28 research outputs found

    Potencial de aquecimento global de sistemas forrageiros.

    Get PDF
    A pecuária catarinense apresenta produção animal com base em distintos sistemas forrageiros, mas pouco é sabido sobre o potencial de aquecimento global (PAG) desses sistemas. O objetivo do estudo foi avaliar o PAG de quatro sistemas forrageiros: PN- Pastagem Natural; PMPastagem Natural Melhorada; PP- Pastagem Perene; e PA- Pastagem Anual. O estudo foi conduzido durante 5 anos na EPAGRI, Lages, SC, Brasil. O PAG parcial (PAGp) das pastagens foi calculado considerando a emissão anual de óxido nitroso (N2O) e metano (CH4) do solo e a taxa de sequestro de carbono anual relativa (TSR). A intensidade de emissão de gases de efeito estufa (IEGEE) foi calculada considerando o PAGp e a produção de matéria seca (MS) das pastagens. A emissão de N2O variou de 0,08 a 2,96 Mg CO2eq. ha-1 ano-1 para PN e PA, respectivamente. A PP apresentou o menor influxo de CH4 no solo (-0,018 Mg CO2eq. ha-1 ano- 1), diferindo de PM e PN. A TSR foi negativa para PN, PM e PP indicando potencial mitigador em relação a PA. A produção de MS variou de 6,62 a 13,04 Mg ha-1 para PN e PP, respectivamente. Apesar das diferenças na produtividade, a IEGEE não diferiu entre as pastagens. Os sistemas forrageiros não diferiram quanto ao PAGp, independentemente do manejo do solo e do pasto. Sequestro de Carbono, Manejo de Pastagens, Gases do Efeito Estuf

    Emisión acumulada de óxido nitroso (N20) en sistemas pastoriles de la Sierra Catarinense - Brasil.

    Get PDF
    En este trabajo se evaluaron y compararon la emisión de N2O generados por los sistemas pastoriles más empleados en Santa Catarina, Brasil.Suplemento 1. Edição do 43º Congreso Argentino de Producción Animal

    Invited review: Large-scale indirect measurements for enteric methane emissions in dairy cattle: A review of proxies and their potential for use in management and breeding decisions

    Get PDF
    Publication history: Accepted - 7 December 2016; Published online - 1 February 2017.Efforts to reduce the carbon footprint of milk production through selection and management of low-emitting cows require accurate and large-scale measurements of methane (CH4) emissions from individual cows. Several techniques have been developed to measure CH4 in a research setting but most are not suitable for large-scale recording on farm. Several groups have explored proxies (i.e., indicators or indirect traits) for CH4; ideally these should be accurate, inexpensive, and amenable to being recorded individually on a large scale. This review (1) systematically describes the biological basis of current potential CH4 proxies for dairy cattle; (2) assesses the accuracy and predictive power of single proxies and determines the added value of combining proxies; (3) provides a critical evaluation of the relative merit of the main proxies in terms of their simplicity, cost, accuracy, invasiveness, and throughput; and (4) discusses their suitability as selection traits. The proxies range from simple and low-cost measurements such as body weight and high-throughput milk mid-infrared spectroscopy (MIR) to more challenging measures such as rumen morphology, rumen metabolites, or microbiome profiling. Proxies based on rumen samples are generally poor to moderately accurate predictors of CH4, and are costly and difficult to measure routinely onfarm. Proxies related to body weight or milk yield and composition, on the other hand, are relatively simple, inexpensive, and high throughput, and are easier to implement in practice. In particular, milk MIR, along with covariates such as lactation stage, are a promising option for prediction of CH4 emission in dairy cows. No single proxy was found to accurately predict CH4, and combinations of 2 or more proxies are likely to be a better solution. Combining proxies can increase the accuracy of predictions by 15 to 35%, mainly because different proxies describe independent sources of variation in CH4 and one proxy can correct for shortcomings in the other(s). The most important applications of CH4 proxies are in dairy cattle management and breeding for lower environmental impact. When breeding for traits of lower environmental impact, single or multiple proxies can be used as indirect criteria for the breeding objective, but care should be taken to avoid unfavorable correlated responses. Finally, although combinations of proxies appear to provide the most accurate estimates of CH4, the greatest limitation today is the lack of robustness in their general applicability. Future efforts should therefore be directed toward developing combinations of proxies that are robust and applicable across diverse production systems and environments.Technical and financial support from the COST Action FA1302 of the European Union

    Cross‐Coupling between Hydrazine and Aryl Halides with Hydroxide Base at Low Loadings of Palladium by Rate‐Determining Deprotonation of Bound Hydrazine

    No full text
    We report the Pd-catalyzed C–N coupling of hydrazine with (hetero)aryl chlorides and bromides to form aryl hydrazines with catalyst loadings as low as 100 ppm of Pd and KOH. Mechanistic studies revealed two catalyst resting states: an arylpalladium(II) hydroxide and arylpalladium(II) chloride. These compounds are present in two interconnected catalytic cycles and react with hydrazine and base or hydrazine alone to give the product. The selectivity of the hydroxide complex with hydrazine to form aryl over diaryl hydrazine was lower than that of the chloride complex, as well as the catalytic reaction. In contrast, the selectivity of the chloride complex closely matches that of the catalytic reaction, indicating that the aryl hydrazine is derived from this complex. Kinetic studies show that the coupling process occurs by rate-limiting deprotonation of a hydrazine-bound arylpalladium(II) chloride complex to give an arylpalladium(II) hydrazido complex

    Understanding the whole city as landscape. A multivariate approach to urban landscape morphology

    No full text
    Abstract The European Landscape Convention implies a requirement for signatory states to identify their urban landscapes which goes beyond the traditional focus on individual parks and green spaces and the links between them. Landscape ecological approaches can provide a useful model for identifying urban landscape types across a whole territory, but the variables relevant for urban landscapes are very different to those usually addressing rural areas. This paper presents an approach for classifying the urban landscape of Vienna that was developed in a research project funded by the Austrian Ministry for Transport, Innovation and Technology: 'Urban Fabric and Microclimate Response' . Nine landscape types and a number of sub-types were defined, using a multivariate statistical approach which takes into account both morphological and urban climate related variables. Although the variables were selected to objectively reflect the factors that could best represent the urban climatic characteristics of the urban landscape, the results also provided a widely plausible representation of the structure of the city's landscapes. Selected examples of the landscape types that were defined in this way were used both to simulate current microclimatic conditions and also to model the effects of possible climatic amelioration measures. Finally the paper looks forward to developing a more general-purpose urban landscape typology that allows investigating a much broader complex of urban landscape functions

    Potencial de Aquecimento Global Parcial (PAGp) em sistemas pastoris catarinenses.

    No full text
    O estudo teve como objetivo quantificar a Intensidade de emissão de gases de efeito estufa (GEE), avaliando os sistemas forrageiros mais utilizados no Planalto Catarinense. Os sistemas avaliados durante o verão foram: pastagem natural (PN), pastagem natural melhorada (PM), pastagem perene (PP), e pastagem anual (PA). As amostragens de gases foram tomadas por meio de câmaras estáticas fechadas e as análises das amostras por cromatografia gasosa. Foram calculadas a emissão de gases do efeito estufa parcial (IEGEEp), resultante do produto do potencial de aquecimento global parcial (PAGp) e a produção de massa seca de forragem em cada sistema forrageiro. Os resultados apontaram que PN apresentou menor IEGEEp (-0,0013), permitindo o sequestro de carbono no sistema solo-planta, seguido por PM, PP e PA, com 0,0683, 0,2386 e 0,3491kg CO2eq kg MS-1 ha-1, respectivamente. Esta variação à alteração da estrutura do solo pelo manejo, modificando o metabolismo microbian

    Venus Express: Scientific goals, instrumentation, and scenario of the mission

    No full text
    The first European mission to Venus (Venus Express) is described. It is based on a repeated use of the Mars Express design with minor modifications dictated in the main by more severe thermal environment at Venus. The main scientific task of the mission is global exploration of the Venusian atmosphere, circumplanetary plasma, and the planet surface from an orbiting spacecraft. The Venus Express payload includes seven instruments, five of which are inherited from the missions Mars Express and Rosetta. Two instruments were specially designed for Venus Express. The advantages of Venus Express in comparison with previous missions are in using advanced instrumentation and methods of remote sounding, as well as a spacecraft with a broad spectrum of capabilities of orbital observations. © Pleiades Publishing, Inc., 2006
    corecore