993 resultados para Peixes - Genética


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Ce travail est une analyse exhaustive des romans publiés par l’écrivain chilien Alejandro Zambra entre 2006 et 2011. Compte tenu de son appartenance à la génération postdictatoriale, on va se concentrer sur la reconstruction autofictionnelle de l’enfance, et sur la façon dont elle reproduit, questionne et renverse le récit dictatorial dominant qui relègue les enfants sur le plan des personnages secondaires. Pour identifier le développement du discours, on va s’appuyer sur des outils critiques de la génétique littéraire dont le concept central « d’avant-texte » nous permet de faire une lecture rétrospective de Bonsái et de La vida privada de los árboles comme des précurseurs idéologiques de Formas de volver a casa. En raison de la centralité jouée par l’espace dans ces romans, on va consacrer une grande partie du travail à la représentation spatiale et la manière dont l’espace configure la position des personnages à l’intérieur du schème narratif. C’est dans cette relation que l’on identifie la dichotomie spatiale élaborée dans les œuvres, car l’espace et la vie privée sont reliés à l’inertie et la résignation dans l’univers textuel, tandis que l’action et le questionnement appartiennent au domaine de l’espace et la vie publics. Lus l’un après l’autre, les romans témoignent du parcours suivi de l’écrivain, qui assimile le récit dictatorial en évitant la confrontation narrative au début, pour, par la suite, approcher le passé, l’histoire familiale et la dictature, dans un processus autofictionnel qui projette les différentes voies du retour chez soi.

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Desde la perspectiva de la genética textual, en este trabajo observamos las representacionesdel personaje de Peter Pan en los textos de J. M. Barrie dedicados a este con respecto a sussemejanzas con el dios griego Pan, para ver de qué manera dialogan con los diferentes sentidosque el dios fue connotando a través de siglos. Analizamos la fotonovela The Boys Castawaysof Black Lake Island (1901); The Little White Bird (1902), novela en la que aparece en seiscapítulos; las "Fairy Notes" (1903) en borrador y el libreto inédito llamado Anon: a play de la obra teatral Peter Pan or The Boy Who Would Not Grow Up (estrenada en 1904); la novela Peter Pan in Kensington Gardens (1906), que consiste en esos seis capítulos de The LittleWhite Bird; la novela Peter and Wendy (1911), adaptación de la obra de teatro; un guion cinematográfico,Scenario for a Proposed Film of Peter Pan (c. 1918), que no se filmó; y ellibreto de la obra, finalmente publicado, con bastantes cambios, en 1928

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Desde la perspectiva de la genética textual, en este trabajo observamos las representacionesdel personaje de Peter Pan en los textos de J. M. Barrie dedicados a este con respecto a sussemejanzas con el dios griego Pan, para ver de qué manera dialogan con los diferentes sentidosque el dios fue connotando a través de siglos. Analizamos la fotonovela The Boys Castawaysof Black Lake Island (1901); The Little White Bird (1902), novela en la que aparece en seiscapítulos; las "Fairy Notes" (1903) en borrador y el libreto inédito llamado Anon: a play de la obra teatral Peter Pan or The Boy Who Would Not Grow Up (estrenada en 1904); la novela Peter Pan in Kensington Gardens (1906), que consiste en esos seis capítulos de The LittleWhite Bird; la novela Peter and Wendy (1911), adaptación de la obra de teatro; un guion cinematográfico,Scenario for a Proposed Film of Peter Pan (c. 1918), que no se filmó; y ellibreto de la obra, finalmente publicado, con bastantes cambios, en 1928

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Desde la perspectiva de la genética textual, en este trabajo observamos las representacionesdel personaje de Peter Pan en los textos de J. M. Barrie dedicados a este con respecto a sussemejanzas con el dios griego Pan, para ver de qué manera dialogan con los diferentes sentidosque el dios fue connotando a través de siglos. Analizamos la fotonovela The Boys Castawaysof Black Lake Island (1901); The Little White Bird (1902), novela en la que aparece en seiscapítulos; las "Fairy Notes" (1903) en borrador y el libreto inédito llamado Anon: a play de la obra teatral Peter Pan or The Boy Who Would Not Grow Up (estrenada en 1904); la novela Peter Pan in Kensington Gardens (1906), que consiste en esos seis capítulos de The LittleWhite Bird; la novela Peter and Wendy (1911), adaptación de la obra de teatro; un guion cinematográfico,Scenario for a Proposed Film of Peter Pan (c. 1918), que no se filmó; y ellibreto de la obra, finalmente publicado, con bastantes cambios, en 1928

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Esta dissertação de mestrado busca pesquisar a relação estabelecida pelo teólogo Ronald Cole-Turner, entre a engenharia genética e o conceito de co-criação , desenvolvido como uma alternativa para que se pense o papel do ser humano frente aos desenvolvimentos tecnológicos atuais. Tendo em vista o conceito da evolução, da criação contínua e dos potenciais gerados pela engenharia genética, Cole-Turner defende que o ser humano pode participar das atividades criativas de Deus por meio desta tecnologia, desde que priorize os aspectos redentivos que podem ser extraídos de seu uso. Faz isto em demonstrar, por meio do relato Jawista da criação, como o agir criativo de Deus está relacionado ao agir humano, através de suas tecnologias, e em relacionar os milagres de cura operados por Jesus nos evangelhos, como explicitação epistêmica da vontade de Deus, que pode ser participada pelos seres humanos. O objetivo básico desta pesquisa será o de relatar, no primeiro capítulo, o aspecto teórico da engenharia genética, nas suas possibilidades positivas e negativas. Em seguida, no capítulo segundo, se fará uma exposição do pensamento de Cole- Turner, em diálogo com outros interlocutores do tema. Por fim, no último capítulo, se verificará as respostas oferecidas às várias observações críticas que seu pensamento recebe. A hipótese é a de que, se a criação é um projeto contínuo e inacabado, e o destino dos seres humanos se encontra inserido dentro desta continuidade, seria coerente afirmar que estes possam participar das atividades de Deus em tais projetos. Como a evolução biológica é uma dimensão da criação, que ocorre por meio de transformações no capital genético dos organismos vivos, os seres humanos, tendo conhecimento e habilidade para repetir os processos verificados nestas modificações, poderão empreender seus esforços, tanto na área da técnica, como na da ética, para participarem da consecução dos propósitos de Deus.(AU)

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Cattleya granulosa Lind is a large and endemic orchid in Atlantic Forest fragments in Northeast Brazil. The facility of collecting, uniqueness of their flowers, which have varying colors between green and reddish brown, and distribution in coastal areas of economic interest make their populations a constant target of predation, which also suffer from environmental degradation. Due to the impact on their populations, the species is threatened. In this study, we evaluate the levels of spatial aggregation in a preserved population, analyze the phylogenetic relationships of C. granulosa Lindl. with four other Laeliinae species (Brassavola tuberculata, C. bicolor, C. labiata and C. schofieldiana) and also to evaluate the genetic diversity of 12 remaining populations of C. granulosa Lindl. through ISSR. There was specificity of epiphytic C. granula Lindl. with a single host tree, species of Eugenia sp. C. granulosa Lindl. own spatial pattern, with the highest density of neighbors within up to 5 m. Regarding the phylogenetic relationships and genetic patterns with other species of the genus, C. bicolor exhibited the greatest genetic diversity (HE = 0.219), while C. labiata exhibited the lowest level (HE = 0.132). The percentage of genetic variation among species (AMOVA) was 23.26%. The principal component analysis (PCA) of ISSR data showed that unifoliate and bifoliolate species are genetically divergent. PCA indicated a close relationship between C. granulosa Lindl. and C. schofieldiana, a species considered to be a variety of C. granulosa Lindl. by many researchers. Population genetic analysis using ISSR showed all polymorphic loci. The high genetic differentiation between populations (ФST = 0.391, P < 0.0001) determined the structure into nine groups according to log-likelihood of Bayesian analysis, with a similar pattern in the dendrogram (UPGMA) and PCA. A positive and significant correlation between geographic and genetic distances between populations was identified (r = 0.794, P = 0.017), indicating isolation by distance. Patterns of allelic diversity suggest the occurrence of population bottlenecks in most populations of C. granulosa Lindl. (n = 8). Genetic data indicate that enable the maintenance of genetic diversity of the species is complex and is directly related to the conservation of different units or groups that are spatially distant.

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The Rachycentron canadum species, commonly known as beijupirá or cobia is the only representative of Rachycentridae family which has been increasingly used in marine fish farming, in intensive cultivation. As advantageous features it has easy adaptation, prolific behavior, early growth in captivity and high commercial value. Additionally, specie of Lutjanidae family (Lutjanus synagris, Lutjanus jocu, Lutjanus analis, Lutjanus alexandrei and Ocyurus chrysurus) represents an important fisheries resource in all areas of its occurrence. In Brazil, the commercial exploitation of Lutjanidae which begun in the 60's and 80's, already has showed a decline in catch volumes. This fact suggests that the snappers must have a conservative management. Despite the economic potential, little is known about the genetic and cytogenetic characteristics of these species, especially with respect to repetitive DNA analysis, which represents the major part of the eukaryotes genome, playing important evolutionary roles in the fish genome. Cytogenetic data is increasingly being used in population studies and biotechnological purposes in fishes. The cytogenetical analyzes were performed using classical methods such as Giemsa staining, C-banding and Ag-NORs, fluorochromes base-specific staining (DAPI and MM) and physical mapping of repetitive sequences among which, telomeric sequences, transposons (Tol2), retrotransposons (Rex1 and Rex3), repetitive DNA (microsatellites and Cot-1) and transcriptionally active regions of the 18S and 5S ribosomal genes and histone (H3 and H2BA) by in situ hybridization with fluorescent probes (FISH). The chromosomal patterns obtained contributed to the organization of repetitive sequences in the genome of the species, as well as karyotypical differentiation. Unusual patterns of histone sequences expansion depict the first occurrence in marine fishes. The obtained data provided subsides to the genetic knowledge of the important fisheries resource represented by the species here analyzed, seeking the marine pisciculture improvement.

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The artifi cial eutrophication is one of the biggest t h reat for the quality of aquatic ecosystems in the whole world. The expectations for the future climatic scenarios in arid and semi - arid regions are intense and frequent droughts enhancing the risk of eutrophicati on and cyanobacterial blooms. Restoration techniques of eutrophic lakes were proposed to reduce nutrient loading and improve the water quality. A successful technique used in temperate regions is the biomanipulation by benthivorous fish removal . Our hypoth esis is that the benthivorous fish removal reduces phytoplankton total biomass and change the composition of phytoplankton functional groups, improving water quality. The aim of the study was evaluate the impact of biomanipulation on phytoplankton function al groups and in the water quality. We applied the technique of biomanipulation in the artificial lake ESEC, in a semi - arid region of Brazil and analyzed the physical and chemical variables and the dynamic of phytoplankton functional groups monthly during November 2012 to August 2013. With the removal of benthivorous fish we observed a significant increase of the euphotic depth, phytoplankton richness and the recruitment of green algae (groups F and J ), indicators of good water quality. However, we did not observe significant differences on total phosphorous concentration and on phytoplankton biomass and diversity. The drought effect in the region during the study was evident , promoting a drastic reduction on water level which influenced the availability of resource and affected phytoplankton community before the biomanipulation. To evaluate the effect of severe drought on the dynamic of phytoplankton functional groups and test if the drought periods are favorable to dominance of cyanobacterial groups, we stu died two artificial neighbors lakes (ESEC and Pocinhos) in a semi - arid tropical region during May 2012 to February 2013. We observed a temporal differentiation of biotic and abiotic variables caused by drought. Both lakes presented reduction of 2 meters of water level and increase on conductivity, turbidity, nutrients concentration and a reduction on water transparency, during the severe drought. The deeper lake (Pocinhos) increased phytoplankton total biomass and presented cyanobacterial functional group d ominance (group S N ) and the shallower lake (ESEC) reduced phytoplankton total biomass and presented dominance of mixotrophic and flagellate functional groups (groups W 1 e W 2 ). Summarizing, the knowledge of the effects of benthivorous fish removal in semi - a rid tropical lakes still unknown and this study had limitations caused by the impact of drought. Thus, it is necessary a long term monitoring to investigate the real effects of biomanipulation on the functioning of the studied ecosystems. Otherwise, period s of drought could have opposite effects (increase or reduction) on total biomass and composition of phytoplankton functional groups. Drought not always leads to dominance of cyanobacterial groups.

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There are several abiotic factors reported in the literature as regulators of the distribution of fish species in marine environments. Among them stand out structural complexity of habitat, benthic composition, depth and distance from the coast are usually reported as positive influencers in the diversity of difentes species, including reef fish. These are dominant elements in reef systems and considered high ecological and socioeconomic importance. Understanding how the above factors influence the distribution and habitat use of reef fish communities are important for their management and conservation. Thus, this study aims to evaluate the influence of these variables on the community of reef fishes along an environmental gradient of depth and distance from shore base in sandstone reefs in the coast of state of Rio Grande do Norte, Brazil. These variables are also used for creating a simple predictive model reef fish biomass for the environment studied. Data collection was performed through visual surveys in situ, and recorded environmental data (structural complexity of habitat, type of coverage of the substrate, benthic invertebrates) and ecological (wealth, abundance and reef fish size classes). As a complement, information on the diet were raised through literature and the biomass was estimated from the length-weight relationship of each species. Overall, the reefs showed a low coverage by corals and the Shallow reefs, Intermediate I and II dominated by algae and the Funds by algae and sponges. The complexity has increased along the gradient and positively influenced the species richness and abundance. Both attributes influenced in the structure of the reef fish community, increasing the richness, abundance and biomass of fish as well as differentiating the trophic structure of the community along the depth gradient and distance from the coast. Distribution and use of habitat by recifas fish was associated with food availability. The predictor model identified depth, roughness and coverage for foliose algae, calcareous algae and soft corals as the most significant variables influencing in the biomass of reef fish. In short, the description and understanding of these patterns are important steps to elucidate the ecological processes. In this sense, our approach provides a new understanding of the structure of the reef fish community of Rio Grande do Norte, allowing understand a part of a whole and assist future monitoring actions, evaluation, management and conservation of these and other reefs of Brazil.

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The present study aimed to develop microsatellite markers (SSR) for Copernicia prunifera; and characterize the demographic pattern and the spatial genetic structure (SGS) in different development stages of C. prunifera in a natural population of Rio Grande do Norte (RN) by using ISSR molecular markers. 17 SSR primers pairs were developed, which were tested by using DNA from samples of different populations. The demographic and genetic spatial structure was assessed in a plot with an area of 0.55 ha, where all individuals were georeferenced. The molecular analyses with the use of microsatellite markers pointed out that all built primers pairs, when submitted to PCR, had amplification. They showed sizes of base pairs ranging between 113 and 250 bp. The demographic analyses showed a clustered standard of spatial distribution in the first distance classes, random between 40 and 50 m and segregated in higher distances. Eight ISSR primers were used, thereby producing a total of 102 loci, with 100 of them being polymorphic. Among the three stages, the young showed the highest Nei’s genetic diversity index (He = 0.37); whilst the lowest index was found in the reproductive adults (He = 0.34). The AMOVA results showed a greater genetic differentiation within the development stages (98.61%) in comparison to the interval among the stages (1.39%). The total population (n = 161) showed a positive and significant relationship of kinship in the first distance class (12.3 m). The young showed a significant kinship up to 10.5 m and negative in the fifth distance class (37.6 m). The non-reproductive adults had a positive relationship of kinship in the first distance class (11.0 m) and random distribution of genotypes in the remaining classes. The reproductive adults showed genotypes spatially distributed in a random way. The values for the genetic bottleneck tests proved that the number of loci with excess observed heterozygosity was greater than expected. The SGS results reflect the restricted dispersion of the species, and the bottleneck tests reflect the reduction genotypes provoked by the anthropization of natural environments of C. prunifera.

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Eutrophication is the most common cause of water quality degradation in the world. This process occurs by excessive nutrients inputs, nitrogen and phosphorus, to the aquatic systems resulting in algal and cyanobacterial blooms. In shallow lakes these effects are pronounced due to the higher interaction of the lake with watershed, air and sediment. There are innumerous restoration techniques of eutrophied lakes with a range of successful results but there is only one case of successful lake restoration in Brazil: Paranoá Lake in Brasília city. The Brazilian semiarid region has many artificial lakes, named açudes, which are mostly eutrophic and shallow lakes. The eutrophication in these lakes is reported and the phytoplankton community is dominated by potentially toxic cyanobacteria species, mainly Cylindrospermopsis raciborskii. The aim of this thesis is to test techniques for water quality management which can be easily applied in Brazilian semiarid lakes. Results from a laboratory experiment suggest that the addition of a phosphorus sorbent clay associated with an aluminium based coagulant is an effective technique in removing soluble reactive phosphorus and reducing C. raciborskii growth rate – cyanobacteria potentially toxic dominant in reservoirs of Brazilian semiarid – but this effect is dependent on the biomass in the application moment. Results from a field experiment in mesocosm in a eutrophied lake showed that the addition of aluminium based coagulant and removal of benthivorous fish is more efficient in removing total phosphorus and chlorophyll-a from water column than the isolated application of one of the techniques. Lastly, laboratory tests showed that aluminium based coagulant exhibited good performance in removing turbidity and total phosphorus from water of six reservoirs but the efficiency was reduced by algal biomass and pH. The results of this study showed that the improvement in water quality of eutrophied reservoirs in semiarid region is possible through internal loading control by phosphorus precipitation and inactivation in sediments or inhibition of phosphorus release by benthivorous fishes, and also that these results show are additives in water quality improvement.

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Eutrophication is the most common cause of water quality degradation in the world. This process occurs by excessive nutrients inputs, nitrogen and phosphorus, to the aquatic systems resulting in algal and cyanobacterial blooms. In shallow lakes these effects are pronounced due to the higher interaction of the lake with watershed, air and sediment. There are innumerous restoration techniques of eutrophied lakes with a range of successful results but there is only one case of successful lake restoration in Brazil: Paranoá Lake in Brasília city. The Brazilian semiarid region has many artificial lakes, named açudes, which are mostly eutrophic and shallow lakes. The eutrophication in these lakes is reported and the phytoplankton community is dominated by potentially toxic cyanobacteria species, mainly Cylindrospermopsis raciborskii. The aim of this thesis is to test techniques for water quality management which can be easily applied in Brazilian semiarid lakes. Results from a laboratory experiment suggest that the addition of a phosphorus sorbent clay associated with an aluminium based coagulant is an effective technique in removing soluble reactive phosphorus and reducing C. raciborskii growth rate – cyanobacteria potentially toxic dominant in reservoirs of Brazilian semiarid – but this effect is dependent on the biomass in the application moment. Results from a field experiment in mesocosm in a eutrophied lake showed that the addition of aluminium based coagulant and removal of benthivorous fish is more efficient in removing total phosphorus and chlorophyll-a from water column than the isolated application of one of the techniques. Lastly, laboratory tests showed that aluminium based coagulant exhibited good performance in removing turbidity and total phosphorus from water of six reservoirs but the efficiency was reduced by algal biomass and pH. The results of this study showed that the improvement in water quality of eutrophied reservoirs in semiarid region is possible through internal loading control by phosphorus precipitation and inactivation in sediments or inhibition of phosphorus release by benthivorous fishes, and also that these results show are additives in water quality improvement.

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Omnivory is a predominant feeding strategy among tropical fishes, but knowledge about its causes and consequences of this pattern is scarce. In this study we hypothesized that tropical fish feed lower in food web as a way to compensate a higher energetic demand, which increases with increasing water temperature and body size. Information about 8172 freshwater and marine fish species from whole world, from tropical and temperate ecosystems, showed that the trophic position of non-carnivore fish decreases with increasing body size in tropical but not in temperate ecosystems. This result indicates that the higher energetic demand of large-bodied tropical fish should exert a selective force in favor of omnivory. As a consequence, trophic dynamics in tropical freshwater ecosystems should have different patterns comparing to temperate ones, with major implications for water management and restoration of eutrophic aquatic ecosystems. Another hypothesis of this work was that effects of tropical omnivorous planktivorous fish on planktonic communities depend of primary producers stoichiometric composition, which depends of light availability relative to nutrients ratios. A mesocosm experiment, manipulating light availability and planktivorous fish presence, confirmed our hypothesis indicating that resource stoichiometric composition (consequently nutritional quality), determine trophic structure of pelagic food webs in tropical lakes. Finally another mesocosm experiment indicated that the removal of omnivorous benthivorous fish should be more efficient than removal of omnivorous planktivorus fish, as a way to improve water quality in tropical lakes and reservoirs. This last experiment showed that omnivorous planktivorous fish increase phytoplankton biomass due to trophic cascade interactions, without increasing nutrient concentrations in the water column. On the other hand, omnivorous benthivorous fish, feeding on detritus and other benthonic food sources and excreting nutrients in the water column, are responsible for translocate nutrient from sediments to the water column, increasing phosphorus pool and phytoplankton biomass. Thereby, internal phosphorus supply should be reduced and water quality of eutrophicated lakes could be improved by removing omnivorous benthivorous fish.

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Omnivory is a predominant feeding strategy among tropical fishes, but knowledge about its causes and consequences of this pattern is scarce. In this study we hypothesized that tropical fish feed lower in food web as a way to compensate a higher energetic demand, which increases with increasing water temperature and body size. Information about 8172 freshwater and marine fish species from whole world, from tropical and temperate ecosystems, showed that the trophic position of non-carnivore fish decreases with increasing body size in tropical but not in temperate ecosystems. This result indicates that the higher energetic demand of large-bodied tropical fish should exert a selective force in favor of omnivory. As a consequence, trophic dynamics in tropical freshwater ecosystems should have different patterns comparing to temperate ones, with major implications for water management and restoration of eutrophic aquatic ecosystems. Another hypothesis of this work was that effects of tropical omnivorous planktivorous fish on planktonic communities depend of primary producers stoichiometric composition, which depends of light availability relative to nutrients ratios. A mesocosm experiment, manipulating light availability and planktivorous fish presence, confirmed our hypothesis indicating that resource stoichiometric composition (consequently nutritional quality), determine trophic structure of pelagic food webs in tropical lakes. Finally another mesocosm experiment indicated that the removal of omnivorous benthivorous fish should be more efficient than removal of omnivorous planktivorus fish, as a way to improve water quality in tropical lakes and reservoirs. This last experiment showed that omnivorous planktivorous fish increase phytoplankton biomass due to trophic cascade interactions, without increasing nutrient concentrations in the water column. On the other hand, omnivorous benthivorous fish, feeding on detritus and other benthonic food sources and excreting nutrients in the water column, are responsible for translocate nutrient from sediments to the water column, increasing phosphorus pool and phytoplankton biomass. Thereby, internal phosphorus supply should be reduced and water quality of eutrophicated lakes could be improved by removing omnivorous benthivorous fish.