1,478 research outputs found

    Ecosystem (dis)benefits arising from formal and informal land-use in Manchester (UK); a case study of urban soil characteristics associated with local green space management

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    Urban soils are subject to anthropogenic influences and, reciprocally, provide benefits and dis-benefits to human wellbeing; for example carbon storage, nutrient cycling and the regulation trace element and contaminant mobility. Collective stewardship of urban green commons provides contemporary examples of the diversity of uses and management of green space in cities and represents a growing movement in user participation in, and awareness of, the importance of urban ecological health. Exploring the range of social-ecological benefits exemplified in the urban environment has generally focused on above-ground processes, with few studies examining the potential for (dis)benefits arising from edaphic characteristics of collectively-managed spaces. An investigation into the influence of formal and informal green space management on carbon fluxes and heavy metal concentrations in urban soils was carried out in Manchester (UK) finding that carbon storage in soils of collectively managed urban green commons (7.15 ±1.42 kg C m⁻²) was significantly greater than at formally managed sites (for example city parks: 5.08 ±0.69 kg C m⁻²), though the latter exhibited reduced losses through CO2 emission. Variation in heavy metal concentrations and mobility were likewise observed, exemplified by the acidification of surface soils by leaf litter at orchard sites, and the resultant increase in the mobility of lead (Pb) and zinc (Zn). The results of this study indicate the importance of small-scale contemporary urban green space management on selected ecosystem services provided by the limited soil resource of cities. Thus, a greater consideration of the effects of horticultural and amenity activities with regards to soil quality/functionality is required to ensure available urban green commons retain or increase their ecological quality over time

    Carbon in urban, brownfield and heavy metal contaminated soils

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    This thesis is comprised of a collection of work on urban, brownfield and heavy metal contaminated soils carried out within the North West of England from March 2007 to December 2009. Field and laboratory based experiments were used to determine the amount of carbon stored in urban soils and fluxes of dissolved organic carbon and soil respiration. The effects of added organic amendments on carbon storage and mobility as well as the onward implications to heavy metals and arsenic mobility and the impact of earthworms on these processes were also investigated. A city-wide topsoil survey of parkland and road verges in Liverpool showed that carbon storage ranged from 10 kg total organic carbon m-2 whilst physico-chemical characteristics and heavy metal and arsenic concentrations also varied considerably. The abundance oftechnogenic material restricted organic carbon storage and flux to the upper 30 cm of an inner city lawn soil studied in greater detail. Brownfield soil carbon storage and fluxes were enhanced by adding a small amount of green waste compost to these soils but large applications did not greatly increase carbon storage further. Enhanced losses of carbon by dissolved organic carbon leaching and increased soil respiration rates were consequences of greenwaste compost additions, although these effects were highly seasonal, occurring in greatest magnitude at the warmest periods of the year. Proportionately, the annual losses of carbon to soil respiration were far greater than those to dissolved organic carbon. An amendment consisting predominantly of woody material and a biochar amendment had a lower impact than composted greenwaste on dissolved organic carbon mobility, and the co-mobilisation of heavy metals and arsenic in a soil from a previously heavily industrialised centre of population. Earthworms reduced dissolved organic carbon when inoculated with compost and biochar amended soil, but increased this soluble fraction of carbon in woody amended soils, with attendant consequence to trace metal and arsenic mobility. Zinc and cadmium mobility were largely independent of changes in soluble carbon, but arsenic, copper and lead were heavily influenced by added carbon. Biochar amendment proved very effective in reducing concentrations of soluble cadmium and zinc in a heavy metal contaminated soil by adsorption, as well as having the added benefit of reducing total and bioavailable polycyclic aromatic hydrocarbon (PAH) concentrations. It is concluded that carbon storage in urban soils can potentially be increased by applying organic amendments, although longer-term carbon storage may only be substantially enhanced with repeated applications of amendments. However, in urban soils with significant residual pollution, it can be questioned whether this practice is environmentally sound, regarding mobilisation of potentially harmful trace elements. Biochar and larger woody fraction amendments to soils may be more efficacious

    HFST—Framework for Compiling and Applying Morphologies

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    HFST–Helsinki Finite-State Technology ( hfst.sf.net ) is a framework for compiling and applying linguistic descriptions with finite-state methods. HFST currently connects some of the most important finite-state tools for creating morphologies and spellers into one open-source platform and supports extending and improving the descriptions with weights to accommodate the modeling of statistical information. HFST offers a path from language descriptions to efficient language applications in key environments and operating systems. HFST also provides an opportunity to exchange transducers between different software providers in order to get the best out of each finite-state library.Peer reviewe

    Clonal amplification of Fasciola hepatica in Galba truncatula: within and between isolate variation of triclabendazole-susceptible and -resistant clones

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    Background: Fasciola hepatica is of worldwide significance, impacting on the health, welfare and productivity of livestock and regarded by WHO as a re-emerging zoonosis. Triclabendazole (TCBZ), the drug of choice for controlling acute fasciolosis in livestock, is also the drug used to treat human infections. However TCBZ-resistance is now considered a major threat to the effective control of F. hepatica. It has yet to be demonstrated whether F. hepatica undergoes a genetic clonal expansion in the snail intermediate host, Galba truncatula, and to what extent amplification of genotypes within the snail facilitates accumulation of drug resistant parasites. Little is known about genotypic and phenotypic variation within and between F. hepatica isolates. Results: Six clonal isolates of F. hepatica (3× triclabendazole-resistant, TCBZ-R and 3× triclabendazole-susceptible, TCBZ-S) were generated. Snails infected with one miracidium started to shed cercariae 42–56 days post-infection and shed repeatedly up to a maximum of 11 times. A maximum of 884 cercariae were shed by one clonally-infected snail (FhLivS1) at a single time point, with > 3000 clonal metacercariae shed over its lifetime. Following experimental infection all 12 sheep were FEC positive at the time of TCBZ treatment. Sheep infected with one of three putative TCBZ-S clones and treated with TCBZ had no parasites in the liver at post-mortem, whilst sheep each infected with putative TCBZ-R isolates had 35–165 adult fluke at post-mortem, despite TCBZ treatment. All six untreated control animals had between 15–127 parasites. A single multi-locus genotype was reported for every fluke from each of the six clonal isolates. Adult F. hepatica showed considerable variation in weight, ranging from 20–280 mg, with variation in weight evident within and amongst clonal isolates. Conclusions: A genetic clonal expansion occurs within G. truncatula, highlighting the potential for amplification of drug resistant genotypes of F. hepatica. Variation in the weight of parasites within and between clonal isolates and when comparing isolates that are either susceptible or resistant to TCBZ represent inherent variation in liver fluke and cannot be attributed to their resistance or susceptibility traits

    Effects of biochar amendment on root traits and contaminant availability of maize plants in a copper and arsenic impacted soil

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    Biochar has been proposed as a tool to enhance phytostabilisation of contaminated soils but little data are available to illustrate the direct effect on roots in contaminated soils. This work aimed to investigate specific root traits and to assess the effect of biochar amendment on contaminant availability. Amendment with two different types of biochar, pine woodchip and olive tree pruning, was assessed in a rhizobox experiment with maize planted in a soil contaminated with significant levels of copper and arsenic. Amendment was found to significantly improve root traits compared to the control soil, particularly root mass density and root length density. Copper uptake to plants and ammonium sulphate extractable copper was significantly less in the biochar amended soils. Arsenic uptake and extractability varied with type of biochar used but was not considered to be the limiting factor affecting root and shoot development. Root establishment in contaminated soils can be enhanced by biochar amendment but choice of biochar is key to maximising soil improvement and controlling contaminant availability

    Exploring atmospheric optical turbulence: observations across zenith angles

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    We present measurements of the atmospheric optical turbulence as a function of zenith angle using two identical instruments, Shack-Hartmann Image Motion Monitors (SHIMMs), to measure atmospheric parameters concurrently. One instrument was pointed near zenith, while the other collected data by tracking a single star until it set and thus sampling zenith angles continuously to the horizon. By comparing these measurements, we can attribute changes in the atmospheric parameters to the changing zenith angle rather than variations in local turbulence conditions. The primary purpose of this experiment is to make comparisons between the measurements of the scintillation index, 2, and Fried parameter, 0, with current theories. In this demonstration, we find that there is a strong agreement between the models and the instrument up until zenith angles of 70∘, above which model and measurements begin to deviate. We discuss various ways in which limitations in models and our instrument may cause these deviations

    Future food contaminants: An assessment of the plant uptake of Technology-critical elements versus traditional metal contaminants

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    Technology-critical elements (TCEs) include most rare earth elements (REEs), the platinum group elements (PGEs), and Ga, Ge, In, Nb, Ta, Te, and Tl. Despite increasing recognition of their prolific release into the environment, their soil to plant transfer remains largely unknown. This paper provides an approximation of the potential for plant uptake by calculating bioconcentration factors (BCFs), defined as the concentration in edible vegetable tissues relative to that in cultivation soil. Here data were obtained from an indoor cultivation experiment growing lettuce, chard, and carrot on 22 different European urban soils. Values of BCFs were determined from concentrations of TCEs in vegetable samples after digestion with concentrated HNO3, and from concentrations in soil determined after 1) Aqua Regia digestion and, 2) diluted (0.1 M) HNO3 leaching. For comparison, BCFs were also determined for 5 traditional metal contaminants (TMCs; As, Cd, Cu, Pb, and Zn). The main conclusions of the study were that: 1) BCF values for the REEs were consistently low in the studied vegetables; 2) the BCFs for Ga and Nb were low as well; 3) the BCFs for Tl were high relative to the other measured TCEs and the traditional metal contaminants; and 4) mean BCF values for the investigated TCEs were generally highest in chard and lowest in carrot. These findings provide initial evidence that there are likely to be real and present soil–plant transfer of TCEs, especially in the case of Tl. Improvements in analytical methods and detection limits will allow this to be further investigated in a wider variety of edible plants so that a risk profile may be developed
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