Molecular modulation of brain development and function: lessons from “old” and “new”

Dissertation presented to obtain the Ph.D degree in Biology

Discrete fractional order system vibrations

A theory of free vibrations of discrete fractional order (FO) systems with a finite number of degrees of freedom (dof) is developed. A FO system with a finite number of dof is defined by means of three matrices: mass inertia, system rigidity and FO elements. By adopting a matrix formulation, a mathematical description of FO discrete system free vibrations is determined in the form of coupled fractional order differential equations (FODE). The corresponding solutions in analytical form, for the special case of the matrix of FO properties elements, are determined and expressed as a polynomial series along time. For the eigen characteristic numbers, the system eigen main coordinates and the independent eigen FO modes are determined. A generalized function of visoelastic creep FO dissipation of energy and generalized forces of system with no ideal visoelastic creep FO dissipation of energy for generalized coordinates are formulated. Extended Lagrange FODE of second kind, for FO system dynamics, are also introduced. Two examples of FO chain systems are analyzed and the corresponding eigen characteristic numbers determined. It is shown that the oscillatory phenomena of a FO mechanical chain have analogies to electrical FO circuits. A FO electrical resistor is introduced and its constitutive voltage–current is formulated. Also a function of thermal energy FO dissipation of a FO electrical relation is discussed.

Relações entre o tipo de respiração, as funções executivas e o comportamento numa amostra de crianças do ensino básico

Envolvido na necessidade emergente de associar a Saúde à Educação e da importância e proeminência que a literatura tem manifestado sobre a respiração e as suas implicações na aprendizagem, este estudo pretende explorar e identificar as principais características anátomo-fisiológicas de alunos com RN e RO, apresentar as alterações do comportamento em alunos com RN e alunos com RO, expôr as modificações das funções executivas em alunos com RN e alunos com RO e a relação entre as funções executivas e o comportamento em alunos com RN e alunos com RO. Foram avaliados 169 alunos do 2º ciclo de escolaridade da Escola Eb2/3 de São João da Madeira na respiração, no comportamento e funções executivas – com recurso à adaptação da Avaliação Miofuncional Orofacial – MBGR, do Questionário de Autoavaliação para Jovens (Youth Self Report) e do Inventário de Classificação Comportamental de Funções Executivas – ICCFE-C/A (versão para crianças/adolescentes). Usou-se a avaliação miofuncional orofacial para se obter a caraterização do modo respiratório e das alterações miofuncionais na amostra; e o questionário de autoavaliação comportamental e o inventário de classificação comportamental de funções executivas para verificar a existência de relação entre o desempenho comportamental e funções executivas com o modo respiratório. Os alunos com modo respiratório predominantemente oral apresentam maior incidência de alterações miofuncionais e de modificações comportamentais e nas funções executivas em comparação de alunos com respiração predominantemente nasal.

Analysis of Systems with Backlash and Impacts through the Describing Function

This paper analyses the dynamical properties of systems with backlash and impact phenomena based on the describing function method. The dynamics is illustrated using the Nyquist and Bode plots and the results are compared with those of standard models.

Adrenal function in 23 children with paracoccidioidomycosis

Adrenal involvement by Paracoccidioides brasiliensis was described at necropsies and in many clinical studies, but only in adults. Therefore, the aim of this study was to evaluate adrenal function in children with paracoccidioidomycosis. Twenty-three children with the systemic form of paracoccidioidomycosis were evaluated and divided in two Groups: Group A (n = 8) included children before treatment and Group B (n = 15) children after the end of treatment. Plasma cortisol (basal and after ACTH test), ACTH, renin activity, aldosterone, sodium and potassium were measured. They were within normal range in all cases, except for renin activity and aldosterone, which were elevated in some cases. Group A patients showed basal and post-ACTH cortisol levels significantly greater than Group B patients. The results showed that adrenal function was not compromised in these children with paracoccidioidomycosis.

The effect of adhesive thickness on the mechanical behavior of a structural polyurethane adhesive

One parameter that influences the adhesively bonded joints performance is the adhesive layer thickness. Hence, its effect has to be investigated experimentally and should be taken into consideration in the design of adhesive joints. Most of the results from literature are for typical structural epoxy adhesives which are generally formulated to perform in thin sections. However, polyurethane adhesives are designed to perform in thicker sections and might have a different behavior as a function of adhesive thickness. In this study, the effect of adhesive thickness on the mechanical behavior of a structural polyurethane adhesive was investigated. The mode I fracture toughness of the adhesive was measured using double-cantilever beam (DCB) tests with various thicknesses of the adhesive layer ranging from 0.2 to 2 mm. In addition, single lap joints (SLJs) were fabricated and tested to assess the influence of adhesive thickness on the lap-shear strength of the adhesive. An increasing fracture toughness with increasing adhesive thickness was found. The lap-shear strength decreases as the adhesive layer gets thicker, but in contrast to joints with brittle adhesives the decrease trend was less pronounced.

Cohesive law estimation of adhesive joints in mode II condition

The adhesive bonding technique enables both weight and complexity reduction in structures that require some joining technique to be used on account of fabrication/component shape issues. Because of this, adhesive bonding is also one of the main repair methods for metal and composite structures by the strap and scarf configurations. The availability of strength prediction techniques for adhesive joints is essential for their generalized application and it can rely on different approaches, such as mechanics of materials, conventional fracture mechanics or damage mechanics. These two last techniques depend on the measurement of the fracture toughness (GC) of materials. Within the framework of damage mechanics, a valid option is the use of Cohesive Zone Modelling (CZM) coupled with Finite Element (FE) analyses. In this work, CZM laws for adhesive joints considering three adhesives with varying ductility were estimated. The End-Notched Flexure (ENF) test geometry was selected based on overall test simplicity and results accuracy. The adhesives Araldite® AV138, Araldite® 2015 and Sikaforce® 7752 were studied between high-strength aluminium adherends. Estimation of the CZM laws was carried out by an inverse methodology based on a curve fitting procedure, which enabled a precise estimation of the adhesive joints’ behaviour. The work allowed to conclude that a unique set of shear fracture toughness (GIIC) and shear cohesive strength (ts0) exists for each specimen that accurately reproduces the adhesive layer’ behaviour. With this information, the accurate strength prediction of adhesive joints in shear is made possible by CZM.

Zero-Time Kidney Histology Predicts Early Graft Function

Our purposes are to determine the impact of histological factors observed in zero-time biopsies on early post transplant kidney allograft function. We specifically want to compare the semi-quantitative Banff Classification of zero time biopsies with quantification of % cortical area fibrosis. Sixty three zero-time deceased donor allograft biopsies were retrospectively semiquantitatively scored using Banff classification. By adding the individual chronic parameters a Banff Chronic Sum (BCS) Score was generated. Percentage of cortical area Picro Sirius Red (%PSR) staining was assessed and calculated with a computer program. A negative linear regression between %PSR/ GFR at 3 year post-transplantation was established (Y=62.08 +-4.6412X; p=0.022). A significant negative correlation between arteriolar hyalinosis (rho=-0.375; p=0.005), chronic interstitial (rho=0.296; p=0.02) , chronic tubular ( rho=0.276; p=0.04) , chronic vascular (rho= -0.360;P=0.007), BCS (rho=-0.413; p=0.002) and GFR at 3 years were found. However, no correlation was found between % PSR, Ci, Ct or BCS. In multivariate linear regression the negative predictive factors of 3 years GFR were: BCS in histological model; donor kidney age, recipient age and black race in clinical model. The BCS seems a good and easy to perform tool, available to every pathologist, with significant predictive short-term value. The %PSR predicts short term kidney function in univariate study and involves extra-routine and expensive-time work. We think that %PSR must be regarded as a research instrument.

De Novo Hypertension and Decline of Renal Function in a Young Woman with Systemic Lupus Erythematosus and Antiphospholipid Syndrome

Antiphospholipid syndrome nephropathy and lupus nephritis have similar clinical and laboratory manifestations and achieving the accuracy of diagnosis required for correct treatment frequently necessitates a kidney biopsy. We report the case of a 29-year-old woman referred to the nephrology service for de novo hypertension, decline of renal function and proteinuria. She had had systemic lupus erythematosus and antiphospholipid syndrome since the age of 21 and was taking oral anticoagulation. Two weeks later, after treatment of hypertension and achievement of adequate coagulation parameters, a percutaneous renal biopsy was performed. The biopsy revealed chronic lesions of focal cortical atrophy, arterial fibrous intimal hyperplasia and arterial thromboses, which are typical features of antiphospholipid syndrome nephropathy. We describe the clinical manifestations and histopathology of antiphospholipid syndrome nephropathy and review the literature on renal biopsy in patients receiving anticoagulation.

Adaptive Penalty and Barrier function based on Fuzzy Logic

Optimization methods have been used in many areas of knowledge, such as Engineering, Statistics, Chemistry, among others, to solve optimization problems. In many cases it is not possible to use derivative methods, due to the characteristics of the problem to be solved and/or its constraints, for example if the involved functions are non-smooth and/or their derivatives are not know. To solve this type of problems a Java based API has been implemented, which includes only derivative-free optimization methods, and that can be used to solve both constrained and unconstrained problems. For solving constrained problems, the classic Penalty and Barrier functions were included in the API. In this paper a new approach to Penalty and Barrier functions, based on Fuzzy Logic, is proposed. Two penalty functions, that impose a progressive penalization to solutions that violate the constraints, are discussed. The implemented functions impose a low penalization when the violation of the constraints is low and a heavy penalty when the violation is high. Numerical results, obtained using twenty-eight test problems, comparing the proposed Fuzzy Logic based functions to six of the classic Penalty and Barrier functions are presented. Considering the achieved results, it can be concluded that the proposed penalty functions besides being very robust also have a very good performance.

Safety function analysis in an industrial production process

Dissertação para obtenção do Grau de Mestre em Engenharia e Gestão Industrial

Tendências de recompensas em empresas portuguesas

Esta dissertação tem como objetivo central conhecer os sistemas de recompensas em empresas portuguesas. Primeiramente é realizada uma abordagem aos conceitos subjacentes ao sistema de recompensas e, simultaneamente é exposta teoria sobre o tipo de recompensas mais utilizadas e como estas diferem consoante o cargo/função. Foi aplicado um inquérito por questionário a uma amostra de 144 empresas localizadas por todo o país. Foram testadas hipóteses de estudo capazes de permitir caraterizar o sistema de recompensas desenvolvido nas empresas em estudo. Os resultados do estudo permitem concluir que: 1) os sistemas de recompensas baseados na antiguidade estão atualmente em desuso, ao contrário dos sistemas de recompensas baseados na função/cargo, no desempenho e nas competências; 2) o principal objetivo do sistema de recompensas das empresas do estudo é a motivação dos colaboradores; 3) a conjugação das recompensas monetárias e não monetárias são as mais valorizadas pelas empresas; 4) predomina a compensação variável nos sistemas de recompensas das empresas bem como os incentivos mistos (individuais e de grupo); 5) predominam os incentivos de curto-prazo no sistema de recompensas; 6) o bónus anual é o incentivo mais utilizado; 7) os benefícios e alguns dos incentivos tendem a ser maiores à medida que se sobe na hierarquia funcional da empresa; 8) o benefício predominante é a atribuição de telemóvel e o seguro de saúde; 9) as formas de reconhecimento mais comuns são os prémios de desempenho, o feedback contínuo, as promoções e as placas comemorativas; 10) a maioria dos inquiridos acredita que as oportunidades de desenvolvimento de carreira é uma importante medida para a retenção dos colaboradores; 11) as oportunidades de desenvolvimento são mais utilizadas pelas empresas de maior dimensão e; 12) os benefícios sociais são considerados a componente mais importante para garantir a retenção dos colaboradores. Com base nestes resultados, na parte final da dissertação são apresentadas algumas implicações teóricas e práticas, algumas limitações do estudo, bem como pistas para investigações futuras.

Design of switched-capacitor filters using low gain amplifiers

Dissertação para obtenção do Grau de Mestre em Engenharia Electrotécnica e de Computadores