377 research outputs found

    Mapping topography and broad vegetation type to characterise the Boxford meadows SSSI (Unit 2)

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    Understanding the dynamic relationship between hydrology and ecology in a complex wetland setting should be considered integral to the sustainable management and conservation of wetland habitats and future water resource planning. Wetland hydrology can exhibit considerable spatial complexity as a result of sub surface and surface heterogeneity. The latter of which may be determined by the relationship between spatial topography variation and broad vegetation distribution. Any study to investigate such a relationship must be at a spatial resolution sufficient to identify patterns in surface topography and vegetation type. In this study state of the art survey technology was used to collect and record for subsequent mapping the topographic and vegetation characteristics of the Boxford lowland chalk groundwater dependent terrestrial ecosystem (GDTE). The resultant survey dataset successfully unveiled distinct patterns in topography and vegetation type. The analysis of the data in a Geographical Information System (GIS) desk confirmed for the first time the presence of paleo-channels and a braided fluvial system within the meadows. In addition the combined survey method gives some indication that the type of vegetation present appears to coincide with some of the more distinctive topographical features. The results demonstrate that combining the field survey campaign alongside desk based GIS analysis is an extremely useful and versatile tool and can provide valuable information to support the decision making process for both further scientific investigation and sustainable habitat management

    Soil mite communities (Acari: Mesostigmata) as indicators of urban ecosystems in Bucharest, Romania

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    The aim of the present study was to establish the effect of management type and of environmental variables on the structure, abundance and species richness of soil mites (Acari: Mesostigmata) in twelve urban green areas in Bucharest-Romania. Three categories of ecosystem based upon management type were investigated: protected area, managed (metropolitan, municipal and district parks) and unmanaged urban areas. The environmental variables which were analysed were: soil and air temperature, soil moisture and atmospheric humidity, soil pH and soil penetration resistance. In June 2017, 480 soil samples were taken, using MacFadyen soil core. The same number of measures was made for quantification of environmental variables. Considering these, we observed that soil temperature, air temperature, air humidity and soil penetration resistance differed significantly between all three types of managed urban green area. All investigated environmental variables, especially soil pH, were significantly related to community assemblage. Analysing the entire Mesostigmata community, 68 species were identified, with 790 individuals and 49 immatures. In order to highlight the response of the soil mite communities to the urban conditions, Shannon, dominance, equitability and soil maturity indices were quantified. With one exception (numerical abundance), these indices recorded higher values in unmanaged green areas compared to managed ecosystems. The same trend was observed between different types of managed green areas, with metropolitan parks having a richer acarological fauna than the municipal or district parks

    Instream and riparian implications of weed cutting in a chalk river

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    Macrophyte growth is extensive in the iconic chalk streams that are concentrated in southern and eastern England. Widespread and frequent weed cutting is undertaken to maintain their key functions (e.g. flood water conveyance and maintenance of viable fisheries). In this study, a multidisciplinary approach was adopted to quantify coincident physico-chemical responses (instream and riparian) that result from weed cutting and to discuss their potential implications. Three weed cuts were monitored at a site on the River Lambourn (The CEH River Lambourn Observatory) and major instream and riparian impacts were observed. Measurements clearly demonstrated how weed cutting enhanced flood flow conveyance, reduced water levels (river and wetland), increased river velocities, and mobilised suspended sediment (with associated chemicals) and reduced the capacity for its retention within the river channel. Potential implications in relation to flood risk, water resources, downstream water quality, instream and riparian ecology, amenity value of the river, and wetland greenhouse gas emissions were considered. Provided the major influence of macrophytes on instream and riparian environments is fully understood then the manipulation of macrophytes represents an effective management tool that demonstrates the great potential of working with nature

    Transcriptional dynamics of pluripotent stem cell-derived endothelial cell differentiation revealed by single-cell RNA sequencing

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    Aims Pluripotent stem cell-derived endothelial cell products possess therapeutic potential in ischaemic vascular disease. However, the factors that drive endothelial differentiation from pluripotency and cellular specification are largely unknown. The aims of this study were to use single-cell RNA sequencing (scRNA-seq) to map the transcriptional landscape and cellular dynamics of directed differentiation of human embryonic stem cell-derived endothelial cells (hESC-EC) and to compare these cells to mature endothelial cells from diverse vascular beds. Methods and results A highly efficient directed 8-day differentiation protocol was used to generate a hESC-derived endothelial cell product (hESC-ECP), in which 66% of cells co-expressed CD31 and CD144. We observed largely homogeneous hESC and mesodermal populations at Days 0 and 4, respectively, followed by a rapid emergence of distinct endothelial and mesenchymal populations. Pseudotime trajectory identified transcriptional signatures of endothelial commitment and maturation during the differentiation process. Concordance in transcriptional signatures was verified by scRNA-seq analysis using both a second hESC line RC11, and an alternative hESC-EC differentiation protocol. In total, 105 727 cells were subjected to scRNA-seq analysis. Global transcriptional comparison revealed a transcriptional architecture of hESC-EC that differs from freshly isolated and cultured human endothelial cells and from organ-specific endothelial cells. Conclusion A transcriptional bifurcation into endothelial and mesenchymal lineages was identified, as well as novel transcriptional signatures underpinning commitment and maturation. The transcriptional architecture of hESC-ECP was distinct from mature and foetal human EC.This work was supported by the Medical Research Council [MRC Precision Medicine Doctoral Training Programme to I.R.M. and both the MRC Discovery Award and Programme grant (MC_PC_15075) and MRC Programme: Computational and Disease Genomics (MC_UU_00007/15) to C.P.P.], the Wellcome Trust [Wellcome Trust Senior Research Fellowship in Clinical Science (ref. 103749) to N.C.H.], the European Research Council [Advanced Grant VASCMIR (RE7644) to A.H.B.], and the British Heart Foundation [BHF CVR grant (RM/17/3/ 33381) and BHF Chair of Translational Cardiovascular Sciences to A.H.B.]

    Resonances in 19Ne with relevance to the astrophysically important 18F(p,{\alpha})15O reaction

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    The most intense gamma-ray line observable from novae is likely to be from positron annihilation associated with the decay of 18F. The uncertainty in the destruction rate of this nucleus through the 18F(p,{\alpha})15O reaction presents a limit to interpretation of any future observed gamma-ray flux. Direct measurements of the cross section of both this reaction and the 18F(p,p)18F reaction have been performed between center of mass energies of 0.5 and 1.9 MeV. Simultaneous fits to both data sets with the R-Matrix formalism reveal several resonances, with the inferred parameters of populated states in 19Ne in general agreement with previous measurements. Of particular interest, extra strength has been observed above ECM \sim1.3 MeV in the 18F(p,p)18F reaction and between 1.3-1.7 MeV in the 18F(p,{\alpha})15O reaction. This is well described by a broad 1/2+ state, consistent with both a recent theoretical prediction and an inelastic scattering measurement. The astrophysical implications of a broad sub-threshold partner to this state are discussed.Comment: 7 pages, 4 figures, 2 table

    Generation of a High Number of Healthy Erythroid Cells from Gene-Edited Pyruvate Kinase Deficiency Patient-Specific Induced Pluripotent Stem Cells

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    Pyruvate kinase deficiency (PKD) is a rare erythroid metabolic disease caused by mutations in the PKLR gene. Erythrocytes from PKD patients show an energetic imbalance causing chronic non-spherocytic hemolytic anemia, as pyruvate kinase defects impair ATP production in erythrocytes. We generated PKD induced pluripotent stem cells (PKDiPSCs) from peripheral blood mononuclear cells (PB-MNCs) of PKD patients by non-integrative Sendai viral vectors. PKDiPSCs were gene edited to integrate a partial codon-optimized R-type pyruvate kinase cDNA in the second intron of the PKLR gene by TALEN-mediated homologous recombination (HR). Notably, we found allele specificity of HR led by the presence of a single-nucleotide polymorphism. High numbers of erythroid cells derived from gene-edited PKDiPSCs showed correction of the energetic imbalance, providing an approach to correct metabolic erythroid diseases and demonstrating the practicality of this approach to generate the large cell numbers required for comprehensive biochemical and metabolic erythroid analyses.info:eu-repo/semantics/publishedVersio

    Fiscal Multipliers and Public Debt Dynamics in Consolidations

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    The success of a consolidation in reducing the debt ratio depends crucially on the value of the multiplier, which measures the impact of consolidation on growth, and on the reaction of sovereign yields to such a consolidation. We present a theoretical framework that formalizes the re spo nse of the public debt ratio to fiscal consolidations in relation to the value of fiscal multipliers, the starting debt level and the cyclical elasticity of the budget balance. We also assess the role of markets confidence to fiscal consolidations under al ternative scenarios. We find that with high levels of public debt and sizeable fiscal multipliers , debt ratios are likely to increase in the short term in response to fiscal consolidations. Hence, the typical horizon for a consolidation during crises episo des to reduce the debt ratio is two - three years , although this horizon depends critically on the size and persistence of fiscal multipliers and the reaction of financial markets. Anyway, such undesired debt responses are mainly short - lived. This effect is very unlikely in non - crisis times, as it requires a number of conditions difficult to observe at the same time , especially high fiscal multipliers
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