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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.
211

Estudo anatomopatológico da mionecrose infecciosa viral (IMNV) no camarão cultivado, Litopenaeus vannamei, em Pernambuco,Brasil

SILVA, Verônica Arns da 22 February 2007 (has links)
Submitted by (edna.saturno@ufrpe.br) on 2017-02-22T16:21:30Z No. of bitstreams: 1 Veronica Arns da Silva.pdf: 500226 bytes, checksum: 2a21789fca9964130708e123521a1f6c (MD5) / Made available in DSpace on 2017-02-22T16:21:30Z (GMT). No. of bitstreams: 1 Veronica Arns da Silva.pdf: 500226 bytes, checksum: 2a21789fca9964130708e123521a1f6c (MD5) Previous issue date: 2007-02-22 / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / The Infectious Myonecrosis Viral (IMNV), restricted action to the Brazilian northeast up to 2006, is disease of bigger negative impact in the shrimp cultured of the region. Having the objective to verify occurrence and evolution of the IMNV in Litopenaeus vannamei cultured on the coast of Pernambuco, Brazil, histopathological examination in 60 samples of shrimps from four farms in two cycles of aquaculture was proceeded. The histopatological findings had been correlated the data of the wet mount and the inquiry. Suggestive injuries of IMNV (coagulation necrosis, muscular hemocitic infiltration, spheroid of the ectopic lynphoid organ) were found in samples of the four studied farms with bigger occurrences in the first cycle. However, in the rainy period it had reduction of the occurrence, being associated the handling change. The raise time and the density were variables which influenced significantly (P<0,05) in the manifestation of the IMNV. / A Mionecrose Infecciosa Viral (IMNV), de ação restrita ao nordeste brasileiro até 2006, é a doença de maior impacto negativo na carcinicultura da região. Com objetivo de verificar ocorrência e evolução da IMNV em Litopenaeus vannamei, cultivado no litoral de Pernambuco, Brasil, procedeu-se ao exame histopatológico em 60 amostras, provenientes de quatro fazendas, em dois períodos (estio e chuvoso). Os resultados histopatológicos foram relacionados com os do exame a fresco e do inquérito. Em amostras das quatro fazendas foram identificadas lesões sugestivas de IMNV (necrose de coagulação, infiltração hemocítica na musculatura, esferóides ectópicos do órgão linfóide), havendo maior ocorrência de lesões no período de estio. Entretanto, no período chuvoso houve redução da ocorrência, sendo associada a mudança de manejo. O tempo de cultivo e a densidade de estocagem, foram variáveis que influenciaram significativamente (P<0,05) na manifestação da IMNV.
212

Influ?ncia de atividades antr?picas sobre a saliniza??o da ?gua em ?rea de dunas no Munic?pio de Guamar? RN

Ferreira, Douglisnilson de Morais 08 August 2011 (has links)
Made available in DSpace on 2014-12-17T15:41:56Z (GMT). No. of bitstreams: 1 DouglisnilsonMF_DISSERT.pdf: 2911685 bytes, checksum: dee3c4e95effc239264141a2b3d730b8 (MD5) Previous issue date: 2011-08-08 / The municipality of Guamar? is located on the north coast of RN, Salineira zone, with a land area of 259 km2 and a population of approximately 12,500 inhabitants (IBGE, 2010). Presents strong morphological instability caused mainly by the influence of human activities in the region. The present study aims to assess the existing levels of salts in the springs of the region, by evaluating the electrical conductivity, pH, salinity, chlorides, hardness, calcium, magnesium and heavy metals in the water. The collection and analysis methods adopted in the survey are based on APHA (2005). The electrical conductivity, salinity and chloride behaved similarly throughout the study. Some points suffered the direct effect of the salt ponds and others. Given the existence of a drainage ditch between the saline and monitored region, there was little change in the environment, including the native vegetation. The opposite situation occurred in farms where the region is fully committed local vegetation and water holes and wells used in the past for domestic use are practically disabled (high salt content). In Rio Miassaba formation of an estuary is reversed, with the farther out from the sea showing higher salt concentracions, which may be associated with the discharge of organic matter and natural evaporation rate. In periods of no rainfall had a few points higher than the levels of salts found in seawater and may be associated with high evaporation in the region. Detected a positive factor is the high resilience and reducing salt, after periods of rainfall incidence / O munic?pio de Guamar? est? localizado no litoral norte do RN, subzona salineira, com uma ?rea territorial de 259 km2 e popula??o de aproximadamente 12.500 habitantes (IBGE, 2010). Apresenta acentuada instabilidade morfol?gica ocasionada principalmente pela influ?ncia de atividades antr?picas na regi?o. O presente estudo tem por finalidade avaliar os ?ndices de sais existentes nos mananciais da regi?o, atrav?s da avalia??o da condutividade el?trica, pH, salinidade, cloretos, dureza, c?lcio e magn?sio na ?gua. As metodologias de coletas e an?lises adotadas na pesquisa est?o baseadas no APHA (2005). A Condutividade El?trica, a Salinidade e o Cloreto apresentaram comportamento semelhante ao longo da pesquisa. No estudo observou-se que alguns pontos sofrem influ?ncia direta dos viveiros e outros das salinas. Tendo em vista a exist?ncia de uma vala de drenagem entre a salina e a regi?o monitorada, observou-se pouca altera??o no meio, inclusive na vegeta??o nativa. Situa??o inversa ocorreu na regi?o dos viveiros onde a vegeta??o local est? completamente comprometida e os po?os e cacimbas, utilizados no passado para uso dom?stico estarem praticamente desativados (alto teor salino). No Rio Miassaba h? forma??o de um estu?rio invertido, com os pontos mais distanciados do mar apresentando concentra??es salinas maiores, o que pode estar associado ? descarga de mat?ria org?nica e taxa de evapora??o natural. Em per?odos de aus?ncia de chuvas alguns pontos apresentaram teores de sais superiores aos encontrados na ?gua do mar, podendo ser associado ? alta taxa de evapora??o na regi?o. Um fator positivo detectado ? o alto poder de recupera??o e redu??o salina, ap?s per?odos de incid?ncia pluviom?trica
213

Susceptibilidade a antimicrobianos e resistência plasmidial de cepas de Salmonella spp isoladas de dois estuários do Estado do Ceará, Brasil /

Figueirêdo, Francileide Vieira. January 2008 (has links)
Resumo: A salmonelose é uma das doenças de origem alimentar mais freqüente e considerada uma das zoonoses mais relevantes para a saúde pública em todo o mundo. A Organização Mundial de Saúde (OMS) assinalou aumento alarmante de estirpes de Salmonella resistentes aos antibióticos devido ao seu uso abusivo em criações intensivas, especialmente nas aquícolas. Diante do exposto, o escopo deste trabalho foi o de isolar e identificar a resistência plasmidial em bactérias do gênero Salmonella, em amostras de água de dois ambientes estuarinos, um do Norte (Acaraú) e outro do Sul (Jaguaribe) do Estado do Ceará, ambos com atividades de carcinicultura. Durante sete meses, de novembro de 2006 a maio de 2007, foram coletadas 84 amostras de água dos dois estuários. A pesquisa de Salmonella seguiu a metodologia do "Bacteriological Analytical Manual". As salmonelas foram testadas quanto à susceptibilidade a dez antimicrobianos: Ácido nalidíxico, Ampicilina, Ciprofloxacina, Ceftriazona, Cloranfenicol, Gentamicina, Imipenem, Nitrofurantoína, Sulfametoxazol e Tetraciclina. A Concentração Inibitória Mínima dos antibióticos seguiu a técnica de macrodiluição em caldo. Em atividade de base, mediu-se o pH, a temperatura e a salinidade da água. Foram confirmadas 103 cepas de Salmonella, 90 no Rio Acaraú e 13 no Rio Jaguaribe, pertencentes aos sorovares: S. Newport, S. Saintpaul, S. Panama, S. Rubislaw, S Albany, S. Anatum, S. Corvallis, S. Madelia. O Rio Acaraú apresentou-se mais contaminado do que o Rio Jaguaribe, onde foram encontradas cepas resistentes a antimicrobianos, com um percentual de 25% para resistência plasmidial, e 75% para a cromossômica. Esses resultados ressaltam dois problemas de saúde pública: a presença de cepas de Salmonella resistentes e a possibilidade de contaminação humana pelo consumo dos crustáceos. Somado a isso,...(Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Salmonellosis is one of the most common foodborne diseases, was considered and the most important for public health authorities throughout the world. The World Health Organization (WHO) recently drew attention to the rapid increase in Salmonella strains resistant to antibiotics employed in farming activities, especially in aquaculture. Thus, the objective of this study was to test the antimicrobial susceptibility of Salmonella strains isolated from water samples collected in the estuaries of the Acaraú and Jaguaribe rivers (respectively in the north and south of Ceará State, Brazil), both of which are subject to extensive shrimp farming. Eighty-four samples were collected between November 2006 and May 2007. The susceptibility tests were performed following the guidelines of the Bacteriological Analytical Manual (BAM). The strains were exposed to 10 different antibiotics: nalidixic acid, ampicillin, ciprofloxacin, ceftriaxone, chloramphenicol, gentamicin, imipenem, nitrofurantoin, sulfamethoxazole and tetracycline. The minimum inhibitory concentration of the antibiotics was determined with the broth macrodilution method. In base activity, mensure the factores as Temperature, salinity and pH values were registered for all water samples. One hundred three Salmonella strains were isolated (Acaraú n=90; Jaguaribe n=13) belonging to the serotypes S. Newport, S. Saintpaul, S. Panama, S. Rubislaw, S Albany, S. Anatum, S. Corvallis and S. Madelia. Thus, the Acaraú river was more severely contaminated than the Jaguaribe river, where strains resistant to antimicrobial were found in a rate of 25% to plasmid resistance and 75% to chromosomal resistance. These results show up two problems of public health: the presence of resistant strains of Salmonella and the possibility of human contamination though crustacean consumption. In addition to this,...(Complete abstract click electronic access below) / Orientador: Julieta Rodini Engracia de Moraes / Coorientador: Regine H. S. dos Fernandes Vieira / Banca: Fabiana Pilarski / Banca: Angela Cleusa de Fátima Banzatto de Carvalho / Banca: Gilson Pereira de Oliveira / Banca: Fabiana Rizzi Bozzo / Doutor
214

InvestigaÃÃo da ocorrÃncia dos vÃrus da sÃndrome da mancha branca (WSSV) e da infecÃÃo hipordermal e necrose hematopoiÃtica (IHHNV) em camarÃes coletados em Ãreas sob influÃncia de efluentes da carcinicultura / Investigation of occurrence of the virus of white spot syndrome (WSSV) infection and hipordermal and haematopoietic necrosis (IHHNV) in shrimps collected in areas under influence of effluents from shrimp

JoÃo Mafaldo de Oliveira Neto 07 September 2006 (has links)
As principais enfermidades virais detectadas na carcinicultura mundial sÃo a SÃndrome da Mancha Branca (WSSV), InfecÃÃo Hipodermal e Necrose HematopoiÃtica (IHHNV), SÃndrome de Taura (TSV) e a SÃndrome da CabeÃa Amarela (YHV), esta Ãltima sem registro nos cultivos brasileiros. As doenÃas virais acima relacionadas nÃo estÃo restritas ao ambiente de cultivo. O WSSV foi detectado em vÃrias espÃcies de peneÃdeos e em outros grupos de crustÃceos silvestres. O IHHNV parece ser restrito aos peneÃdeos, tendo tambÃm sido detectado em populaÃÃes silvestres. O presente estudo teve como Ãrea de investigaÃÃo uma gamboa do EstuÃrio do Rio Juaguaribe, localizada na comunidade de Canavieiras, Aracati-CE, que recebe efluentes de fazendas de carcinicultura. A pesquisa objetivou verificar possÃveis escapes da espÃcie Litopenaeus vannamei para o ambiente de entorno e a ocorrÃncia do WSSV e IHHNV em populaÃÃes de camarÃes silvestres. Foram capturados 450 camarÃes por meio de arrastos e tarrafeamentos em trÃs estaÃÃes durante trÃs coletas realizadas nos meses de marÃo, abril e maio de 2006. Para a pesquisa viral foram utilizadas a ferramenta diagnÃstica de biologia molecular, reaÃÃo em cadeia da polimerase (PCR) e histologia clÃssica. A identificaÃÃo dos animais demonstrou o escape da espÃcie exÃtica. NÃo foi detectada a presenÃa do WSSV nas amostras analisadas. Contudo, foi detectado o IHHNV em 17 indivÃduos, sendo seis L. vannamei, oito Farfantepenaeus subtilis, um Farfantepenaeus brasiliensis e dois Litopenaeus schmitti, ficando demonstrada a suscetibilidade dessas espÃcies nativas ao IHHNV.
215

Efeito da imunoterapia com Dermatophagoides pteronyssinus na resposta clínica e imunológica ao camarão / Effect of immunotherapy with Dermatophagoides pteronyssinus in the clinical and immunological response to shrimp

Ariana Campos Yang 30 July 2009 (has links)
Objetivo: O objetivo desse estudo foi avaliar alterações na resposta clínica e imunológica ao camarão após a imunoterapia com Dermatophagoides pteronyssinus. Métodos: Selecionou-se 35 indivíduos alérgicos a Dermatophagoides pteronyssinus (Der p), os quais foram submetidos a testes cutâneos de leitura imediata para ácaros, baratas, camarão, tropomiosina recombinante, além de cão, gato e fungos. A detecção de IgE espcífica in vitro foi feita para o ácaro, camarão, barata americana e para suas tropomiosinas. Em todos, avaliou-se reatividade clínica ao camarão através de provocação oral. Dez pacientes foram alocados para o grupo controle, e 25 foram submetidos à imunoterapia alérgeno específica para o ácaro. Os testes cutâneos e a dosagem de IgE sérica específica foram repetidas após a indução da imunoterapia, e após 1 ano do início. A reatividade clínica ao camarão foi reavaliada no final do estudo pela provocação oral. Resultados: No grupo dos pacientes que foram submetidos à imunoterapia, observamos diminuição na reatividade nos testes cutâneos e dosagem de IgE específica para Der p, camarão e tropomiosina recombinante. Dos 10 pacientes com testes cutâneos positivos para camarão, 4 foram negativos na dosagem após um ano de imunoterapia (p= 0,04). Quanto à dosagem sérica de IgE para camarão, dos 9 positivos no início, 6 ficaram negativos (p= 0,014). Nenhum paciente submetido a imunoterapia desenvolveu nova sensibilização para camarão. Não houve alteração na reatividade clínica ao camarão após imunoterapia. Conclusão: A imunoterapia para Dermatophagoides pteronyssinus foi acompanhada de diminuição da reatividade imunológica para camarão e clinicamente não houve alteração da sensibilidade a camarão / Objective: The objective of this study was to determine changes in clinical and immunological response to shrimp after immunotherapy with Dermatophagoides pteronyssinus. Methods: We studied 35 allergic subjects to Dermatophagoides pteronyssinus (Der p), submitted to skin tests to mites, cockroach, shrimp, recombinant tropomyosin, and dog, cat and fungi. The detection of serum specific IgE was performed to mite, shrimp, and tropomyosin from American cockroach. In all patients, the clinical reactivity to shrimp was assessed through oral challenge. Ten patients were allocated to the control group, and 25 were submitted to immunotherapy for mite. Skin tests and determination of serum specific IgE were repeated after the induction of immunotherapy (3-4 months) and 1 year after of beginning of the treatment. The clinical reactivity to shrimp was assessed again at the end of the study by oral challenge. Results: In the group of patients who were undergoing immunotherapy, we observed decreased reactivity in the skin tests and specific IgE levels to Der p, shrimp and recombinant tropomyosin. Among the 10 patients with positive skin tests to shrimp, 4 were negative when assessed after one year of immunotherapy (p = 0.04). About serum specific IgE to shrimp, from the 9 positive reactors in the beginning of treatment, 6 became negative (p= 0.014). There was no change in clinical reactivity to shrimp after immunotherapy. Conclusion: The immunotherapy for Dermatophagoides pteronyssinus was accompanied by decreased immune reactivity to shrimp and clinically there was no change in sensitivity to shrimp
216

ExtraÃÃo de pigmentos carotenÃides da carapaÃa do camarÃo e sua utilizaÃÃo em um produto derivado de pescado / Extraction of carotenoid pigments of the carapace of shrimp and their use in a by-product of fish

ErotÃide Leite de Pinho 10 September 2001 (has links)
CoordenaÃÃo de AperfeiÃoamento de NÃvel Superior / O descarte na indÃstria de pescado, inclusive o de carapaÃas de crustÃceos, constitui um percentual bastante elevado. Estas cascas sÃo ricas em pigmentos carotenÃides, os quais, apresentam um alto valor de pigmentaÃÃo, sendo corrente em alguns paÃses a extraÃÃo e posterior utilizaÃÃo dos mesmos em raÃÃes. O objetivo deste experimento foi estudar a extraÃÃo dos pigmentos carotenÃides das cascas de camarÃo e verificar seu potencial de uso como aditivo natural de cor em um produto à base de pescado. Neste estudo foram desenvolvidos testes preliminares para escolha de um mÃtodo para a extraÃÃo dos pigmentos optando-se pela extraÃÃo com solvente. Caracterizou-se ospigmentos extraÃdos das cascas de camarÃo e avaliou-se a influÃncia do extrato pigmentado aplicado em um produto à base de pescado, o qual foi embalado à vÃcuo e sem vÃcuo e submetido à uma estocagem (-20ÂC) durante um perÃodo de60 dias. A cor dos produtos foi medida a cada 15 dias no sistema CIE determinando-se os parÃmetros de L*, a* e b*. A anÃlise espectrofotomÃtrica do extrato de camarÃo apresentou produtos de degradaÃÃo da astaxantina. Os produtos pigmentados com o extrato de camarÃo e embalados à vÃcuo apresentaram valores de luminosidade (L*) menores (p < 0,05) que os embalados sem vÃcuo com 15 e 45 dias de armazenamento. Para o componente de intensidade de cor amarela (b*) os produtos embalados à vÃcuo apresentaram valores maiores (p<0,05) no inÃcio do armazenamento (0 dias) e menores (p<0,05) com 45 dias de armazenamento, em relaÃÃo Ãqueles embalados sem vÃcuo. Contudo, no perÃodo de 60 dias de armazenamento nÃo foi observado efeito significativo da embalagem à vÃcuo sobre as caracterÃsticas de cor dos produtos. / Waste material in the fish industry including the shells from the crustacean, constitute a very high percentage. These shells are rich in carotenoids pigments, which may have a high pigmentation value when used in foods. It is common in some countries the use of the extracted pigments in feeds.The aim of this experiment was to study the process of carotenoids extraction and to verify its pigmenting potential in a minced fish food product. The solvent extraction technique was used after testing other extraction procedures. Extracted pigments were characterized by spectrophotometry. Pigments were then included in the fish formulation. Fish products were packaged with and without vacuum and storage in the dark at â20ÂC for 60 days. The color of the products was measured every 15 days with the CIE system which determines parameters L*, a* and b*. The spectrophotometry study showed products of degradation of astaxanthin in the shell extract. The luminosity (L*) of the color in products packaged under vacuum was lower (p<0.05) with 15 and 45 days of storage than in those stored without vacuum. Vacuum packaged products showed that with 0 days of storage the yellowness component (b*) was higher (p<0.05) in vacuum packaged products than in those stored without vacuum. The reverse occurring with 45 days of storage. After 60 days frozen storage vacuum packaging did not affect the color characteristics of the fish product.
217

Caracterização e idade das intrusivas do sistema pórfiro yarumalito, magmatismo Combia, Colombia

Henrichs, Isadora Alberti January 2013 (has links)
O sistema pórfiro Yarumalito, caracterizado por concentrar minério em veios controlados por estruturas e stockworks encontra-se localizado no distrito mineiro de Marmato, que é considerado um dos mais antigos distritos de ouro da Colômbia, com atividades de extração que remontam da época dos Incas. O sistema ígneo da região é relacionado ao magmatismo Miocênico da Formação Combia. Neste trabalho foram descritas as rochas subvulcânicas diretamente relacionadas às zonas mineralizadas do sistema pórfiro Yarumalito com o objetivo de, após caracterizar as intrusões, realizar datação através do método U-Pb em zircão. Amostras selecionadas de duas intrusões férteis, uma andesítica mais abundante na área e outra diorítica com características intrusivas na primeira e de ocorrência mais restrita, foram criteriosamente descritas e tiveram zircões separados e posteriormente analisados por SHRIMP na Universidade de São Paulo. Os resultados apontaram para um intervalo bastante restrito para as idades, com médias ponderadas das idades 206Pb/238U variando de 7 ± 0.15 Ma para o andesito pórfiro a 6.95 ± 0.16 Ma para o diorito pórfiro. Estes resultados sugerem um período restrito no tempo para a cristalização das intrusivas portadoras de mineralizações na área do projeto e posicionam o sistema Yarumalito para o final do magmatismo Combia. / The Yarumalito porphyry system, characterized to concentrate ore in structure related veins and stockworks is located in the mining district of Marmato, that is considered one of the oldest gold mining districts of Colombia, with exploration activities since the Inca Empire. The igneous system of the region is related to the miocenic magmatism of the Combia formation. In this paper, the subvolcanic rocks directly related with the mineralized zones of the Yarumalito porphyry were described in order to, after characterization, obtain UPb ages in zircon to the intrusions. Selected samples of the two fertile intrusions, one andesitic more abundant in the area and one dioritic more restricted, were carefully described and had their zircon grains separated and analyzed by SHRIMP in the University of São Paulo. The results points to a very restricted interval for the ages, with weighted average 206Pb/238U varying from 7 ± 0.15 Ma for the andesitic porphyry and 6.95 ± 0.16 Ma for the dioritic porphyry. These results suggest a brief period for the crystallization of the mineralized subvolcanic rocks in the area and constrain the Yarumalito system to the final stages of the Combia magmatism.
218

Diadromie, dispersion et histoire évolutive des complexes "Caridina nilotica" et "Caridina weberi" (Crustacea - Decapoda - Atyidae) dans les systèmes insulaires de l’Indo-Pacifique / Diadromy, dispersion and evolutive history of the species complexes Caridina nilotica and Caridina weberi (Crustacea - Decapoda - Atyidae) in insular systems of the Indo-Pacific

Mazancourt, Valentin de 12 October 2018 (has links)
Les cours d’eau des îles tropicales abritent des organismes qui ont développé un cycle de vie diadrome, partagé entre une phase adulte en eau douce et une phase larvaire marine : l’amphidromie. Parmi ces organismes, dans la zone Indo-Pacifique, on trouve les crevettes du genre Caridina H. Milne Edwards, 1837. Avec plus de 300 espèces décrites, il s’agit du genre le plus diversifié de l’infra-ordre des Caridea, avec une systématique extrêmement confuse et compliquée. Au sein de ce genre, deux complexes d’espèces sont particulièrement bien représentés dans les systèmes insulaires de l’Indo-Pacifique, le complexe Caridina nilotica et le complexe C. weberi. Grâce au développement de nouvelles techniques de séquençage de nouvelles méthodes de taxonomie dite intégrative sont apparues, permettant de résoudre une partie des problèmes taxonomiques de ces groupes. L’objectif de la thèse était d’appliquer une approche de taxonomie intégrative aux espèces des complexes C. nilotica et C. weberi afin de clarifier leur systématique et, de fait, mieux appréhender leur biologie et fournir les outils aux gestionnaires pour mettre en place une meilleure conservation de ces espèces et de leurs milieux. Après avoir montré que certains caractères morphologiques traditionnellement utilisés pour décrire les espèces étaient influencés par l’environnement et donc fortement variables, l’étude de taxonomie intégrative a été conduite sur 92 espèces, permettant d’obtenir 1682 séquences auxquelles s’ajoutent 32 génomes mitochondriaux complets et 97 partiels, mettant en évidence 43 espèces nouvelles, certaines décrites au cours de la thèse. Les relations phylogénétiques entre les espèces des deux complexes ont été reconstruites à partir d’un grand jeu de données moléculaires, permettant de montrer que les complexes sont des groupes monophylétiques avec des différences en terme d’habitats occupés. Enfin, la faisabilité de l’étude sclérochronologique de l’amphidromie chez une espèce du complexe C. weberi (C. multidentata) a été testée sur la cuticule du pédoncule oculaire, avec une étude de l’ultrastructure de la cuticule, décrite pour la première fois chez cette espèce. / Rivers of tropical islands harbor organisms that have developped a diadromous lifecycle, shared between a freshwater adult phase and a marine larval phase: amphidromy. Among these organisms, in the Indo-Pacific area are found shrimps of the genus Caridina H. Milne Edwards, 1837. With more than 300 described species it is the most speciose genus of the infra-order Caridea, with a most confused and complicated taxonomy. Within this genus, two species complexes are particularly well-represented in insular systems of the Indo-Pacific, the C. nilotica complex and the C. weberi complex. Thanks to the development of new sequencing techniques, new methods of integrative taxonomy appeared, allowing to resolve part of the taxonomic complexity of these taxa. The aim of the thesis was to apply an integrative taxonomy approach to species belonging to C. nilotica and C. weberi complexes in order to clarify their taxonomy and have a better understanding of their biology and provide tools to managers for establishing a better conservation of these species and their environments. After showing that some morphological characters traditionally used to describe species were influenced by the environment and so, highly variable, the integrative taxonomy was led on 92 species, allowing to obtain 1,682 sequences to which are added 32 complete and 97 partial mitochondrial genomes, highlighting 43 new species, some of them described during the thesis. Phylogenetic relationships among the species of the two complexes were reconstructed from a large molecular dataset, allowing to show that the complexes are monophyletic groups, with habitat differences. Finally, the feasibility of a sclerochronological study of amphidromy in a species of the C. weberi complex (C. multidentata) was tested on the eyestalk cuticle, with a study of the ultrastructure of the cuticle, described for the first time in this species.
219

Sustainability of rice-shrimp farming system in a brackish water area in the Mekong Delta of Vietnam

Tran, Thanh Be, University of Western Sydney, Hawkesbury, Faculty of Agriculture and Horticulture, School of Agriculture and Rural Development January 1994 (has links)
The Mekong Delta, which is considered as the main 'rice bowl and fish basket', is one of seven distinct agro-ecological regions of Vietnam and plays an important role in the economy of the country. Several rice-based farming systems have been developed in various areas of the MD. Rice-shrimp integrated system in brackish areas is a special farming system developed in this delta. It is a profitable system and seems to be environmentally safe on the one hand without the use of pesticides. On the other hand, use of brackish water in this system may result in degradation of land, as some previous studies have found. To understand how this farming system works and to identify the external and internal factors influencing its sustainability, the project 'Sustainability of rice-shrimp farming system in a brackish area in the Mekong delta of Vietnam' was carried out in 1992-1993 by an interdisciplinary team of researchers from the University of Cantho and staff of local district Agricultural Office, representing different fields of sciences. The research methodology was the Farming Systems Research approach with modifications towards soft systems thinking, involving farmers into the research process. One main result of this study is an insight into the rice-shrimp farming system. It includes various physical, biological, technological, economical and sociological aspects of rice production prior to integration and in integrated farm, naturally supplied shrimp growing and giant shrimp rearing, upland crop production as well as off-farm and non-farm work of farm households. Sustainability of the system studied is assessed, in comparison with rice monoculture, through various criteria of the three view points productivity, environmental safety and socio-economic effectiveness. In terms of such points of view, rice-shrimp farming system is rated higher than rice monoculture system. Thus the integrated system so far is considered to be more sustainable than the others. / Master of Science (Hons)
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An Evolutionary History of the Freshwater Shrimp Family Atyidae in Australia

Page, Timothy J, n/a January 2007 (has links)
The aim of this thesis is to use phylogenetic analyses of mitochondrial DNA to investigate the biogeography and evolutionary relationships within the freshwater shrimp family Atyidae in Australia at a nested series of scales, both geographic and systematic. At the largest scale, the relationships between Australian and Indo-West Pacific species were inferred using the two most common atyid genera in Australia, Caridina and Paratya. Most atyids are hypothesised to have colonised Australia from Southeast Asia, but Paratya may be a Gondwanan relict given its distribution. Australian Paratya all form a strong clade, with a sister relationship to species from Tasman Sea islands. Molecular clock estimates place all of the splits within Paratya after the break-up of Gondwana, with Australia being colonised once 3½-8½ million years ago. This transoceanic dispersal is conjectured to have taken place through oceanic currents because of the amphidromous life cycle of some taxa of Paratya. Caridina has a very different biogeographic history in Australia, as numerous Australian species have close evolutionary relationships with non-Australian taxa from locations throughout the region. This implies many colonisations to or from Australia over a long period, and thus highlights the surprising adeptness of freshwater shrimp in dispersal across ocean barriers and the unity of much of the region's freshwater biota. A number of potential species radiations within Australia were also identified. This agrees with patterns detected for a large number of Australian freshwater taxa, and implies a vicariant explanation due to the development of colder, dryer climates. The systematic relationships of the remaining two Australian surface genera (Caridinides, Australatya) and two subterranean genera (Parisia, Pycnisia) were also investigated. Australatya forms a strong clade with Pacific 'Atya-like' genera, and Caridinides falls within a clade containing Australian Caridina. The hypogean genera, Parisia and Pycnisia, form a strong clade in all analyses, implying an Australian subterranean speciation. The possibility of a relationship between Parisia/Pycnisia and some Australian Caridina species may have implications for the monophyly of the highly disjunct genus Parisia, as it may descend from local Caridina species and represent convergent morphologies. The common and speciose genus Caridina was used as a model taxon for analyses within Australia. At the medium scale, molecular taxonomic techniques were used to uncover cryptic species within a problematic east Australian species complex. At least five species were detected. Phylogeographic and population genetic analyses were carried out on each of these five cryptic species, which diverged from each other in the late Miocene/Pliocene. There were very large differences between the species in the scales of overall geographic distribution, intraspecific divergence and population structure. These were characterised as either: 1) species with large ranges, low intraspecific divergence, limited phylogeographic structuring (Caridina sp. D); 2) species with large ranges, high intraspecific divergence, a high level of phylogeographic structuring (sp. B); 3) species with a limited range, low intraspecific divergence, no phylogeographic structuring (sp. E); or 4) species with limited ranges, high intraspecific divergences, a high level of phylogeographic structuring (sp. A & C). These patterns reflect a combination of large-scale factors, such as landscape structure and climate change, and small-scale factors, such as species-specific tolerances to local conditions and differing dispersal capabilities. Life history variation (egg size) between species may be correlated with different dispersal abilities. Species with the smallest eggs have the least intraspecific divergence and largest distribution, while those with the biggest eggs have the most divergence and smallest distribution, with medium-sized egg species in between. At the smallest phylogeographic scale, C. sp. C from the sand dune islands of Moreton Bay in southeastern Queensland was further analysed. Two different lineages (C1, C2) were found which diverged from each other during the late Miocene/Pliocene and so are older than the current landscape in which they are found. Small-scale phylogeographic analyses within C1, C2 and a sympatric fish identified divergences dating to the Pleistocene (about 100-300 thousand years ago). This implies that ice age sea-level changes may have structured these populations, although there is little observable influence of the last glacial maximum (about 18 thousand years ago). This study has highlighted a number of taxonomic anomalies within the Atyidae. The detection of many cryptic species implies that biodiversity within freshwater invertebrates is higher than currently appreciated. The evolutionary and biogeographic relationships of Australian atyids have proved complex, with many taxa having their own individual histories. At the large Indo-Pacific scale, dispersal is most evident, but within Australia, both vicariance and dispersal have been responsible for structuring all taxa at every scale.

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