916 resultados para grazing ecosystem
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Improved understanding and prediction of the fundamental environmental controls on ecosystem service supply across the landscape will help to inform decisions made by policy makers and land-water managers. To evaluate this issue for a local catchment case study, we explored metrics and spatial patterns of service supply for water quality regulation, agriculture production, carbon storage, and biodiversity for the Macronutrient Conwy catchment. Methods included using ecosystem models such as LUCI and JULES, integration of national scale field survey datasets, earth observation products and plant trait databases, to produce finely resolved maps of species richness and primary production. Analyses were done with both 1x1 km gridded and subcatchment data. A common single gradient characterised catchment scale ecosystem services supply with agricultural production and carbon storage at opposing ends of the gradient as reported for a national-scale assessment. Species diversity was positively related to production due to the below national average productivity levels in the Conwy combined with the unimodal relationship between biodiversity and productivity at the national scale. In contrast to the national scale assessment, a strong reduction in water quality as production increased was observed in these low productive systems. Various soil variables were tested for their predictive power of ecosystem service supply. Soil carbon, nitrogen, their ratio and soil pH all had double the power of rainfall and altitude, each explaining around 45% of variation but soil pH is proposed as a potential metric for ecosystem service supply potential as it is a simple and practical metric which can be carried out in the field with crowd-sourcing technologies now available. The study emphasises the importance of considering multiple ecosystem services together due to the complexity of covariation at local and national scales, and the benefits of exploiting a wide range of metrics for each service to enhance data robustness.
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Background - Green infrastructure is a strategic network of green spaces designed to deliver ecosystem services to human communities. Green infrastructure is a convenient concept for urban policy makers, but the term is used too-generically and with limited understanding of the relative values or benefits of different types of green space and how these complement one another. At a finer scale/more practical level– little consideration is given to the composition of the plant-communities, yet this is what ultimately defines extent of service provision. This paper calls for greater attention to be paid to urban plantings with respect to ecosystem service delivery and for plant science to engage more-fully in identifying those plants that promote various services. Scope - Many urban plantings are designed based on aesthetics alone, with limited thought on how plant choice/composition provides other ecosystem services. Research is beginning to demonstrate, however, that landscape plants provide a range of important services, such as helping mitigate floods and alleviating heat islands, but that not all species are equally effective. The paper reviews a number of important services and demonstrates how genotype choice radically affects service delivery. Conclusions – Although research is in its infancy, data is being generated that relates plant traits to specific services; thereby helping identify genotypes that optimise service delivery. The urban environment, however, will become exceedingly bland if future planting is simply restricted to monocultures of a few ‘functional’ genotypes. Therefore, further information is required on how to design plant communities where the plants identified:- a/ provide more than a single benefit (multi-functionality) b/ complement each other in maximising the range of benefits that can be delivered in one location and c/ continue to maintain public acceptance through diversity. The identification/development of functional landscape plants is an exciting and potentially high impact arena for plant science.
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Free-living amoebae of the genus Acanthamoeba are widely distributed in soil and water collections, where trophozoites (vegetative, multiplicative stages) feed mainly by phagocytosis and thus control bacterial populations in the environment. Here, we examined the growth, encystment and survival of Acanthamoeba castellanii receiving different bacteria (Escherichia coli, Pseudomonas aeruginosa, Enterobacter cloacae, Bacillus subtilis, Bacillus megaterium, Micrococcus luteus, and Staphylococcus aureus) in nonnutrient saline. All bacteria assayed induced a dose-dependent proliferative response, in most cases maximized with a bacterial dose of 1 x 10(9) mL(-1); except for M. luteus, trophozoites grew better with viable than with heat-killed bacteria. In addition, Acanthamoeba growth was improved by adding bacteria on alternate days. Single-dose experiments indicated a temporal association between the growth of trophozoite and bacterial consumption, and higher consumption of M. luteus, E. coli and P. aeruginosa, bacterial species that allowed the highest trophozoite yields. Long-term Acanthamoeba-bacteria incubation revealed that encystment was significantly delayed by almost all the bacteria assayed (including S. aureus, which elicited a poor growth response) and that the presence of bacteria markedly increased cyst yield; final cyst recovery clearly depended on both the dose and the type of the bacterium given, being much higher with E. coli, M. luteus and P. aeruginosa.
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In this note we investigate the influence of structural nonlinearity of a simple cantilever beam impacting system on its dynamic responses close to grazing incidence by a means of numerical simulation. To obtain a clear picture of this effect we considered two systems exhibiting impacting motion, where the primary stiffness is either linear (piecewise linear system) or nonlinear (piecewise nonlinear system). Two systems were studied by constructing bifurcation diagrams, basins of attractions, Lyapunov exponents and parameter plots. In our analysis we focused on the grazing transitions from no impact to impact motion. We observed that the dynamic responses of these two similar systems are qualitatively different around the grazing transitions. For the piecewise linear system, we identified on the parameter space a considerable region with chaotic behaviour, while for the piecewise nonlinear system we found just periodic attractors. We postulate that the structural nonlinearity of the cantilever impacting beam suppresses chaos near grazing. (C) 2007 Elsevier Ltd. All rights reserved.
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A study on the benthic ecosystem health was performed to assess the environmental quality of Montevideo coastal zone, in view of the construction of a new sanitation system. Data were compared to previous research undertaken 10 years ago, and biochemical composition of organic matter, heavy metals, organic matter, phytopigments, benthic diatoms, macrofauna community structure and a biotic index (AMBI) were used as proxies. Results indicate an environmental quality-gradient, with the worst conditions within the inner stations of Montevideo Bay and an improvement towards the adjacent coastal zone. Higher levels of chromium, lead, phaeopigments, organic biopolymers and poor benthic macrofauna and diatom communities, characterised the hypertrophic innermost portion of Montevideo Bay. Data indicated a clear deterioration of the adjacent coastal zone comparatively to that observed 10 years ago. The complementary use of approaches not applied before (benthic diatoms and organic biopolymers) with those formerly applied improve our assessment of the trophic status and the environmental health of the area. (C) 2010 Elsevier B.V. All rights reserved.
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In order to evaluate the interactions between Au/Cu atoms and clean Si(l 11) surface, we used synchrotron radiation grazing incidence X-ray fluorescence analysis and theoretical calculations. Optimized geometries and energies on different adsorption sites indicate that the binding energies at different adsorption sites are high, suggesting a strong interaction between metal atom and silicon surface. The Au atom showed higher interaction than Cu atom. The theoretical and experimental data showed good agreement. Crown Copyright (C) 2009 Published by Elsevier B.V. All rights reserved.
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This article presents data-rich findings of a comprehensive follow-up study on the patron-driven/demand-driven ebook acquisitions (DDA) plan chronicled in two prior articles from the DDA ebook plan's October 2011 inception. Into the third fiscal year, print vs. ebook usage preferences have begun to emerge, and the results broken out by discipline are presented.
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Negócios sociais, empresas autossuficientes com objetivos principalmente sociais estão a surgir e a mudar o cenário económico mundial. No Brasil, o campo de Empreendedorismo Social promete ajudar a resolver os vários problemas sociais do país, mas tal promessa depende do desenvolvimento de um ecossistema de suporte. No entanto, a pesquisa desenvolvida no tópico ainda é limitada, especialmente quando considerando pesquisa em contextos macro como estruturas de suporte ao negócio. O presente estudo explora o ecossistema de suporte aos negócios sociais no Brasil, oferecendo uma análise qualitativa preliminar da eficácia da rede de suporte existente para os negócios sociais, de acordo com as perceções de empreendedores sociais e prestadores de suporte. O estudo é desenvolvido baseando-se no modelo conceptual de Turrini et al. (2010) sobre os determinantes de eficácia de redes a fim de facilitar a captura de padrões. Desta forma, cada variável de eficácia de redes é desenvolvida no contexto da presente investigação e as principais conclusões relativas ao ecossistema de suporte para negócios sociais no Brasil são destacadas. Os resultados sugerem um rápido crescimento da disponibilidade de suporte para negócios sociais, mas indicam que estes serviços ainda são em número limitado e concentrados no Sudeste do país. Adicionalmente, os serviços de suporte são percecionados pelos empreendedores sociais como serviços de alta qualidade e embora se observe um sentimento generalizado de que a colaboração entre organizações de suporte tem sido importante para a construção do campo, os resultados indicam que um maior nível de interação e formalização entre prestadores de suporte levaria a maiores níveis de criação de sinergias e potenciaria a construção do ecossistema. Por último, é observado um sentimento generalizado de que o crescente nível de recursos financeiros, consciência pública e apoio do governo ao campo impactarão positivamente o desenvolvimento do ecossistema.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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This study was designed to evaluate the effect of nutritional supplementation offered during the pre- and postpartum periods on serum cholesterol, triglycerides and total lipids of Canchim beef cows and their relationship with folliculogenesis. Thirty cows with predicted calving date between September and October, kept in pastures of Brachiaria brizantha cv. Marandu together with their calves, were randomly distributed into three experimental groups: the first received only a mineral mixture (Control Group, CG); the second group received a concentrate with 16% crude protein/kg dry matter (DM) and 3000 kcal digestible energy/kg DM offered for 45 days prepartum and 120 days postpartum (PREG); the third group received the concentrate from parturition until the 120th day postpartum (POSG). Consumption was estimated at 1% of body weight, and each cow received approximately 4.0 kg/day (fresh weight) of supplement. Blood samples were taken and an ultrasound examination of the ovaries was performed twice a week until the 60th day postpartum. The body condition score (BCS) and the weight of the cows were recorded at 15-day intervals from calving until the 60th day postpartum. Data are presented as mean +/- SEM. Mean weight and BCS at calving were, respectively, 448 +/- 54.9 kg and 6.2 +/- 0.25 (PREG); 432 +/- 71.1 kg and 5.5 +/- 0.69 (POSG); and 434 +/- 66.4 kg and 5.5 +/- 0.69 (CG). Total cholesterol (TC), triglycerides (TRIG) and total lipids (TLIP) were measured using colorimetry until the 60th day postpartum. TC averages were PREG 186 +/- 62.6 mg/dL, POSG 159 +/- 43.1 mg/dL and CG 133 +/- 35.1 mg/dL (P < 0.05). For TRIG, the means were PREG 29 +/- 11.3 mg/dL (P < 0.05), POSG 24 +/- 8.1 mg/dL and CG 26 +/- 12.1 mg/dL (P > 0.05). Serum concentrations of TLIP were PREG 588 +/- 145.6 mg/dL, POSG 512 +/- 137.6 mg/dL and CG 452 +/- 122.4 mg/dL (P < 0.05). The first dominant follicle (DF) was identified on Day 21 +/- 10.3 (PREG), 36 +/- 28.5 (POSG) and 51 +/- 32.8 (CG) after calving. The difference between PREG and CG was significant (P < 0.05). TC was positively correlated with the calving to first estrus interval (P < 0.05). Results showed that nutritional supplementation before parturition assured good body condition at calving and suggested that it was effective at increasing cholesterol availability to maintain ovarian follicle function and to favor earlier resumption of ovarian activity. (C) 2010 Published by Elsevier B.V.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)