Thesis (MSc (Biochemistry))--University of Stellenbosch, 2010. / Please refer to full text for abstract

Approximately 30% of people admitted to ICU in the UK have co-existing cardiovascular disease (CVD), and this may rise as life-expectancy increases. Patients with CVD have impaired compensatory mechanisms to enable maximum oxygen delivery to the tissues in the event of critical illness, which itself increases global oxygen demand, further stressing the heart. This is exacerbated by tachycardia and hypotension, which may relatively reduce blood flow to the coronary arteries, and catecholamines which increase myocardial oxygen demand. The myocardium extracts 75% of the oxygen supplied by the coronary arteries at rest, and atheroma-related flow limitation further compromises myocardial oxygen delivery. However, the diagnosis of acute coronary syndrome in critical illness is not straightforward, due to patient inability to communicate symptoms, non-specific ECG changes, and poorly understood cardiac biomarker troponin elevation. My overall hypothesis is that patients with CVD benefit from increased oxygen delivery to the myocardium during critical illness. A focus is the importance of anaemia. The aims of the studies presented in this thesis are (i) to systematically review the literature regarding blood transfusion thresholds specifically in patients with CVD; (ii) to explore the association between Troponin I (TnI) within 24 hours of ICU admission and hospital mortality (iii) to describe and quantify the dynamics of TnI in patients with CVD during the first ten days after ICU admission; and (iv) to define myocardial infarction in the context of critical illness. I have performed a systematic review and meta-analysis of randomised controlled trials comparing a restrictive with liberal transfusion threshold and that included patients with CVD. In total, 11 trials enrolling patients with CVD (n=3033) were included for meta-analysis (restrictive n=1514, liberal=1519). The pooled risk ratio for the association between a restrictive transfusion threshold and 30 day mortality was 1.15 (95% CI 0.88 to 1.50, p=0.50, I2=14%). The risk of acute coronary syndrome in patients managed with restrictive compared with liberal transfusion was increased (nine trials, risk ratio 1.78, 95% CI 1.18 to 2.70, p=0.0, I2=0%). In contrast to broader literature supporting restrictive thresholds, our systematic review shows that a restrictive transfusion threshold of less than 80g/l may not be safe in patients with co-existing CVD, and highlights the variability in diagnostic definitions of ACS and the potential for ascertainment bias in transfusion trials. I undertook a retrospective cohort study in two independently collected cohorts of general ICU patients who had TnI measured within 24 hours of ICU admission. Importantly, the majority of TnI samples were collected routinely rather than for clinical indications. We used the Abbott ARCHITECT Stat assay (limit of detection 0.01mcg/l. We performed multivariable regression, adjusting for components of the APACHE II model. We derived the risk prediction score from the multivariable model with TnI. TnI was associated with all cause hospital mortality (OR per doubling TnI 1.16, 95% CI 1.13 to 1.20, p < 0.001) which persisted after adjustment for APACHE II model components (OR TnI 1.05, 95% CI 1.01 to 1.09, p=0.003). TnI correlated highly with the Acute Physiological Score component of APACHE II (r=0.39), suggesting that TnI release may be largely explained by acute physiological stress. Addition of TnI to the APACHE II model did not improve the performance of the risk prediction model and we would not advocate the adoption of a routine single troponin sample at admission. I designed, set up, and recruited 279 patients to a prospective cohort study TROPonin I in Cardiovascular patients in CriticAL care (TROPICCAL, UKCRN 19253) in 11 UK centres. The aims were to (i) determine the incidence of Myocardial Injury and Infarction, defined by the Third Universal Definition of Myocardial Infarction; (ii) explore factors associated with Injury and Infarction from multivariable analyses; and (iii) explore the relationship between Injury/Infarction and outcome in unadjusted and adjusted analyses. We recorded baseline characteristics, and took daily hs-TnI for ten days after ICU admission, severity of illness measures and ECGs for 5 days. There was a wide range of peak TnI (med 114ng/l (min 3, Q1 27, Q3 412, max 58820ng/l)) and a high prevalence of myocardial injury on systematic screening: 71% of patients had peak TnI greater than the sex-specific diagnostic threshold ('Injury'), and 24% had peak TnI greater than the sex-specific diagnostic threshold and dynamic changes on ECG consistent with ischaemia ('Infarction'). TnI consistently showed a rise-and-fall pattern consistent with an acute myocardial 'hit' rather than persisting injury, which peaked early during ICU stay. Importantly, only 12 (4.4%) patients were diagnosed with MI by the clinicians looking after the patients. Independent predictors of peak TnI in the preceding 24 hours were SOFA score, dynamic ECG ischaemia, lactate, haemoglobin, and age. The lack of association with CRP (representing systemic inflammation), with stronger association with lactate (representing inadequate perfusion/oxygen supply), Hb and ECG ischaemia support the conjecture that injury results in part from an acute ischaemic hit in this population. Patients with Infarction had similar baseline demographics to patients with Injury, but had higher peak TnI concentrations, and higher hospital and six month mortality (Figure 2). This supports the importance of including systematic assessment of dynamic ECG changes in the myocardial injury 'construct' in ICU. My work has shown an increased risk of ACS in patients with CVD randomised to restrictive transfusion thresholds. TnI elevation is prevalent in general ICU patients, and is independently associated with hospital mortality. A systematic approach to the detection of myocardial injury in critically ill patients with co-existing CVD who are unable to communicate symptoms, can identify a high risk population who have poorer survival than patients with no injury. Markers of ischaemia are more associated with TnI rise than markers of inflammation, supporting the hypothesis that myocardial injury in this population is at least in part due to oxygen supply-demand imbalance 'myocardial infarction'. From this work, I would recommend (i) a more liberal transfusion threshold of at least 80g/l in patients with coexisting CVD; (ii) systematic use of sequential ECGs in ICU to screen for myocardial injury in 'at risk' patients; and (iii) manipulation of physiological parameters such as anaemia, hypotension and tachycardia should be considered for patients with dynamic ECG changes plus troponin increase consistent with Infarction. Future research should include 'precision medicine' trials in the substantial cohort of ICU patients with co-existing CVD to explore whether interventions that increase myocardial oxygen supply and/or treat infarction alter outcomes.

The ecosystem services (ES) concept is meant to facilitate consideration of the value of nature in conservation and landscape management processes by translating ecosystem functions into human benefits. Incorporating the ES concept into policy and decision-making has proven difficult due to challenges in identifying, measuring, and locating services and in predicting the impacts of decisions upon them. ES mapping offers a key solution to increase our understanding of the spatial patterns of ES supply and demand and the spatial relationships between them, but may be challenging to implement given a lack of spatial data related to ES or existence of such data at coarse resolution that may not facilitate accurate ES quantification, mapping and modeling. This issue is particularly acute in urban settings where landscapes are highly heterogeneous and fragmented. This research seeks to improve our understanding of urban ES supply, demand and the relationships between them, as well as the impacts of spatial scale, input data quality and method choice on ES mapping in urban landscapes. The dissertation is composed of three studies. In the first study, I introduce a spatially-explicit framework for quantifying and mapping ES supply and demand using carbon storage and sequestration services as an example. This framework assesses supply based on biophysical conditions and demand based on socioeconomic characteristics, allowing for more integrative ES assessments in urban areas. In the second study, I evaluate the sensitivity of ES maps to input spatial data resolution and method choice (ecosystem component-based and land-cover proxy-based methods) in a heterogeneous urban landscape using biomass carbon storage as an example. I find that ES map accuracy is highly dependent on analytical scales and input data representativeness. ES estimates based on ecosystem-component data are more accurate than those based on land-cover proxies. The accuracy of land-cover proxy-based maps, however, can be increased by using high-resolution land-cover maps. The third study aims to increase understanding of ES supply, demand, and supply-demand balance in urban contexts. To this end, I create a high-thematic-resolution land-cover dataset and combine it with the InVEST pollination model to assess the capacity of urban ecosystems to supply pollination services to satisfy the demands of urban agriculture. I find using land-cover dataset at a higher thematic resolution enhances the accuracy of pollination estimates, highlighting the importance of considering scale and land-use dependencies in urban ES mapping. Combined, these studies advance our knowledge of ES supply, demand and the relationships between them, and provide new insight into the impacts of input data spatial and thematic resolution and method choice on the accuracy of urban ES maps.

Larger size TFT-LCD panels, consists of notebook panel, monitor panel, and TV panel, enjoys great growth momentum for years. To fulfill the growing demand, panel makers keep continuous investment for expansion. Therefore, this creates over-supply, under-supply, or balanced supply-demand. Supply and demand decides the price of an item. So does TFT-LCD panel. Through thorough industry historic and forecasted data, complete supply-demand model is built with 2 years forward forecast. The result shows that in the following 2 years the occurrence of oversupply is very possible. However by controlling utilization rate and carefully talking orders, panel makers create shortage-like situation to raise panel price successfully. By the result of this model, accompanied with current global economics situations, some managerial suggestions are given for TFT-LCD makers.

abstract: University graduates play a significant role in the labor market of China. Universities continuously supply senior talents and provide a strong guarantee to the country’s development. However, with the enlargement of the enrollment scale, more and more graduates become unemployed or forced to be employed. Most literatures mainly focus on the unemployed phenomenon or reasons, but had neglected the relationship among the employment, universities and the labor market. This assay is trying to using the supply and demand theory of classical economics to analyze the training direction and model of university from the perspective of the supply and demand of labor market. This assay proposes that universities have to integrate with the demand of the labor market so that to cultivate the talents to meet the social needs. Firstly, the essay analyzes the relationship between the universities education and the supply and demand labor market by using the view of labor economics, and shows the mainly phenomenon and features of supply-demand imbalance. And then, the writer considered that universities talent cultivation development of China has gone through “absolute shortage”, “relative shortage” and “structural unbalanced” three stages. Thirdly, the survey results confirmed that the talent cultivation in universities does not match the demand of the labor market. On one other hand, over educated is a common phenomenon in the academic education. On the other hand, the graduates are lack of education skills training. Fourthly, the essay analyzes the reasons which lead to the unbalance. The unbalance is not only affected by the macro factors, but also by the micro factors. Fifthly, build up the interaction system model “UPT-LM” for the universities talent cultivation and the labor market, and separately building up the macro interaction system and the micro interaction system to analyze the balance of supply and demand. Based on this, it should strengthen the interaction on the feedback mechanism. At last, strengthening the connection of universities talent cultivation and labor market is a systematic program which needs the corporation from the government, the universities and the labor market. / Dissertation/Thesis / Doctoral Dissertation Business Administration 2017

Power networks are one of the most complex systems in the field of electrical and computer engineering. In power networks, power supply-demand balancing can be achieved in a static or a dynamic model. In a static model, the power network cannot be easily adapted to intentional or unintentional network topology changes because the network design is predetermined, whereas in a dynamic model, the power network can be dynamically constructed and reconfigured at run-time, which leads to a more nimble, flexible, and stable system. In this dissertation, a novel Market-based Multi-agent System (MMS) is proposed to solve supply-demand balancing and power restoration problems in a dynamic model. The power network is modeled as a market environment consisting of Belief-Desire-Intention (BDI) agents representing three characters: 1) consumer, 2) supplier, and 3) middleman. The BDI agents are able to negotiate power supply and demand of the power network, with consumers exploring the market and exchanging power information with neighboring middlemen and suppliers. So long as all consumers and suppliers establish supply-demand relationships represented in tree data structures, a qualified minimal access structure is found as the lower bound of the system reliability. When contingencies occur, the agents can quickly respond and restore loads guided by the relationships using minimum computational resource. Based on case studies and simulation results, the proposed approach delivers more effective performance of contingencies response and better computation time efficiency as the scale of the power network expands. The proposed MMS shows promises for solving various real-world power supply-demand and restoration problems, and serves as a solid foundation for future power networks refinement and improvement. / Electrical and Computer Engineering

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniv. / Härtill 4 uppsatser.

Este estudo propõe uma discussão acerca dos indicadores de desempenho urbano baseados na distribuição espacial das variáveis. Esta abordagem surgiu da conveniência de uma reformulação das estratégias de planejamento urbano, tão presas aos planos diretores normativos. Neste contexto, a avaliação e o monitoramento urbano despontam como uma possível estratégia complementar aos planos normativos, assim como os indicadores e modelos urbanos surgem como ferramentas relacionadas a estes processos. O entendimento acerca dos indicadores usuais da relação oferta-demanda de serviços urbanos leva à crítica dos mesmos como fonte de informação à tomada de decisões, devido a uma lacuna em relação à distribuição espacial das facilidades urbanas nos indicadores do tipo quantidade por habitante. Assim, em termos de análise intra-urbana, este tipo de indicador é enfraquecido no seu papel de auxiliar à leitura do estado da cidade. De acordo com este quadro, na tentativa de avançar em relação à espacialização das variáveis envolvidas na relação oferta-demanda, propõe-se a utilização e integração entre indicadores e modelos urbanos. Esta integração é expressa no uso da medida de oportunidade espacial, que traduz o privilégio locacional de pontos de demanda em relação à distribuição das ofertas, como um indicador de desempenho urbano, a fim de fazer um contraponto aos indicadores usuais. Assim, o estudo busca discutir e explorar esta questão, mediante a revisão bibliográfica, buscando o suporte teórico-metodológico; e o estudo de caso, que toma como base a cidade de Torres, RS, Brasil. Considerando os resultados pode-se inferir que o uso de uma medida de oportunidade espacial como indicador de desempenho urbano pode vir a servir como uma ferramenta na análise da relação entre oferta de facilidades urbanas e demanda, ainda que careça de um refinamento metodológico. As explorações demonstram que, a fim de melhor servir a um sistema de suporte à decisão, os dois tipos de indicadores (baseados em quantidade por habitante e baseados em oportunidade espacial) devem ser avaliados concomitantemente, para um entendimento mais completo da realidade urbana. Isto porque cada qual apresenta ainda suas virtudes e defeitos que se complementam na análise. / This study aims to discuss about urban performance indicators based on the variables spatial distribution. This approach has arisen from the convenience of a reformulation of the urban planning strategies, so tied to normative master plans. In this context, urban evaluation and monitoring emerge like possible complementary strategies to the normative plans, as well as urban indicators and models emerge like tools related to these processes. The understanding about the usual indicators of the supply-demand relation of urban services leads to the criticism of them as a source of information to the decision-making process, because of a gap regarding the spatial distribution of the urban facilities in indicators of the quantity per inhabitant type. Therefore, concerning intraurban analysis, this type of indicator is weakened in its role of assisting in the city state reading. Accordingly, attempting to advance in relation to the spatial distribution of the variables involved in the supply-demand relation, it is proposed the use and joining of urban indicators and models. This joining is expressed by the use of the spatial opportunity measure, which defines the locational privilege of demand points in relation to supply’s distribution, as a urban performance indicator to contrast to usual indicators. This way, the study aims to discuss and explore this topic with a bibliographical review, looking forward to a theoretical and methodological support, and a case study, which takes place in the city of Torres, RS, Brazil. Considering the results, it is possible to infer that the use of a spatial opportunity measure as a urban performance indicator can become a tool in urban supply-demand analysis, even though it is still lacking a methodological refinement. The investigations show that, in order to serve a decision support system in a better way, both types of indicators (based on quantity per inhabitant and based on spatial opportunity) should be concomitantly evaluated, so that it can show a more complete understanding of the urban reality. This is due to the fact that each one still has its virtues and weaknesses that complete them in the analysis.

Este estudo propõe uma discussão acerca dos indicadores de desempenho urbano baseados na distribuição espacial das variáveis. Esta abordagem surgiu da conveniência de uma reformulação das estratégias de planejamento urbano, tão presas aos planos diretores normativos. Neste contexto, a avaliação e o monitoramento urbano despontam como uma possível estratégia complementar aos planos normativos, assim como os indicadores e modelos urbanos surgem como ferramentas relacionadas a estes processos. O entendimento acerca dos indicadores usuais da relação oferta-demanda de serviços urbanos leva à crítica dos mesmos como fonte de informação à tomada de decisões, devido a uma lacuna em relação à distribuição espacial das facilidades urbanas nos indicadores do tipo quantidade por habitante. Assim, em termos de análise intra-urbana, este tipo de indicador é enfraquecido no seu papel de auxiliar à leitura do estado da cidade. De acordo com este quadro, na tentativa de avançar em relação à espacialização das variáveis envolvidas na relação oferta-demanda, propõe-se a utilização e integração entre indicadores e modelos urbanos. Esta integração é expressa no uso da medida de oportunidade espacial, que traduz o privilégio locacional de pontos de demanda em relação à distribuição das ofertas, como um indicador de desempenho urbano, a fim de fazer um contraponto aos indicadores usuais. Assim, o estudo busca discutir e explorar esta questão, mediante a revisão bibliográfica, buscando o suporte teórico-metodológico; e o estudo de caso, que toma como base a cidade de Torres, RS, Brasil. Considerando os resultados pode-se inferir que o uso de uma medida de oportunidade espacial como indicador de desempenho urbano pode vir a servir como uma ferramenta na análise da relação entre oferta de facilidades urbanas e demanda, ainda que careça de um refinamento metodológico. As explorações demonstram que, a fim de melhor servir a um sistema de suporte à decisão, os dois tipos de indicadores (baseados em quantidade por habitante e baseados em oportunidade espacial) devem ser avaliados concomitantemente, para um entendimento mais completo da realidade urbana. Isto porque cada qual apresenta ainda suas virtudes e defeitos que se complementam na análise. / This study aims to discuss about urban performance indicators based on the variables spatial distribution. This approach has arisen from the convenience of a reformulation of the urban planning strategies, so tied to normative master plans. In this context, urban evaluation and monitoring emerge like possible complementary strategies to the normative plans, as well as urban indicators and models emerge like tools related to these processes. The understanding about the usual indicators of the supply-demand relation of urban services leads to the criticism of them as a source of information to the decision-making process, because of a gap regarding the spatial distribution of the urban facilities in indicators of the quantity per inhabitant type. Therefore, concerning intraurban analysis, this type of indicator is weakened in its role of assisting in the city state reading. Accordingly, attempting to advance in relation to the spatial distribution of the variables involved in the supply-demand relation, it is proposed the use and joining of urban indicators and models. This joining is expressed by the use of the spatial opportunity measure, which defines the locational privilege of demand points in relation to supply’s distribution, as a urban performance indicator to contrast to usual indicators. This way, the study aims to discuss and explore this topic with a bibliographical review, looking forward to a theoretical and methodological support, and a case study, which takes place in the city of Torres, RS, Brazil. Considering the results, it is possible to infer that the use of a spatial opportunity measure as a urban performance indicator can become a tool in urban supply-demand analysis, even though it is still lacking a methodological refinement. The investigations show that, in order to serve a decision support system in a better way, both types of indicators (based on quantity per inhabitant and based on spatial opportunity) should be concomitantly evaluated, so that it can show a more complete understanding of the urban reality. This is due to the fact that each one still has its virtues and weaknesses that complete them in the analysis.

Este estudo propõe uma discussão acerca dos indicadores de desempenho urbano baseados na distribuição espacial das variáveis. Esta abordagem surgiu da conveniência de uma reformulação das estratégias de planejamento urbano, tão presas aos planos diretores normativos. Neste contexto, a avaliação e o monitoramento urbano despontam como uma possível estratégia complementar aos planos normativos, assim como os indicadores e modelos urbanos surgem como ferramentas relacionadas a estes processos. O entendimento acerca dos indicadores usuais da relação oferta-demanda de serviços urbanos leva à crítica dos mesmos como fonte de informação à tomada de decisões, devido a uma lacuna em relação à distribuição espacial das facilidades urbanas nos indicadores do tipo quantidade por habitante. Assim, em termos de análise intra-urbana, este tipo de indicador é enfraquecido no seu papel de auxiliar à leitura do estado da cidade. De acordo com este quadro, na tentativa de avançar em relação à espacialização das variáveis envolvidas na relação oferta-demanda, propõe-se a utilização e integração entre indicadores e modelos urbanos. Esta integração é expressa no uso da medida de oportunidade espacial, que traduz o privilégio locacional de pontos de demanda em relação à distribuição das ofertas, como um indicador de desempenho urbano, a fim de fazer um contraponto aos indicadores usuais. Assim, o estudo busca discutir e explorar esta questão, mediante a revisão bibliográfica, buscando o suporte teórico-metodológico; e o estudo de caso, que toma como base a cidade de Torres, RS, Brasil. Considerando os resultados pode-se inferir que o uso de uma medida de oportunidade espacial como indicador de desempenho urbano pode vir a servir como uma ferramenta na análise da relação entre oferta de facilidades urbanas e demanda, ainda que careça de um refinamento metodológico. As explorações demonstram que, a fim de melhor servir a um sistema de suporte à decisão, os dois tipos de indicadores (baseados em quantidade por habitante e baseados em oportunidade espacial) devem ser avaliados concomitantemente, para um entendimento mais completo da realidade urbana. Isto porque cada qual apresenta ainda suas virtudes e defeitos que se complementam na análise. / This study aims to discuss about urban performance indicators based on the variables spatial distribution. This approach has arisen from the convenience of a reformulation of the urban planning strategies, so tied to normative master plans. In this context, urban evaluation and monitoring emerge like possible complementary strategies to the normative plans, as well as urban indicators and models emerge like tools related to these processes. The understanding about the usual indicators of the supply-demand relation of urban services leads to the criticism of them as a source of information to the decision-making process, because of a gap regarding the spatial distribution of the urban facilities in indicators of the quantity per inhabitant type. Therefore, concerning intraurban analysis, this type of indicator is weakened in its role of assisting in the city state reading. Accordingly, attempting to advance in relation to the spatial distribution of the variables involved in the supply-demand relation, it is proposed the use and joining of urban indicators and models. This joining is expressed by the use of the spatial opportunity measure, which defines the locational privilege of demand points in relation to supply’s distribution, as a urban performance indicator to contrast to usual indicators. This way, the study aims to discuss and explore this topic with a bibliographical review, looking forward to a theoretical and methodological support, and a case study, which takes place in the city of Torres, RS, Brazil. Considering the results, it is possible to infer that the use of a spatial opportunity measure as a urban performance indicator can become a tool in urban supply-demand analysis, even though it is still lacking a methodological refinement. The investigations show that, in order to serve a decision support system in a better way, both types of indicators (based on quantity per inhabitant and based on spatial opportunity) should be concomitantly evaluated, so that it can show a more complete understanding of the urban reality. This is due to the fact that each one still has its virtues and weaknesses that complete them in the analysis.