5,908 research outputs found

    19th century London dust-yards: A case study in closed-loop resource efficiency

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    The material recovery methods used by dust-yards in early 19th century London, England and the conditions that led to their development, success and decline are reported. The overall system developed in response to the market value of constituents of municipal waste, and particularly the high coal ash content of household ‘dust’. The emergence of lucrative markets for ‘soil’ and ‘breeze’ products encouraged dust-contractors to recover effectively 100% of the residual wastes remaining after readily saleable items and materials had been removed by the thriving informal sector. Contracting dust collection to the private sector allowed parishes to keep the streets relatively clean, without the need to develop institutional capacity, and for a period this also generated useful income. The dust-yard system is, therefore, an early example of organised, municipal-wide solid waste management, and also of public–private sector participation. The dust-yard system had been working successfully for more than 50 years before the Public Health Acts of 1848 and 1875, and was thus important in facilitating a relatively smooth transition to an institutionalised, municipally-run solid waste management system in England. The dust-yards can be seen as early precursors of modern materials recycling facilities (MRFs) and mechanical–biological treatment (MBT) plants; however, it must be emphasised that dust-yards operated without any of the environmental and occupational health considerations that are indispensable today. In addition, there are analogies between dust-yards and informal sector recycling systems currently operating in many developing countries

    Spud 1.0: generalising and automating the user interfaces of scientific computer models

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    The interfaces by which users specify the scenarios to be simulated by scientific computer models are frequently primitive, under-documented and ad-hoc text files which make using the model in question difficult and error-prone and significantly increase the development cost of the model. In this paper, we present a model-independent system, Spud, which formalises the specification of model input formats in terms of formal grammars. This is combined with an automated graphical user interface which guides users to create valid model inputs based on the grammar provided, and a generic options reading module, libspud, which minimises the development cost of adding model options. <br><br> Together, this provides a user friendly, well documented, self validating user interface which is applicable to a wide range of scientific models and which minimises the developer input required to maintain and extend the model interface

    Topographic microclimates drive microhabitat associations at the range margin of a butterfly

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    Journal Article© 2014 The Authors. Ecography published by Nordic Society Oikos.The habitat associations of individuals underpin the dynamics of species distributions. Broad-scale gradients in climate can alter habitat associations across species' geographic ranges, but topographic heterogeneity creates local microclimates which could generate variation in habitat use at finer spatial scales. We examined the selection of microhabitats for egg-laying by populations of a thermally-constrained butterfly, the skipper Hesperia comma, across 16 sites with different regional temperatures and topographic microclimates. Using models of thermal microclimate, we examined how the association between eggs and warm bare ground microhabitats varied with ambient temperature, and predicted bare ground associations in 287 existing H. comma populations, to investigate the relative impacts of regional temperatures and topographic microclimates on microhabitat use. Eggs were most strongly associated with bare ground in relatively cool sites, indicating climate-driven changes in microhabitat use. The majority of temperature variation between study sites was attributable to topographic microclimates rather than regional temperature differences, such that changes in microhabitat associations occurred principally between north- and south-facing slopes within the same region. Predicted microhabitat associations across the UK distribution of H. comma showed that, due to the large temperature differences generated by topography, most of the between-population variation in microhabitat use occurs locally within 5 km grid squares, with a smaller proportion occurring at a regional level between 5 km squares. Our findings show how microclimatic variation generated by topography alters the habitat associations of populations at fine spatial scales, suggesting that microclimate-driven changes in habitat suitability could shape species' distribution dynamics and their responses to environmental change.NERCUniversity of Exete

    Active Management of Protected Areas Enhances Metapopulation Expansion Under Climate Change

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    Journal ArticleCopyright © 2013 The Authors. Conservation Letters published by Wiley Periodicals, Inc.There is a need to adapt biodiversity conservation to climate change, but few empirical studies are available to guide decision-making. Existing networks of protected areas (PAs) have been preferentially colonized during species' range expansions, but this could be due to their original habitat quality and/or to ongoing management activity. Here, we examine how PA status and active conservation management have influenced the range expansion of a butterfly Hesperia comma through fragmented landscapes. PAs under active conservation management were over three times more likely to be colonized than unprotected, unmanaged sites of the same basic vegetation type. Conservation action also increased the survival rate of existing populations inside and outside of PAs. We conclude that PAs facilitate range expansions by preventing habitat degradation and encouraging active conservation that improves habitat quality, and that conservation interventions on nondesignated sites also have a role to play in adapting conservation to climate change.NERCUniversity of Exete

    Population turnover, habitat use and microclimate at the contracting range margin of a butterfly

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    This is the author accepted manuscript. The final version is available from Springer Verlag via the DOI in this recordThere is another ORE record for this publication: http://hdl.handle.net/10871/16890Climate change is expected to drive patterns of extinction and colonisation that are correlated with geographic gradients in the climate, such as latitude and elevation. However, local population dynamics also depend on the fine-scale effects of vegetation and topography on resource availability and microclimate. Understanding how this fine-scale variation influences population survival in the face of changing climatic favourability could provide clues for adapting conservation to climate change. Here, we document a long-term decline of the butterfly Parnassius apollo in the Sierra de Guadarrama mountain range in central Spain, and examine recent population turnover and habitat use by the species to make inferences about its ecology and conservation. A decline since the 1960s throughout the elevation range suggests a regional deterioration in favourability for the species. Since 2006, local habitat quality has been the main correlate of population persistence, with populations that persisted from 2006 to 2012 associated with high availability of larval host plants. At a finer resolution, the larval distribution in a network of suitable habitat in 2011 and 2012 was most closely related to bare ground cover. Thus, although slope, aspect and elevation lead to considerable variation in microhabitat temperatures during the period of P. apollo larval development, vegetation structure appears to have been the most critical factor for local habitat use and population persistence. The results show that site sele ction and management retain key roles in conservation despite the broad-scale effects of environmental change.Research was funded by Universidad Rey Juan Carlos/Comunidad de Madrid (URJC-CM-2006-CET-0592), the Spanish Ministry of Education and Science with an F.P.U. Scholarship and Research Projects (REN2002-12853-E/GLO, CGL2005-06820/BOS, CGL2008-04950/BOS and CGL2011-30259), and the Royal Society of London (International Joint Project “Climate change and metapopulation dynamics at a contracting range margin”)

    Detection of spatiotemporal variation in ranavirus distribution using eDNA

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    Amphibian population declines have been associated with emerging diseases including ranaviruses, which can cause mass die‐offs across entire amphibian communities. Understanding and mitigating disease spread requires knowledge of spatial and temporal patterns of pathogen distribution, but also how environmental factors influence pathogen occurrence. We applied environmental DNA (eDNA) detection tools to survey spatial and temporal distributions of ranaviruses by sampling 103 waterbodies in southeastern Ontario, Canada and assessed the role of abiotic factors as predictors of pathogen occurrence. Ten waterbodies sampled during June–August (>30 km between sites) revealed that ranavirus was marginally more prevalent (p = .055) during the latter part of the summer. Ninety‐three sites sampled at a finer scale (<10 km between sites) exhibited seasonal variability in ranavirus detection (site prevalence: 56% May; 66% July). Occupancy modeling revealed that wetland size and elevation influenced ranavirus occurrence while sampling date and water temperature influenced probability of detection. These findings indicate that biotic factors, such as host density and alternative hosts, should be investigated further as likely determinants of ranavirus prevalence across the landscape. Further, these results highlight the sensitivity of eDNA for detecting widespread presence of ranavirus and that abiotic factors may have a limited role in determining its prevalence and infectivity

    The discovery of a novel antibiotic for the treatment of Clostridium difficile infections: a story of an effective academic-industrial partnership

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    Academic drug discovery is playing an increasingly important role in the identification of new therapies for a wide range of diseases. There is no one model that guarantees success. We describe here a drug discovery story where chance, the ability to capitalise on chance, and the assembling of a range of expertise, have all played important roles in the discovery and subsequent development of an antibiotic chemotype based on the bis-benzimidazole scaffold, with potency against a number of current therapeutically challenging diseases. One compound in this class, SMT19969, has recently entered Phase 2 human clinical trials for the treatment of Clostridium difficile infections
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