1,070 research outputs found

    Avaliação de reprodutores em bovino de corte.

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    Bovino; Reprodutor; Avaliação; Melhoramento.bitstream/item/104781/1/Avaliacao-de-reprodutores-em-bovino-de-corte.pd

    Comparative measurements of carbon dioxide fluxes from two nearby towers in a central Amazonian rainforest: the Manaus LBA site

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    Forests around Manaus have staged the oldest and the longest forest-atmosphere CO2 exchange studies made anywhere in the Amazon. Since July 1999 the exchange of CO2, water, and energy, as well as weather variables, have been measured almost continuously over two forests, 11 km apart, in the Cuieiras reserve near Manaus, Brazil. This paper presents the sites and climatology of the region based upon the new data sets. The landscape consists of plateaus dissected by often waterlogged valleys, and the two sites differ in terms of the relative areas of those two landscape components represented in the tower footprints. The radiation and wind climate was similar to both towers. Generally, both the long-wave and short-wave radiation input was less in the wet than in the dry season. The energy balance closure was imperfect (on average 80%) in both towers, with little variation in energy partitioning between the wet and dry seasons; likely a result of anomalously high rainfall in the 1999 dry season. Fluxes of CO2 also showed little seasonal variation except for a slightly shorter daytime uptake duration and somewhat lower respiratory fluxes in the dry season. The net effect is one of lower daily net ecosystem exchange (NEE) in the dry season. The tower, which has less waterlogged valley areas in its footprint, measured a higher overall CO2 uptake rate. We found that on first sight, NEE is underestimated during calm nights, as was observed in many other tower sites before. However, a closer inspection of the diurnal variation of CO2 storage fluxes and NEE suggests that at least part of the nighttime deficits is recovered from either lateral influx of CO2 from valleys or outgassing of soil storage. Therefore there is a high uncertainty in the magnitude of nocturnal NEE, and consequently preliminary estimates of annual carbon uptake reflecting this range from 1 to 8 T ha-1 y-1, with an even higher upper range for the less waterlogged area. The high uptake rates are clearly unsustainable and call for further investigations into the integral carbon balance of Amazon landscapes

    Avaliação nacional de touros das raças zebuínas - 1975/1986: Gir, Gir variedade mocha, Guzerá, Indubrasil, Nelore, Nelore variedade mocha, Tabapuã.

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    Avaliação Nacional de Touros. Descrição da metodologia. Raça Gir. Raca Gir variedade mocha. Raça Guzerá. Raça indubrasil. Raça Nelore. Raça Nelore variedade mocha. Raca Tabapuã.bitstream/item/104556/1/Avaliacao-nacional-de-touros.pd

    Integrated system for macroalgae production and conversion into biogas

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    Recently research on energy from macroalgae is being reconsidered driven by the following factors: fuel price increase, CO2 mitigation policies and interest on renewable energy sources after the Kyoto protocol, and need for energy crops not competing with land for food production. However, the commercial expansion of this energy source is limited by its economic feasibility. In this presentation we analyse the development of integrated systems that promote synergies between macroalgae/biogas production and activities such as aquaculture and urban wastewater treatment. The recycling of nutrients and CO2 by macroalgae can be an opportunity to reduce the biomass-biogas production cost. Other advantage is the proximity between biomass production, conversion into energy and its consumption, thus avoiding energy losses and pollution in transportation. Experimental work is underway and includes batch tests to evaluate biodegradability of Ulva spp. and Gracilaria sp. and co-digestion of these macroalgae with sewage sludge from Beirolas wastewater treatment plant (WWTP). Furthermore, continuous co-digestion experiments are planned to be carried out in a 30 L experimental reactor to be placed in the same WWTP. The objectives are to reproduce sludge digestion in Beirolas WWTP and evaluate algae/sludge co-digestion performance. Preliminary results indicate methane yields in accordance with similar batch experiments, whereby our CH4 yields per volatile solids added range between 0.14-0.20 m3 CH4 kg-1 VSadded against 0.16-0.27 m3 CH4 kg-1 VSadded [1,2] depending on the algae species and pretreatment. Overall, Ulva sp. shows a better performance over Gracilaria sp. as also confirmed in other experiments [1]

    Episodic nitrous oxide soil emissions in Brazilian savanna (cerrado) fire-scars

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    The seasonally burned cerrados of Brazil are the largest savanna-type ecosystem of South America and their contribution to the global atmospheric nitrous oxide (N20) budget is unknown. Four types of fire-scarred cerrado along a vegetation gradient from grassland to forest were investigated during the wet season of 1992/93. The effect of fire and subsequent water additions on epiodic emissions of N2O and the associated profile dynamic of soil/gas phase N2O concentrations were studied for several months. Additionally, the effect on episodic emissions of N2O of nitrate and glucose additions to a cerrado soil after fire and the associated profile dynamic of soil/gas phase N2O mixing ratios were determined. Finally, N2O episodic emissions in cerrado converted to corn, soybean, and pasture fields were investigated during one growing/wet season. Results showed N2O consumption/emission for the four fire-scared savanna ecosystems, for nitrogen and carbon fertilization, and for agriculture/pasture ranging from -0.3 to +0.7, 1.8 to 9.1, and 0.5 to 3.7 g N2O-N ha(exp -1) d(exp -1), respectively. During the wet season the cerrado biome does not appear to be a major source of N2O to the troposphere, even following fire events. However, the results of this study suggest that conversion of the cerrado to high input agriculture, with liming and fertilization, can increase N2O emissions more than ten fold

    Biomethanation potential of macroalgae Ulva spp. and Gracilaria spp. and in co-digestion with waste activated sludge

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    Biochemical methane potential of four species of Ulva and Gracilaria genus was assessed in batch assays at mesophilic temperature. The results indicate a higher specific methane production (per volatile solids) for one of the Ulva sp. compared with other macroalgae and for tests running with 2.5% of total solids (196 ± 9 L CH4 kg−1 VS). Considering that macroalgae can potentially be a post treatment of municipal wastewater for nutrients removal, co-digestion of macroalgae with waste activated sludge (WAS) was assessed. The co-digestion of macroalgae (15%) with WAS (85%) is feasible at a rate of methane production 26% higher than WAS alone without decreasing the overall biodegradability of the substrate (42–45% methane yield). The use of anoxic marine sediment as inoculum had no positive effect on the methane production in batch assays. The limiting step of the overall anaerobic digestion process was the hydrolysis.The authors acknowledge the financial support of the "Fundacao para a Ciencia e a Tecnologia" through the grant given to Jose Carlos Costa (SFRH/BDP/48962/2008) and Ana Nobre (SFRH/BPD/64582/2009)

    Reações fisiológicas em diferentes grupos genéticos de bovinos de corte sob pastejo.

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    bitstream/item/137544/1/PESQ-EM-ANDAMENTO-22.pdfCNPGC

    Resultados do controle de desenvolvimento ponderal: raça Nelore - 1975/1984.

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    A raça Nelore. Controle do desenvolvimento ponderal. Considerações sobre os resultados do controle de desenvolvimento ponderal da raça Nelore. Categorias dos animais inscritos. Sexo. Regime alimentar. Ano de nascimento. Mérito dos reprodutores.bitstream/item/104691/1/Resultados-do-controle-desev-podenral.pd

    Pecuária de corte no Pantanal brasileiro: realidade e perspectivas futuras de melhoramento.

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    Apesar da pecuária de corte estar presente no Pantanal à mais de duzentos anos, até o momento, não foi estabelecido um programa de melhoramento genético animal para a região que contemplasse as diferentes condições de manejo e de ambiente no processo seletivo dos bovinos de corte. Um programa desta natureza envolveria, melhorias no manejo geral do rebanho, maior cuidado com as práticas de sanidade animal e gestão mais eficiente da atividade como um todo.bitstream/CPAP/56028/1/DOC93.pdfFormato Eletrônic

    Expression, purification and in vitro biological activity from human recombinant BMP-2 produced by a novel approach

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    Bone morphogenetic proteins have promoted great biomedical interest due to their ability in inducing new bone formation when used as powerful osteoinductive components of several late-stage bone grafting products. Recombinant human bone morphogenetic protein-2 (rhBMP-2) is obtained from mammalian cell expressing systems in low amounts or from bacteria inclusion bodies after timeconsuming refolding methods. Thus, there is a need to establish novel approaches for producing rhBMP-2 in high yields by simple and cheap procedures.Portuguese Foundation for Science and Technolog y, FCT (PhD Grant to PC Bessa , SFRH/BD/17049/2004). This work was also partially supported by the European STREP HIPPOCRATES (NMP3 - CT - 2003 - 505758) and carried out under the scope of European NoE EXPERTISSUES (NMP3 - CT - 2004 - 500283).info:eu-repo/semantics/publishedVersio
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