860 resultados para Model development guidelines
Intuitive and analytical decision-making in a high risk industry: Development and testing of a model
Resumo:
Recent research on teacher stress in primary schools (e.g. Leonard, Bourke & Schofield, 1999) has shown that higher levels of teacher exhaustion are associated with higher levels of student satisfaction. This paper seeks to explain this surprising finding by considering a construct discussed widely in the organisational literature known as extra-role or organisational citizenship behaviour (OCB). Teacher OCB may include extra efforts to make lessons enjoyable and interesting, organising extra-curricular activities and spending personal time talking with students. The proposed model of analysis also draws on literature relating to job burnout (Maslach, 1982), which generally suggests that the three components of chronic occupational stress - exhaustion, depersonalisation and reduced accomplishment - occur together. However, this paper proposes that although teachers who engage in more OCB experience more exhaustion, they may simultaneously increase their feelings of personal accomplishment and work identification, which may in turn help to avert burnout. It is argued that only with this particular set of job attitudes are the effects of exhaustion caused by high levels of OCB sufficiently buffered to avoid job burnout, and thus positively affect students' quality of school life. The development and piloting of an instrument to measure teachers' OCB will be discussed. The preliminary findings reported herein are part of a larger ongoing study investigating the consequences of stress and OCB in primary school teachers.
Resumo:
The mechanism of muscle protein catabolism induced by proteolysis-inducing factor, produced by cachexia-inducing murine and human tumours has been studied in vitro using C2C12 myoblasts and myotubes. In both myoblasts and myotubes protein degradation was enhanced by proteolysis-inducing factor after 24 h incubation. In myoblasts this followed a bell-shaped dose-response curve with maximal effects at a proteolysis-inducing factor concentration between 2 and 4 nM, while in myotubes increased protein degradation was seen at all concentrations of proteolysis-inducing factor up to 10 nM, again with a maximum of 4 nM proteolysis-inducing factor. Protein degradation induced by proteolysis-inducing factor was completely attenuated in the presence of cycloheximide (1 μM), suggesting a requirement for new protein synthesis. In both myoblasts and myotubes protein degradation was accompanied by an increased expression of the α-type subunits of the 20S proteasome as well as functional activity of the proteasome, as determined by the 'chymotrypsin-like' enzyme activity. There was also an increased expression of the 19S regulatory complex as well as the ubiquitin-conjugating enzyme (E214k), and in myotubes a decrease in myosin expression was seen with increasing concentrations of proteolysis-inducing factor. These results show that proteolysis-inducing factor co-ordinately upregulates both ubiquitin conjugation and proteasome activity in both myoblasts and myotubes and may play an important role in the muscle wasting seen in cancer cachexia. © 2002 Cancer Research UK.
Resumo:
Based on recent advances in autonomic computing, we propose a methodology for the cost-effective development of self-managing systems starting from a model of the resources to be managed and using a general-purpose autonomic architecture.
Resumo:
It has been recognised for some time that a full code of amino acid-based recognition of DNA sequences would be useful. Several approaches, which utilise small DNA binding motifs called zinc fingers, are presently employed. None of the current approaches successfully combine a combinatorial approach to the elucidation of a code with a single stage high throughput screening assay. The work outlined here describes the development of a model system for the study of DNA protein interactions and the development of a high throughput assay for detection of such interactions. A zinc finger protein was designed which will bind with high affinity and specificity to a known DNA sequence. For future work it is possible to mutate the region of the zinc finger responsible for the specificity of binding, in order to observe the effect on the DNA / protein interactions. The zinc finger protein was initially synthesised as a His tagged product. It was not possible however to develop a high throughput assay using the His tagged zinc finger protein. The gene encoding the zinc finger protein was altered and the protein synthesised as a Glutathione S-Transferase (GST) fusion product. A successful assay was developed using the GST protein and Scintillation Proximity Assay technology (Amersham Pharmacia Biotech). The scintillation proximity assay is a dynamic assay that allows the DNA protein interactions to be studied in "real time". This assay not only provides a high throughput method of screening zinc finger proteins for potential ligands but also allows the effect of addition of reagents or competitor ligands to be monitored.
Resumo:
In vitro studies of drug absorption processes are undertaken to assess drug candidate or formulation suitability, mechanism investigation, and ultimately for the development of predictive models. This study included each of these approaches, with the aim of developing novel in vitro methods for inclusion in a drug absorption model. Two model analgesic drugs, ibuprofen and paracetamol, were selected. The study focused on three main areas, the interaction of the model drugs with co-administered antacids, the elucidation of the mechanisms responsible for the increased absorption rate observed in a novel paracetamol formulation and the development of novel ibuprofen tablet formulations containing alkalising excipients as dissolution promoters.Several novel dissolution methods were developed. A method to study the interaction of drug/excipient mixtures in the powder form was successfully used to select suitable dissolution enhancing exicipents. A method to study intrinsic dissolution rate using paddle apparatus was developed and used to study dissolution mechanisms. Methods to simulate stomach and intestine environments in terms of media composition and volume and drug/antacid doses were developed. Antacid addition greatly increased the dissolution of ibuprofen in the stomach model.Novel methods to measure drug permeability through rat stomach and intestine were developed, using sac methodology. The methods allowed direct comparison of the apparent permeability values obtained. Tissue stability, reproducibility and integrity was observed, with selectivity between paracellular and transcellular markers and hydrophilic and lipophilic compounds within an homologous series of beta-blockers.
Resumo:
Shropshire Energy Team initiated this study to examine consumption and associated emissions in the predominantly rural county of Shropshire. Current use of energy is not sustainable in the long term and there are various approaches to dealing with the environmental problems it creates. Energy planning by a local authority for a sustainable future requires detailed energy consumption and environmental information. This information would enable target setting and the implementation of policies designed to encourage energy efficiency improvements and exploitation of renewable energy resources. This could aid regeneration strategies by providing new employment opportunities. Associated reductions in carbon dioxide and other emissions would help to meet national and international environmental targets. In the absence of this detailed information, the objective was to develop a methodology to assess energy consumption and emissions on a regional basis from 1990 onwards for all local planning authorities. This would enable a more accurate assessment of the relevant issues, such that plans are more appropriate and longer lasting. A first comprehensive set of data has been gathered from a wide range of sources and a strong correlation was found between population and energy consumption for a variety of regions across the UK. In this case the methodology was applied to the county of Shropshire to give, for the first time, estimates of primary fuel consumption, electricity consumption and associated emissions in Shropshire for 1990 to 2025. The estimates provide a suitable baseline for assessing the potential contribution renewable energy could play in meeting electricity demand in the country and in reducing emissions. The assessment indicated that in 1990 total primary fuel consumption was 63,518,018 GJ/y increasing to 119,956,465 GJ/y by 2025. This is associated with emissions of 1,129,626 t/y of carbon in 1990 rising to 1,303,282 t/y by 2025. In 1990, 22,565,713 GJ/y of the primary fuel consumption was used for generating electricity rising to 23,478,050 GJ/y in 2025. If targets to reduce primary fuel consumption are reached, then emissions of carbon would fall to 1,042,626 by 2025, if renewable energy targets were also reached then emissions of carbon would fall to 988,638 t/y by 2025.
Resumo:
In this thesis, I view the historical background of Zimbabwe to show the patterns of traditional life that existed prior to settlerism. The form, nature, pace and impact of settlerism and colonialism up to the time of independence are also discussed to show how they affected the health of the population and the pace of development of the country. The political, social and economic underdevelopment of the African people that occurred in Zimbabwe prior to independence was a result of deliberate, politically motivated and controlled policy initiatives. These led to inequatable, inadequate, inappropriate and inaccessible health care provision. It is submitted that since it was the politics that determined the pace of underdevelopment, it must be the politics that must be at the forefront of the development strategy adopted. In the face of the amed conflict that existed in Zimbabwe, existing frameworks of analyses are shown to be inadequate for planning purposes because of their inability to provide indications about the stability of future outcomes. The Metagame technique of analysis of options is proposed as a methology that can be applied in such situations. It rejects deterministic predicative models as misleading and advocates an interactive model based on objective and subjective valuation of human behaviour. In conclusion, the search for stable outcomes rather than optimal and best solutions strategies is advocated in decision making in organisations of all sizes.