142 research outputs found

    Efeito da dieta no assentamento de larvas e no crescimento e sobrevivência de sementes de ostras Crassostrea gigas

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    Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Ciências Agrárias, Programa de Pós-Graduação em Aquicultura, Florianópolis, 2022.A alimentação adequada é um fator essencial no processo de produção de sementes em laboratório. O objetivo do presente estudo foi avaliar o efeito da dieta com diferentes concentrações de microalgas na fase de assentamento e metamorfose de larvas pedivéliger e de pré-sementes da ostra C. gigas em laboratório. Foram testadas dietas com microalgas nas concentrações de 8, 12 e 16 x 104 células mL-1, na fase de assentamento larval, sobre a taxa de metamorfose, crescimento, rendimento e sobrevivência de larvas pediveliger e pré-sementes por 7 dias, com avalição dos parâmetros ao final do estudo. Também avaliou dietas com microalgas nas concentrações de 8, 16, 24 e 32 x 104 células mL-1 e um controle sem alimentação no crescimento, rendimento e sobrevivência nas fases de cultivo de pré-sementes iniciais (early spat) e de pré-sementes desenvolvidas (late spat), por um período de 14 e 21 dias, respectivamente, com avaliação dos parâmetros a cada 7 dias. A dieta foi composta pelas microalgas Isochrysis galbana (30%) e Chaetoceros muelleri (70%). A temperatura, o pH e a salinidade da água foram aferidos diariamente após a troca total de água. Na fase de metamorfose, os resultados não demonstraram diferenças significativas em relação as dietas testadas para a taxa de metamorfose larval e sobrevivência, porém houve diferenças entre os tratamentos para o crescimento e rendimento de sementes. Na fase de cultivo de pré-sementes iniciais (early spat) e pré-sementes desenvolvidas (late spat) as concentrações testadas não apresentaram diferenças entre si para a sobrevivência, no entanto, apresentaram diferenças em relação ao crescimento e rendimento dos animais. Os resultados demonstram que a concentração de microalgas ofertadas nas dietas, é um fator essencial na produção de sementes de C. gigas em laboratório. Concluiu-se que na fase de assentamento e metamorfose larval, dietas com microalgas ofertadas nas concentrações de 12 e 16 x 104 células mL-1, proporcionam altas taxas de metamorfose larval e rendimento de sementes, e nas fases de cultivo de pré-sementes dietas com microalgas nas concentrações de 32 e 24 x 104 células mL-1 otimizam o tempo de cultivo com altos rendimentos de sementes de C. gigas em laboratório. Considerando somente a sobrevivência, constatou-se que não há vantagem no fornecimento de uma dieta com concentração de microalgas acima de 8 x 104 células mL-1 em todas as fases de cultivo da ostra C. gigas.Abstract: Proper nutrition is an essential factor for oyster seed production in hatcheries. The objective of the present study was to evaluate the effect of diet at different concentrations of microalgae on the settlement phase and metamorphosis of veliger larvae and spats of C. gigas in laboratory. Microalgae diets concentration at 8, 12 and 16 x 104 cells ml-1 were tested at the larval settlement phase to evaluate metamorphosis rate, growth, yield and survival of larvae pediveliger and pre-seeds after 7 days of cultivation. Settled oysters were fed with microalgae at concentrations of 8, 16, 24 and 32 x 104 cells ml-1 along with an unfed treatment to evaluate growth, yield and survival rates in the Early Spat (Early Spat) and Developed (Late Spat) cultivation phases, for a period of 14 and 21 days, respectively, with evaluation of the parameters every 7 days. The diet consisted of Isochrysis galbana (30%) and Chaetoceros muelleri (70%). Temperature, pH and salinity of water were measured daily after total water exchange. At the metamorphosis phase, the results showed no significant differences in relation to diets tested for the larval metamorphosis rate and survival, but there were differences between treatments for seed growth and performance. In the Early Spat and Late Spat cultivation phase, the tested concentrations showed differences only in the growth and yield of oysters. The results show the concentration of microalgae offered in the diets is an essential factor in the production of C. gigas seeds in the laboratory. It was concluded at the larval settlement and metamorphosis phase, diets at concentrations of 12 and 16 x 104 cells ml-1 provide high rates of larval metamorphosis and seed yields, and, at the Early Spat and Late Spat cultivation phase, diets at concentrations of 32 and 24 x 104 cells ml-1 optimize cultivation time with high yields of C. gigas in laboratory. As for survival rate, a minimal concentration of diet above 8 x 104 cells ml-1 is capable of maintaining the highest rates at all C. gigas cultivation phases

    Oxidative stress, muscle damage and inflammtion in kayakers and canoeists: effects of acute and chronic exercise and antioxidants supplementation

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    Tese de doutoramento em Nutrição Humana apresentada à Faculdade de Ciências da Nutrição e Alimentação da Universidade do PortoResumo da tese:Presume‐se que o exercício possa elevar a geração de espécies reactivas de oxigénio a um nível que ultrapasse a fortalecida defesa antioxidante dos atletas, causando danos oxidativos irreparáveis a nível celular, com prejuízo da sua saúde e performance física. Este trabalho teve como objectivo descrever o estado antioxidante, o stress e dano oxidativos de um grupo de caiaquistas e canoístas em repouso e em resposta ao exercício agudo (prova de caiaque de 1000 m) e ao exercício crónico (1 ano de treino e competição), bem como investigar se a sumplementação com uma combinação de antioxidantes poderia atenuar estes efeitos. Estimou‐se a ingestão alimentar de antioxidantes e determinou‐se a actividade da dismutase do superóxido (SOD), reductase da glutationa (Gr), peroxidase da glutationa e cínase da creatina e os níveis do estado antioxidante total (TAS), ácido úrico, α‐tocoferol, retinol, α‐caroteno, β‐caroteno, licopeno, luteína e zeaxantina, substâncias reactivas ao ácido tiobarbitúrico (TBARS), interleucina‐6 (IL‐6) e cortisol em várias ocasiões em 2 épocas deportivas, quando os atletas se encontravam no Centro de Treinos Nacional. As amostras de sangue foram colhidas em repouso e 15 minutos depois do conclusão da prova de 1000m de caiaque, antes e após do período de suplementação. Neste último estudo, os atletas foram distribuídos aleatoriamente para receber um placebo ou um suplemento antioxidante (272 mg α‐tocoferol, 400 mg vitamina C, 30 mg β‐caroteno, 2 mg luteína, 400 μg selénio, 30 mg zinco and 600 mg magnésio) durante 4 semanas. (...)Thesis abstract:It is postulated that exercise generates a surplus production of reactive oxygen species that may even surpass the strengthened antioxidant defences of athletes, causing irreparable cellular oxidative damage, which can harm their health and physical performance. This work aimed to describe antioxidant status, oxidative stress and damage of a group of elite kayakers and canoeists at rest and in response to acute exercise (1000m kayak trial) and chronic exercise (1 year of habitual training and competition), and investigate if a supplementation with a combination of antioxidants could attenuate these effects. Dietary intake of antioxidants was estimated, and blood superoxide dismutase (SOD), glutathione reductase (Gr), glutathione peroxidase (GPx) and creatine kinase (CK) activities, and total antioxidant status (TAS), uric acid, α‐tocopherol, retinol, α‐carotene, β‐carotene, lycopene, lutein plus zeaxanthin, thiobarbituric acid reactive substances (TBARS), interleukin‐6 (IL‐6) and cortisol levels were determined in several occasions in 2 seasons, while athletes were training on the Portuguese National Team Campus. The blood samples were collected in resting conditions and 15 min after a 1000m kayak race, both before and after supplementation. In last study, athletes were randomly assigned to receive a placebo or an antioxidant supplement (272 mg α‐tocopherol, 400 mg vitamin C, 30 mg β‐carotene, 2 mg lutein, 400 μg selenium, 30 mg zinc and 600 mg magnesium) for 4 weeks. Kayakers/canoeists exhibited significantly elevated markers of lipid peroxidation (TBARS) and muscle damage (CK) compared with sedentary subjects, despite having increased α‐ tocopherol, α‐carotene and β‐carotene levels and SOD activity. The activities of GPx and Gr, and the levels of lycopene, lutein + zeaxanthin, retinol and uric acid were similar between groups. (...

    .DOCente - facilitando a vida do professor

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    O portal .DOCente é direcionado a elaboração de materiais avaliativos para que os professores utilizem em sala de aula. Teve fundamento após a análise de uma pesquisa realizada com os professores do IFPR - Campus Paranaguá. O portal permite que os docentes cadastrem exercícios, que abastecem o banco usado pela pratica ferramenta para criar avaliações para seus alunos

    Effects of different environmental conditions on the mechanical characteristics of a structural epoxy

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    With the aim of characterising a commercially available epoxy adhesive used for fibre-reinforced polymers strengthening applications, when submitted to different environmental conditions, mainly thermal (TC), freeze-thaw (FT), and wet-dry (WD) cycles and immersion in pure (PW) and water with chlorides (CW) for periods of exposure that lasted up to 16 months, an experimental program was carried out. Several methodologies were used in its characterization, mainly the scanning electron microscope (SEM), dynamic mechanical analysis (DMA), standard tensile tests (STT) coupled with digital image correlation (DIC). In general the results revealed that the chemical composition was not affected by the environmental conditions. Nevertheless, it was verified through DMA and STT that the modulus of elasticity and tensile strength of the epoxy adhesive increased in the TC, while the specimens submitted to PW and CW faced a high degradation in terms of its mechanical properties. Eventually, the glass transition temperature (Tg) was not affected by the environmental conditions, apart from the specimens subjected to TC and FT, presenting a higher and lower Tg, respectively, when compared with the reference specimens.This work is supported by FEDER funds through the Operational Program for Competitiveness Factors - COMPETE and National Funds through FCT - Portuguese Foundation for Science and Technology under the project FPReDur PTDC/ECM-EST/2424/2012. The first and second authors wishes also to acknowledge the grants SFRH/BD/89768/2012 and SFRH/BD/80338/2011, respectively, provided by FCT

    Dilated Cardiomyopathy Due To H1N1 Virus

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    Mulher de 58 anos, sem antecedentes médicos relevantes, apresenta infecção respiratória pelo vírus H1N1, requerendo internação na Unidade de Cuidados Intensivos. Após a alta, refere progressiva astenia e dispneia, sendo internada nove meses depois por derrame pleural e infecção respiratória. Avaliação específica pela Cardiologia revela cardiomiopatia dilatada com má função sistólica do ventrículo esquerdo, compatível com miocardite. A ressonância magnética se apresenta compatível com miocardite. Dados os antecedentes e havendo sido descartada doença autoimune e tóxica, associou-se a doença ao vírus H1N1. O prognóstico é muito positivo, com recuperação quase total da função do ventrículo esquerdo.info:eu-repo/semantics/publishedVersio

    Enviromental temperature and age of seeds in tolerance to thermoinhibition in lettuce genotypes1

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    ABSTRACT Lettuce seeds usually show germination problems that can be related to dormancy and or thermoinhibition, as well as to the genotype constitution. The knowledge of the temperature at which the thermoinhibition process begins, as well as the influence of the age of the seed on its germination, is extremely important to establish more suitable parameters for the selection of higher genotypes in breeding programs. The objective of this work was to evaluate the seed germination of three lettuce cultivars according to the enviromental temperature and the age of the seeds. The cultivars Everglades (tolerant to thermoinhibition), Luisa (medium tolerant) and Verônica (sensitive) were used. Seeds of each cultivar were evaluated by the standard germination test, first count test, germination speed index and germination test of remaining seeds. The analyses were performed at four environmental temperatures and in seven storage periods after harvest. None of the cultivars showed primary dormancy. The tolerance to thermoinhibition showed by cultivars Everglades and Luisa and the sensitivity of cultivar Verônica were confirmed. The most suitable temperature for differentiating tolerant and sensitive thermoinhibition genotypes occurred from 30.5 ºC and 260 days after harvest
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