. We recognize nine species in the species complex. M. brevicaudata, M. palliolata, and M. glirina are considered valid species; M. touan is re‐established from the synonymy of M. brevicaudata and two new species are described and named; the species M. domestica proved to be closely related to specimens of the M. brevicaudata complex, and thus are considered as part of that group; we also recognized two new species without formallly naming them; M. maraxina is considered a synonym of M. glirina. Sexual dimorphism is observed in the species, and in two species males showed skulls significantly larger than females. Major rivers seem to have played an important role in generating genetic differentiation and phylogeographical structure of the species. The phylogeographical pattern suggests at least two diversification centers for the group, one in the Guiana shield, comprising species ranging north of the Amazon river, and another in the Brazilian shield, comprising M. glirina and M. domestica.

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