44,438 research outputs found
Rotating Metal Band Target for Pion Production at Muon Colliders and Neutrino Factories
A conceptual design is presented for a high power pion production target for
muon colliders and neutrino factories that is based around a rotating metal
band.Comment: 28 pages, 16 figures; to be published in Phys. Rev. ST Accel. Beam
Role of the community matron in advance care planning and âdo not attempt CPRâ decision-making: a qualitative study
The community matron (CM) is often the key worker caring for patients with chronic, life-limiting, long-term conditions, but these patients are not always recognised as palliative cases. This study explored the experiences of CMs with regard to advance care planning (ACP) and âdo not attempt cardiopulmonary resuscitationâ (DNACPR) decision-making to understand whether or not they felt adequately prepared for this aspect of their role, and why. Qualitative data were generated from six CMs using a broad interpretive phenomenological approach. Face-to-face recorded interviews were analysed using template analysis. The study found that although participants faced complex ethical situations around ACP and DNACPR almost on a daily basis, none had received any formal training despite the emphasis on training in national and local guidelines. Participants often struggled to get their patients accepted on to the Gold Standards Framework. The research found variability and complexity of cases to be the main barriers to clear identification of the palliative phase
A review of knowledge: inter-row hoeing & its associated agronomy in organic cereal & pulse crops
The aim of this project was to establish the âstate of the artâ for inter-row hoeing and its associated agronomic practices in organic cereal and pulse crops. To achieve this a detailed review of literature was undertaken.
⢠To facilitate inter-row cultivation in cereal and pulse crops, some adjustment of row spacing may be required. For cereals, drilling crops in 25 cm rows can reduce yield compared with normal drilling practice, primarily due to greater intra-specific competition amongst the crop (i.e. competition between crop plants).
⢠The yield penalty resulting from widely spaced crop rows can be minimised using a number of approaches, depending on the drill:
1. Reducing the seed rate in widely spaced crop rows can help to minimise excessive intra-specific competition.
2. Band sowing the crop in wide rows can also help to minimise intra-specific competition as the seed is distributed over a greater area.
3. Using a twin-row arrangement can completely overcome the yield penalty.
⢠The recommended row spacing for peas (up to 20 cm) and beans (up to 35 cm) does not require any further adjustment for inter-row hoeing.
⢠Recent developments in automated guidance of inter-row hoeing equipment mean that weeding operations can now be conducted a much higher speeds (10 km h-1). This has highlighted the limitations of some of the cultivators currently used (e.g. âAâ blades), as excessive soil throw can occur at this high speed. Rolling cultivators may prove to be the most suitable at high forward speeds. For manually guided hoes working at slower speeds (5 km h-1), âAâ and âLâ blades offer an effective low cost solution.
⢠In terms of the timing of inter-row hoeing, it is suggested that weeding operations should be conducted at an early stage in the growing season, as the weeds that emerge with or shortly after the crop are the ones that pose the most significant threat for crop yield. Weeding on two occasions can provide better levels of weed control than weeding once, but weeding more frequently offered little additional benefit. Reductions of weed biomass of up to 99 % have been reported as a result of inter-row hoeing, although this has not always resulted in a positive crop yield response. This is probably due to crop damage resulting from inaccurate hoeing, a problem that can be overcome with automated guidance.
⢠There is some evidence to suggest that mechanical weeding operations can mineralise soil bound nitrogen.
⢠The impact of inter-row hoeing on ground nesting birds is uncertain. Early indications suggest that skylarks prefer to nest directly adjacent to or in the crop row rather than between rows.
The information contained within this review should enable farmers to make best use of inter-row hoeing in their arable crops.
There are a number of areas that require further research and development:
⢠The interaction of seed rate and row spacing needs to be confirmed in organic systems.
⢠Relatively little is known about the mechanisms of weed kill and the detailed interaction between the cultivator blade, the weed and the soil. This is particularly important with the new automated guidance equipment that allows weeding at high forward speeds.
⢠The timing and frequency of inter-row hoeing has received very little attention. The optimum weed control timings are based on small-plot crop:weed competition studies and need to be verified under field scale management with inter-row hoeing equipment.
⢠Finally, the impact of inter-row hoeing and widely spaced crop rows on ground-nesting birds has not been looked at directly, but is of importance.
Please see the main report for a more detailed summary before the full text
Microbiology, ecology and microclimatology of soil sites in Dry Valleys of southern Victoria land, Antarctica
Doing it differently: Engaging interview participants with imaginative variation
Imaginative variation was identified by Husserl (1936/1970) as a phenomenological technique for the purpose of elucidating the manner in which phenomena appear to consciousness. Briefly, by engaging in the phenomenological reduction and using imaginative variation, phenomenologists are able to describe the experience of consciousness, having stepped outside of the natural attitude through the epochÄ. Imaginative variation is a stage aimed at explicating the structures of experience, and is best described as a mental experiment. Features of the experience are imaginatively altered in order to view the phenomenon under investigation from varying perspectives. Husserl argued that this process will reveal the essences of an experience, as only those aspects that are invariant to the experience of the phenomenon will not be able to change through the variation.
Often in qualitative research interviews, participants struggle to articulate or verbalise their experiences. The purpose of this article is to detail a radical and novel way of using imaginative variation with interview participants, by asking the participants to engage with imaginative variation, in order to produce a rich and insightful experiential account of a phenomenon. We will discuss how the first author successfully used imaginative variation in this way in her study of the erotic experience of bondage, discipline, dominance & submission, and sadism & masochism (BDSM), before considering the usefulness of this technique when applied to areas of study beyond sexuality
NERVA irradiation program, GTR test 21. Volume 4 - Effect of radiation on structural materials tested at cryogenic and elevated temperatures
Effect of radiation on structural materials for NERVA engine tested at cryogenic and elevated temperatures - Vol.
Cooling of cryogenic electron bilayers via the Coulomb interaction
Heat dissipation in current-carrying cryogenic nanostructures is problematic
because the phonon density of states decreases strongly as energy decreases. We
show that the Coulomb interaction can prove a valuable resource for carrier
cooling via coupling to a nearby, cold electron reservoir. Specifically, we
consider the geometry of an electron bilayer in a silicon-based
heterostructure, and analyze the power transfer. We show that across a range of
temperatures, separations, and sheet densities, the electron-electron
interaction dominates the phonon heat-dissipation modes as the main cooling
mechanism. Coulomb cooling is most effective at low densities, when phonon
cooling is least effective in silicon, making it especially relevant for
experiments attempting to perform coherent manipulations of single spins.Comment: 9 pages, 5 figure
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