1000 resultados para Dióxido de carbono - Efeitos fisiológicos
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Algumas plantas são uma fonte natural de compostos bioativos, tais como polifenóis, vitaminas, carotenóides e ácidos gordos insaturados. Esta diversidade de biomoléculas permite a sua utilização em diversas áreas, especialmente como aditivos alimentares e ingredientes naturais para promoção da saúde. Estes fitoquímicos têm sido utilizados na industria farmacêutica, bem como na formulação de suplementos dietéticos, alimentos funcionais e nutracêuticos. No entanto, a utilização de matérias-primas de boa qualidade microbiológica é um dos requisitos essenciais na indútria, uma vez que os microrganismos podem contaminar o produto final, levando à sua deterioração. Assim, a irradiação é creditada para que a sua aplicação seja permitida em ingredientes secos, sendo cada vez mais reconhecida mundialmente, devido à eficiência na redução das perdas causadas por processos fisiológicos naturais (brotamento, maturação e envelhecimento), para eliminar ou reduzir microorganismos, parasitas e pragas, sem que ocorra qualquer alteração (química ou organoléptica) no alimento, tornando-o mais seguro para o consumidor [1-3]. O objetivo deste estudo foi avaliar os efeitos da aplicação de diferentes doses de radiação gama e feixe de eletrões na composição química e bioatividade de várias plantas (Ginkgo biloba L., Melissa officinalis L., Melittis melissophyllum L., Mentha piperita L., Aloysia citrodora Palàu, Arenaria montana L. e Thymus vulgaris L.).
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Ajustes de comportamento podem ocorrer rapidamente e a custo menor do que os ajustes fisiológicos. Considerando o comportamento social, é sugestivo que a freqüência e a intensidade de interações agressivas, o total de coesão social e a extensão de vícios sociais possam ser utilizados para avaliação de bem-estar. Esta pesquisa apresenta uma análise das interações entre os fatores experimentais, como temperatura, linhagem e período do dia, nos comportamentos de matrizes pesadas alojadas em câmara climática, buscando evidenciar as diferentes reações das aves submetidas a distintas condições ambientais. Os resultados encontrados mostraram diferenças significativas entre os comportamentos expressos pelas diferentes linhagens, reforçando a necessidade do monitoramento em tempo real do bem-estar de matrizes pesadas em alojamentos comerciais, dada a complexidade com que as variáveis ambientais interferem no bem-estar. A pesquisa permitiu concluir também que a avaliação do bem-estar de matrizes pesadas deve considerar o período do dia na observação dos comportamentos.
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Tese de dout. em Ciências do Mar, Instituto de Investigação das Pescas e do Mar, Univ. do Algarve, 1996
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Tese (doutorado)—Universidade de Brasília, Centro de Desenvolvimento Sustentável, 2015.
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A aplicação de dejetos de suínos em solos cultivados pode alterar suas características químicas, físicas e biológicas. Estes estudos são importantes para compreensão e recomendação de práticas conservacionistas de uso do solo, que visam minimizar os efeitos da produção agrícola nos recursos naturais. O objetivo deste trabalho foi avaliar o carbono da biomassa microbiana (CBM) do solo, em três profundidades, após a aplicação de cinco doses de dejetos líquidos de suínos (DLS) em sistema de plantio direto (SPD) e convencional (SPC). O experimento foi instalado em 1997, na Estação Experimental do Instituto Agronômico do Paraná, em Palotina, Paraná, em Latossolo Vermelho distroférrico de textura argilosa. Os tratamentos foram a aplicação de 0, 30, 60, 90 e 120 m3 ha-1 ano-1 de dejetos de suínos no solo cultivado em SPD ou SPC, em delineamento experimental de blocos casualizados, com três repetições. Em outubro de 2015, após o cultivo de aveia (Avena strigosa), foram coletadas amostras de solo, nas profundidades de 0-10 cm, 10-20 cm e 20-40 cm, para determinação dos atributos químicos e do CBM. O DLS apresentou em g L-1 58,20 de massa seca; 5,52 N; 3,97 P; 1,4 K; 3,32 Ca; 2,16 Mg; 0,01 Cu; 0,23 Zn; 0,06 Mn; densidade de 1,01 g cm-3 e condutividade de 10,72 mS cm-1. O CBM foi avaliado pelo método de fumigação-extração. O teor de carbono nos extratos foi quantificado por titulação com sulfato ferroso amoniacal, após a oxidação do dicromato de potássio por digestão sulfúrica. O CBM foi calculado utilizando um fator de correção Kc de 0,33. A análise de variância foi realizada a 5% de probabilidade e, quando significativo pelo teste F, as médias foram comparadas pelo teste de Tukey. O CBM, com a aplicação de DLS no SPD, apresentou valores médios de 457, 355 e 284 micrograma C-CBM g solo nas profundidades de 0-10, 10-20 e 20-40 cm, respectivamente. No SPC, o CBM, com a aplicação de DLS, apresentou valores médios de 400, 284 e 253 micrograma C-CBM g solo, respectivamente, nas mesmas profundidades. Não houve efeito significativo das doses de DLS sobre o CBM nas profundidades 0-10, 10-20 e 20-40 cm, tanto sob SPD quanto SPC. Os valores de CBM foram maiores no SPD quando comparados com SPC na profundidade de 0-10 cm e 10-20 cm, não diferindo entre si na profundidade de 20-40 cm. Houve interação significativa entre as doses de DLS e SPD sobre o CBM, somente na adição das doses de 0 e 120 m3 ha-1 ano-1 DLS na profundidade de 10-20 cm.
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As most current studies, reinforced plastics have been, in recent years, a viable alternative in building structural elements of medium and large, since the lightness accompanied by high performance possible. The design of hybrid polymer composites (combination of different types of reinforcements) may enable structural applications thereof, facing the most severe service conditions. Within this class of composite materials, reinforced the underlying tissues hybrid high performance are taking space when your application requires high load bearing and high rigidity. The objective of this research work is to study the challenges in designing these fabrics bring these materials as to its mechanical characterization and fracture mechanisms involved. Some parameters associated with the process and / or form of hybridization stand out as influential factors in the final performance of the material such as the presence of anisotropy, so the fabric weave, the process of making the same, normative geometry of the specimens, among others. This sense, four laminates were developed based hybrid reinforcement fabrics involving AS4 carbon fiber, kevlar and glass 49-E as the matrix epoxy vinyl ester resin (DERAKANE 411-350). All laminates were formed each with four layers of reinforcements. Depending on the hybrid fabric, all the influencing factors mentioned above have been studied for laminates. All laminates were manufactured industrially used being the lamination process manual (hand-lay-up). All mechanical characterization and study of the mechanism of fracture (fracture mechanics) was developed for laminates subjected to uniaxial tensile test, bending in three and uniaxial compression. The analysis of fracture mechanisms were held involving the macroscopic, optical microscopy and scanning electron microscopy
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O objetivo deste estudo foi avaliar os efeitos do sistema silvicultural policíclico na dinâmica de carbono de uma floresta manejada comercialmente no Amazonas.
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O objetivo deste estudo foi avaliar os efeitos do sistema silvicultural policíclico na dinâmica de carbono de uma floresta manejada comercialmente no Amazonas.
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In insects that utilize patchy and ephemeral resources for feeding and egg laying, the outcome of larval competition for food resources depends on the amount of resources and the spatial distribution of immatures among patches of food. In the present study, the results of larval competition for food in Chrysomya megacephala, in traits such as female weight, fecundity and reproductive investment, were different in situations where the level of larval aggregation (proportion of competitors per amount of food) was the same, but with densities of competitors and amounts of food proportionally different. These results are indicative that the larval competition may depend both on the larval density and the amount of food, in different situations with the same proportion of larvae per gram of food.
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This article is divided into two parts. The first presents two abstract arguments that constitute the starting point for the development of the second part, which is directed towards discussing some aspects of the distance learning policies, i.e., the role of public authorities in encouraging and shaping this type of education. First of all, it is intended to establish some assumptions to understand the emergence of this phenomenon and some of its conditioning factors and consequences; then to suggest some analytical tools to allow us to reflect on public policy in this area.
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The covering of the soil is an agricultural practice that intends to control the harmful herbs, to reduce the losses of water by evaporation of the soil, and to facilitate the harvest and the commercialization, once the product is cleaner and healthier. However, when the soil is covered important microclimatic parameters are also altered, and consequently the germination of seeds, the growth of roots, the absorption of water and nutrients, the metabolic activity of the plants and the carbohydrates storage. The current trial intended to evaluate the effect of soil covering with blue colored film on consumptive water-use in a lettuce crop (Lactuca sativa, L.). The experiment was carried out in a plastic greenhouse in Araras - São Paulo State, Brazil from March 3rd, 2001 to May 5th, 2001. The consumptive water-use was measured through two weighing lysimeter installed inside the greenhouse. Crop spacing was 0.25 m x 0.25 m and the color of the film above soil was blue. Leaf area index (IAF), was measured six times (7; 14; 21; 28; 35; 40 days after transplant) and the water-use efficiency (EU) was measured at the end. The experimental design was subdivided portions with two treatments, bare soil and covered soil. The average consumptive water-use was 4.17 mm day-1 to the bare soil treatment and 3.11 mm day-1 to the covered soil treatment. The final leaf area index was 25.23 to the bare soil treatment and 24.39 to the covered soil treatment, and there was no statistical difference between then.
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Tomatoes are one of the most important vegetable crops grown in Brazil and are among the crops that have one of the highest post-harvest losses indexes in the country. The present work aimed at evaluating impact damage observed in packing lines of fresh tomatoes as well as to determine, under laboratory conditions, quality alterations of tomato fruits submitted to impact damage in different surface types. Critical points evaluation was accomplished using an instrumented sphere. Critical transference points found showed variations in acceleration levels from 30 to 129 G (m s-2). Tests carried out under laboratory conditions showed that padded surfaces reduced up to 31% impact damage. Incidence of severe internal physical damage was evaluated by a subjective scale and increased by 79% on hard surfaces for the highest fall drop. On the other hand, it was observed an effective reduction in physical damage on fruits when padded surfaces were used. When a 10-cm drop was performed, the maximum reduction measured was 10% for hard surfaces and 5% for previously padded surfaces. For quality parameters, it was observed for high drops on hard surfaces, highest values for weight loss, total acidity, lower values for vitamin C and Soluble Solids.
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Handball is a sport that demands endurance associated with fast and powerful actions such as jumps, blocks, sprints and throws. The aim of this study was to evaluate the effects of a 38-week systematic physical training applied to a women's under 21 handball team on upper and lower limb power, 30m sprints speed and endurance. The periodization applied was an adaptation of the Verkhoshansky theory, and aimed at two performance peaks during the season with six data collections. The median and range values for three kg medicine ball throwing was: 2.98m (2.15-3.50); 2.84m (2.43-3.20); 2.90m (2.60-3.38); 3.10 (2.83-3.81); 2.84 (2.55-3.57) and 3.34 (2.93-3.83). Regarding the three-pass running test: 5.60m (4.93-6.58); 5.37m (5.04-6.38); 5.36m (4.93-6.12); 5.65m (4.80-6.78); 5.63m (5.00-6.40) and 5.83m (5.14-6.05). Regarding the 30-m sprint test: 5.8m/s (5.45-6.44); 6,64 m/s (6,24-7,09); 5.65m/s (5.17-5.95); (there was not IV moment for this test); 6.19 m/s (5.57-6.26) and 5.83 (5.14-6.05).Regarding the 30-m sprint endurance test until 10% decrease: 4 sprints (4-6); 5 sprints (4-9); 4,5 sprints (4-16); (there was not IV moment for this test); 6 sprints (4-12) and 5 sprints (4-5). Significant differences (p<0.05) were observed in three kg medicine ball throwing and three-pass running tests at least in one of the performance peak planned, with no significant differences in 30-m sprint speed or endurance tests. The applied physical training was efficient at improving the specific physical fitness in the performance peaks, as well as giving support for better physical training adjustment for the upcoming season.
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A wild strain of Streptococcus thermophilus isolated from pasteurized milk was evaluated using an experimental model with respect to its adhesion onto stainless steel surfaces and its behaviour when submitted to cleansing and sanification. In milk, the adhesion of the microorganism on to stainless steel surfaces was studied after 6 hours of contact at 45°C with agitation, and after a cleansing process involving cleaning stages with alkaline and acid detergents followed by sanification, in order to evaluate the resistance of the adhered cells. The microorganism adhered to stainless steel surfaces producing a cell load of 10(4) CFU/cm². After alkaline cleansing, no adhered cells were detected but 6 CFU/cm² were still detected on the surfaces after acid cleansing. Cleansing, followed by sanification with sodium hypochlorite, was sufficient to reduce the load of wild S. thermophilus on the stainless steel surfaces to non-detectable levels. The experimental model proved adequate for the study indicating that the wild microorganism S. thermophilus produces biofilms on stainless steel surfaces. Alkaline cleansing remove more that 99.9% of the adhered cells. The few cells adhered on the surface are removed by acid cleansing demonstrating the need to use different steps and types of detergent for efficient cleansing. The best results for the removal of these biofilms are obtained by using alkaline cleansing followed by acid cleaning, this procedure being more efficient when complemented by sanification with sodium hypochlorite.
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Purpose: To study the effects of pupillary constriction on frequency doubling perimetry in a group of normal subjects. Methods: Eighteen healthy volunteers participated in the study. Only one eye per patient (right eye) underwent frequency doubling perimetry (Full Threshold C-20 strategy). For the second session, one drop of 2% pilocarpine was administered to the volunteers' right eye and the examination was repeated after 60 minutes. Results: Sixty minutes after administration of 2% pilocarpine, there was a significant reduction of the pupillary diameter from 4.22 ± 0.17 mm to 1.55 ± 0.51 mm (p<0.05). There was a significant reduction of the mean retinal sensibility after pupillary constriction. The threshold sensitivity of the central 5º worsened by 5.67 ± 2.49 dB; the area between 2.5º and 10º worsened by 4.49 ± 2.73 dB; and the area between 10º and 20º worsened by 5.10 ± 3.55 dB (p<0.01). A reduction of 4.06 ± 2.67 dB was observed in the mean deviation, as well as an increase of 0.64 ± 0.94 dB in the pattern standard deviation (p<0.01). No differences were observed regarding the number of fixation losses, false-positive and false-negatives responses, and duration of the examination. Conclusion: Changes in pupillary diameter may produce significant declines in threshold sensitivities of the 20º visual field tested by frequency doubling perimetry. These results suggest that is important to maintain a constant pupillary diameter in seriate examinations.