Small NFAs from Regular Expressions: Some Experimental Results

Regular expressions (res), because of their succinctness and clear syntax, are the common choice to represent regular languages. However, efficient pattern matching or word recognition depend on the size of the equivalent nondeterministic finite automata (NFA). We present the implementation of several algorithms for constructing small epsilon-free NFAss from res within the FAdo system, and a comparison of regular expression measures and NFA sizes based on experimental results obtained from uniform random generated res. For this analysis, nonredundant res and reduced res in star normal form were considered.Comment: Proceedings of 6th Conference on Computability in Europe (CIE 2010), pages 194-203, Ponta Delgada, Azores, Portugal, June/July 201

Hamiltonian elliptic systems: a guide to variational frameworks

Consider a Hamiltonian system of type $$-\Delta u=H_{v}(u,v),\ -\Delta v=H_{u}(u,v) \ \ \text{ in } \Omega, \qquad u,v=0 \text{ on } \partial \Omega$$ where $H$ is a power-type nonlinearity, for instance $H(u,v)= |u|^p/p+|v|^q/q$, having subcritical growth, and $\Omega$ is a bounded domain of $\mathbb{R}^N$, $N\geq 1$. The aim of this paper is to give an overview of the several variational frameworks that can be used to treat such a system. Within each approach, we address existence of solutions, and in particular of ground state solutions. Some of the available frameworks are more adequate to derive certain qualitative properties; we illustrate this in the second half of this survey, where we also review some of the most recent literature dealing mainly with symmetry, concentration, and multiplicity results. This paper contains some original results as well as new proofs and approaches to known facts.Comment: 78 pages, 7 figures. This corresponds to the second version of this paper. With respect to the original version, this one contains additional references, and some misprints were correcte

Dynamic Mode Decomposition and Koopman Operator (Data-Driven Modeling of Complex Dynamical Systems)

Data-driven schemes are in high demand, given the growing abundance and accessibility to large amounts of measurements from historical records, numerical simulations, and experimental data. However, despite the abundance of data, modeling high-dimensional complex dynamical systems remains a challenge. In this thesis we present a data-driven method for modeling dynamical systems called the Dynamic Mode Decomposition (DMD). This is a recent method that has first emerged in the fluid mechanics community as a tool for analyzing the dynamics of nonlinear systems. However, given its ability to provide an accurate decomposition of a complex system into spatiotemporal coherent structures, it gained popularity and interest from other fields where complex nonlinear processes cannot be accurately characterized by known governing equations, or that exhibit a rich multiscale dynamic properties. This method relies on the fact that many of these systems evolve on a low-dimensional attractor that may be characterized by dominant spatiotemporal coherent structures. The confidence that the DMD is useful to characterize non-linear dynamics is given by theoretical framework provided by Koopmans theory, which will also be presented in the thesis. Short examples are used to illustrate the DMD application and the Koopmans operator theory. Finally, two data-sets generated from two different fields (from a 2D ocean model, and a neuron strip experiment) are tested using the DMD. We will use the decomposition results to identify structures which we may relate to a physical phenomena, and discuss the performance.Master's Thesis in MathematicsMAB399MAMN-MA

The effect of heteroscedasticity on bayesian variable selection

Mestrado em Econometria Aplicada e PrevisãoNesta dissertação estudamos o efeito da heterocedasticidade na seleção bayesiana de variáveis. Através de um estudo de simulação, e utilizando dois conjuntos de dados reais, avaliamos os efeitos de introduzir heteroscedasticidade numa regressão linear, bem como o efeito de transformar dados heterocedásticos em homocedásticos. Analisando as variáveis selecionadas, probabilidades de inclusão e medidas de performance preditiva, concluimos que a seleção bayesiana de variáveis é robusta à heterocedasticidade, mas é possível obter melhor perfomance preditiva se a estrutura de variância dos erros for tomada em conta.This dissertation aims to study the effect of heteroscedasticity on Bayesian Variable Selection. It employs a simulation study, using two distinct datasets, to evaluate the effects of introducing heteroscedasticity in a linear regression, and whether transforming an heteroscedastic dataset into an homoscedastic one results in any considerable differences. We look at the variables selected, inclusion probabilities and performance measures. We find Bayesian Variable Selection to be robust to heteroscedasticity, although a better predictive performance may be attained if we take the error variance's structure explicitly into account.info:eu-repo/semantics/publishedVersio

Investigating the mechanisms of α-particle therapy in prostate cancer

The use of α-particle radionuclide emitters in the treatment of bone metastasis has been an active area of research within targeted radionuclide therapies. From a radiobiological perspective, α-particles are known to be more effective at killing cells in comparison to low linear energy transfer (LET) radiation particles, such as X-rays, with increased relative biological effectiveness of around a factor of 3 in most models. α-particle irradiated cells also show a reduced dependency on radioresistance mechanisms observed in the absence of oxygen, with an oxygen enhancement ratio (OER) close to 1.0. Such advantageous radiobiological properties of α-particles demonstrate their potential for radiotherapy treatments. In recent years, the bone targeting high LET radionuclide Radium-223 (223Ra) has been shown to not only have a palliative effect but also a survival prolonging effect in castration resistant prostate cancer patients with bone metastases. This has encouraged the use of 233Ra in more extensive clinical trials. Despite the clinical utility of 233Ra, little is known regarding the radionuclide’s mechanisms of action in this treatment setting, where accurate assessments of the dosimetry underpinning its effectiveness are lacking. There is a pressing need to model and quantify α-emitter effects in pre-clinical models so the next generation of trials utilising 223Ra can be optimally designed. The research work presented in this thesis focused on studying the dosimetry involved in α-particle irradiation systems for in vitro and clinical settings, using computational simulation methods. We have also studied the α-particle irradiation effects on cell survival, DNA damage and tumour control, focusing specifically on 223Ra treatment scenarios

Gendered Spaces at Home Feminine and Masculine Traits in Domestic Interiors

As a cultural product, the home and its settings are shaped according to social norms and characteristics. Throughout history, domestic interiors continuously changed as a mirror of Feminine and Male roles in society. This paper focuses on the analysis of domestic interiors from the modern age until present times, describing and depicting cases of spatial segregation and specialization based on the gender of its users or occupants. The historical account that is portrayed revisits the domestic arrangements where genderization was more evident, namely bedrooms, kitchen and, at times, rooms for specific uses or functions. The goal of the study is to understand in which manner gender roles and society’s views of gender character and behaviour have impacted domestic interiors and living modes. The produced scholarship shows that the former have indeed determined the latter and that from the beginning of the modern era until today western society has witnessed a cyclical evolution: from degendered spaces to highly segregated homes, from these to spatial democratizing and, finally, from a democratic home to a return to segregating models. The study concludes that domestic interiors were and somewhat continue to be greatly determined by social concepts of gender attributes, hierarchy and behaviour. Furthermore, although the paper focuses only on western homes, being limited by this context, further research could be developed on the analysis of gendered spaces in other cultures, societies and geographic contexts, to consolidate enlightenment on the subject

Maternal food intake and socioeconomic status to tackle childhood malnutrition

Von Wilh. Bloh

Vitamin K in hemodialysis patients

Os doentes hemodialisados por doença renal geralmente apresentam défices de vitamina K no sangue, provavelmente devido às dietas a que são sujeitos. De facto, devido à sua patologia, estes doentes devem reduzir a ingestão de produtos ricos em sódio e potássio, como queijos e vegetais verdes, que são ricos em vitamina K. Como esta vitamina atua como cofator da carboxilase dependente de vitamina K, as proteínas que dependem desta enzima, tais como a matrix Gla protein (MGP), osteocalcin (OC), growth arrest specific protein 6 (Gas6) e a Gla-rich protein (GRP), vão ficar descarboxiladas e inativadas. Isto resultará num conjunto de alterações, como alterações fenotípicas das células do endotélio vascular que se transformam em células osteocondrogénicas, processo apelidado de calcificação vascular. A calcificação vascular será depois responsável pelo aumento da rigidez dos vasos sanguíneos, músculo e válvulas cardíacas, e contribuirá também para o aceleramento do processo aterosclerótico. Compreende-se então que seja considerada um fator de risco sobretudo para a mortalidade e morbilidade cardiovascular. O elevado número de pacientes afetados por esta complicação resulta numa necessidade de procura de uma terapêutica capaz de tratar o défice de vitamina K e consequentemente retardar a evolução do processo de calcificação. A hipótese de suplementar estes doentes com vitamina K pode ser importante e protetora para o desenvolvimento da calcificação vascular. Assim, neste artigo de revisão pretendemos analisar vários estudos que têm sido realizados com este objetivo e perceber se o uso desta terapêutica pode ter utilidade na gestão e tratamento do doente hemodialisado.Hemodialysis patients with kidney disease usually have vitamin K deficits in their blood, probably due to their diets. In fact, due to their pathology, these patients must reduce their intake of products rich in sodium and potassium, such as cheeses and green vegetables, which are rich in vitamin K. As this vitamin acts as a cofactor for vitamin K-dependent carboxylase, proteins that depend on this enzyme, such as matrix Gla protein (MGP), osteocalcin (OC), growth arrest specific protein 6 (Gas6) and Gla-rich protein (GRP), will be decarboxylated and inactivated. This will result in a set of changes, such as phenotypic changes in the cells of the vascular endothelium that turn into osteochondrogenic cells, a process called vascular calcification. Vascular calcification will then be responsible for increasing the stiffness of blood vessels, muscle and heart valves, and will also contribute to the acceleration of the atherosclerotic process. So, this is considered a risk factor especially for cardiovascular mortality and morbidity. The high number of patients affected by this complication results in a need to search for a therapy capable of treating vitamin K deficiency and consequently delaying the evolution of the calcification process. The possibility of supplementing these patients with vitamin K may be important and protective for the development of vascular calcification. Thus, in this article review weintend to analyze several studies that have been carried out with this objective and to understand if the use of this therapy can be useful in the management and treatment of hemodialysis patients