10,068 research outputs found

    Influential Functionals

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    Learning about density functional approximations (DFAs), or approximations for the exchange-correlation functional, can be intimidating. Density Functional Theory is now one of the primary simulation tools for the practicing chemist or materials scientist, and its accuracy relies upon an appropriate choice of DFA. Over the past decades, there has been extensive research effort to find better DFAs, and there is now a large body of literature to read through for someone learning about DFAs for the first time. In this brief report, I share an analysis that suggests which functionals and publications have been the most influential, as a potential reading list to new scientists in this area. Here, "influential" is defined as "likely to have informed the design of another functional," and not simply a measure of number of citations, or how much that functional has been used for practical applications. This analysis is not claimed to be complete.Comment: For associated data see https://contribs.materialsproject.org/projects/influential_functional

    An in situ probe‐spacing‐correcting thermo‐TDR sensor to measure soil water content accurately

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    To reduce the possibility of probe deflections, conventional thermo-time domain reflectometry (T-TDR) sensors have relatively short probe lengths (≤4 cm). However, short probes lead to large errors in TDR-estimated soil water content (θv). In this study, two new 6-cm-long probe-spacing-correcting T-TDR (CT-TDR) sensors were investigated. Compared to conventional 4-cm-long T-TDR sensors, the 6-cm-long CT-TDR sensors reduced errors in TDR-estimated θv. Errors in heat pulse (HP) estimated θv because of probe deflections were reduced when linear or nonlinear probe spacing correcting algorithms were implemented. The 6-cm-long CT-TDR sensors provided more accurate θv estimations than do the conventional 4-cm-long TTDR sensors

    Effective use of ERTS multisensor data in the Northern Great Plains

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    The author has identified the following significant results. ERTS imagery was used as a tool in the identification and refinement of soil association areas; to classify land use patterns between crop and fallow fields; to identify corn, soybeans, and oats; and to identify broad generalized range ecosystems. Various data handling techniques were developed and applied to accomplish these tasks. A map outlining soil associations and relative land values was completed on a base mosaic of ERTS imagery and is included as an appendix to the report

    The agrin gene codes for a family of basal lamina proteins that differ in function and distribution

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    We isolated two cDNAs that encode isoforms of agrin, the basal lamina protein that mediates the motor neuron-induced aggregation of acetylcholine receptors on muscle fibers at the neuromuscular junction. Both proteins are the result of alternative splicing of the product of the agrin gene, but, unlike agrin, they are inactive in standard acetylcholine receptor aggregation assays. They lack one (agrin-related protein 1) or two (agrin-related protein 2) regions in agrin that are required for its activity. Expression studies provide evidence that both proteins are present in the nervous system and muscle and that, in muscle, myofibers and Schwann cells synthesize the agrin-related proteins while the axon terminals of motor neurons are the sole source of agrin

    Extended methodology for determining wetting properties of porous media

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    [1] Because most methods for assessing the wettability of porous materials are restricted in their applicability, we developed two new methods for measuring contact angles and particle surface energy. The proposed methods (the Wilhelmy plate method (WPM) and the modified capillary rise method (MCRM)) were tested on 24 soils. For comparison, the water drop penetration time test (WDPTT) and the sessile drop method (SDM) were also applied. It was found that advancing contact angles, measured either with WPM or MCRM, agreed well in the range of 0° to 142°. Sessile drop contact angles were within the domain enclosed by the range of advancing and receding contact angles as determined with WPM. WDPTT, however, was only sensitive in the narrow range of 85° to 115°. We conclude that both WPM and MCRM are reliable methods for determining contact angles and particle surface energy over a wide range of porous material wettabilities

    Utilization of Dedicated Electric Vehicle Plug-In Charging Stations in a College Campus Environment

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    As electric mobility is expanding at a rapid pace, the standardized availability of gas stations compared to a scarcity of charging stations continues to be the greatest challenge for electric vehicles. With cities, university campuses and businesses promoting electric vehicle infrastructure and incentives, it is necessary to develop key performance metrics and visualizations that can track the utilization of the charging infrastructure. This study performs a manual data collection at dedicated plug-in charging stations across Purdue University to assess their utilization. Approximately 2,800 observations were conducted over 50 days across seven level 2 plug-in charging stations. Results showed that for large portion of the observations, vehicles were parked at the spots (40%) but not plugged in. Vehicles plugged in to charging stations accounted for 34% of observations. Charging station spots were vacant for 25% of observations indicating that current infrastructure meets the demand. There were 74 unique vehicles that used the spots, of which 27% were plugged in more than 10 times. Illegally parked vehicles accounted for less than 1% with only 4 repeat offenders who used these spots more than once. As electric deployment continues to increase, performance metrics will be an integral tool for agencies and decision makers to help with the maintenance and expansion of electric vehicle infrastructure

    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

    CXSFIT User Manual

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    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
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