1,926 research outputs found

    Flood vulnerability, risk and social disadvantage: current and future patterns in the UK

    Get PDF
    Present day and future social vulnerability, flood risk and disadvantage across the UK are explored using the UK Future Flood Explorer. In doing so, new indices of neighbourhood flood vulnerability and social flood risk are introduced and used to provide a quantitative comparison of the flood risks faced by more and less socially vulnerable neighbourhoods. The results show the concentrated nature of geographic flood disadvantage. For example, ten local authorities account for fifty percent of the most socially vulnerable people that live in flood prone areas. The results also highlight the systematic nature of flood disadvantage. For example, flood risks are higher in socially vulnerable communities than elsewhere; this is shown to be particularly the case in coastal areas, economically struggling cities and dispersed rural communities. Results from a re-analysis of the Environment Agency’s Long-Term Investment Scenarios (for England) suggests a long-term economic case for improving the protection afforded to the most socially vulnerable communities; a finding that reinforces the need to develop a better understanding of flood risk in socially vulnerable communities if flood risk management efforts are to deliver fair outcomes. In response to these findings the paper advocates an approach to flood risk management that emphasizes Rawlsian principles of preferentially targeting risk reduction for the most socially vulnerable and avoids a process of prioritisation based upon strict utilitarian or purely egalitarian principles

    Investigation of Graded La2NiO4+ Cathodes to Improve SOFC Electrochemical Performance

    Get PDF
    Mixed ionic and electronic conducting MIEC oxides are promising materials for use as cathodes in solid oxide fuel cells SOFCs due to their enhanced electrocatalytic activity compared with electronic conducting oxides. In this paper, the MIEC oxide La2NiO4+ was prepared by the sol-gel route. Graded cathodes were deposited onto yttria-stabilized zirconia YSZ pellets by dip-coating, and electrochemical impedance spectroscopy studies were performed to characterize the symmetrical cell performance. By adapting the slurries, cathode layers with different porosities and thicknesses were obtained. A ceria gadolinium oxide CGO barrier layer was introduced, avoiding insulating La2Zr2O7 phase formation and thus reducing resistance polarization of the cathode. A systematic correlation between microstructure, composition, and electrochemical performance of these cathodes has been performed. An improvement of the electrochemical performance has been demonstrated, and a reduction in the area specific resistance ASR by a factor of 4.5 has been achieved with a compact interlayer of La2NiO4+ between the dense electrolyte and the porous La2NiO4+ cathode layer. The lowest observed ASR of 0.11 cm2 at 800°C was obtained from a symmetrical cell composed of a YSZ electrolyte, a CGO interlayer, an intermediate compact La2NiO4+ layer, a porous La2NiO4+ electrode layer, and a current collection layer of platinum paste

    Rumen fluke in Irish sheep: prevalence, risk factors and molecular identification of two paramphistome species

    Get PDF
    peer-reviewedBackground Rumen flukes are trematode parasites found globally; in tropical and sub-tropical climates, infection can result in paramphistomosis, which can have a deleterious impact on livestock. In Europe, rumen fluke is not regarded as a clinically significant parasite, recently however, the prevalence of rumen fluke has sharply increased and several outbreaks of clinical paramphistomosis have been reported. Gaining a better understanding of rumen fluke transmission and identification of risk factors is crucial to improve the control of this parasitic disease. In this regard, a national prevalence study of rumen fluke infection and an investigation of associated risk factors were conducted in Irish sheep flocks between November 2014 and January 2015. In addition, a molecular identification of the rumen fluke species present in Ireland was carried out using an isolation method of individual eggs from faecal material coupled with a PCR. After the DNA extraction of 54 individual eggs, the nuclear fragment ITS-2 was amplified and sequenced using the same primers. Results An apparent herd prevalence of 77.3 % was determined. Several risk factors were identified including type of pasture grazed, regional variation, and sharing of the paddocks with other livestock species. A novel relationship between the Suffolk breed and higher FEC was reported for the first time. The predominant rumen fluke species found was C. daubneyi. Nevertheless, P. leydeni was unexpectedly identified infecting sheep in Ireland for the first time. Conclusions An exceptionally high prevalence of rumen fluke among Irish sheep flocks has been highlighted in this study and a more thorough investigation is necessary to analyse its economic impact. The isolation of individual eggs coupled with the PCR technique used here has proven a reliable tool for discrimination of Paramphistomum spp. This technique may facilitate forthcoming studies of the effects of paramphistomosis on livestock production. The most noteworthy finding was the identification of P. leydeni affecting sheep in Ireland, however further studies are required to clarify its implications. Also, a significant relationship between Suffolk breed and a heavier infection was found, which can be used as a starting point for future research on control strategies of rumen fluke infection.This study was funded by Irish Department of Agriculture, Food and the Marine research stimulus funding; project reference 13/ S/405

    Voltage- and light-induced hysteresis effects at the high-k dielectric- poly(3-hexylthiophene) interface

    Get PDF
    Capacitance-voltage (C-V) measurements have been undertaken on metal-insulator-semiconductor capacitors formed from atomic-layer-deposited films of aluminium titanium oxide as the insulator and poly(3-hexylthiophene) as the insulator. Upon cycling from -30 to +30 V in the dark, the C-V plots show large, temperature-dependent, reversible shifts in the flatband voltage to more negative voltages consistent with reversible, shallow hole trapping at or near the insulator-semiconductor interface. When illuminated with photons of energy exceeding the polymer band gap, even larger shifts to positive voltages are observed accompanied by inversion layer formation. This latter effect has potential applications in optical sensing. (c) 2007 American Institute of Physics

    A model for transition of 5 '-nuclease domain of DNA polymerase I from inert to active modes

    Get PDF
    Bacteria contain DNA polymerase I (PolI), a single polypeptide chain consisting of similar to 930 residues, possessing DNA-dependent DNA polymerase, 3'-5' proofreading and 5'-3' exonuclease (also known as flap endonuclease) activities. PolI is particularly important in the processing of Okazaki fragments generated during lagging strand replication and must ultimately produce a double-stranded substrate with a nick suitable for DNA ligase to seal. PolI's activities must be highly coordinated both temporally and spatially otherwise uncontrolled 5'-nuclease activity could attack a nick and produce extended gaps leading to potentially lethal double-strand breaks. To investigate the mechanism of how PolI efficiently produces these nicks, we present theoretical studies on the dynamics of two possible scenarios or models. In one the flap DNA substrate can transit from the polymerase active site to the 5'-nuclease active site, with the relative position of the two active sites being kept fixed; while the other is that the 5'-nuclease domain can transit from the inactive mode, with the 5'-nuclease active site distant from the cleavage site on the DNA substrate, to the active mode, where the active site and substrate cleavage site are juxtaposed. The theoretical results based on the former scenario are inconsistent with the available experimental data that indicated that the majority of 5'-nucleolytic processing events are carried out by the same PolI molecule that has just extended the upstream primer terminus. By contrast, the theoretical results on the latter model, which is constructed based on available structural studies, are consistent with the experimental data. We thus conclude that the latter model rather than the former one is reasonable to describe the cooperation of the PolI's polymerase and 5'-3' exonuclease activities. Moreover, predicted results for the latter model are presented

    Galaxy Cluster Scaling Relations between Bolocam Sunyaev-Zel'dovich Effect and Chandra X-ray Measurements

    Get PDF
    We present scaling relations between the integrated Sunyaev-Zel'dovich Effect (SZE) signal, YSZY_{\rm SZ}, its X-ray analogue, YX≡MgasTXY_{\rm X}\equiv M_{\rm gas}T_{\rm X}, and total mass, MtotM_{\rm tot}, for the 45 galaxy clusters in the Bolocam X-ray-SZ (BOXSZ) sample. All parameters are integrated within r2500r_{2500}. Y2500Y_{2500} values are measured using SZE data collected with Bolocam, operating at 140 GHz at the Caltech Submillimeter Observatory (CSO). The temperature, TXT_{\rm X}, and mass, Mgas,2500M_{\rm gas,2500}, of the intracluster medium are determined using X-ray data collected with Chandra, and MtotM_{\rm tot} is derived from MgasM_{\rm gas} assuming a constant gas mass fraction. Our analysis accounts for several potential sources of bias, including: selection effects, contamination from radio point sources, and the loss of SZE signal due to noise filtering and beam-smoothing effects. We measure the Y2500Y_{2500}--YXY_{\rm X} scaling to have a power-law index of 0.84±0.070.84\pm0.07, and a fractional intrinsic scatter in Y2500Y_{2500} of (21±7)%(21\pm7)\% at fixed YXY_{\rm X}, both of which are consistent with previous analyses. We also measure the scaling between Y2500Y_{2500} and M2500M_{2500}, finding a power-law index of 1.06±0.121.06\pm0.12 and a fractional intrinsic scatter in Y2500Y_{2500} at fixed mass of (25±9)%(25\pm9)\%. While recent SZE scaling relations using X-ray mass proxies have found power-law indices consistent with the self-similar prediction of 5/3, our measurement stands apart by differing from the self-similar prediction by approximately 5σ\sigma. Given the good agreement between the measured Y2500Y_{2500}--YXY_{\rm X} scalings, much of this discrepancy appears to be caused by differences in the calibration of the X-ray mass proxies adopted for each particular analysis.Comment: 31 pages, 15 figures, accepted by ApJ 04/11/2015. This version is appreciably different from the original submission: it includes an entirely new appendix, extended discussion, and much of the material has been reorganize

    Molecular interactions of Escherichia coli ExoIX and identification of its associated 3′–5′ exonuclease activity

    Get PDF
    The flap endonucleases (FENs) participate in a wide range of processes involving the structure-specific cleavage of branched nucleic acids. They are also able to hydrolyse DNA and RNA substrates from the 5′-end, liberating mono-, di- and polynucleotides terminating with a 5′ phosphate. Exonuclease IX is a paralogue of the small fragment of Escherichia coli DNA polymerase I, a FEN with which it shares 66% similarity. Here we show that both glutathione-S-transferase-tagged and native recombinant ExoIX are able to interact with the E. coli single-stranded DNA binding protein, SSB. Immobilized ExoIX was able to recover SSB from E. coli lysates both in the presence and absence of DNA. In vitro cross-linking studies carried out in the absence of DNA showed that the SSB tetramer appears to bind up to two molecules of ExoIX. Furthermore, we found that a 3′–5′ exodeoxyribonuclease activity previously associated with ExoIX can be separated from it by extensive liquid chromatography. The associated 3′–5′ exodeoxyribonuclease activity was excised from a 2D gel and identified as exonuclease III using matrix-assisted laser-desorption ionization mass spectrometry

    High Spectral Resolution Measurement of the Sunyaev–Zel'dovich Effect Null with Z-Spec

    Get PDF
    The Sunyaev-Zel'dovich (SZ) effect spectrum crosses through a null where ΔT_CMB = 0 near ν_0 = 217 GHz. In a cluster of galaxies, ν0 can be shifted from the canonical thermal SZ effect value by corrections to the SZ effect scattering due to the properties of the inter-cluster medium. We have measured the SZ effect in the hot galaxy cluster RX J 1347.5 – 1145 with Z-Spec, an R ~ 300 grating spectrometer sensitive between 185 and 305 GHz. These data comprise a high spectral resolution measurement around the null of the SZ effect and clearly exhibit the transition from negative to positive ΔT_CMB over the Z-Spec band. The SZ null position is measured to be ν_0 = 225.8 ± 2.5(stat.) ± 1.2(sys.) GHz, which differs from the canonical null frequency by 3.0σ and is evidence for modifications to the canonical thermal SZ effect shape. Assuming the measured shift in ν0 is due only to relativistic corrections to the SZ spectrum, we place the limit kT_e = 17.1 ± 5.3 keV from the zero-point measurement alone. By simulating the response of the instrument to the sky, we are able to generate likelihood functions in {y_0, T_e, v_pec} space. For v_pec = 0 km s^(–1), we measure the best-fitting SZ model to be y_0 = 4.6^(+0.6)_(–0.9) × 10^(–4), T_e, 0 = 15.2^(+12)_(–7.4) keV. When v pec is allowed to vary, a most probable value of v_pec = + 450 ± 810 km s^(–1) is found
    • …
    corecore