1,009 research outputs found

    Seasonal patterns of metals and nutrients in Phragmites australis (Cav.) Trin. ex Steudel in a constructed wetland in the west of Ireland

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    Ā© 2017 Elsevier B.V. An understanding of the seasonal variation in the standing stock of metals and nutrients in emergent vegetation of constructed wetlands (CWs), as well as the amounts present in aboveground (AG) and belowground (BG) biomass, is crucial to their design and management. Given that biomass harvesting is a labour and time consuming operation, a paucity of information currently exists on accumulation and standing stocks in biomass in CWs, in particular in North Western European countries. To address this knowledge gap, this paper examined the seasonal variations of metals and nutrients in Phragmites australis (Cav.) Trin. ex Steudel in a CW treating municipal wastewater, with a view to identifying an optimal time for biomass harvesting of the AG vegetation. Although the AG biomass was greatest in August (1636Ā Ā±Ā 507Ā gĀ m āˆ’2 ), the maximum concentrations and accumulations of metals and nutrients occurred at different times throughout the duration of the study (April to November). Furthermore, with the exception of zinc and nitrogen, metals and nutrients measured in BG biomass ranged from 66% (phosphorus) to greater than 80% (nickel and chromium) of the AG biomass. This indicates that analysis of only the emergent shoots may significantly underestimate the metal and nutrient uptake and capacity of the plant. In order to effectively target the bulk of metals and nutrients, an AG harvest in late August or September is suggested

    On an apparent dearth of recurrent nova super-remnants in the Local Group

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    The Andromeda Galaxy is home to the annually erupting recurrent nova (RN) M31N 2008-12a (12a); the first nova found to host a nova super-remnant (NSR). A NSR is an immense structure surrounding a RN, created from many millions of eruptions sweeping up material in the local environment to form a shell tens of parsecs across. Theory has demonstrated that NSRs should be found around all RNe, even those systems with long periods between eruptions. Befittingly, the second NSR was found around the Galactic classical (and long suspected recurrent) nova, KT Eridani. In this Paper, we aim to find more of these phenomena through conducting the first ever survey for NSRs in M31 and the Large Magellanic Cloud (LMC). We find that the surroundings of fourteen RNe in M31 as well as the surroundings of the four RNe in the LMC do not show any evidence of vast parsec-scale structures in narrowband (HĪ± and [S II]) images, unlike the one clearly seen around 12a, and therefore conclude that observable NSRs are either rare structures, or they are too faint (or small) to be detected in our existing datasets. Yet, the NSR surrounding 12a would also likely to have been overlooked in our study if it were approximately one magnitude fainter. Searches for NSRs around other RNe 'masquerading' as classical novae may prove to be fruitful as would whole surveys of other Local Group galaxies

    Discovery of a nova super-remnant cavity surrounding RS Ophiuchi

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    The prototypical nova super-remnant (NSR) was uncovered around the most rapidly recurring nova (RN), M31N 2008-12a. Simulations of the growth of NSRs revealed that these large structures should exist around all novae, whether classical or recurrent. NSRs consist of large shell-like structures surrounding excavated cavities. Predictions, informed by these simulations, led to the discovery of an extended cavity coincident with the Galactic RN, RS Ophiuchi, in far-infrared archival IRAS images. We propose that this cavity is associated with RS Oph and is therefore evidence of another NSR to be uncovered

    Sciomyzidae (Diptera) Assemblages in Constructed and Natural Wetlands: Implications for Constructed Wetland Design

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    Wetlands constructed primarily for the treatment of wastewaters have been shown to have a role in enhancing biodiversity. However, while most biodiversity studies of constructed wetlands focus on the larger, more iconic animal groups, there is a paucity of information on the aerial phases of wetland invertebrate species associated with constructed wetlands. This study compares Sciomyzidae (Diptera) assemblages, established indicators of wetland dipteran communities, in Irish constructed and natural wetlands, in addition to determining the impacts of water quality and surrounding habitats on Sciomyzidae community structure. Natural wetlands had significantly greater species richness, abundances and diversity (measured as Shannonā€™s entropy) of sciomyzid flies than constructed wetlands. Nevertheless, although concentrations of nitrogen and phosphorus in waters were significantly greater in constructed wetlands, seven of the eight constructed wetlands examined hosted species of Sciomyzidae listed as scarce or threatened in Britain. In addition, sciomyzid species richness increased as areas of semi-natural habitat immediately surrounding constructed and natural wetlands increased. Composition of Sciomyzidae assembalges in both natural and constructed wetlands were analysed. The results of this study demonstrate that constructed wetlands can be important contributors to biodiversity particularly in the context of current losses of natural wetlands worldwide. The importance of habitats immediately surrounding constructed wetlands also highlights the need for relatively simple design recommendations (e.g. wet grassland creation or judicious planting of wetland trees) that could enhance the biodiversity of existing and future constructed wetlands

    Objective measurement of sedentary behaviour using accelerometers

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    Background: Sedentary behaviour (SB) is an important risk factor for a number of chronic diseases. Although gaps remain in our knowledge of the elements of SB most associated with reduced health outcomes, measuring SB is important, especially in less active patient populations where treatment-related changes may be seen first in changes in SB.Methods: We review current published work in the measurement of SB to make recommendations for SB measurement in clinical studies.Results: To help move our understanding of the area forward, we propose a set of derived measures of SB that can be easily understood and interpreted.Conclusion: Although there is more work required to determine and validate the most clinically relevant and sensitive measures of SB, there is enough understanding of how to measure SB to enable its inclusion in study protocols

    Climate Change Effects on Slope Stability

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    Global warming is taking place and there is no doubt that the stability of natural and artificial slopes is influenced by climate change. In this context, the present study intends to show, as more quantitatively as possible, the effects of climate change on slopes stability. The analysis was developed considering a non-static approach suitable for meteorological phenomena which are expected to change in the next years. In the analysis a statistical method was combined with a mechanical one: the forecasts of the intensity growth of heavy precipitation were used, as well as the physical laws for describing the response of groundwater table to these rainfall events and the resulting slopes stability. A case study located in Monchiero (Cn), Italy, was used as a test for the analysis and the forecasts described above

    Habitat suitability assessment of constructed wetlands for the smooth newt (Lissotriton vulgaris [Linnaeus, 1758]): A comparison with natural wetlands

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    Given the current decline of natural wetlands worldwide and the consequent negative impacts on amphibians, wetlands constructed for the treatment of wastewaters have the potential to play a role in the protection of these animals. However, there is a paucity of information regarding the value of constructed wetlands (CWs) to amphibians, particularly relating to the terrestrial phase of their life-cycle. This study compares the terrestrial habitats of natural wetlands (NWs) and CWs as refuges for the smooth newt (Lissotriton vulgaris, [L., 1758]) with the aim of developing recommendations for CWs (both new and existing) to enhance their usefulness as newt-friendly habitats. Terrestrial habitats surrounding NWs and CWs were mapped using ArcGIS. Potential barriers to newt movement in addition to the presence of features such as wood or stone which could act as potential newt refuges were also mapped. Natural wetlands had significantly more terrestrial habitat types than CWs and while woodlands at both wetland types were most likely to contain features of benefit to newts, terrestrial habitats of NWs contained more features compared to those of CWs. The application of a Habitat Suitability Index, which assesses the likelihood of the presence of newts, resulted in seven of eight NWs compared to only two of eight CWs receiving ā€œgoodā€ scores, the lower scores for CWs being due primarily to the presence of a barrier to newt movement. Recommendations for enhancing the design and management of CWs for smooth newts include less intensive ground maintenance, reduction of barriers to newt movement, judicious planting of suitable trees or shrubs and the provision of additional refuges such as wood or stone

    Hydrodynamic simulations of the KT Eridani nova super-remnant

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    A nova super-remnant (NSR) is an immense structure associated with a nova that forms when frequent and recurrent nova eruptions sweep up surrounding interstellar material (ISM) into a high density and distant shell. The prototypical NSR, measuring over 100 pc across, was discovered in 2014 around the annually erupting nova M31N 2008-12a. Hydrodynamical simulations demonstrated that the creation of a dynamic NSR by repeated eruptions transporting large quantities of ISM is not only feasible but that these structures should exist around all novae, whether the white dwarf (WD) is increasing or decreasing in mass. But it is only the recurrent nova (RNe) with the highest WD masses and accretion rates that should host observable NSRs. KT Eridani is, potentially, the eleventh RNe recorded in the Galaxy and is also surrounded by a recently unveiled H{\alpha} shell tens of parsecs across, consistent with a NSR. Through modelling the nova ejecta from KT Eri, we demonstrate that such an observable NSR could form in approximately 50,000 years, which fits with the proper motion history of the nova. We compute the expected H{\alpha} emission from the KT Eri NSR and predict that the structure might be accessible to wide-field X-ray facilities

    Pathogenic Parkinson's disease mutations across the functional domains of LRRK2 alter the autophagic/lysosomal response to starvation

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    LRRK2 is one of the most important genetic contributors to Parkinson's disease (PD). Point mutations in this gene cause an autosomal dominant form of PD, but to date no cellular phenotype has been consistently linked with mutations in each of the functional domains (ROC, COR and Kinase) of the protein product of this gene. In this study, primary fibroblasts from individuals carrying pathogenic mutations in the three central domains of LRRK2 were assessed for alterations in the autophagy/lysosomal pathway using a combination of biochemical and cellular approaches. Mutations in all three domains resulted in alterations in markers for autophagy/lysosomal function compared to wild type cells. These data highlight the autophagy and lysosomal pathways as read outs for pathogenic LRRK2 function and as a marker for disease, and provide insight into the mechanisms linking LRRK2 function and mutations
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