2,459 research outputs found

    On the relativistic iron line and soft excess in the Seyfert 1 galaxy Markarian 335

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    We report on a 133 ks XMM-Newton observation of the Seyfert 1 galaxy Markarian 335. The 0.4-12 keV spectrum contains an underlying power law continuum, a soft excess below 2 keV, and a double-peaked iron emission feature in the 6-7 keV range. We investigate the possibility that the double-peaked emission might represent the characteristic signature of the accretion disc. Detailed investigations show that a moderately broad, accretion disc line is most likely present, but that the peaks may be owing to narrower components from more distant material. The peaks at 6.4 and 7 keV can be identified, respectively, with the molecular torus in active galactic nucleus unification schemes, and very highly ionized, optically thin gas filling the torus. The X-ray variability spectra on both long (~100 ks) and short (~1 ks) timescales disfavour the recent suggestion that the soft excess is an artifact of variable, moderately ionized absorption.Comment: 6 pages, 2 figures, accepted for publication in MNRA

    What Determines Inter-Coder Agreement in Manual Annotations? A Meta-Analytic Investigation

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    Recent discussions of annotator agreement have mostly centered around its calculation and interpretation, and the correct choice of indices. Although these discussions are important, they only consider the "back-end" of the story, namely, what to do once the data are collected. Just as important in our opinion is to know how agreement is reached in the first place and what factors influence coder agreement as part of the annotation process or setting, as this knowledge can provide concrete guidelines for the planning and set-up of annotation projects. To investigate whether there are factors that consistently impact annotator agreement we conducted a meta-analytic investigation of annotation studies reporting agreement percentages. Our meta-analysis synthesized factors reported in 96 annotation studies from three domains (word-sense disambiguation, prosodic transcriptions, and phonetic transcriptions) and was based on a total of 346 agreement indices. Our analysis identified seven factors that influence reported agreement values: annotation domain, number of categories in a coding scheme, number of annotators in a project, whether annotators received training, the intensity of annotator training, the annotation purpose, and the method used for the calculation of percentage agreements. Based on our results we develop practical recommendations for the assessment, interpretation, calculation, and reporting of coder agreement. We also briefly discuss theoretical implications for the concept of annotation quality

    A Method Impact Assessment Framework for User Experience Evaluations with Children

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    Based upon a review of the literature, this paper presents a Method Impact Assessment Framework. Theoretically synthesized, the framework offers five dimensions: (1) the role of the child, (2) the user experience construct, (3) system, (4) epistemological perspective, (5) Practical and Ethical Concerns. Although other dimensions could have been construed, these were judged to be the most pertinent to understanding evaluation methods with children. The framework thus provides a critical lens in which evaluation methods can be assessed by the Children Computer Interaction (CCI) Community to inform method selection

    Working Ethically in Participatory Research with Children

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    In this paper we present the ABCD framework for working ethically with children and young people in participatory design studies. This framework covers A – Agreement and consent made between all participants and interested parties; B – Behaviour of the research team towards the activities, requiring them to examine their motivations and to be honest in their interactions with children; C – Classroom experience in participatory sessions during which children are encouraged to discuss the nature of their participation, and D – Dissemination of the work and planning appropriate follow on activities to ensure that children are informed about the outputs from their contributions. We discuss the process by which we developed the framework, the challenges raised by working in this way with children and the role of values in participatory research

    Chromaticity Measurements via RF Phase Modulation and Continuous Tune Tracking

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    Chromaticity diagnostics with high time resolution is of paramount importance for the control of the dynamic events in various accelerators, in particular for the LHC collider. This paper describes the possibility of measuring the machine chromaticity via RF phase modulation and continuous tune tracking. The RF phase modulation can be done at much higher frequencies than a classical RF frequency variation and thus, allows chromaticity measurements with a time resolution below the second. The paper describes the general measurement principle and discusses in detail open questions, which still have to be addressed experimentally. First results from machine measurements in the CERN SPS on beam stability during RF phase modulation are presented

    Direct medical cost of type 2 diabetes in Singapore

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    10.1371/joumal.pone.0122795PLoS ONE103e012279

    Beam Echoes in the CERN SPS

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    Longitudinal echo signals have been produced in the CERN SPS by exciting a proton beam at 120~GeV/c with two short RF pulses separated by a suitable time-delay. The aim of the experiments was to confirm the analytical predictions for beam echoes in the SPS and to probe the applicability of beam echoes for a measurement of the energy distribution and diffusion coefficients in the accelerator. We summarise here the results obtained with bunched and un-bunched beams. For an un-bunched beam, the excitation frequencies are at different harmonics of the revolution frequency and result in an echo response at the difference frequency of the two RF kicks. For the case of a bunched beam, the RF kicks are adjusted to excite the quadrupole mode of the bunch motion and the beam echo response can also be observed as a quadrupole mode

    Accuracy of alcohol and breast cancer risk information on Drinkaware's website

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    A recent paper in Drug and Alcohol Review analysed the information on cancer disseminated by 27 alcohol industry funded organisations. The independent UK alcohol education charity Drinkaware was among the organisations whose information was studied, and based on the analysis claims were made of misrepresentation of evidence about the alcohol-related risk of cancer and alcohol industry influence. This commentary challenges the validity of these findings in respect to the evidence relating to the Drinkaware information, as the analysis is found to be misrepresenting the information by both disregarding the wider information content provided and the order and prominence with which alcohol-related cancer risk is presented. Furthermore, it is argued that the public has a right to be provided with relevant evidence-based information about cancer risk. It is critical that Drinkaware's important public health function is not compromised by unjustified allegations of inaccuracy and by unwarranted attacks on its independence and integrity.</p

    Longitudinal beam echo in the CERN SPS

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    The presented work summarizes the results of two experiments in the CERN SPS. Longitudinal echo signals can be produced in the CERN-SPS by exciting a coasting proton beam at 120 GeV/c with two short RF pulses at different harmonics of the revolution frequency,separated by a suitable time-delay. The aim of the experiments was to confirm the analytical predictions for a beam echo in the SPS and to probe the applicability of the beam echo for a measurement of the energy distribution and diffusion coefficients in the accelerator

    Characteristics and incidence of transfusion-associated necrotizing enterocolitis in the UK

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    BACKGROUND AND AIMS: The etiology of necrotizing enterocolitis (NEC) is unclear and postulated as being multifactorial. It has been suggested that one causative factor is the transfusion of packed red blood cells (PRBCs) leading to the disease entity commonly referred to as transfusion-associated NEC (TANEC). TANEC has been reported in North America but its incidence has not been formally investigated in the UK. Our aims were to identify the incidence of NEC and TANEC in tertiary-level UK neonatal units and to describe characteristics of TANEC cases. MATERIALS AND METHODS: Using strict case definitions for NEC and TANEC, we undertook a retrospective review to estimate the incidence of TANEC cases occurring in four UK tertiary-level centers during a 38-month period. RESULTS: Of 8007 consecutive neonatal admissions of all gestations to the four centers, 68 babies went on to develop NEC and all affected infants were of very low birth weight (VLBW); 34 of these had previously received a transfusion of PRBCs but did not fit the diagnostic criteria for TANEC, whereas 15 (22%) of the 68 babies with NEC qualified as TANEC cases. UK cases occurred at an earlier postnatal age than cases reported in multiple large North American series and were of a lower birth weight. CONCLUSIONS: We have confirmed the presence of TANEC in the UK VLBW neonatal population. Its incidence lies within the wide range described in previous reports of this phenomenon globally, though with some local variation in characteristics. Further work is needed to clarify causation, pathophysiology, and possible mechanisms of prevention of TANEC
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