425 research outputs found

    The management of scarce water resources using GNSS, InSAR and in-situ micro gravity measurements as monitoring tools

    Get PDF
    South Africa is a water scarce country hence the careful monitoring and management of available water resources is critical for the wellbeing of the citizens of the country. A high percentage of the Earth’s water supply is stored underground which can be extracted either through pumping or using artesian pressure. This paper describes the application of GNSS, InSAR and In-Situ Micro Gravity measurements for the monitoring of an artesian wellfield in the Oudtshoorn District in the Western Cape province of South Africa. GNSS receivers were run continuously for a period of 133 days between March and August 2014 to detect possible surface subsidence during pumping and artesian free flow extraction of water in the wellfield. Two InSAR scenes were processed, one during the peak period of water extraction from the wellfield and the other approximately 4 months after all boreholes were closed and pumps switched off. A micro-gravity campaign was conducted over two days in the wellfield with the gravity meter co-located at one borehole which was opened on the second day of the campaign. The results from the GNSS monitoring showed a subsidence of approximately 15 to 20 mm at the peak of the free flow and pump while those from the InSAR and microgravity measurements were largely inconclusive

    X-ray Spectra of the RIXOS source sample

    Get PDF
    We present results of an extensive study of the X-ray spectral properties of sources detected in the RIXOS survey, that is nearly complete down to a flux limit of 3e-14 cgs (0.5-2 keV). We show that for X-ray surveys containing sources with low count rate spectral slopes estimated using simple hardness ratios in the ROSAT band can be biased. Instead we analyse three-colour X-ray data using statistical techniques appropriate to the Poisson regime which removes the effects of this bias. We have then applied this technique to the RIXOS survey to study the spectral properties of the sample. For the AGN we find an average energy index of 1.05+-0.05 with no evidence for spectral evolution with redshift. Individual AGN are shown to have a range of properties including soft X-ray excesses and intrinsic absorption. Narrow Emission Line Galaxies also seem to fit to a power-law spectrum, which may indicate a non-thermal origin for their X-ray emission. We infer that most of the clusters in the sample have a bremsstrahlung temperature >3 keV, although some show evidence for a cooling flow. The stars deviate strongly from a power-law model but fit to a thermal model. Finally, we have analysed the whole RIXOS sample containing 1762 sources. We find that the mean spectral slope of the sources hardens at lower fluxes in agreement with results from other samples. However, a study of the individual sources demonstrates that the hardening of the mean is caused by the appearance of a population of very hard sources at the lowest fluxes. This has implications for the nature of the soft X-ray background.Comment: 31,LaTeX file, 2 PS files with Table 2 and 22 PS figures. MNRAS in pres

    Do acute elevations of serum creatinine in primary care engender an increased mortality risk?

    Get PDF
    Background: The significant impact Acute Kidney Injury (AKI) has on patient morbidity and mortality emphasizes the need for early recognition and effective treatment. AKI presenting to or occurring during hospitalisation has been widely studied but little is known about the incidence and outcomes of patients experiencing acute elevations in serum creatinine in the primary care setting where people are not subsequently admitted to hospital. The aim of this study was to define this incidence and explore its impact on mortality. Methods: The study cohort was identified by using hospital data bases over a six month period. Inclusion criteria: People with a serum creatinine request during the study period, 18 or over and not on renal replacement therapy. The patients were stratified by a rise in serum creatinine corresponding to the Acute Kidney Injury Network (AKIN) criteria for comparison purposes. Descriptive and survival data were then analysed. Ethical approval was granted from National Research Ethics Service (NRES) Committee South East Coast and from the National Information Governance Board. Results: The total study population was 61,432. 57,300 subjects with ‘no AKI’, mean age 64.The number (mean age) of acute serum creatinine rises overall were, ‘AKI 1’ 3,798 (72), ‘AKI 2’ 232 (73), and ‘AKI 3’ 102 (68) which equates to an overall incidence of 14,192 pmp/year (adult). Unadjusted 30 day survival was 99.9% in subjects with ‘no AKI’, compared to 98.6%, 90.1% and 82.3% in those with ‘AKI 1’, ‘AKI 2’ and ‘AKI 3’ respectively. After multivariable analysis adjusting for age, gender, baseline kidney function and co-morbidity the odds ratio of 30 day mortality was 5.3 (95% CI 3.6, 7.7), 36.8 (95% CI 21.6, 62.7) and 123 (95% CI 64.8, 235) respectively, compared to those without acute serum creatinine rises as defined. Conclusions: People who develop acute elevations of serum creatinine in primary care without being admitted to hospital have significantly worse outcomes than those with stable kidney function

    Sampling molecular conformations and dynamics in a multiuser virtual reality framework

    Get PDF
    Copyright © 2018 The Authors, some rights reserved. We describe a framework for interactive molecular dynamics in a multiuser virtual reality (VR) environment, combining rigorous cloud-mounted atomistic physics simulations with commodity VR hardware, which we have made accessible to readers (see isci.itch.io/nsb-imd). It allows users to visualize and sample, with atomic-level precision, the structures and dynamics of complex molecular structures “on the fly” and to interact with other users in the same virtual environment. A series of controlled studies, in which participants were tasked with a range of molecular manipulation goals (threading methane through a nanotube, changing helical screw sense, and tying a protein knot), quantitatively demonstrate that users within the interactive VR environment can complete sophisticated molecular modeling tasks more quickly than they can using conventional interfaces, especially for molecular pathways and structural transitions whose conformational choreographies are intrinsically three-dimensional. This framework should accelerate progress in nanoscale molecular engineering areas including conformational mapping, drug development, synthetic biology, and catalyst design. More broadly, our findings highlight the potential of VR in scientific domains where three-dimensional dynamics matter, spanning research and education

    Modelling Effects of Tariff Liberalisation on India’s Key Export Sectors: Analysis of the EU–India Free Trade Agreement

    Get PDF
    Trade agreements are increasingly being negotiated between developed and emerging economy partners. An example is the EU–India Free Trade Agreement (FTA) for which negotiations began in 2007. There has been a debate on the potential effects of the proposed FTA and how this can impact on India’s key export sectors. Our study addresses this aspect from a global computable general equilibrium (CGE) modelling perspective. Using the Global Trade Analysis Project (GTAP) framework, we analyse trade and welfare impacts of the proposed FTA between the EU and India. Two scenarios are modelled: first, complete and immediate elimination of tariff on all goods traded and second, selective tariff elimination on textiles, wearing apparel and leather goods—products in which India has a comparative advantage. Results under both scenarios show that India enjoys positive welfare effects though there is a possibility of trade diversion. Under scenario 1, India loses due to a negative terms of trade (ToT) effect. Under scenario 2, with selective sectoral liberalisation, gains are mainly concentrated in the textiles, wearing apparel and leather sectors. There is a positive output effect from change in demand for factors of production, suggesting that the proposed FTA could lead to relocation of labour-intensive production to India

    “It ain’t (just) what you do, it’s (also) the way that you do it”: The role of Procedural Justice in the Implementation of Anti-social Behaviour Interventions with Young People

    Get PDF
    This paper provides an analysis of the introduction and implementation of hybrid powers to regulate anti-social behaviour, during a period of regulatory ‘hyperactivity’ in the UK. It explores the role of procedural justice by drawing on findings from a study conducted in England which investigated the implementation practices and experiences of young people and parents. These are considered against seven characteristics of procedural justice: voice; voluntariness; respectful treatment; parsimony; accuracy of information; fairness; and neutrality. The paper analyses the manner in which principles of voluntary cooperation can be corrupted by threats of punitive sanctions. It questions the extent to which the use of such hybrid orders fosters perceptions of legitimacy and supports the capacity of young people to avoid criminalisation

    The ROSAT International X-ray/Optical Survey (RIXOS): source catalogue

    Get PDF
    We describe the ROSAT International X-ray/Optical Survey (RIXOS), a medium-sensitivity survey and optical identification of X-ray sources discovered in ROSAT high Galactic latitude fields (|b|>28°) and observed with the Position Sensitive Proportional Counter (PSPC) detector. The survey made use of the central 17 arcmin of each ROSAT field. A flux limit of 3×10−14 erg cm−2 s−1 (0.5–2 keV) was adopted for the survey, and a minimum exposure time of 8000 s was required for qualifying ROSAT observations. X-ray sources in the survey are therefore substantially above the detection threshold of each field used, and many contain enough counts to allow the X-ray spectral slope to be estimated. Spectroscopic observations of potential counterparts were obtained of all sources down to the survey limit in 64 fields, totalling a sky area of 15.77 deg2. Positive optical identifications are made for 94 per cent of the 296 sources thus examined. A further 18 fields (4.44 deg2), containing 105 sources above the 3×10−14 erg cm−2 s−1 survey limit, are completely optically identified to a higher flux of 8×10−14 erg cm−2 s−1 (0.5–2 keV). Optical spectroscopic data are supplemented by deep CCD imaging of many sources to reveal the morphology of the optical counterparts, and objects too faint to register on Sky Survey plates. The faintest optical counterparts have R∼22. This paper describes the survey method, and presents a catalogue of the RIXOS sources and their optical identifications. Finding charts based on Sky Survey data are given for each source, supplemented by CCD imaging where necessary

    Towards a multi-arm multi-stage platform trial of disease modifying approaches in Parkinson’s disease

    Get PDF
    \ua9 The Author(s) 2023. Published by Oxford University Press on behalf of the Guarantors of Brain.An increase in the efficiency of clinical trial conduct has been successfully demonstrated in the oncology field, by the use of multi-arm, multi-stage trials allowing the evaluation of multiple therapeutic candidates simultaneously, and seamless recruitment to phase 3 for those candidates passing an interim signal of efficacy. Replicating this complex innovative trial design in diseases such as Parkinson’s disease is appealing, but in addition to the challenges associated with any trial assessing a single potentially disease modifying intervention in Parkinson’s disease, a multiarm platform trial must also specifically consider the heterogeneous nature of the disease, alongside the desire to potentially test multiple treatments with different mechanisms of action. In a multi-arm trial, there is a need to appropriately stratify treatment arms to ensure each are comparable with a shared placebo/standard of care arm; however, in Parkinson’s disease there may be a preference to enrich an arm with a subgroup of patients that may be most likely to respond to a specific treatment approach. The solution to this conundrum lies in having clearly defined criteria for inclusion in each treatment arm as well as an analysis plan that takes account of predefined subgroups of interest, alongside evaluating the impact of each treatment on the broader population of Parkinson’s disease patients. Beyond this, there must be robust processes of treatment selection, and consensus derived measures to confirm target engagement and interim assessments of efficacy, as well as consideration of the infrastructure needed to support recruitment, and the long-term funding and sustainability of the platform. This has to incorporate the diverse priorities of clinicians, triallists, regulatory authorities and above all the views of people with Parkinson’s disease

    Atypical birdsong and artificial languages provide insights into how communication systems are shaped by learning, use and transmission

    Get PDF
    In this article, I argue that a comparative approach focusing on the cognitive capacities and behavioral mechanisms that underlie vocal learning in songbirds and humans can provide valuable insights into the evolutionary origins of language. The experimental approaches I discuss use abnormal song and atypical linguistic input to study the processes of individual learning, social interaction, and cultural transmission. Atypical input places increased learning and communicative pressure on learners, so exploring how they respond to this type of input provides a particularly clear picture of the biases and constraints at work during learning and use. Furthermore, simulating the cultural transmission of these unnatural communication systems in the laboratory informs us about how learning and social biases influence the structure of communication systems in the long run. Findings based on these methods suggest fundamental similarities in the basic social–cognitive mechanisms underlying vocal learning in birds and humans, and continuing research promises insights into the uniquely human mechanisms and into how human cognition and social behavior interact, and ultimately impact on the evolution of language
    corecore