Finding Association Rules in College Course Progression

Association Rules are a data mining technique that aims at finding patterns in data that explain how different elements of the data influence each other. In this project this technique is used to find associations that describe the trends of college course completions and results. This project used a dataset from the University of Évora for rule finding. This paper shows how the dataset had to be preprocessed first in order to be mined, and describes the techniques and algorithms used

Classificação de Atividades a partir da Aceleração

Resumo Um dos tipos de problemas mais populares em Mineração de Dados ́e a classificacão. Através da aplicação de algoritmos, como o J48, k-Nearest Neighbours ou Naive Bayes é efetuada uma tentativa de classificação de várias atividades quotidianas como Andar a pé, correr, andar de bicicleta ou de automóvel a partir da aceleração registada pelo smartphone. Os dados recolhidos serão tratados de forma a que possam ser utilizados pelos algoritmos. No final será apresentada uma comparação de desempenho entre os mesmos. Dadas as semelhanças com o tipo de problemas tratados, é feito ainda um teste suplementar no campo da deteção de quedas

Regulação hormonal da produção de lactato e expressão do NHE3 pelas células de Sertoli ex vivo

Sertoli cells cells play a key role on the establishment of an adequate luminal environment in the seminiferous tubules of the male reproductive tract. The secretion of the seminiferous tubular fluid (STF), as well as, the control of the pH of this fluid is crucial for male fertility. Sertoli cells express various types of ion membrane transporters that are directly involved on the movement basic and acidic particles across the membrane. Among them, is Na+/H+ exchanger (NHE3), which belongs to the Na+/H+ exchanger family, one of the most relevant epithelial ion transporter families, catalyzes the electroneutral transport of extracellular Na+ for intracellular H+. Several authors have provided confirmation that estrogens and androgens play an important role in male fertility, and regulate fluid transport on the male reproductive tract. On the other hand, as germ cells are unable to use glucose for their energy metabolism (Sertoli cells metabolize glucose and the majority of it is converted to lactate, which is preferentially used by developing germ cells). There is a growing awareness that androgens and estrogens have general metabolic roles that reach far beyond reproductive processes. Thus, is important to understand the role of the sex steroids in expression of NHE3 in Sertoli cells, as wells as, its modulation in metabolism of these “nurse” cells. For this purpose, primary Sertoli cell cultures were prepared from 20 days-old rats in serum-free medium supplemented with insulin, transferrin and selenium supplement (ITS medium) and divided in 7 experimental groups, being subjected to hormonal treatment during 50 hours. The groups were: E2 (17β-estradiol); dihydrotestosterone (DHT); ICI 182,720 (ICI); flutamide (Flut); ICI/ E2; Flut/DHT and control. The hormonal concentration was 100nM for all groups, except control group, which was not treated. The presence of NHE3 in Sertoli cells was confirmed by RT-PCR and western blot analysis. NHE3 was semi-quantified by RT-PCR for all experimental groups, there have been no significant differences when compared to control group. As for, analysis of the metabolites secretion or consumption by Sertoli cell culture, it was recovered 250 μL of the culture medium at 5h,15h, 25, 35h and 50h, after beginning treatment, for hydrogen nuclear magnetic resonance spectra analysis. The results obtained showed that glucose consumption was significantly higher in DHT-treated Sertoli cells after 50 hours than in control conditions or E2-treated cells. Unexpectedly, DHT-treated cells produced less lactate than those treated with E2 or in control conditions. This may be due to several factors such as to a decrease in cellular production of lactate, to a delay in lactate transport to extracellular medium or even to lactate utilization as substrate by DHT-treated cells. In pyruvate consumption there were no significant changes with hormonal treatment, however alanine production was higher in E2-treated cells. In summary, this study demonstrates that sex steroids do not exert significant effects in NHE3 expression by Sertoli cells. It is likely that control of intracellular pH of the Sertoli cells and luminal acidification in seminiferous tubules do not depend on directly of estrogen and androgen actions mediated by its receptors. In other hand, DHT increases glucose consumption in Sertoli cells and E2 increase alanine production. Thus, sex steroids seem to play an important role in modulation of Sertoli cells metabolism.As células de Sertoli desempenham um papel importante no estabelecimento de um ambiente luminal adequado nos tubulos seminíferos do tracto reprodutivo masculino. A secreção do fluído do tubulo seminífero, bem como a regulação do seu pH é essencial para a fertilidade masculina. As células de Sertoli expressam na sua membrana vários tipos de transportadores de iões que estão envolvidos no movimento de partículas básicas e ácidas através da membrana. Entre eles está o transportador de Na+ /H+ 3 (NHE3) que pertence à família de transportadores de Na+ /H+ , uma das famílias mais relevantes de transportadores iónicos epiteliais, que cataliza o transporte de um Na+ extracelular por um H+ intracelular. Vários autores têm demonstrado que o NHE3 é importante para a fertilidade masculina e que a sua expressão parece ser regulada pelos esteróides sexuais. Por outro lado, as células germinativas são incapazes de usar a glucose para o seu metabolismo (as células de Sertoli metabolizam a glucose e a maioria é convertida a lactato, que é preferencialmente usado pelas células germinativas em desenvolvimento). Existe uma crescente consciencialização de que os androgénios e estrogénios têm papéis metabólicos gerais que vão para além dos processos reprodutivos. Assim, é importante perceber o papel dos esteróides sexuais na expressão do NHE3 em células de Sertoli, bem como, a sua modulação no metabolismo destas células. Deste modo, foram estabelecidas culturas primárias de células de Sertoli a partir de ratos com 20 dias de idade, em meio livre de soro com o suplemento de insulina, transferrina e selénio (meio ITS) e divididas por 7 grupos experimentais, sendo sujeitas a tratamento hormonal durante 50 horas. Os grupos experimentais foram: 17β-estradiol (E2); dihidrotestosterona (DHT); ICI 182,720 (ICI); flutamida (Flut); ICI/ E2; Flut/DHT e controlo. A concentração hormonal para todos os grupos experimentais foi 100nM, excepto para o grupo controlo que não foi tratado. A presença do NHE3 nas células de Sertoli foi confirmada por RT-PCR e por western blot. O NHE3 foi semi-quantificado por RT-PCR em todos os grupos experimentais, não tendo sido registadas diferenças significativas quando comparado com o controlo. Quanto à análise da secreção de metabolitos ou consumo pela cultura de células de Sertoli, foi feita uma recolha de 250 μL de meio de cultura às 5h, 15h, 25h, 35h e 50h após o início do tratamento hormonal, para análise do espectro de ressonância magnética. Os resultados obtidos mostraram que o consumo da glucose foi significativamente maior após 50 horas nas células tratadas com DHT quando comparadas com o grupo tratado com E2 e com o controlo. Inesperadamente, as células tratadas com DHT produziram menos lactato que o grupo tratado com E2 e que o controlo. Isto pode ser devido a vários factores tais como a diminuição da produção de lactato, atraso no transporte de lactato para o meio extracelular ou mesmo a utilização do lactato como substrato nas células tratadas com DHT. No consumo de piruvato não se verificaram alterações significativas com o tratamento hormonal, no entanto a produção de alanina foi maior nas células tratadas com E2. Em conclusão, este estudo demonstra que os esteróides sexuais não exercem efeitos significativos na expressão do NHE3 pelas células de Sertoli. É provável que a regulação do pH intracelular nas células de Sertoli e acidificação luminal dos tubulos não depende directamente da acção dos estrogénios e androgénios mediada pelos seus receptores. Por outro lado, conclui-se que a DHT aumenta o consumo de glucose nas células de Sertoli e o E2 aumenta a produção de alanina. Deste modo, os esteróides sexuais parecem desempenhar um papel importante na modulação do metabolismo das células de Sertoli

QoS em servidores HTTP Apache

Os serviços baseados na Internet têm registado um crescimento contínuo e acelerado nos últimos anos, dependendo o seu sucesso, em larga medida, da qualidade de serviço (QoS) prestada. A sociedade moderna tornou-se fortemente dependente da Internet e dos vários serviços nela disponibilizados. Neste artigo é apresentado um sistema original de controlo em cadeia fechada de QoS, aplicado ao servidor HTTP Apache. O objetivo principal do sistema é implementar um mecanismo capaz de realizar a diferenciação de serviço (DiffServ) entre duas classes de sítios: Premium e Outro

The Impact of Endocrine-Disrupting Chemicals in Male Fertility: Focus on the Action of Obesogens

The current scenario of male infertility is not yet fully elucidated; however, there is increasing evidence that it is associated with the widespread exposure to endocrine-disrupting chemicals (EDCs), and in particular to obesogens. These compounds interfere with hormones involved in the regulation of metabolism and are associated with weight gain, being also able to change the functioning of the male reproductive axis and, consequently, the testicular physiology and metabolism that are pivotal for spermatogenesis. The disruption of these tightly regulated metabolic pathways leads to adverse reproductive outcomes. The permanent exposure to obesogens has raised serious health concerns. Evidence suggests that obesogens are one of the leading causes of the marked decline of male fertility and key players in shaping the future health outcomes not only for those who are directly exposed but also for upcoming generations. In addition to the changes that lead to inefficient functioning of the male gametes, obesogens induce alterations that are “imprinted” on the genes of the male gametes, establishing a link between generations and contributing to the transmission of defects. Unveiling the molecular mechanisms by which obesogens induce toxicity that may end-up in epigenetic modifications is imperative. This review describes and discusses the suggested molecular targets and potential mechanisms for obesogenic–disrupting chemicals and the subsequent effects on male reproductive health

Online learning occupancy grid maps for mobile robots

Robot mapping is the basic work for robot navigation and path planning. Static map is also important to deal with dynamic environment. Occupancy grid maps are used to represent the environment. This paper focuses on the dependence between grid cells. We assume that if one point of the map is free, then the neighbors are likely to be free. This knowledge is encoded in a Markov random field (MRF) that is used as our prior belief about the world. Data from range sensors will then update our knowledge. By maximizing the posterior distribution of MRF model, a linear filter is generated. It can be used to filter the noise in observations or static maps. This linear filter can be implemented online. It is also additive if the sensor model is in the log odds form

Predicting calcium in grape must and base wine by FT-NIR spectroscopy

Calcium content in sparkling wines may not exceed 80 mg/L due to the risk of aggregation with alginate capsules. The high calcium content usually found in wine and must emphasizes the need to develop alternative and appropriate techniques faster and cleaner than atomic absorption spectrometry (AAS). To obtain a robust model to predict calcium content, FT-NIR spectroscopy was used in 98 base white wine samples and 60 must samples from an Alentejo winery. The reference method for calcium determination was AAS technique, with a dry ashing sample procedure, as a prior treatment. Results confirmed the ability of FT-NIR as an alternative technique to AAS, to predict calcium content in grape must and base wine. Advance knowledge of the calcium content in the grape must will help avoid obtaining a mixture of musts with a high calcium content in the same container

Identifying Risky Dropout Student Profiles using Machine Learning Models

Student dropout prediction is essential to measure the success of an educa- tion institute system. This paper focuses on identifying the dropout risk at the University of Évora based on student’s academic performance. Educa- tional data was collected from four different programs, from the academic years of 2006/2007 until 2018/2019. After gathering the raw data, some data pre-processing was done aiming to build a dataset capable of being used by Machine Learning algorithms. Decision trees, Naïve Bayes, Sup- port Vector Machines and Random Forests were evaluated, with the best model reaching an accuracy of around 96% when distinguishing between risky dropout and non-dropout students

Time scaling internal state predictive control of a solar plant

The control of a distributed collector solar field is addressed in this work, exploiting the plant's transport characteristic. The plant is modeled by a hyperbolic type partial differential equation (PDE) where the transport speed is the manipulated flow, i.e. the controller output. The model has an external distributed source, which is the solar radiation captured along the collector, approximated to depend only of time. From the solution of the PDE, a linear discrete state space model is obtained by using time-scaling and the redefinition of the control input. This method allows overcoming the dependency of the time constants with the operating point. A model-based predictive adaptive controller is derived with the internal temperature distribution estimated with a state observer. Experimental results at the solar power plant are presented, illustrating the advantages of the approach under consideration

MR Brain Image Classification: A Comparative Study on Machine Learning Methods

The brain tissue classification from magnetic resonance images provides valuable insight in neurological research study. A significant number of computational methods have been developed for pixel classification of magnetic resonance brain images. Here, we have shown a comparative study of various machine learning methods for this. The results of the classifiers are evaluated through prediction error analysis and several other performance measures. It is noticed from the results that the Support Vector Machine outperformed other classifiers. The superiority of the results is also established through statistical tests called Friedman test