Aplicação das redes neuronais aditivas generalizadas à Medicina

RESUMO: A aplicação das redes neuronais artificiais tem vindo a aumentar em várias áreas de conhecimento, muito em parte devido à flexibilidade que caracteriza estes modelos, e que permite modelar não só dados provenientes de situações reais mais complexas, tais como o reconhecimento de padrões e de voz, mas também dados mais simples como, por exemplo, os que refletem relações entre várias variáveis independentes e uma resposta (variável dependente). Uma arquitetura bastante utilizada é a do Perceptrão Multicamada (MLP), no entanto, apesar da sua popularidade em várias áreas do conhecimento, este modelo é menos utilizado no âmbito clínico do que os Modelos Lineares Generalizados (GLMs) e os Modelos Aditivos Generalizados (GAMs). O principal motivo deve-se ao facto da MLP funcionar de forma opaca quanto à interpretabilidade dos efeitos de cada variável explicativa na resposta. Assim sendo, a aplicação de uma rede neuronal aditiva generalizada (GANN) no âmbito da Medicina é bastante mais promissor uma vez que, além de produzir boas estimativas, também os seus resultados são, à partida, interpretáveis. Por outro lado, no que respeita aos modelos de regressão, vários autores referem que uma má escolha da função de ligação pode afetar, em determinados casos, o desempenho do modelo, pelo que foram desenvolvidos estudos no intuito de melhorar este aspecto através da flexibilização da função de ligação quer de uma forma paramétrica quer não paramétrica. No caso da GANN, dada a exiguidade de estudos sobre esta arquitetura, constatamos que nada foi feito quanto à estimação da função de ligação recorrendo a métodos paramétricos, tornando-se este um dos objetivos deste estudo. Adicionalmente, a estimação da função de ligação recorrendo a métodos não paramétricos também foi sugerida e analisada. Outro objetivo do estudo passou pela introdução de métodos para a determinação de intervalos de confiança das funções parciais e da função da razão de possibilidades de modo a permitir uma melhoria substancial na interpretabilidade deste tipo de rede neuronal.ABSTRACT: The application of artificial neural networks has been increasing in many areas of knowledge, much due to the flexibility that features these models and they allow to model data not only from more complex situations, such as pattern recognition and voice data but also simpler such as, for example, those that reflect relationships between multiple independent variables, and a outcome (dependent variable). A widely used architecture is the Multi Layer Perceptron (MLP). However, despite its popularity in several areas of knowledge, this model is less used in the clinical context that the Generalized Linear Models (GLMs) and the Generalized Additive Models (GAMs), due to the fact that, the MLP works as a black box. In the other hand, the Generalized Additive Neural Network (GANN) besides producing good estimates, allows the interpretation of the effect of each covariate on the outcome. Those features makes this type of neural network much more promising in the clinical area. On the other hand, concerning the regression models, several authors have reported that a bad choice of the link function can affect, in some cases, the model performance; so, studies have been developed in order to solve this issue by the introduction of a flexible link function either (parametric or nonparametric). In the case of a GANN, given the low number of studies about this architecture, we find that nothing has been done regarding the estimation of the link function using parametric methods, becoming this one goal of the present study. The link function estimation by using nonparametric methods was also approached. Another goal included the implement of methods for the determination of confidence intervals of the partial functions and the odds ratio function, which substantially improved the interpretability of the results of this type of neural network

Redes de Comunicações de Emergência e Segurança

Este trabalho pretende fazer uma retrospetiva do trabalho do autor, envolvido na concepção do Sistema Integrado das Redes Nacionais de Emergência e Segurança de Portugal (SIRESP) entre os anos 1996 e 2001. Para um melhor entendimento dos fundamentos desse projeto, o relatório também aborda alguns aspectos da norma de telecomunicações Trans European TErrestrial Trunked RAdio (TETRA) que serviu de base a boa parte das redes de comunicações de emergência e segurança na Europa e em particular ao SIRESP. Encontram-se também descritos os projetos e as funções mais importantes da sua carreira, que cobrem um largo espectro da Engenharia Eletrotécnica e de Computadores, onde se incluem a concepção de redes de telecomunicações de âmbito nacional, a implementação e gestão de um Centro de Informática e de Telecomunicações e a investigação na área da Inteligência Artificial. Este relatório foi redigido com o objetivo de provar que o autor possui as qualidades técnicas e a maturidade para obter o grau de Mestre ao abrigo do Despacho de 12-2011 da Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa, no programa designado por "Para ser Mestre"

The potential role of peak nasal inspiratory flow to evaluate active sinonasal inflammation and disease severity

Although the pathophysiology of nasal polyposis is incompletely understood, rhinologists have seldom studied it with rhinomanometry or peak nasal inspiratory flow (PNIF) due to technical limitations and the perception that polyp size might impair reproducibility and the usefulness of recordings. The objective of this study is to assess how measures of rhinomanometry and PNIF relate to disease activity. Nineteen patients with polyps, 15 patients with chronic sinusitis without polyps and 11 negative controls were evaluated with active anterior rhinomanometry and PNIF. Sinusitis and polyp patients were re-evaluated after medical treatment. Polyp patients had the highest median Lund-Mackay score (14) and a median Johansen score of 1. PNIF and its variation after treatment were also lowest in this group (median 90 L/min before and after treatment; median variation of 0 L/min). Nasal resistance was similar between groups, and only correlated with Johansen score (Spearman = 0.517, p = 0.048) after treatment. Our study suggests that evaluating polyp patients using rhinomanometry and PNIF may provide useful and reproducible data. Several findings considered together suggest that polyp size is not the main determinant of nasal functional changes in these patients, warranting further studies to verify whether PNIF changes reflect sinus inflammation or merely airway obstruction.publishersversionpublishe

Wind power forecasting with machine learning: single and combined methods

In Portugal, wind power represents one of the largest renewable sources of energy in the national energy mix. The investment in wind power started several decades ago and is still on the roadmap of political and industrial players. One example is that by 2030 it is estimated that wind power is going to represent up to 35% of renewable energy production in Portugal. With the growth of the installed wind capacity, the development of methods to forecast the amount of energy generated becomes increasingly necessary. Historically, Numerical Weather Prediction (NWP) models were used. However, forecasting accuracy depends on many variables such as on-site conditions, surrounding terrain relief, local meteorology, etc. Thus, it becomes a challenge to obtain improved results using such methods. This article aims to report the development of a machine learning pipeline with the objective of improving the forecasting capability of the NWP’s to obtain an error lower than 10%.info:eu-repo/semantics/publishedVersio

Improving diagnostic models for temporomandibular disease using cost-effective variables:an analysis of the Dimitroulis Classification

Temporomandibular disorders (TMD) are a class of degenerative musculoskeletal and neuromuscular conditions involving the temporomandibular joint (TMJ) complex and surrounding musculature. The etiology of TMD is multifactorial, including biological,environmental, social, emotional, and cognitive triggers. Due to the complexity of the disease’s signs and symptoms, the diagnosis and correct treatment of TMD remain a challenge. The Dimitroulis classification (DC) divides TMD into five categories (DC1, DC2, . . . , DC5) based on the degree of disease severity with an indication for treatment. The classification is based on history and physical examination and diagnostic imaging is used to access intra-articular derangements. This process presented some subjectivity in the analysis and, has significant associated costs. The present study aims to identify variables based on patient complaints with lower associated costs and more objective, prompt, and less burdensome classification.info:eu-repo/semantics/publishedVersio

An interactive dashboard for statistical analysis of intensive care unit COVID-19 data

COVID-19 caused a pandemic, due to its ease of transmission and high number of infections. The evolution of the pandemic and its consequences for the mortality and morbidity of populations, especially the elderly, generated several scientific studies and many research projects. Among them, we have the Predictive Models of COVID-19 Outcomes for Higher Risk Patients Towards a Precision Medicine (PREMO) research project. For such a project with many data records, it is necessary to provide a smooth graphical analysis to extract value from it. Methods: In this paper, we present the development of a full-stack Web application for the PREMO project, consisting of a dashboard providing statistical analysis, data visualization, data import, and data export. The main aspects of the application are described, as well as the diverse types of graphical representations and the possibility to use filters to extract relevant information for clinical practice. Results: The application, accessible through a browser, provides an interactive visualization of data from patients admitted to the intensive care unit (ICU), throughout the six waves of COVID-19 in two hospitals in Lisbon, Portugal. The analysis can be isolated per wave or can be seen in an aggregated view, allowing clinicians to create many views of the data and to study the behavior and consequences of different waves. For instance, the experimental results show clearly the effect of vaccination as well as the changes on the most relevant clinical parameters on each wave. Conclusions: The dashboard allows clinicians to analyze many variables of each of the six waves as well as aggregated data for all the waves. The application allows the user to extract information and scientific knowledge about COVID-19’s evolution, yielding insights for this pandemic and for future pandemics.info:eu-repo/semantics/publishedVersio

Characteristics and laboratory findings of SARS-CoV-2 infected patients during the first three COVID-19 waves in Portugal – a retrospective single-center study

Background and Objectives: Given the wide spectrum of clinical and laboratory manifestations of the coronavirus disease 2019 (COVID-19), it is imperative to identify potential contributing factors to patients’ outcomes. However, a limited number of studies have assessed how the different waves affected the progression of the disease, more so in Portugal. Therefore, our main purpose was to study the clinical and laboratory patterns of COVID-19 in an unvaccinated population admitted to the intensive care unit, identifying characteristics associated with death, in each of the first three waves of the pandemic. Materials and Methods: This study included 337 COVID-19 patients admitted to the intensive care unit of a single-center hospital in Lisbon, Portugal, between March 2020 and March 2021. Comparisons were made between three COVID-19 waves, in the second (n = 325) and seventh (n = 216) days after admission, and between discharged and deceased patients. Results: Deceased patients were considerably older (p = 0.021) and needed greater ventilatory assistance (p = 0.023), especially in the first wave. Differences between discharged and deceased patients’ biomarkers were minimal in the first wave, on both analyzed days. In the second wave significant differences emerged in troponins, lactate dehydrogenase, procalcitonin, C-reactive protein, and white blood cell subpopulations, as well as platelet-to-lymphocyte and neutrophil-to-lymphocyte ratios (all p < 0.05). Furthermore, in the third wave, platelets and D-dimers were also significantly different between patients’ groups (all p < 0.05). From the second to the seventh days, troponins and lactate dehydrogenase showed significant decreases, mainly for discharged patients, while platelet counts increased (all p < 0.01). Lymphocytes significantly increased in discharged patients (all p < 0.05), while white blood cells rose in the second (all p < 0.001) and third (all p < 0.05) waves among deceased patients. Conclusions: This study yields insights into COVID-19 patients’ characteristics and mortality-associated biomarkers during Portugal’s first three COVID-19 waves, highlightinginfo:eu-repo/semantics/publishedVersio

Need-Opportunity-Accessibility, how to engage them?

Funding Information: We thank Professor Helder Trindade to promote the study and investigation, Dr. Jo?o Paulo Almeida Sousa for supporting the research, and ONT ? Organizaci?n Nacional de Trasplantes for data supplementation. The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. Publisher Copyright: © 2021Background: Despite all efforts, the demand for organs increases. New and better strategies are still needed, critical in a crisis like pandemics. Methodology: A mathematical approach that integrates need, Opportunity, and Accessibility to kidney transplantation, was created. NOA method, corresponds to the lateral surface area of a trigonal pyramid with the need, Opportunity, and Accessibility as axis, resulting in an intuitional chart output (NOA chart) and a percentage score (NOA score). Higher NOA scores are associated with larger NOA chart areas. Method Application: We found some natural variability among the European Member States regarding Need, Opportunity, and Accessibility to kidney transplantation, concomitant with NOA scores. In 2019, in the European Union, 129 patients pmp on the waiting list for a kidney transplant were registered, 47 kidneys pmp were procured, and 36 kidneys pmp were transplanted, corresponding to 25% of kidney transplantation's response capacity. Conclusion: Transplantation is frequently the better treatment for end-stage kidney failure. NOA method may be, in the future, an indicator for evaluating the overall transplantation performance regarding the need for it and a tool for policy definition. With NOA method we seek to contribute for: • A transplantation overall performance normalizing score; • Transplantation response capacity evaluation.publishersversionpublishe

COVID-19: nothing is normal in this pandemic

This manuscript brings attention to inaccurate epidemiological concepts that emerged during the COVID-19 pandemic. In social media and scientific journals, some wrong references were given to a "normal epidemic curve" and also to a "log-normal curve/distribution". For many years, textbooks and courses of reputable institutions and scientific journals have disseminated misleading concepts. For example, calling histogram to plots of epidemic curves or using epidemic data to introduce the concept of a Gaussian distribution, ignoring its temporal indexing. Although an epidemic curve may look like a Gaussian curve and be eventually modelled by a Gauss function, it is not a normal distribution or a log-normal, as some authors claim. A pandemic produces highly-complex data and to tackle it effectively statistical and mathematical modelling need to go beyond the "onesize-fits-all solution". Classical textbooks need to be updated since pandemics happen and epidemiology needs to provide reliable information to policy recommendations and actions.info:eu-repo/semantics/publishedVersio

Planeamento em saúde: diferentes conceitos

O planeamento é a determinação de uma sequência de ações que têm por objetivo alcançar um resultado desejado; determina aquilo que deve ser feito e como deve ser feito. Deve procurar maximizar os resultados e minimizar as deficiências, buscando maior eficiência, eficácia e efetividade. O seu objetivo deve ser definido de forma clara, com precisão, para favorecer a implementação do próprio plano. (Gama, 2010). É preciso um método de planeamento que possibilite a compreensão e a compartilha de uma mesma “linguagem” (conceitos básicos, terminologia, instrumentos utilizados, etc.); que seja capaz de contribuir para o diálogo e para efetiva participação de todos aqueles envolvidos na formulação e na operacionalização de um plano. (Campos, Faria e Santos, 2010). Pretendeu-se com este trabalho analisar conceitos e perspetivas do Planeamento em Saúde em enfermeiras que frequentam o Curso de Especialização em Enfermagem Comunitária. É um estudo descritivo de carater qualitativo. Foram efetuadas cinco entrevistas não estruturadas sobre o planeamento em Saúde a 13 enfermeiras, alunas do Curso de Especialização em Enfermagem Comunitária em 2013. A amostra é constituída por 13 enfermeiras, alunas do Curso de Especialização em Enfermagem Comunitária, com idades compreendidas entre 26 e 43 anos, para além de possuírem o Curso de Licenciatura em Enfermagem, uma delas é Mestres em Gestão. Maioritariamente exercem funções profissionais em Cuidados de Saúde Primários 6 enfermeiras, em cuidados de saúde diferenciados 5 e duas em outras instituições. Constatámos, que os conceitos e objetivos do Planeamento em Saúde referidos eram diferentes conforme o local de trabalho e o nível de habilitações. No que respeita ao processo, aos requisitos e ao espaço de planeamento, assim como às dificuldades ou barreiras à intervenção ou implementação de planos em saúde, são apresentados também diferentes conceitos ou terminologias, dependentes do local de trabalho onde exercem funções. Concluímos que as participantes que exercem funções em Cuidados de Saúde Primários são aquelas que possuem e referem conceitos mais próximos dos apresentados na literatura