241 research outputs found

    Pip and Pop: When auditory alarms facilitate visual change detection in dynamic settings

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    Dynamic and complex command and control situations often require the timely recognition of changes in the environment in order to detect potentially malicious actions. Change detection can be challenging within a continually evolving scene, and particularly under multitasking conditions whereby attention is necessarily divided between several subtasks. On-screen tools can assist with detection (e.g., providing a visual record of changes, ensuring that none are overlooked), however, in a high workload environment, this may result in information overload to the detriment of the primary task. One alternative is to exploit the auditory modality as a means to support visual change detection. In the current study, we use a naval air-warfare simulation, and introduce an auditory alarm to coincide with critical visual changes (in aircraft speed/direction) on the radar. We found that participants detected a greater percentage of visual changes and were significantly quicker to detect these changes when they were accompanied by an auditory alarm than when they were not. Furthermore, participants reported that mental demand was lower in the auditory alarm condition, and this was reflected in reduced classification omissions on the primary task. Results are discussed in relation to Wickens’ multiple resource theory of attention and indicate the potential for using the auditory modality to facilitate visual change detection

    A statistical approach for identifying the ionospheric footprint of magnetospheric boundaries from SuperDARN observations

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    Identifying and tracking the projection of magnetospheric regions on the high-latitude ionosphere is of primary importance for studying the Solar Wind-Magnetosphere-Ionosphere system and for space weather applications. By its unique spatial coverage and temporal resolution, the Super Dual Auroral Radar Network (SuperDARN) provides key parameters, such as the Doppler spectral width, which allows the monitoring of the ionospheric footprint of some magnetospheric boundaries in near real-time. In this study, we present the first results of a statistical approach for monitoring these magnetospheric boundaries. The singular value decomposition is used as a data reduction tool to describe the backscattered echoes with a small set of parameters. One of these is strongly correlated with the Doppler spectral width, and can thus be used as a proxy for it. Based on this, we propose a Bayesian classifier for identifying the spectral width boundary, which is classically associated with the Polar Cap boundary. The results are in good agreement with previous studies. Two advantages of the method are: the possibility to apply it in near real-time, and its capacity to select the appropriate threshold level for the boundary detection

    A quantitative test of Jones NTC beaming theory using CLUSTER constellation

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    Non-thermal continuum (NTC) radiation is, with auroral kilometric radiation (AKR), one of the two electromagnetic emissions generated within the Earth's magnetosphere and radiated into space. The location of the source of NTC has been sought for several decades, with only limited success. The constellation formed by the four CLUSTER spacecraft provides the possibility of triangulation in the vicinity of the source, thus allowing progress in source localisation, while simultaneously revealing the beaming properties of NTC radio sources. <br><br> We present a case event showing two beams localised on opposite sides of the magnetic equator. At any selected frequency, triangulation points to a single region source of small size. Its position is compatible with the range of possible loci of sources predicted by the radio window theory of Jones (1982) in a frame of constraints relaxed from the simple sketch proposed in early works. The analysis of similar observations from the Dynamics Explorer 1 by Jones et al. (1987) enabled the authors to claim validation of the radio window theory. CLUSTER observations, however, reveal a large beaming cone angle projected onto the ecliptic plane, a feature unobservable by Dynamics Explorer which had a different spin axis orientation. According to the radio window theory, such a large observed cone angle can only be formed by a series of point sources, each beaming in a narrow cone angle. This study demonstrates the difficulty of validating NTC linear generation mechanisms using global beaming properties alone

    Qualitative studies of insomnia : current state of knowledge in the field

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    Despite its high prevalence and burden, insomnia is often trivialized, under-diagnosed, and under-treated in practice. Little information is available on the subjective experience and perceived consequences of insomnia, help-seeking behaviors, and treatment preferences. The use of qualitative approaches (e.g., ethnography, phenomenology, grounded theory) may help gain a better understanding of this sleep disorder. The present paper summarizes the evidence derived from insomnia studies using a qualitative research methodology (e.g., focus group, semi-structured interviews). A systematic review of the literature was conducted using PsycINFO and Medline databases. The review yielded 22 studies and the quality of the methodology of each of them was evaluated systematically using the critical appraisal skills programme (CASP) appraisal tool. Selected articles possess at least a very good methodological rigor and they were categorized according to their main focus: “Experience of insomnia”, “Management of insomnia” and “Medicalization of insomnia”. The main findings indicate that: 1) insomnia is often experienced as a 24-h problem and is perceived to affect several domains of life, 2) a sense of frustration and misunderstanding is very common among insomnia patients, which is possibly due to a mismatch between patients' and health care professionals' perspectives on insomnia and its treatment, 3) health care professionals pay more attention to sleep hygiene education and medication therapies and less to the patient's subjective experience of insomnia, and 4) health care professionals are often unaware of non-pharmacological interventions other than sleep hygiene education. An important implication of these findings is the need to develop new clinical measures with a broader scope on insomnia and more targeted treatments that take into account the patient's experience of insomnia. Greater use of qualitative approaches in future research may produce novel and more contextualized information leading to a more comprehensive understanding of insomnia

    Solution of the Nuclear Shell Model by Symmetry-Dictated Truncation

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    The dynamical symmetries of the Fermion Dynamical Symmetry Model are used as a principle of truncation for the spherical shell model. Utilizing the usual principle of energy-dictated truncation to select a valence space, and symmetry-dictated truncation to select a collective subspace of that valence space, we are able to reduce the full shell model space to one of manageable dimensions with modern supercomputers, even for the heaviest nuclei. The resulting shell model then consists of diagonalizing an effective Hamiltonian within the restricted subspace. This theory is not confined to any symmetry limits, and represents a full solution of the original shell model if the appropriate effective interaction of the truncated space can be determined. As a first step in constructing that interaction, we present an empirical determination of its matrix elements for the collective subspace with no broken pairs in a representative set of nuclei with 130A250130\le A \le 250. We demonstrate that this effective interaction can be parameterized in terms of a few quantities varying slowly with particle number, and is capable of describing a broad range of low-energy observables for these nuclei. Finally we give a brief discussion of extending these methods to include a single broken collective pair.Comment: invited paper for J. Phys. G, 57 pages, Latex, 18 figures a macro are available under request at [email protected]

    Modulation of NTC frequencies by Pc5 ULF pulsations : experimental test of the generation mechanism and magnetoseismology of the emitting surface

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    Nonthermal continuum (NTC) radiation is believed to be emitted by the conversion of an electrostatic wave into an electromagnetic one, which takes place at the Earth's magnetic equator. It is generally accepted that the frequency of the electrostatic wave at the source meets a local characteristic frequency placed in between two multiples of the electron cyclotron frequency, fce, which results in emission of a narrow band frequency element. In an event on 14 August 2003, we compare oscillations of the central frequency of distinct NTC frequency elements observed from Cluster orbiting near perigee, with simultaneous Pc5 Ultra Low Frequency (ULF) pulsations in the magnetic field observed from the same platform. The latter magnetic perturbations are interpreted as magnetohydrodynamic poloidal waves, where fundamental and second harmonic modes coexist. The NTC oscillation and the fundamental wave have similar periods, but are phase shifted by a quarter of period. From the correlation between both signals, and the proximity of the NTC source (localized via triangulation) with Cluster, we infer that the poloidal perturbations are spatially uniform between the source and the satellites. From the phase shift between signals, we conclude that the electrostatic wave which converts into NTC is mainly governed by the plasma density, affected by movements of the magnetic field lines. Furthermore, we demonstrate that the observations can be used to perform a magnetoseismology of the emitting surface. The results show a steepening of the plasmapause density profile near the satellites, which can be responsible for the generation of NTC emission

    Does supportive supervision enhance community health worker motivation? A mixed-methods study in four African countries.

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    Supportive supervision is an important element of community health worker (CHW) programmes and is believed to improve CHW motivation and performance. A group supervision intervention, which included training and mentorship of supervisors, was implemented in Ethiopia, Kenya, Malawi and Mozambique. In three of the countries, this was combined with individual and/or peer supervision. A mixed-methods implementation study was conducted to assess the effect of the supervision intervention on CHWs' perceptions of supervision and CHW motivation-related outcomes. In total, 153 in-depth interviews were conducted with CHWs, their supervisors and managers. In addition, questionnaires assessing perceived supervision and motivation-related outcomes (organizational and community commitment, job satisfaction and conscientiousness) were administered to a total of 278 CHWs pre- and post-intervention, and again after 1 year. Interview transcripts were thematically analysed using a coding framework. Changes in perceived supervision and motivation-related outcomes were assessed using Friedman's ANOVA and post hoc Wilcoxon signed-rank tests. Interview participants reported that the supervision intervention improved CHW motivation. In contrast, the quantitative survey found no significant changes for measures of perceived supervision and inconsistent changes in motivation-related outcomes. With regard to the process of supervision, the problem-solving focus, the sense of joint responsibilities and team work, cross-learning and skill sharing, as well as the facilitating and coaching role of the supervisor, were valued. The empowerment and participation of supervisees in decision making also emerged in the analysis, albeit to a lesser extent. Although qualitative and quantitative findings differed, which could be related to the slightly different focus of methods used and a 'ceiling effect' limiting the detection of observable differences from the survey, the study suggests that there is potential for integrating supportive group supervision models in CHW programmes. A combination of group with individual or peer supervision, preferably accompanied with methods that assess CHW performance and corresponding feedback systems, could yield improved motivation and performance

    Electronic Medical Record Inaccuracies: Multicenter Analysis of Challenges with Modified Lung Cancer Screening Criteria.

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    The National Comprehensive Cancer Network expanded their lung cancer screening (LCS) criteria to comprise one additional clinical risk factor, including chronic obstructive pulmonary disease (COPD). The electronic medical record (EMR) is a source of clinical information that could identify high-risk populations for LCS, including a diagnosis of COPD; however, an unsubstantiated COPD diagnosis in the EMR may lead to inappropriate LCS referrals. We aimed to detect the prevalence of unsubstantiated COPD diagnosis in the EMR for LCS referrals, to determine the efficacy of utilizing the EMR as an accurate population-based eligibility screening trigger using modified clinical criteria. We performed a multicenter review of all individuals referred to three LCS programs from 2012 to 2015. Each individual\u27s EMR was searched for COPD diagnostic terms and the presence of a diagnostic pulmonary functionality test (PFT). An unsubstantiated COPD diagnosis was defined by an individual\u27s EMR containing a COPD term with no PFTs present, or the presence of PFTs without evidence of obstruction. A total of 2834 referred individuals were identified, of which 30% (840/2834) had a COPD term present in their EMR. Of these, 68% (571/840) were considered unsubstantiated diagnoses: 86% (489/571) due to absent PFTs and 14% (82/571) due to PFTs demonstrating no evidence of postbronchodilation obstruction. A large proportion of individuals referred for LCS may have an unsubstantiated COPD diagnosis within their EMR. Thus, utilizing the EMR as a population-based eligibility screening tool, employing expanded criteria, may lead to individuals being referred, potentially, inappropriately for LCS
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