3,986 research outputs found

    Analysis of a Vertically Rising Vehicle

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    Flight crew aiding for recovery from subsystem failures

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    Some of the conceptual issues associated with pilot aiding systems are discussed and an implementation of one component of such an aiding system is described. It is essential that the format and content of the information the aiding system presents to the crew be compatible with the crew's mental models of the task. It is proposed that in order to cooperate effectively, both the aiding system and the flight crew should have consistent information processing models, especially at the point of interface. A general information processing strategy, developed by Rasmussen, was selected to serve as the bridge between the human and aiding system's information processes. The development and implementation of a model-based situation assessment and response generation system for commercial transport aircraft are described. The current implementation is a prototype which concentrates on engine and control surface failure situations and consequent flight emergencies. The aiding system, termed Recovery Recommendation System (RECORS), uses a causal model of the relevant subset of the flight domain to simulate the effects of these failures and to generate appropriate responses, given the current aircraft state and the constraints of the current flight phase. Since detailed information about the aircraft state may not always be available, the model represents the domain at varying levels of abstraction and uses the less detailed abstraction levels to make inferences when exact information is not available. The structure of this model is described in detail

    Perceived coach autonomy support, basic need satisfaction and the well- and ill-being of elite youth soccer players: A longitudinal investigation

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    Objectives: Drawing from the Basic Needs Theory [BNT; Ryan, R. M., & Deci, E. L. (2002). An overview of self-determination theory. In E. L. Deci & R. M. Ryan (Eds.), Handbook of self-determination research (pp. 3-33). Rochester, NY: University of Rochester Press], the major purpose of the present study was to test a hypothesized sequence of temporal relationships between perceptions of coach autonomy support, basic need satisfaction and indices of well- and ill-being. A subsidiary aim was to ascertain the assumed mediational role of basic need satisfaction in explicating the perceived autonomy support and well-/ill-being relationships over time.\ud \ud Method: Participants (N = 54 males) from an elite youth soccer academy in the UK completed a multi-section questionnaire tapping the targeted variables on six occasions across two competitive seasons.\ud \ud Results: Multi-level regression analyses revealed that perceptions of coach autonomy support positively predicted within-person changes and between-person mean differences in basic need satisfaction and well-being over time. \ud \ud Satisfaction scores for the needs for competence and relatedness were found to predict within-person changes in subjective vitality. These same needs partially mediated the coach autonomy support-subjective vitality link over the two seasons.\ud \ud Conclusions: The findings partially support the tenets of BNT, and are discussed in terms of their practical application to participants involved in an elite youth sport setting. \u

    Positive Result in the Early Passive Phase of the Tilt-table Test: A Predictor of Neurocardiogenic Syncope in Young Men

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    Background/Aims: This study elucidated the prognostic factors for neurocardiogenic syncope in males in their late teens and early twenties. Methods: Tilt-table testing (TTT) was performed on 665 males (age range, 17 to 27 years) following the Italian protocol. The subjects were tilted head-up at a 70 ° angle on a table for 30 minutes during the passive phase. If the passive phase was negative, the subjects were given sublingual nitroglycerin and tilted to the same angle for 20 minutes during the drugprovocation phase. The subjects with positive results were followed without medication. We analyzed factors related to the recurrence rate of syncope. Results: Of 305 subjects (45.8%) with positive results, 223 (age range, 18 to 26 years) were followed for 12 months. The frequency of previous syncopal episodes ≄ 4 (p = 0.001) and a positive result during the passive phase (p = 0.022) were significantly related to a high recurrence rate. A positive result during the early passive phase ( ≀ 12 minutes) was significantly related to a higher recurrence rate than was that during the late passive phase (> 12 minutes; p = 0.011). Conclusions: A positive result during the early passive phase of TTT and frequent previous syncopal episodes were prognostic factors for neurocardiogenic syncope in men in their late teens and early twenties. Keywords: Syncope, vasovagal; Prognosis; Tilt-table tes

    Autonomy support, basic need satisfaction and the optimal functioning of adult male and female sport participants: A test of basic needs theory

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    Grounded in Basic Needs Theory (BNT; Ryan and Deci, American Psychologist, 55, 68–78, 2000a), the present study aimed to: (a) test a theoretically-based model of coach autonomy support, motivational processes and well-/ill being among a sample of adult sport participants, (b) discern which basic psychological need(s) mediate the link between autonomy support and well-/ill-being, and (c) explore gender invariance in the hypothesized model. Five hundred and thirty nine participants (Male = 271;Female = 268; Mage = 22.75) completed a multi-section questionnaire tapping the targeted variables. Structural Equation Modeling (SEM) analysis revealed that coach autonomy support predicted participants’ basic need satisfaction for autonomy, competence and relatedness. In turn, basic need satisfaction predicted greater subjective vitality when engaged in sport. Participants with low levels of autonomy were more susceptible to feeling emotionally and physically exhausted from their sport investment. Autonomy and competence partially mediated the path from autonomy support to subjective vitality. Lastly, the results supported partial invariance of the model with respect to gender

    Reliability, Validity and Responsiveness of the Syncope Functional Status Questionnaire

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    BACKGROUND: Patients with transient loss of consciousness (TLOC) have poor health-related quality of life (HR-QoL). OBJECTIVE: To test the reliability, validity, and responsiveness of the disease-specific Syncope Functional Status HR-QoL Questionnaire (SFSQ), which yields two summary scales--impairment score (IS) and fear-worry score (FWS). DESIGN: Cohort-study. PARTICIPANTS: 503 adult patients presenting with TLOC. MEASUREMENTS: HR-QoL was assessed using the SFSQ and the Short Form-36 (SF-36) after presentation and 1 year later. To test reliability, score distributions, internal consistency, and test-retest reliability were assessed. To assess validity, scores on the SFSQ and the SF-36 were compared. Clinical validity was tested using known-group comparison. Responsiveness was assessed by comparing changes in SFSQ scores with changes in health status and clinical condition. RESULTS: Response rate was 82% at baseline and 72% at 1-year follow-up. For all scales the full range of scores was seen. Score distributions were asymmetrical. Internal consistency was high (alpha = 0.88 for IS, 0.92 for FWS). Test-retest reliability was moderate to good for individual items and high for summary scales (inter-class correlation = 0.78 for both IS and FWS). Correlations between SFSQ scores and the SF-36 were modest. The SFSQ did not discriminate between patients differing in age and gender but did discriminate between patients differing in number of episodes and comorbid conditions. Changes in SFSQ scores were related to changes in health status and the presence of recurrences but did not vary by TLOC diagnosis. CONCLUSION: The SFSQ is an adequately reliable, valid, and responsive measure to assess HR-QoL in patients with TLO

    Recommendations for tilt table testing and other provocative cardiovascular autonomic tests in conditions that may cause transient loss of consciousness. Consensus statement of the European Federation of Autonomic Societies (EFAS) endorsed by the American Autonomic Society (AAS) and the European Academy of Neurology (EAN)

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    An expert committee was formed to reach consensus on the use of tilt table testing (TTT) in the diagnosis of disorders that may cause transient loss of consciousness (TLOC) and to outline when other provocative cardiovascular autonomic tests are needed. While TTT adds to history taking, it cannot be a substitute for it. An abnormal TTT result is most meaningful if the provoked event is recognised by patients or eyewitnesses as similar to spontaneous events. The minimum requirements to perform TTT are a tilt table, a continuous beat-to-beat blood pressure monitor, at least one ECG lead, protocols for the indications stated below and trained staff. This basic equipment lends itself to the performance of (1) additional provocation tests, such as the active standing test, carotid sinus massage and autonomic function tests; (2) additional measurements, such as video, EEG, transcranial Doppler, NIRS, end-tidal CO2 or neuro-endocrine tests; and (3) tailor-made provocation procedures in those with a specific and consistent trigger of TLOC. TTT and other provocative cardiovascular autonomic tests are indicated if the initial evaluation does not yield a definite or highly likely diagnosis, but raises a suspicion of (1) reflex syncope, (2) the three forms of orthostatic hypotension (OH), i.e. initial, classic and delayed OH, as well as delayed orthostatic blood pressure recovery, (3) postural orthostatic tachycardia syndrome or (4) psychogenic pseudosyncope. A therapeutic indication for TTT is to teach patients with reflex syncope and OH to recognise hypotensive symptoms and to perform physical counter manoeuvres

    Fluctuating levels of personal role engagement within the working day: a multilevel study

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    In this diary study, we examined a theoretical model in which the psychological conditions of meaningfulness, availability, and safety serve as mechanisms through which the work context during discrete situations within the workday influences ‘state’ engagement. We further theorised that a person’s ‘trait’ level of engagement would exert cross-level effects on the ‘state’ level relationships. Multilevel analyses based on a sample of 124 individuals in six organisations and 1,446 situational observations revealed that meaningfulness and availability (but not safety) mediated the relationships between perceptions of the work context and ‘state’ engagement. High levels of ‘trait’ engagement strengthened the within-person relation between availability and ‘state’ engagement, yet weakened the within-person relation between meaningfulness and ‘state’ engagement; suggesting two different processes may be at play. Overall, the findings advance our understanding of engagement as a multilevel and temporally dynamic psychological phenomenon, and promote a contextually-based HRM approach to facilitating engagement

    Are managerial pressure, technological control and intrinsic motivation effective in improving data quality?

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    Can data collectors be “pushed” into collecting high quality data or would being “pulled” be more effective? This paper finds that managers should be careful of the degree to which “push” factors, such as managerial pressure and technological input control, are relied upon. While they may be helpful for motivating those data collectors who are not intrinsically motivated, they are either not helpful or may discourage those data collectors who are intrinsically motivated. Instead, self-concordance may act as a longer-term, more stable approach to increasing the motivation of data collectors and thus increasing the quality of data that enter reliability systems. This study uses a sequential mixed-method approach involving interviews with 20 data collectors and a quantitative survey of 109 data collectors in a water utility. It examines the interactive effect of managerial pressure, technological input control and self-concordance on data collection performance
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