4,727 research outputs found

    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

    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

    Marinbiologiske forbedringer av miljøet i Bjørvika/Bispevika. Vurdering av muligheter

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    Årsliste 2006Rapporten beskriver hvilke muligheter som foreligger for å forbedre det marinbiologiske miljøet i Bjørvika-/Bispevikaområdet etter at anleggsarbeider som berører vannet i området er fullført. Hensikten er å få et rikere plante- og dyreliv i området ved transplantasjon av enkelte makroalger og ålegras samt utplassering av kunstige rev spesielt konstruert til å begunstige dyrelivet (bl.a. fisk). Forholdene i området vil ikke bli like bra som i øvrige deler av fjorden, men en klar forbedring av forholdene er mulig, sammenlignet med dagens tilstand. Det forutsettes at tilførsler fra overløp og andre lokale tilførsler blir redusert ved rensetekniske tiltak. Etablering av nytt liv i området vil også kunne ha en selvrensingseffekt i tillegg til de estetiske og rekreasjonsmessige fordelene. For god gjennomføring av arbeidet er det nødvendig med pilotprosjekt for å finne frem til teknikker og gunstige substrater, samt at de enkelte artene og de kunstige revene gir forventet resultat. Kostnader for pilotprosjekt og fullskalaforsøk er anslått.Oslo Vann- og Avløpsetate

    Optical properties of carbon nanofiber photonic crystals

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    Carbon nanofibers (CNF) are used as components of planar photonic crystals. Square and rectangular lattices and random patterns of vertically aligned CNF were fabricated and their properties studied using ellipsometry. We show that detailed information such as symmetry directions and the band structure of these novel materials can be extracted from considerations of the polarization state in the specular beam. The refractive index of the individual nanofibers was found to be n_CNF = 4.1.Comment: 10 pages, 4 figure

    Cross-sectional survey of users of internet depression communities

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    Background: Internet-based depression communities provide a forum for individuals to communicate and share information and ideas. There has been little research into the health status and other characteristics of users of these communities. Methods: Online cross-sectional survey of Internet depression communities to identify depressive morbidity among users of Internet depression communities in six European countries; to investigate whether users were in contact with health services and receiving treatment; and to identify user perceived effects of the communities. Results: Major depression was highly prevalent among respondents (varying by country from 40% to 64%). Forty-nine percent of users meeting criteria for major depression were not receiving treatment, and 35% had no consultation with health services in the previous year. Thirty-six percent of repeat community users who had consulted a health professional in the previous year felt that the Internet community had been an important factor in deciding to seek professional help. Conclusions: There are high levels of untreated and undiagnosed depression in users of Internet depression communities. This group represents a target for intervention. Internet communities can provide information and support for stigmatizing conditions that inhibit more traditional modes of information seeking

    An exchange format for multimodal annotations

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    This paper presents the results of a joint effort of a group of multimodality researchers and tool developers to improve the interoperability between several tools used for the annotation of multimodality. We propose a multimodal annotation exchange format, based on the annotation graph formalism, which is supported by import and export routines in the respective tool
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