5,111 research outputs found

    Ku-Band rendezvous radar performance computer simulation model

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    All work performed on the Ku-band rendezvous radar performance computer simulation model program since the release of the preliminary final report is summarized. Developments on the program fall into three distinct categories: (1) modifications to the existing Ku-band radar tracking performance computer model; (2) the addition of a highly accurate, nonrealtime search and acquisition performance computer model to the total software package developed on this program; and (3) development of radar cross section (RCS) computation models for three additional satellites. All changes in the tracking model involved improvements in the automatic gain control (AGC) and the radar signal strength (RSS) computer models. Although the search and acquisition computer models were developed under the auspices of the Hughes Aircraft Company Ku-Band Integrated Radar and Communications Subsystem program office, they have been supplied to NASA as part of the Ku-band radar performance comuter model package. Their purpose is to predict Ku-band acquisition performance for specific satellite targets on specific missions. The RCS models were developed for three satellites: the Long Duration Exposure Facility (LDEF) spacecraft, the Solar Maximum Mission (SMM) spacecraft, and the Space Telescopes

    Concurrent affective and linguistic prosody with the same emotional valence elicits a late positive ERP response

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    Change in linguistic prosody generates a mismatch negativity response (MMN), indicating neural representation of linguistic prosody, while change in affective prosody generates a positive response (P3a), reflecting its motivational salience. However, the neural response to concurrent affective and linguistic prosody is unknown. The present paper investigates the integration of these two prosodic features in the brain by examining the neural response to separate and concurrent processing by electroencephalography (EEG). A spoken pair of Swedish words—[ˈfɑ́ːsɛn] phase and [ˈfɑ̀ːsɛn] damn—that differed in emotional semantics due to linguistic prosody was presented to 16 subjects in an angry and neutral affective prosody using a passive auditory oddball paradigm. Acoustically matched pseudowords—[ˈvɑ́ːsɛm] and [ˈvɑ̀ːsɛm]—were used as controls. Following the constructionist concept of emotions, accentuating the conceptualization of emotions based on language, it was hypothesized that concurrent affective and linguistic prosody with the same valence—angry [ˈfɑ̀ːsɛn] damn—would elicit a unique late EEG signature, reflecting the temporal integration of affective voice with emotional semantics of prosodic origin. In accordance, linguistic prosody elicited an MMN at 300–350 ms, and affective prosody evoked a P3a at 350–400 ms, irrespective of semantics. Beyond these responses, concurrent affective and linguistic prosody evoked a late positive component (LPC) at 820–870 ms in frontal areas, indicating the conceptualization of affective prosody based on linguistic prosody. This study provides evidence that the brain does not only distinguish between these two functions of prosody but also integrates them based on language and experience

    Evaluation of laser range-finder mapping for agricultural spraying vehicles

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    In this paper, we present a new application of laser range-finder sensing to agricultural spraying vehicles. The current generation of spraying vehicles use automatic controllers to maintain the height of the sprayer booms above the crop. However, these control systems are typically based on ultrasonic sensors mounted on the booms, which limits the accuracy of the measurements and the response of the controller to changes in the terrain, resulting in a sub-optimal spraying process. To overcome these limitations, we propose to use a laser scanner, attached to the front of the sprayer's cabin, to scan the ground surface in front of the vehicle and to build a scrolling 3d map of the terrain. We evaluate the proposed solution in a series of field tests, demonstrating that the approach provides a more detailed and accurate representation of the environment than the current sonar-based solution, and which can lead to the development of more efficient boom control systems

    Clustering of vacancy defects in high-purity semi-insulating SiC

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    Positron lifetime spectroscopy was used to study native vacancy defects in semi-insulating silicon carbide. The material is shown to contain (i) vacancy clusters consisting of 4--5 missing atoms and (ii) Si vacancy related negatively charged defects. The total open volume bound to the clusters anticorrelates with the electrical resistivity both in as-grown and annealed material. Our results suggest that Si vacancy related complexes compensate electrically the as-grown material, but migrate to increase the size of the clusters during annealing, leading to loss of resistivity.Comment: 8 pages, 5 figure

    Putting knowledge to work in clinical practice: understanding experiences of preceptorship as outcomes of interconnected domains of learning

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    Aim: To understand newly qualified nurses’ learning during the preceptorship period. Background: Newly qualified nurses’ learning during their transition to confident professional practice is facilitated by effective and supportive preceptorship. Several studies have alluded to, but not directly investigated or addressed contextual factors which may prevent the delivery of effective and supportive preceptorship. Design: Two-phase ethnographic case study design in three hospital sites in England from 2011-2014. Methods: Phase One included participant observation, interviews with 33 newly qualified nurses, 10 healthcare assistants and 12 ward managers, the design of a tool to develop newly qualified nurses’ delegation skills during their preceptorship period. This tool was piloted in Phase Two with thirteen newly qualified nurses in the same sites. Data were analysed using thematic analysis. Findings: Constraints on available time for preceptorship, unsupportive ward cultures, and personal learning styles may limit effective preceptorship if time for learning and knowledge recontextualisation is restricted. For newly qualified nurses in supportive ward cultures, limited access to formal preceptorship can be bolstered by team support. Newly qualified nurses in less supportive ward cultures may have both a greater need for preceptorship and have fewer compensatory mechanisms available to them when formal preceptorship is not available. We argue that organisational learning contexts and individual learning styles which facilitate recontextualisation of knowledge in this group of nurses are key to understanding effective preceptorship. Conclusions: This study reports constraints to effective preceptorship which affect newly qualified nurses in their early careers. We recommend a need for greater prioritisation and ‘ring-fencing’ of time for formal preceptorship to ensure newly qualified nurses are appropriately supported in their transition to confident professional practice. Relevance to clinical practice: We discuss ways to improve preceptorship at ward and organizational level through policy, practice and education and suggest future research in this are

    Delegation and supervision of health care assistants’ work in the daily management of uncertainty and the unexpected in clinical practice: invisible learning among newly qualified nurses

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    The invisibility of nursing work has been discussed in the international literature but not in relation to learning clinical skills. Evans and Guile’s (2012) theory of recontextualisation is used to explore the ways in which invisible or unplanned and unrecognised learning takes place as newly qualified nurses learn to delegate to and supervise the work of the health care assistant. In the British context, delegation and supervision are thought of as skills which are learnt ‘on the job’. We suggest that learning ‘on-the-job’ is the invisible construction of knowledge in clinical practice and that delegation is a particularly telling area of nursing practice which illustrates invisible learning. Using an ethnographic case study approach in three hospital sites in England from 2011-2014, we undertook participant observation, interviews with newly qualified nurses, ward managers and health care assistants. We discuss the invisible ways newly qualified nurses learn in the practice environment and present the invisible steps to learning which encompass the embodied, affective and social, as much as the cognitive components to learning. We argue that there is a need for greater understanding of the ‘invisible learning’ which occurs as newly qualified nurses learn to delegate and supervise

    'Doing the writing' and 'working in parallel': how 'distal nursing' affects delegation and supervision in the emerging role of the newly qualified nurse

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    Background: The role of the acute hospital nurse has moved away from the direct delivery of patient care and more towards the management of the delivery of bedside care by healthcare assistants. How newly qualified nurses delegate to and supervise healthcare assistants is important as failures can lead to care being missed, duplicated and/or incorrectly performed. Objectives: The data described here form part of a wider study which explored how newly qualified nurses recontextualise knowledge into practice, and develop and apply effective delegation and supervision skills. This article analyses team working between newly qualified nurses and healthcare assistants, and nurses' balancing of administrative tasks with bedside care. Methods and Analysis: Ethnographic case studies were undertaken in three hospital sites in England, using a mixed methods approach involving: participant observations; interviews with 33 newly qualified nurses, 10 healthcare assistants and 12 ward managers. Data were analysed using thematic analysis, aided by the qualitative software NVivo. Findings:Multiple demands upon the newly qualified nurses' time, particularly the pressures tomaintain records, can influence how effectively they delegate to, and supervise, healthcare assistants. While some nurses and healthcare assistants work successfully together, others work ‘in parallel’ rather than as an efficient team. Conclusions: While some ward cultures and individual working styles promote effective team working, others lead to less efficient collaboration between newly qualified nurses and healthcare assistants. In particular the need for qualified nurses to maintain records can create a gap between them, and between nurses and patients. Newly qualified nurses require more assistance in managing their own time and developing successful working relationships with healthcare assistants

    Non-equilibrium dynamics in an interacting nanoparticle system

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    Non-equilibrium dynamics in an interacting Fe-C nanoparticle sample, exhibiting a low temperature spin glass like phase, has been studied by low frequency ac-susceptibility and magnetic relaxation experiments. The non-equilibrium behavior shows characteristic spin glass features, but some qualitative differences exist. The nature of these differences is discussed.Comment: 7 pages, 11 figure
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