35 resultados para Capacity utilization rate
Resumo:
A dissertation submitted to Departamento de Engenharia Electrotécnica of Faculdade de Ciências e Tecnologia of Universidade Nova de Lisboa in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Engenharia Electrotécnica e de Computadores
Resumo:
A Work Project, presented as part of the requirements for the Award of a Masters Degree in Management from the NOVA – School of Business and Economics
Resumo:
ABSTRACT - The problem of how to support “intentions to make behavioural changes” (IBC) and “behaviour changes” (BC) in smoking cessation when there is a scarcity of resources is a pressing issue in public health terms. The present research focuses on the use of information and communications technologies and their role in smoking cessation. It is developed in Portugal after the ratification of WHO Framework Convention on Tobacco Control (on 8 November 2005). The prevalence of smokers over fifteen years of age within the population stood at 20.9% (30.9% for men and 11.8% for women). While the strategy of helping people to quit smoking has been emphasised at National Health Service (NHS) level, the uptake of cessation assistance has exceeded the capacity of the service. This induced the search of new theoretical and practical venues to offer alternative options to people willing to stop smoking. Among these, the National Health Plan (NHP) of Portugal (2004-2010), identifies the use of information technologies in smoking cessation. eHealth and the importance of health literacy as a means of empowering people to make behavioural changes is recurrently considered an option worth investigating. The overall objective of this research is to understand, in the Portuguese context, the use of the Internet to help people to stop smoking. Research questions consider factors that may contribute to “intentions to make behavioural changes” (IBC) and “behavioural changes” (BC) while using a Web-Assisted Tobacco Intervention Probe (WATIP). Also consideration is given to the trade-off on the use of the Web as a tool for smoking cessation: can it reach a vast number of people for a small cost (efficiency) demonstrating to work in the domain of smoking cessation (efficacy)”? In addition to the introduction, there is a second chapter in which the use of tobacco is discussed as a public health menace. The health gains achieved by stopping smoking and the means of quitting are also examined, as is the use of the Internet in smoking cessation. Then, several research issues are introduced. These include background theory and the theoretical framework for the Sense of Coherence. The research model is also discussed. A presentation of the methods, materials and of the Web-Assisted Tobacco Intervention Probe (WATIP) follows. In chapter four the results of the use of the Web-Assisted Tobacco Intervention Probe (WATIP) are presented. This study is divided into two sections. The first describes results related to quality control in relation to the Web-Assisted Tobacco Intervention Probe (WATIP) and gives an overview of its users. Of these, 3,150 answered initial eligibility questions. In the end, 1,463 met all eligibility requirements, completed intake, decided on a day to quit smoking (Dday) and declared their “intentions to make behavioural changes” (IBC) while a second targeted group of 650 did not decide on a Dday. With two quit attempts made before joining the platform, most of the participants had experienced past failures while wanting to stop. The smoking rate averaged 21 cigarettes per day. With a mean age of 35, of the participants 55% were males. Among several other considerations, gender and the Sense of Coherence (SOC) influenced the success of participants in their IBC and endeavour to set quit dates. The results of comparing males and females showed that, for current smokers, establishing a Dday was related to gender differences, not favouring males (OR=0.76, p<0.005). Belonging to higher Socio-economic strata (SES) was associated with the intention to consider IBC (when compared to lower SES condition) (OR=1.57, p<0.001) and higher number of school years (OR=0.70, p<0.005) favoured the decision to smoking cessation. Those who demonstrated higher confidence in their likelihood of success in stopping in the shortest time had a higher rate of setting a Dday (OR=0.51, p<0.001). There were differences between groups in IBC reflecting the high and low levels of the SOC score (OR=1.43, p=0.006), as those who considered setting a Dday had higher levels of SOC. After adjusting for all variables, stages of readiness to change and SOC were kept in the model. This is the first Arm of this research where the focus is a discussion of the system’s implications for the participants’ “intentions to make behavioural changes” (IBC). Moreover, a second section of this study (second Arm) offers input collected from 77 in-depth interviews with the Web-Assisted Tobacco Intervention Probe (WATIP) users. Here, “Behaviour Change” (BC) and the usability of the platform are explored a year after IBC was declared. A percentage of 32.9% of self-reported, 12-month quitters in continuous abstinence from smoking from Dday to the 12-month follow- up point of the use of the Web-Assisted Tobacco Intervention Probe (WATIP) has been assessed. Comparing the Sense of Coherence (SOC) scores of participants by their respective means, according to the two groups, there was a significant difference in these scores of non smokers (BC) (M=144,66, SD=22,52) and Sense of Coherence (SOC) of smokers (noBC) (M=131,51, SD=21,43) p=0.014. This WATIP strategy and its contents benefit from the strengthening of the smoker’s sense of coherence (SOC), so that the person’s progress towards a life without tobacco may be experienced as comprehensible, manageable and meaningful. In this sample the sense of coherence (SOC) effect is moderate although it is associated with the day to quit smoking (Dday). Some of the limitations of this research have to do with self-selection bias, sample size (power) and self-reporting (no biochemical validation). The enrolment of participants was therefore not representative of the smoking population. It is not possible to verify the Web-Assisted Tobacco Intervention Probe (WATIP) evaluation of external validity; consequently, the results obtained cannot be applied generalized. No participation bias is provided. Another limitation of this study is the associated limitations of interviews. Interviewees’ perception that fabricating answers could benefit them more than telling the simple truth in response to questions is a risk that is not evaluated (with no external validation like measuring participants’ carbon monoxide levels). What emerges in this analysis is the relevance of the process that leads to the establishment of the quit day (Dday) to stop using tobacco. In addition, technological issues, when tailoring is the focus, are key elements for scrutiny. The high number of dropouts of users of the web platform mandates future research that should concentrate on the matters of the user-centred design of portals. The focus on gains in health through patient-centred care needs more research, so that technology usability be considered within the context of best practices in smoking cessation.
Resumo:
Dissertação para obtenção do Grau de Mestre em Engenharia Química e Bioquímica
Resumo:
Dissertação para obtenção do Grau de Mestre em Genética Molecular e Biomedicina
Resumo:
RESUMO - A Terapêutica de Ressincronização Cardíaca (TRC) apresenta benefícios significativos na classe funcional, função ventricular, hospitalização e mortalidade. É uma técnica com custos elevados e, com os actuais métodos de selecção de doentes, a taxa de não-respondedores ronda os 30%. Objectivo: Compreender se a inclusão da dessincronia mecânica (DM) na selecção de doentes para TRC contribui para a sua relação custo-efectividade, na perspectiva do Serviço Nacional de Saúde português. Metodologia: Estudo prospectivo baseado em coortes histórias de 12 meses de dois grupos submetidos a TRC com desfibrilhador, o grupo de intervenção com doentes seleccionados com inclusão da DM (n=133) e o de controlo com selecção baseada exclusivamente nas recomendações internacionais (n=71). Reuniram-se dados clínicos e de custos nos 12 meses subsequentes à implantação, para cálculo do rácio custo-efectividade incremental (RCEI). Resultados: O grupo de intervenção apresentou uma sobrevivência de 91% e o de controlo de 93%, aos 12 meses (p=0,335). O grupo de intervenção apresentou 60 re-internamentos e o de controlo 46 re-internamentos por qualquer causa aos 12 meses (p=0,032), com RCEI=6.886,09€/re-internamento evitado. O grupo de intervenção apresentou 19 re-internamentos e o de controlo apresentou 31 re-internamentos por Insuficiência Cardíaca (IC) descompensada aos 12 meses (p<0,001), com RCEI=2.686,26€/re-internamento por IC descompensada evitado. Relativamente à melhoria da classe funcional e da fracção de ejecção não foi possível estabelecer associações com custos (p>0,05). Conclusão: É seguro afirmar que recomendar a selecção com inclusão da DM, nos hospitais com capacidade instalada, é um passo positivo na redução de custos com re-internamentos de doentes com TRC.
Resumo:
A Work Project, presented as part of the requirements for the Award of a Masters Degree in Management from the NOVA – School of Business and Economics
Resumo:
Dissertação para obtenção do Grau de Doutor em Estatística e Gestão do Risco
Energy-efficient diversity combining for different access schemes in a multi-path dispersive channel
Resumo:
Dissertação para obtenção do Grau de Doutor em Engenharia Electrotécnica e Computadores
Resumo:
This study focuses on the assessment of the fermentation conditions required to modulate the metabolic flux in the osmotolerant yeast Candida magnoliae and evaluate its potential to produce low-alcoholic and low-caloric fermented beverages. For that purpose, two strains, PYCC 2903 and PYCC 3191, were used and fermentation conditions as oxygenation, sugar concentration and the ratio of glucose to fructose were studied using synthetic culture media. Candida magnoliae PYCC 2903 was subsequently used to ferment real industrial fructose-rich substrates such as fruit juices. Sugar consumption profiles for C.magnoliae PYCC 2903 incubated aerobically in the presence of high fructose and glucose concentrations (15%, 10% and 5%) showed a selective utilization of fructose, denoting a preference for this sugar over glucose. The lower ratio between ethanol and sugar alcohols yield was obtained for both strains incubated under oxygen limitation simulating industrial fructose-rich substrates, confirming the ability of this yeast to direct fermentation towards alternative products. Enzymatic assays for hexokinase activity in terms of capacity and affinity for glucose and fructose were performed, aiming to elucidate its contribution to the fructophilic behaviour of this yeast. Enzymatic assays for both strains showed that the Vmax is two to threefold higher for fructose than for glucose but Km is also 10-20-fold higher for this sugar than for glucose. Hence, hexokinase kinetic properties do not explain fructophily in C.magnoliae. This indicates that fructose transport is probably determining in this respect, as observed for other fructophilic yeasts. Fruit juice fermentations with C.magnoliae PYCC 2903 revealed a potential for the production of beverages with interesting sensorial properties. Pear and peach fermentations exhibited the best results with the lowest ratio between ethanol and sugar alcohols yield and the most pleasant organoleptic features.
Resumo:
Mannans (linear mannan, glucomannan, galactomannan and galactoglucomannan) are the major constituents of the hemicellulose fraction in softwoods and show great importance as a renewable resource for fuel or feedstock applications. As complex polysaccharides, mannans can only be degraded through a synergistic action of different mannan-degrading enzymes, mannanases. Microbial mannanases are mainly extracellular enzymes that can act in wide range of pH and temperature, contributing to pulp and paper, pharmaceutical, food and feed, oil and textile successful industrial applications. Knowing and controlling these microbial mannan-degrading enzymes are essential to take advantage of their great biotechnological potential. The genome of the laboratory 168 strain of Bacillus subtilis carries genes gmuA-G dedicated to the degradation and utilization of glucomannan, including an extracellular -mannanase. Recently, the genome sequence of an undomesticated strain of B. subtilis, BSP1, was determined. In BSP1, the gmuA-G operon is maintained, interestingly, however, a second cluster of genes was found (gam cluster), which comprise a second putative extracellular β-mannanase, and most likely specify a system for the degradation and utilization of a different mannan polymer, galactoglucomannan. The genetic organization and function of the gam cluster, and whether its presence in BSP1 strain results in new hemicellulolytic capabilities, compared to those of the laboratory strain, was address in this work. In silico and in vivo mRNA analyses performed in this study revealed that the gam cluster, comprising nine genes, is organized and expressed in at least six different transcriptional units. Furthermore, cloning, expression, and production of Bbsp2923 in Escherichia coli was achieved and preliminary characterization shows that the enzyme is indeed a β-mannanase. Finally, the high hemicellulolytic capacity of the undomesticated B. subtilis BSP1, demonstrated in this work by qualitative analyses, suggests potential to be used in the food and feed industries.
Resumo:
Enhanced biological phosphorus removal (EBPR) is the most economic and sustainable option used in wastewater treatment plants (WWTPs) for phosphorus removal. In this process it is important to control the competition between polyphosphate accumulating organisms (PAOs) and glycogen accumulating organisms (GAOs), since EBPR deterioration or failure can be related with the proliferation of GAOs over PAOs. This thesis is focused on the effect of operational conditions (volatile fatty acid (VFA) composition, dissolved oxygen (DO) concentration and organic carbon loading) on PAO and GAO metabolism. The knowledge about the effect of these operational conditions on EBPR metabolism is very important, since they represent key factors that impact WWTPs performance and sustainability. Substrate competition between the anaerobic uptake of acetate and propionate (the main VFAs present in WWTPs) was shown in this work to be a relevant factor affecting PAO metabolism, and a metabolic model was developed that successfully describes this effect. Interestingly, the aerobic metabolism of PAOs was not affected by different VFA compositions, since the aerobic kinetic parameters for phosphorus uptake, polyhydroxyalkanoates (PHAs) degradation and glycogen production were relatively independent of acetate or propionate concentration. This is very relevant for WWTPs, since it will simplify the calibration procedure for metabolic models, facilitating their use for full-scale systems. The DO concentration and aerobic hydraulic retention time (HRT) affected the PAO-GAO competition, where low DO levels or lower aerobic HRT was more favourable for PAOs than GAOs. Indeed, the oxygen affinity coefficient was significantly higher for GAOs than PAOs, showing that PAOs were far superior at scavenging for the often limited oxygen levels in WWTPs. The operation of WWTPs with low aeration is of high importance for full-scale systems, since it decreases the energetic costs and can potentially improve WWTP sustainability. Extended periods of low organic carbon load, which are the most common conditions that exist in full-scale WWTPs, also had an impact on PAO and GAO activity. GAOs exhibited a substantially higher biomass decay rate as compared to PAOs under these conditions, which revealed a higher survival capacity for PAOs, representing an advantage for PAOs in EBPR processes. This superior survival capacity of PAOs under conditions more closely resembling a full-scale environment was linked with their ability to maintain a residual level of PHA reserves for longer than GAOs, providing them with an effective energy source for aerobic maintenance processes. Overall, this work shows that each of these key operational conditions play an important role in the PAO-GAO competition and should be considered in WWTP models in order to improve EBPR processes.
Resumo:
RESUMO: Tivemos como objectivo do presente trabalho avaliar a capacidade funcional, e factores eventualmente a ela associados, numa amostra de 152 idosos ambulatórios, sem doenças agudas ou graves, utentes de um centro de saúde urbano. Cada avaliação consistiu numa entrevista, mediante um inquérito sobre capacidade funcional, morbilidade, estado mental e aspectos sociais, e no estudo da composição corporal. As perguntas referentes às variáveis estudadas foram por nós desenvolvidas e estruturadas com base em escalas internacionais validadas e de utilização comum na avaliação de idosos, excepto para as variáveis em que não encontrámos escalas com essas características. Os seus quesitos foram incluídos como perguntas e respostas estruturadas e pré-codificadas, permitindo a atribuição de uma pontuação a cada variável e a sua posterior divisão dicotómica. Aplicámos as escalas de Katz e de Lawton para a avaliação das actividades de autonomia física e instrumental da vida diária, a escala de Grimby para a avaliação da actividade física, a escala de Hamilton e o teste de Folstein para a avaliação do estado mental nas vertentes afectiva e cognitiva e a escala de Graffar para caracterizar a classe social, e perguntas sobre locomoção, autoavaliação da saúde, queixas de saúde presentes e rede social. Fizemos o registo da morbilidade segundo a International Classification of Primary Care - ICPC. A avaliação antropométrica constou da medição do peso, da altura, dos perímetros do braço, da cintura, da anca e proximal da coxa, e das pregas bicipital, tricipital, sub-escapular e supra-ilíaca. Foi também feita a estimativa da composição corporal por cálculos derivados de índices antropométricos e de bioimpedância eléctrica corporal total, o doseamento de algumas proteínas plasmáticas e a quantificação da força de preensão. Analisámos os resultados obtidos por grupos quanto ao sexo e à idade, dividida nos escalões etários 65 a 74 anos e mais do que 74 anos. Por regressão linear múltipla, foi testado o efeito do sexo e da idade sobre os valores medidos, para cada uma das variáveis e cada uma das suas pontuações parciais, sendo considerado como evidência de um efeito estaticamente significativo um valor “p” inferior a 0,05.Resumimos do seguinte modo os dados obtidos e a sua comparação com os dos estudos que seleccionámos como referência: A média de idades da amostra foi de 74 anos, sendo um terço destes do sexo masculino. Na sua maioria eram independentes em locomoção e funcionalidade, praticavam alguma actividade física, classificavam a sua saúde como razoável ou boa, apresentavam sintomatologia activa, não tinham depressão ou demência, tinham quem os acompanhasse embora cerca de metade apresentasse algum grau de isolamento, eram de baixa classe social, tinham excesso de peso, valores elevados de massa gorda, parâmetros plasmáticos proteicos compatíveis com ausência de doenças agudas ou graves e considerável força muscular de preensão. Na análise descritiva por grupos quanto ao sexo e/ou à idade, verificou-se que as mulheres e os mais idosos apresentavam maior isolamento social e os valores mais baixos de massa magra, hemoglobina e força de preensão. As mulheres tinham maior prevalência de dependência em autonomia física, depressão e valores mais baixos de transferrina. Os mais idosos apresentavam maior dependência em funcionalidade, menor actividade física, maior prevalência de demência, índice de massa corporal menos elevado, e valores mais baixos de albumina. Não se verificou prevalência de piores resultados dicotómicos nos homens nem no escalão etário menos idoso. Não teve relação com o sexo ou a idade o compromisso em autonomia instrumental, a presença de morbilidade ou a baixa classe social, assim como a não perturbação da locomoção e dos níveis de somatomedina-C. A análise comparativa com estudos multidimensionais em idosos portugueses e europeus ambulatórios revelou que a nossa amostra apresentava muitas características semelhantes às desses idosos. Assim, tinham elevada independência em locomoção, considerável independência em autonomia física e menor independência em autonomia instrumental; prática de actividade física ligeira, as mulheres dentro e os homens fora de casa; maior prevalência de morbilidade a nível dos aparelhos locomotor e cardiocirculatório, nos nossos idosos com pouca flutuação na autoavaliação de saúde; pequena prevalência de depressão e de demência; maior isolamento social nas mulheres e nas mais idosas; factores de classe social de baixo nível, diferindo apenas em relação aos idosos do norte da Europa que apresentavam elevada escolaridade e profissões mais diferenciadas; características biométricas sobreponíveis às dos idosos portugueses e às dos do sul da Europa, com tendência para o excesso de peso e proporção elevada de massa gorda; e doseamentos plasmáticos proteicos e força muscular de preensão compatíveis com ausência de doenças agudas ou crónicas graves. A comparação com os referidos estudos em relação ao risco de dependência, revelou semelhanças na associação entre dependência funcional e idade avançada, morbilidade, alteração do estado mental e isolamento social. Na amostra que estudámos não obtivemos associação entre dependência e o sexo feminino, facto que se verificou no estudo nacional de Almeida et al. e nos estudos multicêntricos europeus, ou o grau de escolaridade, como no estudo francês. Podemos concluir que, com o instrumento de avaliação que utilizámos, foi possível detectar e caracterizar perturbações numa amostra de idosos ambulatórios, a maioria funcionalmente independentes, sem alterações do estado mental, mas apresentando morbilidade activa, tendência para a obesidade, e actividade física ligeira. Nos que apresentaram alterações, estas foram mais frequentes no sexo feminino e nos indivíduos com mais de 74 anos. A escala de funcionalidade desenvolvida foi sensível aos efeitos da idade e permitiu o cálculo do risco de dependência em relação às outras variáveis estudadas, sendo mais marcante a associação com baixa actividade física, presença de queixas de saúde, demência e índice de massa corporal elevado. Consideramos que a metodologia que empregámos poderá contribuir para a avaliação de capacidades, cujo conhecimento sistemático nos idosos se impõe. ------------- ABSTRACT: The main objective of the present work was to evaluate functional capacity and related factors, in a sample of 152 ambulatory elderly, free from acute or serious disease, attending an urban health centre. Each evaluation included an interview, with a questionnaire about functional capacity, morbidity, mental health and social aspects, and the study of body composition. The questions were developed and structured in accordance with international validated scales usually applied in the evaluation of the elderly, whenever there were scales for that purpose. Their items were included as structured pre-coded questions and answers, so that each variable could have its own quotation and be dichotomised. We employed Katz and Lawton scales for basic and instrumental activities of daily living, Grimby scale for physical activity, Hamilton scale for depression, Folstein’s Mini Mental State Examination for cognitive ability and Graffar scale for social class, and questions about walking, health perception, active complaints and social network. The symptoms register was done according to the International Classification of Primary Care - ICPC. The anthropometric exam involved the determination of height and weight, arm, waist, hip and proximal thigh circumferences, and biceps, triceps, subscapular and suprailiac skinfolds. For the body composition calculation we employed equations derived from anthropometric indices, and from measurement of total body bioelectric impedance. We also measured some plasma proteins and handgrip strength. The analysis of results was done by sex and age groups, separating those with 65 to 74 years from those older than 74 years. The effects of sex and age were tested by linear multiple regression, for each variable and its components. Presented "p" values being considered statistically significative if less than 0,05. The results we obtained and their comparison with the studies we choose as reference can be summarised as follows: Mean age of the sample was 74 years and about one third were men. Most of them were independent in gait and functionality, practised some physical activity, rate their health as fair or good, had physical complaints, had not depression or dementia, had some companionship although almost half of them with stigmas of isolation, belonged to low social class, were in the range of overweight, had raised values of fat mass, plasma proteins in accordance with no acute or serious disease, and considerable handgrip strength. The analysis of groups by sex and age revealed that women and the eldest had the greater social isolation and the lowest values of free fat mass, haemoglobin and handgrip strength. Women had the higher dependence in basic activities of daily living, more depression and lower levels of transferrin. The eldest were more dependent in functionality, had greater prevalence of dementia, less physical activity, less raised body mass index and lower levels of albumin. Men alone and the age range of 65 to 74 did not show any prevalence of the worse dichotomised results. There was no relationship between sex or age and instrumental activities of daily living, morbidity or low social class, and unaffected gait or somatomedin-C levels. The comparison of results with multidimensional studies in portuguese and european ambulatory elderly showed that our sample had many similarities with theirs. They were independent in gait and activities of daily living; practiced light physical activity, women indoors and men outdoors; had greater morbidity at locomotor and cardiovascular systems, with small latitude in health evaluation; low prevalence of depression and dementia; social isolation predominantly in older women; and low social class factors, witch is only different from those of north Europe who had higher education levels and professional carriers; biometric characteristics similar to other portuguese and south Europe elders, with tendency for overweight and high proportion of fat mass; and plasma protein levels and handgrip strength in accordance with no acute or chronic serious disease. The comparison to the referred studies in relation to dependency risk, showed similarities in the association of dependency and age, morbidity,altered mental state and social isolation. We did not find association between dependency and sex, as it was found in the portuguese study of Almeida et al. and the european multicentric studies, or the education level, as in the french study. We conclude that, with the evaluation battery we employed, it was possible to detect and characterise alterations in a sample of ambulatory elderly, most of whom were functionally independent and had no alterations in mental state, but had active morbidity, tendency to obesity, and only light physical activity. Those that had some alteration, were more frequently women and the eldest. The functionality scale we developed showed to be sensitive to age effects and suitable for the calculation of risk of dependency, being more important the association with low physical activity, active complaints, dementia and high body mass index. We consider that the methodology we applied can contribute to the evaluation of capabilities that should be systematically sought for in the elderly.
Resumo:
Directed Research Internship
Resumo:
Cyanobacteria are photoautotrophic microorganisms with great potential for the biotechnological industry due to their low nutrient requirements, photosynthetic capacities and metabolic plasticity. In biotechnology, the energy sector is one of the main targets for their utilization, especially to produce the so called third generation biofuels, which are regarded as one of the best replacements for petroleum-based fuels. Although, several issues could be solved, others arise from the use of cyanobacteria, namely the need for high amounts of freshwater and contamination/predation by other microorganisms that affect cultivation efficiencies. The cultivation of cyanobacteria in seawater could solve this issue, since it has a very stable and rich chemical composition. Among cyanobacteria, the model microorganism Synechocystis sp. PCC 6803 is one of the most studied with its genome fully sequenced and genomic, transcriptomic and proteomic data available to better predict its phenotypic behaviors/characteristics. Despite suitable for genetic engineering and implementation as a microbial cell factory, Synechocystis’ growth rate is negatively affected by increasing salinity levels. Therefore, it is important to improve. To achieve this, several strategies involving the constitutive overexpression of the native genes encoding the proteins involved in the production of the compatible solute glucosylglycerol were implemented, following synthetic biology principles. A preliminary transcription analysis of selected mutants revealed that the assembled synthetic devices are functional at the transcriptional level. However, under different salinities, the mutants did not show improved robustness to salinity in terms of growth, compared with the wild-type. Nevertheless, some mutants carrying synthetic devices appear to have a better physiological response under seawater’s NaCl concentration than in 0% (w/v) NaCl.