433 research outputs found

    A Controlled Study on the Characterisation of Bioaerosols Emissions from Compost

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    Bioaerosol emissions arising from biowaste treatment are an issue of public concern. To better characterise the bioaerosols, and to assess a range of measurement methods, we aerosolised green waste compost under controlled conditions. Viable and non-viable Andersen samplers, cyclone samplers and a real time bioaerosol detection system (Spectral Intensity Bioaerosol Sensor (SIBS)) were deployed simultaneously. The number-weighted fraction of fluorescent particles was in the range 22–26% of all particles for low and high emission scenarios. Overall fluorescence spectral profiles seen by the SIBS exhibited several peaks across the 16 wavelength bands from 298 to 735 nm. The size-fractionated endotoxin profile showed most endotoxin resided in the 2.1–9 μm aerodynamic diameter fraction, though up to 27% was found in a finer size fraction. A range of microorganisms were detected through culture, Matrix Assisted Laser Desorption and Ionisation Time of Flight Mass Spectrometry (MALDI-TOF) and quantitative polymerase chain reaction (qPCR), including Legionella pneumophila serogroup 1. These findings contribute to our knowledge of the physico-chemical and biological characteristics of bioaerosols from composting sites, as well as informing future monitoring approaches and data interpretation for bioaerosol measurement

    Stigma of living as an autism carer: a brief psycho-social support intervention (SOLACE). Study protocol for a randomised controlled feasibility study.

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    Stigma is prominent in the lives of autistic individuals and their families and contributes significantly to the challenges faced by families raising an autistic child. Parents and carers can feel blamed for their child's behaviour, feel socially excluded and isolated and suffer from low self-esteem and poor psychological well-being. This increases the risk of experiencing self-stigma which further exacerbates these and other negative consequences. Therefore, there is a need for interventions that help parents/family carers cope with autism-related stigma as well as prevent the internalisation of stigma. The primary objective of this study is to assess the feasibility and acceptability of a stigma support intervention for parents and carers of autistic children titled 'Stigma of Living as an Autism Carer (SOLACE)'. The secondary objective is to explore the preliminary impact of the intervention on the mental health of the parents and carers. tests for differences within the group. Other outcomes of interest are stigma, self-stigma, self-esteem, self-blame, social isolation, self-compassion and perceived responsibility and control. Results from the feasibility randomised controlled trial will be used to refine the study protocol and inform the design of an intervention for future use in a larger, powered trial. SOLACE could potentially improve the psychological well-being of parents/family carers of autistic children through increased resistance to stigma. ISRCTN Registry number ISRCTN61093625 (October 13, 2017)

    Scoping studies to establish the capability and utility of a real-time bioaerosol sensor to characterise emissions from environmental sources

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    A novel dual excitation wavelength based bioaerosol sensor with multiple fluorescence bands called Spectral Intensity Bioaerosol Sensor (SIBS) has been assessed across five contrasting outdoor environments. The mean concentrations of total and fluorescent particles across the sites were highly variable being the highest at the agricultural farm (2.6 cm−3 and 0.48 cm−3, respectively) and the composting site (2.32 cm−3 and 0.46 cm−3, respectively) and the lowest at the dairy farm (1.03 cm−3 and 0.24 cm−3, respectively) and the sewage treatment works (1.03 cm−3 and 0.25 cm−3, respectively). In contrast, the number-weighted fluorescent fraction was lowest at the agricultural site (0.18) in comparison to the other sites indicating high variability in nature and magnitude of emissions from environmental sources. The fluorescence emissions data demonstrated that the spectra at different sites were multimodal with intensity differences largely at wavelengths located in secondary emission peaks for λex 280 and λex 370. This finding suggests differences in the molecular composition of emissions at these sites which can help to identify distinct fluorescence signature of different environmental sources. Overall this study demonstrated that SIBS provides additional spectral information compared to existing instruments and capability to resolve spectrally integrated signals from relevant biological fluorophores could improve selectivity and thus enhance discrimination and classification strategies for real-time characterisation of bioaerosols from environmental sources. However, detailed lab-based measurements in conjunction with real-world studies and improved numerical methods are required to optimise and validate these highly resolved spectral signatures with respect to the diverse atmospherically relevant biological fluorophores

    Topographically Influenced Evolution of Large-scale Changes in Comet 67P/Churyumov-Gerasimenko's Imhotep Region

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    Large portions of comet 67P/Churyumov–Gerasimenko’s northern hemisphere are blanketed by fallback material consisting of centimeter-sized particles termed the smooth terrains. Observations from the Rosetta mission show that the most drastic transient changes during 67P’s 2015 perihelion passage occurred within a subset of these deposits. However, we still do not understand the processes driving these changes, limiting our overall understanding of how comets evolve over both seasonal and multiorbit timescales. Herein we provide a complete documentation of scarp-driven activity on 67P’s largest smooth terrain deposit, a highly active portion of the Imhotep region that is the southernmost of all smooth terrain basins on 67P. We also present a thermal model that accurately predicts when and where scarps originate during the course of the observed activity. Assuming a uniform surface composition, our model shows that activity is heavily controlled by local topography rather than the presence of ice-enhanced hot spots on the surface. Scarps within the smooth terrain deposits in central Imhotep also exhibit a peculiar behavior, where three scarps originate from the same location but at different times and migrate in opposite directions. This behavior indicates that the landscape retains a memory of previous cycles of erosion and deposition, reflected by the depth of the volatile-rich layer. Future work will need to couple our thermal model with a landscape evolution model in order to explain the complete dynamic evolution of these terrains

    Quick fabrication VCSELs for characterisation of epitaxial material

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    A systematic analysis of the performance of VCSELs, fabricated with a decreasing number of structural elements, is used to assess the complexity of fabrication (and therefore time) required to obtain sufficient information on epitaxial wafer suitability. Initially, sub-mA threshold current VCSEL devices are produced on AlGaAs-based material, designed for 940 nm emission, using processing methods widely employed in industry. From there, stripped-back Quick Fabrication (QF) devices, based on a bridge-mesa design, are fabricated and this negates the need for benzocyclcobutane (BCB) planarisation. Devices are produced with three variations on the QF design, to characterise the impact on laser performance from removing time-consuming process steps, including wet thermal oxidation and mechanical lapping used to reduce substrate thickness. An increase in threshold current of 1.5 mA for oxidised QF devices, relative to the standard VCSELs, and a further increase of 1.9 mA for unoxidised QF devices are observed, which is a result of leakage current. The tuning of the emission wavelength with current increases by ~0.1 nm/mA for a VCSEL with a 16 μm diameter mesa when the substrate is unlapped, which is ascribed to the increased thermal resistance. Generally, relative to the standard VCSELs, the QF methods employed do not significantly impact the threshold lasing wavelength and the differences in mean wavelengths of the device types that are observed are attributed to variation in cavity resonance with spatial position across the wafer, as determined by photovoltage spectroscopy measurements

    Brief of Tax Law Professors as \u3ci\u3eAmici Curiae\u3c/i\u3e in Support of Petitioner in \u3ci\u3eLoudoun County, Virginia v. Dulles Duty Free, LLC\u3c/i\u3e

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    Amici are professors of tax law at universities across the United States. As scholars and teachers, they have considered the doctrinal roots and practical consequences of judicial limits on state and local taxation. Amici join this brief solely on their own behalf and not as representatives of their universities. A full list of amici appears in the Appendix to this brief

    Towards a standardized protocol to assess natural capital and ecosystem services in solar parks

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    1. Natural capital and ecosystem services have emerged as fundamental concepts of ecosystem management strategies in the past two decades, particularly within major international land assessment frameworks, including the UN's Millennium Ecosystem Assessment and the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services' Global Assessment Report. 2. Despite the recent development of several analytical methods and models to quantify changes in natural capital and ecosystem services resulting from land use change, incorporating them into the land planning process can be challenging from a practical point of view without guidance on standard methods. 3. In an attempt to decarbonize energy supply systems to meet internationally agreed targets on climate change, solar energy production, in the form of ground-mounted solar parks, is emerging as one of the dominant forms of temporary land use for renewable energies globally. 4. We propose 19 directly measurable indicators associated with 16 ecosystem services within three major stocks of natural capital (biodiversity, soil and water) that are most likely to be impacted by the development of solar parks. Indicators are supported by well-established methods that have been widely used in pure and applied land use research within terrestrial ecosystems. Moreover, they can be implemented flexibly according to interest or land management objectives. 5. Whilst not intended as a precise recipe for how to assess the effects of solar park development on hosting ecosystems, the protocol will guide the solar energy industry and all actors involved, be they researchers, practitioners, ecological consultancies or statutory bodies, to implement a standardized approach to evaluate temporal and spatial changes in natural capital and ecosystem services resulting from solar park development and operation, with the ultimate aim of generating comparable and reproducible data on ecosystem impact assessment across the solar energy sector
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