8,967 research outputs found
Formative feedback to improve learning on a teacher education degree using a personal learning environment
This paper reports on an action research project involving a structured, formative assessment feedback process, within a personal learning environment (PLE), to address concerns about effectiveness of previous course delivery. The project ran during session 2006-07 involving the use of a series of tutor mediated self and peer assessed core tasks associated with five distinct learning milestones. These were associated with identifiable blocks of lectures delivered by different staff involved in the programme. The series of Core Tasks placed progressively increasing demands on students so helping them develop more sophisticated learning skills as the year progresses. The PLE is used as the medium for self/peer assessment processes and for tutor feedback and mediation
Solar energy conversion through the interaction of plasmons with tunnel junctions. Part A: Solar cell analysis. Part B: Photoconductor analysis
A solar cell utilizing guided optical waves and tunnel junctions was analyzed to determine its feasibility. From this analysis, it appears that the limits imposed upon conventional multiple cell systems also limit this solar cell. Due to this limitation, it appears that the relative simplicity of the conventional multiple cell systems over the solar cell make the conventional multiple cell systems the more promising candidate for improvement. It was discovered that some superlattice structures studied could be incorporated into an infrared photodetector. This photoconductor appears to be promising as a high speed, sensitive (high D sup star sub BLIP) detector in the wavelength range from 15 to over 100 micrometers
The Management of Pay as the Influence of Collective Bargaining Diminishes.
The management of pay in Britain has changed substantially in recent years. The paper starts with a theoretical discussion of the extent to which individual employers can exercise discretion in the management of their employees' pay. It then examines the ways in which pay is used to secure productive effort. An analysis of the influence of trade unions leads on to an examination of the diminishing influence of collective bargaining in British pay determination. The implications of this are discussed for employer pay strategies, within and between firms, and internationally. It concludes with the consequences of diminishing trade union influence for the distribution of pay.wage determination; collective bargaining; remuneration management; bargaining structure; income distribution; trade union effects; employer pay strategy
Particles in RSOS paths
We introduce a new representation of the paths of the Forrester-Baxter RSOS
models which represents the states of the irreducible modules of the minimal
models M(p',p). This representation is obtained by transforming the RSOS paths,
for the cases p> 2p'-2, to new paths for which horizontal edges are allowed at
certain heights. These new paths are much simpler in that their weight is
nothing but the sum of the position of the peaks. This description paves the
way for the interpretation of the RSOS paths in terms of fermi-type charged
particles out of which the fermionic characters could be obtained
constructively. The derivation of the fermionic character for p'=2 and p=kp'+/-
1 is outlined. Finally, the particles of the RSOS paths are put in relation
with the kinks and the breathers of the restricted sine-Gordon model.Comment: 15 pages, few typos corrected, version publishe
The long-term agronomic performance of organic stockless rotations
This report was presented at the UK Organic Research 2002 Conference. Two long-term experiments were established with the aim of evaluating the agronomic and economic performance of organic stockless rotations. In total, four different rotations were evaluated at two sites in the south (Elm Farm Research Centre) and east (ADAS Terrington) of England. All of the rotations included either a one or two-year red clover green manure crop to provide nitrogen for subsequent crops and it was found that this was sufficient to support three or four years of arable cropping. Over a period of eleven years at EFRC and five years at ADAS Terrington, there was no evidence of a decline in crop yield, although there were significant year-to-year variations. Crop yields were generally equivalent to or greater than average organic yields. Levels of soil available P and K was maintained at both sites at non-limiting levels. Pest and diseases were not problematic, but perennial weeds posed the most significant problem
Psychology and the "At Risk Mental State"
Over the last decade there have been orchestrated efforts to detect and intervene during the earliest stages of psychotic illness. This article reviews some of the literature and highlights the current and future contributions of psychology to a rapidly expanding area of research and clinical practice
A review of knowledge: inter-row hoeing & its associated agronomy in organic cereal & pulse crops
The aim of this project was to establish the āstate of the artā 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.
ā¢ 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).
ā¢ 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.
ā¢ 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.
ā¢ 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. āAā 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), āAā and āLā blades offer an effective low cost solution.
ā¢ 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.
ā¢ There is some evidence to suggest that mechanical weeding operations can mineralise soil bound nitrogen.
ā¢ 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:
ā¢ The interaction of seed rate and row spacing needs to be confirmed in organic systems.
ā¢ 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.
ā¢ 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.
ā¢ 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
State of the Art of Soil Improvements with Case Histories
Soil improvement techniques for geotechnical construction can be broadly classified as densification, reinforcement, adhesion and excavation/replacement. This paper presents an overview of selected soil improvement techniques, with significant case histories. The soil improvement techniques discussed include Vibro-Compaction, Vibro-Replacement (stone columns), Dynamic Deep Compaction, compaction grouting, chemical grouting, jet grouting and soil fracture grouting
Validation of empirical measures of welfare change: comment
In an excellent article from a recent issue of this journal, Sellar, Stoll and Chavas (1985) make a technical error which causes them to misstate their closed-ended estimates of willingness to pay. Truncation of the estimated cummulative distribution function must we made explicit in compution of willingness to pay.nonmarket valuation; contingent valuation; stated preferences; welfare evaluation; willingness to pay
Space shuttle engineering and operations support. Avionics system engineering
The shuttle avionics integration laboratory (SAIL) requirements for supporting the Spacelab/orbiter avionics verification process are defined. The principal topics are a Spacelab avionics hardware assessment, test operations center/electronic systems test laboratory (TOC/ESL) data processing requirements definition, SAIL (Building 16) payload accommodations study, and projected funding and test scheduling. Because of the complex nature of the Spacelab/orbiter computer systems, the PCM data link, and the high rate digital data system hardware/software relationships, early avionics interface verification is required. The SAIL is a prime candidate test location to accomplish this early avionics verification
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