146 resultados para Duncan, Isadora
Resumo:
Declines of farmland birds have been pronounced in landscapes dominated by lowland livestock production and densities of seed-eating birds are particularly low in such areas. Modern livestock production often entails a simple cropping system dominated by ley grassland and maize grown for animal feed. These crops often lack invertebrate and seed resources for foraging birds and can be hostile nesting environments. Cereal-based wholecrop silages (CBWCS) offer potential benefits for farmland birds because they can be grown with minimal herbicide applications and can be spring-sown with following winter stubbles. We compared the biodiversity benefits and agronomic yields of winter-sown wheat and spring-sown barley as alternatives to grass and maize silage in intensive dairy livestock systems. Seed-eating birds foraged mainly in CBWCS fields during summer, and mainly on barley stubbles during winter and this reflected the higher densities of seed-bearing plants therein. Maize and grass fields lacked seed-bearing vegetation and were strongly avoided by most seed-eating birds. Production costs of CBWCS are similar to those of maize and lower than those of grass silage. Selective (rather than broad-spectrum) herbicide application on spring barley crops increased forb cover, reduced yields (by 11%) but caused only a small (<4%) increase in production costs. CBWCS grown with selective herbicide and with following winter stubbles offer a practical conservation measure for seed-eating farmland birds in landscapes dominated by intensively-managed grassland and maize. However, the relatively early harvesting of CBWCS could destroy a significant proportion of breeding attempts of late-nesting species like corn bunting (Emberiza calandra) or yellow wagtail (Motocilla flava). Where late-breeding species are likely to nest in CBWCS fields, harvesting should be delayed until most nesting attempts have been completed (e.g. until after 1st August in southern Britain). (C) 2010 Elsevier Ltd. All rights reserved.
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The Agri-Environment Footprint Index (AFI) has been developed as a generic methodology to assess changes in the overall environmental impacts from agriculture at the farm level and to assist in the evaluation of European agri-environmental schemes (AES). The methodology is based on multicriteria analysis (MCA) and involves stakeholder participation to provide a locally customised evaluation based on weighted environmental indicators. The methodology was subjected to a feasibility assessment in a series of case studies across the EU. The AFI approach was able to measure significant differences in environmental status between farms that participated in an AES and nonparticipants. Wider environmental concerns, beyond the scheme objectives, were also considered in some case studies and the benefits for identification of unintentional (and often beneficial) impacts of AESs are presented. The participatory approach to AES valuation proved efficient in different environments and administrative contexts. The approach proved to be appropriate for environmental evaluation of complex agri-environment systems and can complement any evaluation conducted under the Common Monitoring and Evaluation Framework. The applicability of the AFI in routine monitoring of AES impacts and in providing feedback to improve policy design is discussed.
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Modern farming has caused considerable declines in UK bumblebee populations, and, while options exist for farmers to increase the quantity of bee-friendly habitat, uptake has been low. Robin Blake explains how existing habitats on farms could be enhanced for the benefit of bumblebees
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On 16 UK livestock holdings within pastoral landscapes, we investigated the provision of plant and invertebrate resources for farmland birds in spring barley and winter wheat cereal-based whole crop silages as alternatives to maize and grass silages. The benefits of low input barley systems were also investigated; barley fields were subjected to two separate herbicide sub-treatments on a split-field design (high input broad-spectrum or low input narrow spectrum herbicides). The abundance of plant resources and invertebrates was assessed for three growing seasons during summer and winter for each crop type. The study clearly demonstrated the value of spring barley for the provision of plant resources when compared to the other silage cropping systems, whilst invertebrate responses were variable. No differences in plant and invertebrate resources were found between the barley treatments. Throughout the year, forage maize afforded the lowest provision of resources for farmland birds, and because it is likely that maize will continue to be grown in pastoral areas, the value of this habitat needs to be improved if farmland birds are to benefit. To provide plant and invertebrate resources for farmland birds in pastoral landscapes we strongly advocate the growing of spring sown barley whole-crop silage followed by over-wintering stubbles. © 2011 Elsevier B.V. All rights reserved.
Resumo:
There are approximately 29,000 ha of grass buffer strips in the UK under Agri-Environment Schemes; however, typically they are floristically poor and as such are of limited biodiversity value. Introducing a sown wildflower component has the potential to increase dramatically the value of these buffer strips for a suite of native species, including butterflies. This study investigates management practices aiming to promote the establishment and maintenance of wildflowers in existing buffer strips. The effectiveness of two methods used to increase the establishment of wildflowers for the benefit of native butterfly species were tested, both individually and in combination. The management practices were: (1) the application of a selective graminicide (fluazifop-P-butyl) which reduces the dominance of competitive grasses; and (2) scarification of the soil which creates germination niches for sown wildflower seeds. A wildflower seed mix consisting of nine species was sown in conjunction with the scarification treatment. Responses of wildflowers and butterflies were monitored for two years after establishment. Results indicate that the combined scarification and graminicide treatment produced the greatest cover and species richness of sown wildflowers. Butterfly abundance, species richness and diversity were positively correlated with sown wildflower species richness, with the highest values in the combined scarification and graminicide treatment. These findings have confirmed the importance of both scarification as a means of introducing wildflower seed into existing buffer strips, and subsequent management using graminicides, for the benefit of butterflies. Application of this approach could provide tools to help butterfly conservation on farmland in the future.
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BACKGROUND: The selective graminicide fluazifop-P-butyl is used for the control of grass weeds in dicotyledonous crops, and commonly applied in amenity areas to reduce grass productivity and promote wildflower establishment. However, evidence suggests that fluazifop-P-butylmight also have phytotoxic effects on somenon-target plants. This study investigates the effects of fluazifop-P-butyl on the emergence, phytotoxicity and above-ground biomass of nine perennial wildflower species and two grass species, following pre- and post-emergent applications at half, full and double label rates in a series of glasshouse experiments. RESULTS: While pre- and post-emergent applications of fluazifop-P-butyl caused reductions in seedling emergence and increased phytotoxicity on native wildflower and grass species, these effects were temporary for the majority of wildflower species tested, and generally only occurred at the double application rate. No differences in biomass were observed at any of the rates, suggesting good selectivity and no long-term effects of fluazifop-P-butyl application on the wildflower species from either pre-emergent or post-emergent applications. CONCLUSION: These results have direct relevance to the management of amenity areas for biodiversity, as they confirm the suitability of these wildflower species for inclusion in seed mixtures where fluazifop-P-butyl is to be applied to control grass productivity.
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Platelets play a vital role in maintaining haemostasis. Human platelet activation depends on Ca2+ release, leading to cell activation, granule secretion and aggregation. NAADP (nicotinic acid-adenine dinucleotide phosphate) is a Ca2+-releasing second messenger that acts on acidic Ca2+ stores and is used by a number of mammalian systems. In human platelets, NAADP has been shown to release Ca2+ in permeabilized human platelets and contribute to thrombin-mediated platelet activation. In the present study, we have further characterized NAADP-mediated Ca2+ release in human platelets in response to both thrombin and the GPVI (glycoprotein VI)-specific agonist CRP (collagen-related peptide). Using a radioligand-binding assay, we reveal an NAADP-binding site in human platelets, indicative of a platelet NAADP receptor. We also found that NAADP releases loaded 45Ca2+ from intracellular stores and that total platelet Ca2+ release is inhibited by the proton ionophore nigericin. Ned-19, a novel cell-permeant NAADP receptor antagonist, competes for the NAADP-binding site in platelets and can inhibit both thrombin- and CRP-induced Ca2+ release in human platelets. Ned-19 has an inhibitory effect on platelet aggregation, secretion and spreading. In addition, Ned-19 extends the clotting time in whole-blood samples. We conclude that NAADP plays an important role in human platelet function. Furthermore, the development of Ned-19 as an NAADP receptor antagonist provides a potential avenue for platelet-targeted therapy and the regulation of thrombosis.
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RATIONALE: Children with congenital heart disease are at risk of gut barrier dysfunction and translocation of gut bacterial antigens into the bloodstream. This may contribute to inflammatory activation and organ dysfunction postoperatively. OBJECTIVES: To investigate the role of intestinal injury and endotoxemia in the pathogenesis of organ dysfunction after surgery for congenital heart disease. METHODS: We analyzed blood levels of intestinal fatty acid binding protein and endotoxin (endotoxin activity assay) alongside global transcriptomic profiling and assays of monocyte endotoxin receptor expression in children undergoing surgery for congenital heart disease. MEASUREMENTS AND MAIN RESULTS: Levels of intestinal fatty acid binding protein and endotoxin were greater in children with duct-dependent cardiac lesions. Endotoxemia was associated with severity of vital organ dysfunction and intensive care stay. We identified activation of pathogen-sensing, antigen-processing, and immune-suppressing pathways at the genomic level postoperatively and down-regulation of pathogen-sensing receptors on circulating immune cells. CONCLUSIONS: Children undergoing surgery for congenital heart disease are at increased risk of intestinal mucosal injury and endotoxemia. Endotoxin activity correlates with a number of outcome variables in this population, and may be used to guide the use of gut-protective strategies.
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Interest in the effects of insulin on the heart came with the recognition that hyperglycemia in the context of myocardial infarction is associated with increased risks of mortality, congestive heart failure, or cardiogenic shock. More recently, instigated by research findings on stress hyperglycemia in critical illness, this interest has been extended to the influence of insulin on clinical outcome after cardiac surgery. Even in nondiabetic individuals, stress hyperglycemia commonly occurs as a key metabolic response to critical illness, eg, after surgical trauma. It is recognized as a major pathophysiological feature of organ dysfunction in the critically ill. The condition stems from insulin resistance brought about by dysregulation of key homeostatic processes, which implicates immune/inflammatory, endocrine, and metabolic pathways. It has been associated with adverse clinical outcomes, including increased mortality, increased duration of mechanical ventilation, increased intensive care unit (ICU) and hospital stay, and increased risk of infection. Hyperglycemia in critical illness is managed with exogenous insulin as standard treatment; however, there is considerable disagreement among experts in the field as to what target blood glucose level is optimal for the critically ill patient. Conventionally, the aim of insulin therapy has been to maintain blood glucose levels below the renal threshold, typically 220 mg/dL (12.2 mmol/L). In recent years, some have advocated tight glycemic control (TGC) with intensive insulin therapy (IIT) to normalize blood glucose levels to within the euglycemic range, typically 80 to 110 mg/dL (4.4–6.1 mmol/L).
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Species-rich lowland hay meadows are of conservation importance for both plants and invertebrates; however, they have declined in area across Europe as a result of conversion to other land uses and management intensification. The re-creation of these grasslands on ex-arable land provides a valuable approach to increasing the extent and conservation value of this threatened habitat. Over a 3-year period a replicated block design was used to test whether introducing seeds promoted the re-creation of both plant and phytophagous beetle assemblages typical of a target hay meadow. Seeds were harvested from local hay meadows, and applied to experimental plots in the form of either green hay or brush harvesting seeds. Green hay spreading achieved the greatest success in re-creating plant and phytophagous beetle assemblages. While re-creation success increased over time for both taxa, for the phytophagous beetles the greatest increase in re-creation success relative to the establishment year also occurred where green hay was applied. We also considered the phytophagous beetles in terms of functional traits that describe host plant specificity, larval feeding location and dispersal. Phytophagous beetle functional trait composition was most similar to the target hay meadow assemblage where some form of seed addition was used, i.e. hay spreading or brush harvested seeds. This study identified the importance of introducing target plant species as a mechanism to promote the re-creation of phytophagous beetle communities. Seed addition methods (e.g. green hay spreading) are crucial to successful hay meadow re-creation.
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Postharvest quality of Alphonso mangoes (Mangifera indica L) is vital to ensure proper ripening and good quality. 500 g mature green mangoes, were subjected to three pre- packaging hot water dips (20, 30 & 40°C) for 40 min, two packaging films (OPP unperforated and perforated), using three levels of gas concentrations of 25,50 and 75% v/v CO2 treatments (balance N2) and stored at 10°C for 21 days. During the storage period headspace gas composition, weight loss, ascorbic acid, pulp firmness, external fruit colour and overall quality score were measured to determine optimum storage conditions. The most effective postharvest condition was found to be dipping in water maintained at 40°C for 40 min, followed by packaging under 50% CO2 in bags made of unperforated film when compared to mangoes packed under 25 and 75% CO2 which showed deteriorated quality including spoilage and mould. Good keeping quality of at least 21 days was achieved under these conditions, which was much superior to the control samples that showed deterioration after 12 days of storage.