24 resultados para Reserves

em CentAUR: Central Archive University of Reading - UK


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This paper examines the debate surrounding a recent decision made by the Ghanaian government to permit gold exploration - and potentially, mining - in 'protected' forest reserves. In 2001, four mining companies were awarded mineral exploration concessions in forested regions of the country, and have since put forward applications to mine for gold. Notwithstanding the sharp divide in opinion on the issue, the continued uncertainty surrounding the implications of the proposed activities makes further research on the ground imperative in the short term. Work aiming to elicit indigenous perspectives on the projects, as well as research that facilitates dialogue between and/or among stakeholder parties, should be prioritized.

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Combining geological knowledge with proved plus probable ('2P') oil discovery data indicates that over 60 countries are now past their resource-limited peak of conventional oil production. The data show that the global peak of conventional oil production is close. Many analysts who rely only on proved ('1P') oil reserves data draw a very different conclusion. But proved oil reserves contain no information about the true size of discoveries, being variously under-reported, over-reported and not reported. Reliance on 1P data has led to a number of misconceptions, including the notion that past oil forecasts were incorrect, that oil reserves grow very significantly due to technology gain, and that the global supply of oil is ensured provided sufficient investment is forthcoming to 'turn resources into reserves'. These misconceptions have been widely held, including within academia, governments, some oil companies, and organisations such as the IEA. In addition to conventional oil, the world contains large quantities of non-conventional oil. Most current detailed models show that past the conventional oil peak the non-conventional oils are unlikely to come on-stream fast enough to offset conventional's decline. To determine the extent of future oil supply constraints calculations are required to determine fundamental rate limits for the production of non-conventional oils, as well as oil from gas, coal and biomass, and of oil substitution. Such assessments will need to examine technological readiness and lead-times, as well as rate constraints on investment, pollution, and net-energy return. (C) 2007 Elsevier Ltd. All rights reserved.

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Traditionally, siting and sizing decisions for parks and reserves reflected ecological characteristics but typically failed to consider ecological costs created from displaced resource collection, welfare costs on nearby rural people, and enforcement costs. Using a spatial game-theoretic model that incorporates the interaction of socioeconomic and ecological settings, we show how incorporating more recent mandates that include rural welfare and surrounding landscapes can result in very different optimal sizing decisions. The model informs our discussion of recent forest management in Tanzania, reserve sizing and siting decisions, estimating reserve effectiveness, and determining patterns of avoided forest degradation in Reduced Emissions from Deforestation and Forest Degradation programs.

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This study considers the role that reserve prices may play in residential property auctions. In comparison to much of the previous empirical work, this study has access to undisclosed reserve prices from English auctions. Consistent with theoretical arguments in the auction literature, the results obtained illustrate that whilst higher reserve prices increase the revenue obtained for the seller, they also reduce the probability of sale. The findings also highlight the importance of auction participation, with the number of individual bidders and the number of bids significant in most specifications.

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This study considers the role that reserve prices may play in residential property auctions. In comparison to much of the previous empirical work, this study has access to undisclosed reserve prices from English auctions. Consistent with theoretical arguments in the auction literature, the results obtained illustrate that whilst higher reserve prices increase the revenue obtained for the seller, they also reduce the probability of sale. The findings also highlight the importance of auction participation, with the number of individual bidders and the number of bids significant in most specifications.

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This paper describes the results of field research to dissect how social interactions differ between two reserves in Paraguay having very different styles of governance. The two reserves were Mbaracayu Natural Forest Reserve (Reserva Natural del Bosque de Mbaracayti, RNBM) and San Rafael Managed Resource Reserve (Reserva de Recursos Manejados San Rafael, RRMSR). RNBM is a private reserve owned by a non-governmental organisation. while RRNISR is a publicly-managed reserve, albeit with a substantial degree of private land ownership. Both reserves are intended to protect Atlantic Forest, one of the five world biodiversity 'hotspots', and also one of the most highly threatened. Each reserve and its buffer zone comprises a set of stakeholders, including indigenous communities and farmers, and the paper explores the interactions between these and the management regime. Indeed, while the management regimes of the two reserves are different, one being highly top-down (RNBM) and the other more socially inclusive (RRMSR), the issues that they have to deal with are much the same. However, while both management regimes will readily acknowledge the need to address poverty, inequality appears to be a far more sensitive issue. Whereas this may be expected for the privately-owned RNBM it is perhaps more surprising in RRNISR even when allowing for the fact that much of the land in the latter is in private hands. It is argued that the origins of this sensitivity rest within the broader features of Paraguayan society, and the prevalence of private land ownership. Yet ironically, it is the inequality in land ownership that is perhaps the most significant threat to conservation in both reserves. Therefore, while reserve-level analyses can provide some insight into the driving forces at play in the interaction between conservation and sustainable management, larger scales may be necessary to gain a fuller appreciation of the dynamics operating at site level. Even in a society with a history of centralised control these dynamics may be surprising. (c) 2005 Elsevier Ltd. All rights reserved.

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Little consideration has been given to the genetic composition of populations associated with marine reserves, as reserve designation is generally to protect specific species, communities or habitats. Nevertheless, it is important to conserve genetic diversity since it provides the raw material for the maintenance of species diversity over longer, evolutionary time-scales and may also confer the basis for adaptation to environmental change. Many current marine reserves are small in size and isolated to some degree (e.g. sea loughs and offshore islands). While such features enable easier management, they may have important implications for the genetic structure of protected populations, the ability of populations to recover from local catastrophes and the potential for marine reserves to act as sources of propagules for surrounding areas. Here, we present a case study demonstrating genetic differentiation, isolation, inbreeding and reduced genetic diversity in populations of the dogwhelk Nucella lapillus in Lough Hyne Marine Nature Reserve (an isolated sea lough in southern Ireland), compared with populations on the local adjacent open coast and populations in England, Wales and France. Our study demonstrates that this sea lough is isolated from open coast populations, and highlights that there may be long-term genetic consequences of selecting reserves on the basis of isolation and ease of protection.

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Iron is essential to virtually all organisms, but poses problems of toxicity and poor solubility. Bacteria have evolved various mechanisms to counter the problems imposed by their iron dependence, allowing them to achieve effective iron homeostasis under a range of iron regimes. Highly efficient iron acquisition systems are used to scavenge iron from the environment under iron-restricted conditions. In many cases, this involves the secretion and internalisation of extracellular ferric chelators called siderophores. Ferrous iron can also be directly imported by the G protein-like transporter, FcoB. For pathogens, host-iron complexes (transferrin, lactoferrin, haem, haemoglobin) are directly used as iron sources. Bacterial iron storage proteins (ferritin, bacterioferritin) provide intracellular iron reserves for use when external supplies are restricted, and iron detoxification proteins (Dps) are employed to protect the chromosome from iron-induced free radical damage. There is evidence that bacteria control their iron requirements in response to iron availability by downregulating the expression of iron proteins during iron-restricted growth. And finally, the expression of the iron homeostatic machinery is subject to iron-dependent global control ensuring that iron acquisition, storage and consumption are geared to iron availability and that intracellular levels of free iron do not reach toxic levels. (C) 2003 Federation of European Microbiological Societies. Published by Elsevier Science B.V. All rights reserved.

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Geological carbon dioxide storage (CCS) has the potential to make a significant contribution to the decarbonisation of the UK. Amid concerns over maintaining security, and hence diversity, of supply, CCS could allow the continued use of coal, oil and gas whilst avoiding the CO2 emissions currently associated with fossil fuel use. This project has explored some of the geological, environmental, technical, economic and social implications of this technology. The UK is well placed to exploit CCS with a large offshore storage capacity, both in disused oil and gas fields and saline aquifers. This capacity should be sufficient to store CO2 from the power sector (at current levels) for a least one century, using well understood and therefore likely to be lower-risk, depleted hydrocarbon fields and contained parts of aquifers. It is very difficult to produce reliable estimates of the (potentially much larger) storage capacity of the less well understood geological reservoirs such as non-confined parts of aquifers. With the majority of its large coal fired power stations due to be retired during the next 15 to 20 years, the UK is at a natural decision point with respect to the future of power generation from coal; the existence of both national reserves and the infrastructure for receiving imported coal makes clean coal technology a realistic option. The notion of CCS as a ‘bridging’ or ‘stop-gap’ technology (i.e. whilst we develop ‘genuinely’ sustainable renewable energy technologies) needs to be examined somewhat critically, especially given the scale of global coal reserves. If CCS plant is built, then it is likely that technological innovation will bring down the costs of CO2 capture, such that it could become increasingly attractive. As with any capitalintensive option, there is a danger of becoming ‘locked-in’ to a CCS system. The costs of CCS in our model for UK power stations in the East Midlands and Yorkshire to reservoirs in the North Sea are between £25 and £60 per tonne of CO2 captured, transported and stored. This is between about 2 and 4 times the current traded price of a tonne of CO2 in the EU Emissions Trading Scheme. In addition to the technical and economic requirements of the CCS technology, it should also be socially and environmentally acceptable. Our research has shown that, given an acceptance of the severity and urgency of addressing climate change, CCS is viewed favourably by members of the public, provided it is adopted within a portfolio of other measures. The most commonly voiced concern from the public is that of leakage and this remains perhaps the greatest uncertainty with CCS. It is not possible to make general statements concerning storage security; assessments must be site specific. The impacts of any potential leakage are also somewhat uncertain but should be balanced against the deleterious effects of increased acidification in the oceans due to uptake of elevated atmospheric CO2 that have already been observed. Provided adequate long term monitoring can be ensured, any leakage of CO2 from a storage site is likely to have minimal localised impacts as long as leaks are rapidly repaired. A regulatory framework for CCS will need to include risk assessment of potential environmental and health and safety impacts, accounting and monitoring and liability for the long term. In summary, although there remain uncertainties to be resolved through research and demonstration projects, our assessment demonstrates that CCS holds great potential for significant cuts in CO2 emissions as we develop long term alternatives to fossil fuel use. CCS can contribute to reducing emissions of CO2 into the atmosphere in the near term (i.e. peak-shaving the future atmospheric concentration of CO2), with the potential to continue to deliver significant CO2 reductions over the long term.

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This paper examines aspects of the case against global oil peaking, and in particular sets out to answer a viewpoint that the world can have abundant supplies of oil "for years to come". Arguments supporting the latter view include: past forecasts of oil shortage have proved incorrect, so current predictions should also be discounted; many modellers depend on Hubbert's analysis but this contained fundamental flaws; new oil supply will result from reserves growth and from the wider deployment of advanced extraction technology; and that the world contains large resources of unconventional oil that can come on-stream if the production of conventional oil declines. These arguments are examined in turn and shown to be incorrect, or to need setting into a broader context. The paper concludes therefore that such arguments cannot be used to rule out calculations that the resource-limited peak in the world's production of conventional oil will occur in the near term. Moreover, peaking of conventional oil is likely to impact the world's total availability of oil where the latter includes non-conventional oil and oil substitutes. (C) 2008 Elsevier Ltd. All rights reserved.

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Urban areas have both positive and negative influences on wildlife. For terrestrial mammals, one of the principle problems is the risk associated with moving through the environment whilst foraging. In this study, we examined nocturnal patterns of movement of urban-dwelling hedgehogs (Erinaceus europaeus) in relation to (i) the risks posed by predators and motor vehicles and (ii) nightly weather patterns. Hedgehogs preferentially utilised the gardens of semi-detached and terraced houses. However, females, but not males, avoided the larger back gardens of detached houses, which contain more of the habitat features selected by badgers. This difference in the avoidance of predation risk is probably associated with sex differences in breeding behaviour. Differences in nightly movement patterns were consistent with strategies associated with mating behaviour and the accumulation of fat reserves for hibernation. Hedgehogs also exhibited differences in behaviour associated with the risks posed by humans; they avoided actively foraging near roads and road verges, but did not avoid crossing roads per se. They were, however, significantly more active after midnight when there was a marked reduction in vehicle and foot traffic. In particular, responses to increased temperature, which is associated with increased abundance of invertebrate prey, were only observed after midnight. This variation in the timing of bouts of activity would reduce the risks associated with human activities. There were also profound differences in both area ranged and activity with chronological year which warrant further investigation.

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The Baja California Peninsula is home to 85 species of cacti, of which 54 are endemic, highlighting its importance as a cactus diverse region within Mexico. Many species are under threat due to collection pressure and habitat loss, but ensuring maximal protection of cacti species requires a better understanding of diversity patterns. We assessed species richness, endemism, and phylogenetic and morphological diversity using herbarium records and a molecular phylogeny for 82 species of cacti found in the peninsula. The four diversity measures were estimated for the existing nature reserve network and for 314 hexagrids of 726 km2. Using the hexagrid data, we surveyed our results for areas that best complement the current protected cacti diversity in the Baja California Peninsula. Currently, the natural reserve network in Baja shelters an important amount of the cacti diversity (74% of the species, 85.9% of the phylogenetic diversity, 76% of endemics and all the growth forms). While species richness produced several solutions to complement the diversity protected, by identifying priority species (endemic species with high contribution to overall PD) one best solution is reported. Three areas (San Matías, Magdalena and Margarita Islands and El Triunfo), selected using species richness, PD and endemism, best complement the diversity currently protected, increasing species richness to 89%, PD to 94% and endemism to 89%, and should be considered in future conservation plans. Two of these areas could be included within nature reserves already established.

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The distribution of nutrients and assimilates in different organs and tissues is in a constant state of flux throughout the growth and development of a plant. At key stages during the life cycle profound changes occur, and perhaps one of the most critical of these is during seed filling. By restricting the competition for reserves in Arabidopsis plants, the ability to manipulate seed size, seed weight, or seed content has been explored. Removal of secondary inflorescences and lateral branches resulted in a stimulation of elongation of the primary inflorescence and an increase in the distance between siliques. The pruning treatment also led to the development of longer and larger siliques that contained fewer, bigger seeds. This seems to be a consequence of a reduction in the number of ovules that develop and an increase in the fatty acid content of the seeds that mature. The data show that shoot architecture could have a substantial impact on the partitioning of reserves between vegetative and reproductive tissues and could be an important trait for selection in rapid phenotyping screens to optimize crop performance.