6 resultados para systemic model

em Aston University Research Archive


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This work is the result of an action-research-type study of the diversification effort of part of a major U.K. industrial company. Work in contingency theory concerning the impact of environmental factors on organizational design, and the systemic model of viable systems put forward by Stafford Beer form the theoretical basis of the vvork. The two streams of thought are compared and found to offer similar conclusions about the design of effective organizations. These findings are taken as the framework for an analysis both of organization structures for promoting innovation described in the literature, and of those employed by the company for this purpose in recent years. Much attention is given to the use of venture groups, and conclusions are drawn on particular factors which may influence their success or failure. Both theoretical considerations, and the examination of the company' s recent experience suggested that the formation of the policy of diversification, as well as the method of implementation of the police, might affect its outcorre. Attention is therefore focused on the policy-making and planning process, and in particular on possible problems that this process could generate in a multi-division company. The view finally taken of diversification effort is that it should be regarded as a learning system. This view helps to expose some ambiguities in the concepts of success and failure in this area, and demonstrates considerable weaknesses in traditional project evaluation procedures.

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Despite the growth of spoken academic corpora in recent years, relatively little is known about the language of seminar discussions in higher education. This thesis compares seminar discussions across three disciplinary areas. The aim of this thesis is to uncover the functions and patterns of talk used in different disciplinary discussions and to highlight language on a macro and micro level that would be useful for materials design and teaching purposes. A framework for identifying and analysing genres in spoken language based on Hallidayan Systemic Functional Linguistics (SFL) is used. Stretches of talk sharing a similar purpose and predictable functional staging, termed Discussion Macro Genres (DMGs) are identified. Language is compared across DMGs and across disciplines through use of corpus techniques in conjunction with SFL genre theory. Data for the study comprises just over 180,000 tokens and is drawn from the British Academic Spoken English corpus (BASE), recorded at two universities in the UK. The discipline areas investigated are Arts and Humanities, Social Sciences and Physical Sciences. Findings from this study make theoretical, empirical and methodological contributions to the field of spoken EAP. The empirical findings are firstly, that the majority of the seminar discussion can be assigned to one of the three main DMG in the corpus: Responding, Debating and Problem Solving. Secondly, it characterises each discipline area according to two DMGs. Thirdly, the majority of the discussion is non-oppositional in nature, suggesting that ‘debate’ is not the only form of discussion that students need to be prepared for. Finally, while some characteristics of the discussion are tied to the DMG and common across disciplines, others are discipline specific. On a theoretical level, this study shows that an SFL genre model for investigating spoken discourse can be successfully extended to investigate longer stretches of discourse than have previously been identified. The methodological contribution is to demonstrate how corpus techniques can be combined with SFL genre theory to investigate extended stretches of spoken discussion. The thesis will be of value to those working in the field of teaching spoken EAP/ ESAP as well as to materials developers.

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We present a probabilistic, online, depth map fusion framework, whose generative model for the sensor measurement process accurately incorporates both long-range visibility constraints and a spatially varying, probabilistic outlier model. In addition, we propose an inference algorithm that updates the state variables of this model in linear time each frame. Our detailed evaluation compares our approach against several others, demonstrating and explaining the improvements that this model offers, as well as highlighting a problem with all current methods: systemic bias. © 2012 Springer-Verlag.

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Background - Our previous studies showed that the direct injection of an adenovirus construct expressing urokinase-type plasminogen activator (uPA) into experimental venous thrombi significantly reduces thrombus weight. The systemic use of adenovirus vectors is limited by inherent hepatic tropism and inflammatory response. As macrophages are recruited into venous thrombi, it is reasonable to speculate that these cells could be used to target the adenovirus uPA (ad-uPA) gene construct to the thrombus. The aims of this study were to determine whether macrophages transduced with ad-uPA have increased fibrinolytic activity and whether systemic injection of transduced cells could be used to target uPA expression to the thrombus and reduce its size. Methods - The effect of up-regulating uPA was examined in an immortalized macrophage cell line (MM6) and macrophages differentiated from human blood monocyte-derived macrophages (HBMMs). Cells were infected with ad-uPA or blank control virus (ad-blank). Fibrinolytic mediator expression, cell viability, and cytokine expression were measured by activity assays and enzyme-linked immunosorbent assays. Monocyte migration was measured using a modified Boyden chamber assay. A model of venous thrombosis was developed and characterized in mice with severe combined immunodeficiency (SCID). This model was used to study whether systemically administered macrophages over-expressing uPA reduced thrombus size. Uptake of HBMMs into the thrombus induced in these mice was confirmed by a combination of PKH2-labeled cell tracking and colocalization with human leukocyte antigen (HLA) by immunohistology. Results - Compared with ad-blank, treated HBMMs transduction with ad-uPA increased uPA production by >1000-fold (P = .003), uPA activity by 150-fold (P = .0001), and soluble uPA receptor (uPAR) by almost twofold (P = .043). Expression of plasminogen activator inhibitor (PAI-1) and PAI-2 was decreased by about twofold (P = .011) and threefold (P = .005), respectively. Up-regulation of uPA had no effect on cell viability or inflammatory cytokine production compared with ad-blank or untreated cells. Ad-uPA transduction increased the migration rate of HBMMs (about 20%, P = .03) and MM6 cells (>twofold, P = .005) compared with ad-blank treated controls. Human macrophage recruitment into the mouse thrombus was confirmed by the colocalization of HLA with the PKH2-marked cells. Systemic injection of uPA-up-regulated HBMMs reduced thrombus weight by approximately 20% compared with ad-blank (P = .038) or sham-treated controls (P = .0028). Conclusion - Transduction of HBBM with ad-uPA increases their fibrinolytic activity. Systemic administration of uPA up-regulated HBBMs reduced thrombus size in an experimental model of venous thrombosis. Alternative methods of delivering fibrinolytic agents are worth exploring.

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Early detection of glaucoma relies on a detailed knowledge of how the normal optic nerve (ONH) varies within the population. The purpose of this study focused on two main areas; 1. To explore the optic nerve head appearance in the normal optometric population and compare the south Asian (principally Pakistani) with the European white population, correcting for possible ocular and non-ocular influences in a multiple regression model. The main findings were: • The optic discs of the South Asian (SA) and White European (WE) populations were not statistically different in size. The SA group possessed discs with increased cupping and thinner neuro-retinal rims (NRR) compared with the WE group. The SA group also demonstrated a more vertically oval shape than the WE population. These differences were significant at the p<0.01 level. • The upper limits of inter-eye asymmetry were: ≤0.2 for cup to disc area ratio, and 3mmHg for intra-ocular pressure (IOP) for both ethnic groups and this did not increase with age. IOP asymmetry did not vary with gender, ethnicity or a family history of glaucoma and was independent of ONH asymmetry. ONH and IOP asymmetry are therefore independent risk factors when screening for glaucoma for both ethnic groups. 2. To investigate the validity of the ISNT rule: inferior> superior> nasal> temporal NRR thickness in the optometric population. The main findings were: • As disc size increased the disc become rounder and less vertically oval in shape. Vertically oval discs had thicker superior and inferior NRRs and thinner nasal and temporal NRRs compared with rounder disc shapes due to cup shape being independent of disc shape. Vertically oval discs were therefore more likely to obey the ISNT rule than larger rounder discs. • The ISNT rule has a low adherence in our sample of normal eyes (5.7%). However, by removing the nasal sector to become the IST rule, 74.5% of normal eyes obeyed. SA eyes and female gender were more likely to obey the ISNT rule due to increased disc ovality. The IST rule is independent of disc shape and therefore more suitable for assessing discs from both ethnic backgrounds. Obeying the ISNT rule or IST rule was not related to disc or cup size.

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Animal models of acquired epilepsies aim to provide researchers with tools for use in understanding the processes underlying the acquisition, development and establishment of the disorder. Typically, following a systemic or local insult, vulnerable brain regions undergo a process leading to the development, over time, of spontaneous recurrent seizures. Many such models make use of a period of intense seizure activity or status epilepticus, and this may be associated with high mortality and/or global damage to large areas of the brain. These undesirable elements have driven improvements in the design of chronic epilepsy models, for example the lithium-pilocarpine epileptogenesis model. Here, we present an optimised model of chronic epilepsy that reduces mortality to 1% whilst retaining features of high epileptogenicity and development of spontaneous seizures. Using local field potential recordings from hippocampus in vitro as a probe, we show that the model does not result in significant loss of neuronal network function in area CA3 and, instead, subtle alterations in network dynamics appear during a process of epileptogenesis, which eventually leads to a chronic seizure state. The model’s features of very low mortality and high morbidity in the absence of global neuronal damage offer the chance to explore the processes underlying epileptogenesis in detail, in a population of animals not defined by their resistance to seizures, whilst acknowledging and being driven by the 3Rs (Replacement, Refinement and Reduction of animal use in scientific procedures) principles.