Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / O óleo essencial de gerânio (Pelargonium graveolens L´Her) é amplamente usado em sabonetes, nas indústrias de perfumaria e cosméticos. Há um déficit na produção do óleo essencial de gerânio pelo mundo e assim tornou-se necessário o investimento em pesquisas que garantam o aumento da produção mundial de gerânio. O objetivo do presente trabalho foi de avaliar a influência do uso de diferentes cores de filme plástico, tipos de adubação, espaçamentos de plantio e intervalos de colheita na biomassa e no óleo essencial de gerânio. Dois ensaios foram conduzidos. No primeiro ensaio avaliou-se o efeito de diferentes cores de filme plástico e tipos de adubação e no segundo avaliou-se o efeito de diferentes espaçamentos de plantio e intervalos de colheita. As variáveis avaliadas foram: sobrevivência, altura de plantas, diâmetro de copas, massa fresca e seca de folhas e caules, teor e rendimento de óleo essencial e os teores dos seguintes compostos majoritários: geraniol, citronelol, formiato de citronelil, linalol, 6,9-guaiadieno, formiato de geranila, geranial e iso-mentona. No primeiro ensaio a ausência de filme plástico resultou na redução significativa para praticamente todas as variáveis e o uso de esterco bovino, isolado ou combinado com NPK (3-12-6), resultou em valores mais elevados em boa parte das variáveis. Para o cultivo de gerânio pode se recomendar o uso de filme plástico, preferencialmente de cor preta que é mais barato, espaçamento de plantio de 50 x 50 cm e os intervalos de colheita da parte aérea de oito semanas.

A pesquisa relativa ao transporte ferroviário no Brasil tem se intensificado nos últimos anos visando principalmente a melhoria no desempenho do par rodatrilho. Isso se deve à demanda de se transportar cada vez mais carga por eixo com a finalidade de reduzir o custo de transporte. Através de mudanças na microestrutura do material ou de mudanças na composição das ligas utilizadas na fabricação pode se aumentar a resistência do par roda-trilho. Neste trabalho foi analisada a influência de diferentes microestruturas (puramente perlíticas e perlíticas-bainíticas), obtidas por meio de tratamento térmico por dilatometria, nas propriedades de um aço alto carbono similar ao utilizado em rodas convencionais classe C AAR destinadas ao transporte de carga pesada. As análises empregaram técnicas metalográficas (identificação de fases presentes e distância interlamelar da perlita), ensaios magnéticos (saturação magnética e ruído magnético de Barkhausen), ensaio mecânico de dureza e ensaio tribológico de resistência ao desgaste por deslizamento. Foram caracterizadas rodas ferroviárias classe C AAR em quatro condições distintas: usadas e novas, fundidas e forjadas. / Research about rail transport in Brazil has been intensified recently due the need to improve the wheel-rail performance, considering the demand of increasing axle load aiming for transportation cost reduction. Changes in the material microstructure or in the alloys composition can improve the wheel-rail resistance. A eutectoid steel similar to that used in conventional class C AAR wheels (designed to heavy haul transportation - high loads and low speeds) was submitted to isothermal heat treatments applying dilatometry techniques at ten different cycles. Different microstructures (totally pearlitic and pearlitic-bainitic) were obtained and their influence on the mechanical and magnetic properties was analyzed. The analysis included metallographic techniques (identification of phases and pearlite interlamellar spacing), magnetic testing (magnetic saturation and magnetic Barkhausen noise) and mechanical testing (hardness and pin-ondisc tests). Railway wheels Class C ARR were characterized in four different conditions: new and used, cast and forged.

Com o objetivo de estudar o comportamento fenológico, morfológico e produtivo de cultivares de algodoeiro com diferentes arquiteturas de plantas em diferentes espaçamentos, através do manejo com regulador de crescimento, foi realizado o presente trabalho, na área experimental da ESALQ/USP, no município de Piracicaba, Estado de São Paulo, no ano agrícola de 2000/01. O delineamento experimental utilizado foi o de blocos ao acaso com parcelas sub-subdivididas e 4 repetições. As parcelas constituíram-se dos espaçamentos de 0,76 e 1,01 m, as subparcelas das três cultivares (IAC 23, DeltaOpal e CD 401) e as sub-subparcelas em presença ou ausência de regulador de crescimento. Em seis plantas marcadas de cada parcela foram analisados os seguintes parâmetros: acompanhamento das fases fenológicas (emergência, aparecimento do primeiro botão floral, antese da primeira flor e abertura do primeiro capulho) e caracteres agronômicos de campo (altura de planta, diâmetro do caule, número de ramos vegetativos e frutíferos, conformação da planta, número de capulhos por planta e altura de inserção do primeiro ramo frutífero). Na área útil de cada parcela foi determinada, a produção de algodão em caroço por hectare e a precocidade de colheita. Em amostras de 20 capulhos tomadas aleatoriamente em cada parcela foram realizadas as análises dos caracteres agronômicos de laboratório (massa de 100 sementes, porcentagem de fibras e massa média de um capulho) e das características tecnológicas da fibra (comprimento, uniformidade de comprimento, maturidade, tenacidade e índice micronaire). Os resultados obtidos permitem concluir que não houve interações significativas para as cultivares x espaçamentos x regulador de crescimento, para a produção de algodão em caroço, precocidade de colheita, caracteres agronômicos de laboratório e características tecnológicas das fibras, com exceção da tenacidade. Desta forma, as cultivares avaliadas, independente da arquitetura da planta, apresentaram capacidade de ajustar-se às variações dos espaçamentos testados e aplicação de regulador de crescimento com relação a estas características. Os caracteres agronômicos de campo como: a altura das plantas e o diâmetro de caule, de modo geral, apresentaram médias reduzidas com a redução do espaçamento e aplicação do regulador de crescimento, para as cultivares de desenvolvimento mais vigoroso (IAC 23 e DeltaOpal), não influenciando, porém, a cultivar de plantas morfologicamente mais compactas (CD 401). / The purpose of this work was to study the phenological, morphological and productive behavior of cotton cultivars presenting different plant shapes under different spacing layouts managed with the use of plant growth regulator. The experiment was established in the experimental field of ESALQ/USP, Piracicaba, Sao Paulo, during the 2000/01 growing season and was arranged in a randomized block experimental design with subdivided plots and 4 replications. The plots represented spacing layouts of 0.76 and 1.01 m, subplots consisted of the IAC 23, DeltaOpal and CD 401 cultivars, while the sub-subplots were characterized by the use or absence of growth regulator. Six plants per plot were labeled and analyzed for the phenological phases (emergence, appearance of the first flower bud, anthesis of the first flower, opening of the first cotton boll) and field agronomical characteristics (plant height, stem diameter, number of vegetative and fruit branches, plant shape, number of cotton boll per plant and insertion height of the first fruit branch). The harvest early and raw cotton yield per hectare were determined considering the effective plot area. The agronomical lab characteristics (mass of 100 seeds, fiber percentage and cotton boll mass), as well as the fiber technological characteristics (length, length uniformity, maturity, strength, and micronaire) were analyzed using a sample of 20 bolls taken at random. Based on the results obtained, it can be concluded that there were no significant interactions among cultivars x spacing x growth regulator, as to cotton yield, harvest early, agronomical lab characteristics and fiber technological characteristics, except for stremgth. The analyzed cultivars, regardless of the plant shape, showed good adaptation to the variation in spacing layouts, as well as to the application of growth regulator, considering the analyzed characteristics. The field agronomical characteristics, such as plant height and stem diameter, generally decreased with the reduction in spacing and with the application of growth regulator, considering the most vigorous cultivars (IAC 23 and DeltaOpal). On the other hand, the cultivar presenting a more compact plant (CD 401) pattern was not influenced by spacing or use of growth regulator.

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No. of bitstreams: 2 Dissertação PPGA - Fruticultura - Diego Weber.pdf: 3305024 bytes, checksum: 66ae9f28f00f60359ff57524fe3c8cb1 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2013-03-27 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / A fruticultura apresenta-se como importante fonte de renda ao alcance do pequeno agricultor familiar, devido a alta demanda de mão de obra e o considerável rendimento para pequenas propriedades. Uma frutífera adaptada e de grande potencial no Brasil é o maracujazeiro-amarelo (Passiflora edulis Sims), devido o seu ciclo produtivo ser relativamente curto, alta produtividade e ótima qualidade do suco. Com a adaptabilidade da cultura na diversidade edafoclimática do Brasil, faz -se possível a produção de maracujá-amarelo em todas as regiões do país. Entretanto, pouco se conhece de seu crescimento, desenvolvimento e desempenho nas condições edafoclimáticas do Sul do Rio Grande do Sul, onde tem se invernos com geadas e verões mais curtos em relação as regiões tropicais. Objetivou-se avaliar as características produtivas e físico-químicas dos frutos do maracujazeiro-amarelo produzidos em Pelotas/RS, sob três densidades de plantio. O trabalho foi desenvolvido na UFPel/FAEM, nos anos de 2011 e 2012. Utilizou-se a seleção ‘Ovalado Grande’ de maracujazeiro-amarelo, desenvolvida pela Epagri/EEUR. O plantio foi realizado em outubro de 2011, sob sistema de condução em espaldeira, com irrigação por gotejamento e polinização manual. Os tratamentos (densidade de plantio) foram: tratamento D1 com distância entre plantas de 2,5m utilizando uma planta por cova, 1.600 plantas por hectare (plantas ha -¹); tratamento D2 com distância entre plantas de 1,5m utilizando uma planta por cova, 2.666 plantas ha -¹ e; tratamento D3 com distância entre plantas de 2,5m utilizando duas plantas por cova, 3.200 plantas ha -¹. Em todos os tratamentos o espaçamento entre filas foi de 2,5m. As variáveis de produção foram: produtividade estimada (P), produção por planta(PP), número de frutos por planta (NFP), número de frutos por hectare (NFH), massa média de frutos (MMF) e dias da antese até a maturação do fruto (DAMF). As variáveis físico-químicas foram: sólidos solúveis (SS), acidez titulável (AT), relação SS/AT (RATIO), coloração da epiderme (CE), espessura média do pericarpo (EP), comprimento médio do fruto (CMF), diâmetro médio do fruto (DMF) e rendimento de polpa (RP). Não houve diferença estatística significativa entre os tratamentos para as variáveis MMF (249,24g) e DAMF (73,5 dias). Para as variáveis de produção, PP, NFP e NFH houve superioridade para os sistemas menos adensados, assim o tratamento D1, obteve melhor desempenho. Porém, considerando que o adensamento no plantio do maracujazeiro-amarelo promove maior produtividade, o tratamento D3 obteve melhor desempenho produtivo neste contexto, alcançando uma excelente produtividade, de 25,45 t ha -¹. Para as variáveis físico-químicas, não houve influência dos tratamentos em todas as variáveis. Porém os frutos apresentaram ótima qualidade, com ótimo padrão para o mercado ‘in natura’ , com valores considerados de alto padrão para as variáveis CMF (107,30mm), DMF(85,39mm), SS (11,25ºBrix) AT (5,67%) e EP (5,73mm) e RP (51,42%). Recomendase o cultivo do maracujazeiro-amarelo na região de Pelotas, RS, utilizando-se a densidade de plantio de 3.200 plantas ha -¹ (2,5 x 2,5m com duas mudas por cova). / The fruticulture presents itself as important income source adapted for the small family farmer, due to high demand on hand labor and high performance on small farms. A fruit tree adapted and great potential in Brazil is the yellow Passion fruit (Passiflora edulis Sims), due its production cycle to be relatively short, high productivity and high quality juice. According to the excellent adaptability of culture diversity in climate and soil of Brazil, it is possible the production of Passion fruit in all regions of the country. However, little is known of their growth, development and performance at conditions of southern Rio Grande do Sul, where there winters with frosts and shorter summers over the tropics. This study aims to evaluate the productive and physicochemical characteristics in fruits of yellow Passion fruit tree produced in Pelotas/RS, under three planting densities. The work was developed in UFPel/FAEM, in the years 2011 and 2012. It was used the selection ‘Ovalado Grande' of yellow Passion fruit, developed by Epagri/EEUR. The planting was realized in October 2011, under the conduction system in trellis, with drip irrigation and manual pollination. The treatments (planting density) were: treatment D1 with distance of 2,5m between plants using one plant per hole, 1.600 plants per hectare (plants ha -¹); treatment D2 with distance of 1,5m between plants using o ne plant per hole, 2.666 plants ha -¹; treatment D3 with distance of 2,5m between plants using two plants per hole, 3.200 plants.ha -¹. In all treatments the spacing between rows was 2,5m. The production variables were estimated productivity (P), production per plant (PP), number of fruits per plant (NFP), number of fruits per hectare (NFH), average fruit weight (MMF) and days from anthesis through fruit ripening (DAMF). The physicochemical variables were: soluble solids (SS), titratable acidity (AT), SS/AT ratio (RATIO), skin color (CE), the average thickness of pericarp (EP), the average length of fruit (CMF) average width of fruit (DMF) and yield pulp (RP). There was no statistically significant difference between treatments for the variables MMF (249,24g) and DAA (73,5 days). For the production variables, PP, NFP and NFH were superior to systems less dense, so the treatment D1, performed better. However, considering that higher density planting of yellow Passion fruit promotes greater produtivity, the treatment D3 obtained better performance in this context, achieving an excellent produtivity, 25,45 t ha -¹. For physicochemical variables, there was no influence of the treatments on all variables. However, fruits showed great quality, with excellent standard for the fresh fruit market, with values considered high standard for the variables CMF (107,30mm), DMF (85,39mm), SS (11.25ºBrix) AT (5,67%), EP (5,73mm) and RP (51,42%). It is recommended the cultivation of yellow Passion fruit tree in Pelotas, RS, using a planting density of 3.200 plants ha -¹ (2,5 x 2,5m with two plants per hole).

L’effet de l’espacement interlamellaire sur le comportement sous chargements monotone et cyclique de l’acier perlitique C70 a été étudié. Une démarche expérimentale conjuguant les essais de traction « in-situ » sous DRX et traction « in-situ » sous MEB couplées à une modélisation auto-cohérente a été adoptée. Les essais ont été effectués sur deux microstructures, à deux espacements interlamellaires différents. Il a été montré que l'écoulement plastique de la perlite est contrôlé par celui de la ferrite lequel est gouverné par l’espacement interlamellaire, il en est de même pour les distributions des contraintes résiduelles. La modélisation auto-cohérente met en évidence l'anisotropie élastique à l'échelle des phases et l'effet de l'espacement interlamellaire sur les rigidités et les limites d'écoulement directionnelles. L'analyse microstructurale des mécanismes de déformation montre que la déformation plastique de la perlite est caractérisée par le développement de bandes de cisaillement. Ces bandes sont le siège de l'amorçage des fissures par cisaillement des lamelles de cémentite pour les taux de déformation élevés. L’effet de l’espacement interlamellaire sur le comportement en fatigue giga-cyclique a été étudié par des essais de fatigue sous une fréquence de 20 KHz. Des différences de 30 MPa, pour la perlite à SP= 230 nm et de 50 MPa pour la perlite à SP= 170 nm entre les limites de fatigue conventionnelle (106cycles) et giga-cyclique (109cycles) ont été obtenues. L’effet de l’espacement interlamellaire sur le comportement en fatigue apparait peu significatif comparativement aux caractéristiques mécaniques de traction. Les limites de fatigue giga-cycliques obtenues intègrent l’effet bénéfique des contraintes résiduelles stabilisées ainsi que les effets d’écrouissage induit par l’usinage et par écrouissage cyclique. L’examen des sites d’amorçage, révèle essentiellement un amorçage en surface dans le domaine méga-cyclique et mixte en surface et/ou en sous-couches dans le domaine giga-cyclique. Ces résultats peuvent être interprétés sur la base des effets des propriétés de surface stabilisées et de la microstructure. Le recours à un critère de fatigue de type Goodman permet d’identifier d’une manière qualitative la contribution des différents facteurs d’influence, ci-dessus cités, dans l’amorçage des fissures de fatigue. / The effect of interlamellar spacing on the monotonic and cyclic behavior of C70 pearltic steel was investigated. Tensile tests under scanning electron microscope and under X-ray diffraction coupled with self-consistent model have been used. Tests have been carried out on two microstructures with different interlamellar spacing. It has been demonstrated that pearlite yielding is controlled by ferrite critical shear stress), which depend on the interlamellar spacing. The pearlite deforms inhomogeneously under tensile loading by localized shearing in intense shear bands. In the large shear bands, parallel cementite plate offsets before fracture and contributes to the occurrence of localized damage. The residual stress in ferrite is higher for the coarse pearlite. Giga-cycle fatigue tests were performed to identify the effect of interlamellar spacing on the fatigue behavior; tests were performed at a frequency of 20 KHz. The difference of the fatigue strength between 106 and 109 cycles is about 30 MPa for coarse pearlite and 50 MPa for fine pearlite. The effect of interlamellar spacing on the mega-cycle and giga-cycle fatigue limit appears not significant compared to the mechanical characteristics. Giga-cycle fatigue limit obtained includes the beneficial effect of stabilized residual stress. It also includes the effect of hardening induced by machining and cyclic hardening. However, any significant effect of interlamellar spacing on the C70 fatigue limits has been shown. SEM examinations shows that failures initiated on surface for the mega-cycle regime and on different sites for the giga-cycle regime. The experimental results can be interpreted based on the effects of stabilized surface properties and microstructure. The use of a fatigue Goodman criterion would identify qualitatively the contribution of different factors, cited above, in the fatigue life.

Conselho Nacional de Desenvolvimento Científico e Tecnológico / This thesis aims at studying the efficiency of models which express the size-density relationship in even-aged stands of Pinus taeda L., handled in complete and full stock densities. For that, Reineke, Yoda, Zeide and Tang models were tested using data obtained from 50 permanent sample plots placed in stands implanted in spacing of 1.5x1.0 m, 2.5x1.0 m, 1.5x2.0 m, 2.0x2.0 m, 1.5x3.0 m, 2.5x2.0 m, 2.0x3.0 m, 2.5x3.0 m, measured every year until the age of 18 and maintained in full stocks. Results indicated that all of the size-density relationship models presented good statistical precision. However, the no-linear model of Tang was more efficient than the others, presenting excellent coefficient of determination (0.99), low standard error of estimate (0.0948), low coefficient of variation (1.17%), low bias (0.0086) and high efficiency (0,8976), in the estimate of the values of density of trees per hectare for average diameter, and the smallest considered value of the scores of the statistical criteria, equal to 6 points, with good distribution of residues of the number of trees per hectare. The self-tinning occurs in a dimension of average diameter directly proportional to the density of trees per hectare of planting. As bigger is the initial spacing, bigger is the average diameter in the moment of the beginning in the stand the self-thinning. The slope of the size-density and diameter equation varied per planting spacing, not allowing proving the universality of the self-tinning law, with value of this slope is equal -3/2. With help of the size-density model, 5 Indexes of Density of the Stand (IDS) were generated, with variation from the maximum 1400 to the minimum 600, with interval of class of IDS equal to 200, having as reference the standard diameter of 25 cm. The stand s Density Management Diagram (DMD), elaborated for the dendrometric variables average diameter, basal area and volume for hectare by IDS presented good efficiency with low mistake in the estimate of the values of these variables. Real volume and estimate volume per hectare in DMD presented an absolute difference of just -7.39 m3 ha-1 and a relative difference of -1.79 %, showing a great precision of the DMD model. The estimates volume of DMD per hectare, in relation to the real values, presented a value of efficiency equal to 0.99, what indicates a high precision, and a χ 2 value equal to 0.00034, not significant to 0.01% of probability, demonstrating that the real and the estimate values don't differ statistical amongst themselves. / A presente dissertação foi desenvolvida com o objetivo de estudar a eficiência dos modelos que expressam a relação de densidade e diâmetro em povoamentos equiâneos de Pinus taeda L., manejados em densidade completa e altamente estocados. Para isto, foram testados os modelos de Reineke, Yoda, Zeide e Tang, através de dados originados de 50 parcelas permanentes, medidas anualmente até os 18 anos, alocados em povoamentos implantadas em espaçamentos de 1,5x1,0 m, 2,5x1,0 m, 1,5x2,0 m, 2,0x2,0 m, 1,5x3,0 m, 2,5x2,0 m, 2,0x3,0 m, 2,5x3,0 m, e mantidas em densidade completa. Os resultados indicaram que todos os modelos de densidade e diâmetro apresentaram boa precisão estatística, porém o modelo não linear de Tang foi mais eficiente que os demais, tendo apresentado ótimo coeficiente de determinação, igual a 0,99, baixo erro padrão da estimativa igual a 0,0948, baixo coeficiente de variação, igual a 1,17 %, mínima tendência, com valor igual a 0,0086, e elevada eficiência, com valor igual a 0,8976. Na estimativa dos valores de densidade de árvores por hectare por diâmetro médio, e a menor soma de escores dos critérios estatísticos, foi igual a 6 pontos, com boa distribuição dos resíduos do número de árvores por hectare. O autodesbaste ocorre numa dimensão de diâmetro médio diretamente proporcional a densidade de árvores por hectare de plantio. Quanto maior o espaçamento inicial maior é o diâmetro médio no momento do início do autodesbaste da população. O coeficiente angular da equação de densidade e diâmetro variou por espaçamento de plantio, não permitindo comprovar a universalidade da lei do autodesbaste, cujo valor do coeficiente angular é estipulado em -3/2. Com o modelo de densidade e diâmetro foram gerados 5 Índices de Densidade do Povoamento - IDP, que variaram de um valor máximo de 1400 até o mínimo de 600, com intervalo de classe de IDP de 200, tendo com referência o diâmetro padrão de 25 cm. Os Diagramas de Manejo da Densidade - DMD da população, elaborados para as variáveis dendrométricas: diâmetro médio, área basal e volume por hectare, por IDP, apresentaram uma boa eficiência com baixo erro na estimativa dos valores destas variáveis. Os volumes reais por hectare e os estimados no DMD apresentaram uma diferença absoluta de apenas -7,39 m3ha-1 e relativa de -1,79 %, demonstrando elevada precisão do modelo de DMD. As estimativas volumétricas por hectare do DMD em relação aos valores reais, apresentaram valor de eficiência igual a 0,99, o que indica uma alta precisão, e um valor de χ 2 igual a 0,00034, não significativo a 0,01 % de probabilidade, demonstrando que os valores reais e os estimados não diferem estatisticamente entre si.

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A three dimensional nonlinear finite element model has been developed to study the behaviour of composite beams with profiled sheeting oriented perpendicular to its axis. The analysis of the push test was carried out using ABAQUS/Explicit with slow load application to ensure a quasi-static solution. Both material and geometric nonlinearities were taken into account. Elastic¿plastic material models were used for all steel components and the Concrete Damaged Plasticity model was used for the concrete slab. The post-failure behaviour of the push test was accurately predicted, which is crucial for realistic determination of shear capacity, slip and failure mode. The results obtained from finite element analysis were verified against the experimental push tests conducted in this research and also from other studies. After validation, the model was used to carry out an extensive parametric study to investigate the effect of transverse spacing in push tests with double studs placed in favourable and staggered positions with various concrete strengths. The results were also compared with the capacity of a single shear stud. It was found that shear connector resistance of pairs of shear connectors placed in favourable position was 94% of the strength of a single shear stud on average, when the transverse spacing between studs was 200 mm or more. For the same spacing, the resistance of staggered pairs of studs was only 86% of the strength of a single stud. The strength of double shear studs in favourable position was higher than that of the staggered pairs of shear connectors.

Effective delineation and management of stream fish populations requires a thorough knowledge of dispersal patterns, because these patterns affect a number of other demographic rates such as population growth, reproduction, survival, and gene flow. Previous studies of stream fish dispersal patterns have generally established species- and stream-specific home ranges and movement rates, but have largely failed to account for the environmental variables that may cause these parameters to vary. Many fishes occupy a variety of streams across a broad spectrum of ecological conditions, and movement rates (and thus population dynamics) may respond to these environmental gradients. Furthermore, enhanced understanding of the ecological features that induce or impede dispersal will help guide future management of stream channels for population connectivity. To determine the instream features that influence the dispersal patterns of darters, I conducted a spatially intensive mark/recapture study of three darter species in the upper Roanoke River watershed. Logistic regression was used to relate observed inter-riffle movements to gradients in riffle and corridor attributes. During the first study period, habitat area loss and habitat spacing drove dispersal patterns. However, a model developed from these data transferred poorly to the second study period, in which density dependence was a more effective predictor of dispersal. Individual size did not seem to influence the probability of emigration, but did influence the distance traveled following emigration, particularly for the two more specialist species. This finding suggests a size-based dominance hierarchy for habitat selection and occupancy in darters. Predation threat had only a minor effect on the probability of traversing inhospitable corridors, but experimentally introduced structural cover significantly elevated dispersal rates through such corridors. Taken together, results of this study indicate that a complex array of ecological features interact to produce heterogeneity in dispersal rates across the stream landscape. Knowledge of these influences can be used to manage stream channels for dispersal permeability. In addition to field studies, laboratory studies were undertaken to determine the efficacy of visible implant elastomer (VIE) and injectable photonic dye (IPD) for marking darters. No previous studies have rigorously evaluated these marks in darters, and comparisons of the two technologies in any taxa are few. Results of the laboratory study indicated that VIE is preferable to IPD for marking darters, particularly when mark longevity greater than 80 days is desired. Individuals marked with VIE exhibited higher survival and mark retention rates than did individuals marked with IPD. Additionally, VIE mark retention was more consistent across body locations. Retention of both marking technologies was biased by color. My study indicates that the results of tagging efficiency studies are not applicable across taxa, and that pilot studies are necessary prior to field use of marks in previously untested species. / Master of Science