Antena multi-banda para comunicações móveis

O desenvolvimento dos sistemas de comunicações móveis tem vindo a ser cada vez maior, fazendo com que os sistemas funcionem em várias bandas de operação. Neste sentido, surge a necessidade de desenvolver antenas que superem aquelas já existentes, ao nível das suas propriedades electromagnéticas, para que os sistemas apresentem uma maior qualidade e possam corresponder às exigências inerentes ao desenvolvimento das sociedades. O objectivo desta dissertação de Mestrado é dimensionar, construir e medir uma antena multi-banda para comunicações móveis, com base em estruturas EBG (Electromagnetic Band-Gap) que melhorem o comportamento electromagnético daquelas já existentes, para a banda de frequências de 2.4 GHz e de 5.2 GHz. Começa-se por fazer-se um estudo acerca do estado da arte de estruturas EBG, muito utilizadas em várias áreas, nomeadamente a área das antenas, área sobre a qual esta dissertação assenta. Posteriormente é feita uma breve introdução às antenas microstrip, particularizando de seguida para antenas PIFA e as suas características. Posteriormente é feito o estudo de uma antena PIFA, com e sem a influência de estruturas EBG, para as bandas de 2.4 GHz e 5.2 GHz. Posteriormente são apresentados e comparados resultados das várias antenas. Da análise desses resultados, verifica-se que é possível obter uma antena de baixo perfil com a utilização de estruturas EBG como plano de massa. Além disso, verifica-se também que é possível diminuir a radiação traseira e aumentar a largura de banda. Finalmente, são apresentadas algumas conclusões e várias propostas de trabalho futuro.

Mapping multi-species habitat use for marine conservation planning

Tese de Doutoramento, Ciências do Mar (Biologia Marinha)

3D-2D image registration by nonlinear regression

We propose a 3D-2D image registration method that relates image features of 2D projection images to the transformation parameters of the 3D image by nonlinear regression. The method is compared with a conventional registration method based on iterative optimization. For evaluation, simulated X-ray images (DRRs) were generated from coronary artery tree models derived from 3D CTA scans. Registration of nine vessel trees was performed, and the alignment quality was measured by the mean target registration error (mTRE). The regression approach was shown to be slightly less accurate, but much more robust than the method based on an iterative optimization approach.

The adjusted effect of maternal body mass index, energy and macronutrient intakes during pregnancy, and gestational weight gain on body composition of full-term neonates

Objective - To evaluate the effect of prepregnancy body mass index (BMI), energy and macronutrient intakes during pregnancy, and gestational weight gain (GWG) on the body composition of full-term appropriate-for-gestational age neonates. Study Design - This is a cross-sectional study of a systematically recruited convenience sample of mother-infant pairs. Food intake during pregnancy was assessed by food frequency questionnaire and its nutritional value by the Food Processor Plus (ESHA Research Inc, Salem, OR). Neonatal body composition was assessed both by anthropometry and air displacement plethysmography. Explanatory models for neonatal body composition were tested by multiple linear regression analysis. Results - A total of 100 mother-infant pairs were included. Prepregnancy overweight was positively associated with offspring weight, weight/length, BMI, and fat-free mass in the whole sample; in males, it was also positively associated with midarm circumference, ponderal index, and fat mass. Higher energy intake from carbohydrate was positively associated with midarm circumference and weight/length in the whole sample. Higher GWG was positively associated with weight, length, and midarm circumference in females. Conclusion - Positive adjusted associations were found between both prepregnancy BMI and energy intake from carbohydrate and offspring body size in the whole sample. Positive adjusted associations were also found between prepregnancy overweight and adiposity in males, and between GWG and body size in females.

Magnesium, insulin resistance and body composition in healthy postmenopausal women

Objective: This study was conducted to determine the association between magnesium (Mg), body composition and insulin resistance in 136 sedentary postmenopausal women, 50 to 77 years of age. Methods: Diabetics, hypertensives and women on hormonal replacement therapy were excluded and the remaining 74 were divided according to BMI≥25 (obese: OG) and BMI<25 kg/m2 (non-obese: NOG). Nutritional data disclosed that intakes were high for protein and saturated fat, low for carbohydrates, polyunsaturated fat and Mg and normal for the other nutrients, according to recommended dietary allowances (RDA). Mg values in red blood cells (RBC-Mg) and plasma (P-Mg), were determined, as were fasting glucose, and insulin levels, Homeostasis Model Assessment (HOMA), body mass index (BMI), body fat percent (BF %), abdominal fat (AF) and free fat mass (FFM). Results: RBC-Mg values were low in both groups when compared with normal values. There were significant differences in body composition parameters, HOMA and insulin levels, with higher basal insulin levels in OG. RBC-Mg was directly correlated with insulin, HOMA and FFM in both groups, according to Pearson correlations. HOMA in OG was also directly correlated with BMI, FFM and AF. In NOG, HOMA was only correlated with FFM. The low RBC-Mg levels observed were probably due to low Mg intake and to deregulation of factors that control Mg homeostasis during menopause. Conclusions: Both Mg deficit and obesity may independently lead to a higher risk for insulin resistance and cardiovascular disease.

Multi index model - uma abordagem para aplicação ao mercado accionista em Portugal

O mercado accionista, de uma forma global, tem-se revelado nos últimos tempos uma das principais fontes de incentivo ao mercado de valores mobiliários. O seu impacto junto do público em geral é enorme e a sua importância para as empresas é vital. Interessa, então, perceber como é que a teoria financeira tem obordado a avaliação e a compreensão do processo de formação de uma cotação. Desde os anos 50 até aos dias de hoje, interessa perceber como é que os diferentes autores têm tratado esta abordagem e quais os resultados deste confronto. Interessa sobretudo perceber o abordogem de Stephen Ross e a teoria do arbitragem. Na sequência desta obordagem e com o aparecimento do Multi Index Model, passou a ser possível extimar com maior precisão a evolução da cotação, na medida em que esta estaria dependente de um vasto conjunto de variavéis, que abragem uma vasta área de influência. O contributo de Ross é por isso decisivo. No final interessa reter a melhor técnica e teoria, que defende os interesses do investidor. Face o isto resta, então, saber qual a melhor técnica estatística para proceder a estes estudos empíricos.

Familial amyloid polyneuropathy (FAP): clinical features, pathophysiology and treatment

In the literature, concepts of “polyneuropathy”, “peripheral neuropathy” and “neuropathy” are often mistakenly used as synonyms. Polyneuropathy is a specific term that refers to a relatively homogenous process that affects multiple peripheral nerves. Most of these tend to present as symmetric polyneuropathies that first manifest in the distal portions of the affected nerves. Many of these distal symmetric polyneuropathies are due to toxic-metabolic causes such as alcohol abuse and diabetes mellitus. Other distal symmetric polyneuropathies may result from an overproduction of substances that result in nerve pathology such as is observed in anti-MAG neuropathy and monoclonal gammopathy of undetermined significance. Other “overproduction” disorders are hereditary such as noted in the Portuguese type of familial amyloid polyneuropathy (FAP). FAP is a manifestation of a group of hereditary amyloidoses; an autosomal dominant, multisystemic disorder wherein the mutant amyloid precursor, transthyretin, is produced in excess primarily by the liver. The liver accounts for approximately 98% of all transthyretin production. FAP is confirmed by detecting a transthyretin variant with a methionine for valine substitution at position 30 [TTR (Met30)]. Familial Amyloidotic Polyneuropathy (FAP) – Portuguese type was first described by a Portuguese neurologist, Corino de Andrade in 1939 and published in 1951. Most persons with this disorder are descended from Portuguese sailors who sired offspring in various locations, primarily in Sweden, Japan and Mallorca. Their descendants emigrated worldwide such that this disorder has been reported in other countries as well. More than 2000 symptomatic cases have been reported in Portugal. FAP progresses rapidly with an average time course from symptom onset to multi-organ involvement and death between ten and twenty years. Treatments directed at removing this aberrant protein such as plasmapheresis and immunoadsorption proved to be unsuccessful. Liver transplantation has been the only effective solution as evidenced by almost 2000 liver transplants performed worldwide. A therapy for FAP with a novel agent, “Tafamidis” has shown some promise in ongoing phase III clinical trials. It is well recognized that regular physical activity of moderate intensity has a positive effect on physical fitness as gauged by body composition, aerobic capacity, muscular strength and endurance and flexibility. Physical fitness has been reported to result in the reduction of symptoms and lesser impairment when performing activities of daily living. Exercise has been advocated as part of a comprehensive approach to the treatment of chronic diseases. Therefore, this chapter concludes with a discussion of the role of exercise training on FAP.

Serial experiments lain's body: o corpo enquanto fronteira entre o físico e o virtual

Dissertação apresentada à Escola Superior de Comunicação Social como parte dos requisitos para obtenção de grau de mestre em Audiovisual e Multimédia.

Intervenção baseada no conceito de Bobath em indivíduos com doença de Parkinson: quatro estudos de caso

Introdução: O padrão de recrutamento temporal inerente a uma sequência de ativação muscular (SAM), permite a organização multi-segmentar para a realização de uma tarefa motora. Este depende da conexão neural entre estruturas corticais e sub-corticais, incluindo os núcleos da base (NB), podendo, assim, estar comprometido em indivíduos com Doença de Parkinson (DP). As SAM poderão ser melhoradas através de uma intervenção baseada no conceito de Bobath (CB). Objetivo: Estudar o potencial da intervenção, baseada no CB, a longo prazo, nas SAM ao nível da tibio-társica (TT), durante as tarefas motoras sit-to-stand (SitTS) e o stand-to-sit (StandTS), em quatro indivíduos com DP. Metodologia: O estudo apresenta quatro casos de indivíduos com DP, que realizaram intervenção em fisioterapia baseada no CB, durante 12 semanas. Antes e após a intervenção, foram avaliadas as sequências de ativação do gastrocnémio medial (GM), do solear (SOL) e do tibial anterior (TA), durante as tarefas SitTS e StandTS, recorrendo à eletromiografia de superfície e à plataforma de forças, para a divisão cinética das diferentes fases das tarefas. Avaliou-se ainda o equilíbrio funcional, através da Escala de Berg, e a percepção subjetiva dos indivíduos acerca da sua capacidade para realizar atividades sem cair, através da Modified Falls Efficacy Scale. Resultados: Após a intervenção, os indivíduos em estudo apresentaram, na sua maioria, uma diminuição da co-ativação muscular, bem como um aumento do equilíbrio funcional e diminuição da probabilidade de risco de queda, refletindo uma melhoria do controlo postural (CP). As modificações na percepção subjetiva dos indivíduos acerca da sua capacidade para realizar atividades sem cair não foram homogéneas. Conclusão: A intervenção baseada no CB teve efeitos positivos do ponto de vista do CP nos quatro indivíduos com DP. Pensa-se que uma intervenção mais duradoura poderá intensificar as melhorias observadas.

Body mass index for predicting hyperglycemia and serum lipid changes in Brazilian adolescents

OBJECTIVE: To determine the best cut-offs of body mass index for identifying alterations of blood lipids and glucose in adolescents. METHODS: A probabilistic sample including 577 adolescent students aged 12-19 years in 2003 (210 males and 367 females) from state public schools in the city of Niterói, Southeastern Brazil, was studied. The Receiver Operating Characteristic curve was used to identify the best age-adjusted BMI cut-off for predicting high levels of serum total cholesterol (>150mg/dL), LDL-C (>100mg/dL), serum triglycerides (>100mg/dL), plasma glucose (>100mg/dL) and low levels of HDL-C (< 45mg/dL). Four references were used to calculate sensitivity and specificity of BMI cut-offs: one Brazilian, one international and two American. RESULTS: The most prevalent metabolic alterations (>50%) were: high total cholesterol and low HDL-C. BMI predicted high levels of triglycerides in males, high LDL-C in females, and high total cholesterol and the occurrence of three or more metabolic alterations in both males and females (areas under the curve range: 0.59 to 0.67), with low sensitivity (57%-66%) and low specificity (58%-66%). The best BMI cut-offs for this sample (20.3 kg/m² to 21.0 kg/m²) were lower than those proposed in the references studied. CONCLUSIONS: Although BMI values lower than the International cut-offs were better predictor of some metabolic abnormalities in Brazilian adolescents, overall BMI is not a good predictor of these abnormalities in this population.

Factores de rentabilização do processo de serragem de granitos com engenhos multi-lâminas

Este trabalho visa apresentar um enquadramento da realidade económica e industrial do sector transformador de granitos ornamentais em Portugal e fazer uma análise do processo de serragem, com engenhos multi-lâminas e granalha de aço, na medida em que este é o método de seccionamento de blocos de granito mais utilizado pelas grandes indústrias do sector. Tendo em conta a importância económica desta operação produtiva na indústria em causa, foi definido como fito deste projecto a análise estatística dos custos de produção; a definição de fórmulas de cálculo que permitam prever o custo médio de serragem; e o estudo de soluções economicamente viáveis e ambientalmente sustentáveis para o problema das lamas resultantes do expurgo dos engenhos. Para a persecução deste projecto foi realizada uma recolha de dados implementando rotinas de controlo e registo dos mesmos, em quadros de produção normalizados e de fácil preenchimento, pelos operadores destes equipamentos. Esta recolha de dados permitiu isolar, quantificar e formular os factores de rentabilização do processo de serragem selecionando, dentro da amostra de estudo obtida, um conjunto de serragens com características similares e com valores próximos dos valores da média estatística. Apartir dos dados destas serragens foram geradas curvas de tendência polinomial com as quais se analisaram as variações provocadas no custo médio de serragem, pelas variações do factor em estudo. A formulação dos factores de rentabilização e os dados estatísticos obtidos permitiram depois o desenvolvimento de fórmulas de cálculo do custo médio de serragem que establecem o custo de produção diferenciado em função das espessuras com, ou sem, a incorporação dos factores de rentabilização. Como consequência do projecto realizado obteve-se um conjunto de conclusões util, para o sector industrial em causa, que evidencia a importancia da Ocupação dos engenhos e rentabilização de um espaço confinado, da Resistência oferecida à serragem pelos granitos, e da Diferença de altura entre os blocos de uma mesma carga, nos custos de transformação.

Does the intake of LC-PUFAS during pregnancy affect the body composition of term neonates? Preliminary results

Background: The effect of the intake of polynsaturated long chain fatty acids (LCPUFAs) during pregnancy on fetal body composition has been assessed by studies using mostly neonatal anthropometry. Their results have been inconsistent, probably because neonatal anthropometry has several validity limitations. Air displacement plethismography (ADP) is a recently validated non-invasive method for assessing body composition in neonates. Objective: To determine the effect of the intake of LCPUFAs during pregnancy on the body composition of term neonates, measured by ADP. Methods: Cross-sectional study of a convenience sample of healthy full-term neonates and their mothers. The diet during pregnancy was assessed using a validated semi-quantitative food frequency questionnaire; Food Processor Plus® was used to convert food intake into nutritional values. Body composition was estimated by anthropometry and measured by ADP using Pea Pod™ Life Measurements Inc (fat mass - FM, fat-free mass and %FM) within the first 72h after birth. Univariate and multivariate analysis (linear regression model) were performed. Results: 54 mother-neonate pairs were included. Multivariate analysis adjusted to the maternal body mass index shows positive association between LCPUFAs intake and neonatal mid-arm circumference (= 0,610, p = 0,019) and negative association between n-6:n-3 ratio intake and neonatal %FM (= -2,744, p=0,066). Conclusion: To the best of our knowledge, this is the first study on this subject using ADP and showing a negative association between LCPUFAs n-6:n-3 ratio intake in pregnancy and neonatal %FM. This preliminary finding requires confirmation increasing the study power with a greater sample and performing interventional studies.

High Performance Multi-Standard Architecture for DCT Computation in H.264/AVC High Profile and HEVC Codecs

A new high performance architecture for the computation of all the DCT operations adopted in the H.264/AVC and HEVC standards is proposed in this paper. Contrasting to other dedicated transform cores, the presented multi-standard transform architecture is supported on a completely configurable, scalable and unified structure, that is able to compute not only the forward and the inverse 8×8 and 4×4 integer DCTs and the 4×4 and 2×2 Hadamard transforms defined in the H.264/AVC standard, but also the 4×4, 8×8, 16×16 and 32×32 integer transforms adopted in HEVC. Experimental results obtained using a Xilinx Virtex-7 FPGA demonstrated the superior performance and hardware efficiency levels provided by the proposed structure, which outperforms its more prominent related designs by at least 1.8 times. When integrated in a multi-core embedded system, this architecture allows the computation, in real-time, of all the transforms mentioned above for resolutions as high as the 8k Ultra High Definition Television (UHDTV) (7680×4320 @ 30fps).

Sustainable blended-learning in HEI: developing and implementing multi-level interventions

This chapter aims to demonstrate how PAOL - Unit for Innovation in Education, a project from ISCAP - School of Accounting and Administration of Oporto ....

Multi-criteria design optimization study of solvent extraction in mixer–settler units

Solvent extraction is considered as a multi-criteria optimization problem, since several chemical species with similar extraction kinetic properties are frequently present in the aqueous phase and the selective extraction is not practicable. This optimization, applied to mixer–settler units, considers the best parameters and operating conditions, as well as the best structure or process flow-sheet. Global process optimization is performed for a specific flow-sheet and a comparison of Pareto curves for different flow-sheets is made. The positive weight sum approach linked to the sequential quadratic programming method is used to obtain the Pareto set. In all investigated structures, recovery increases with hold-up, residence time and agitation speed, while the purity has an opposite behaviour. For the same treatment capacity, counter-current arrangements are shown to promote recovery without significant impairment in purity. Recycling the aqueous phase is shown to be irrelevant, but organic recycling with as many stages as economically feasible clearly improves the design criteria and reduces the most efficient organic flow-rate.