Repositório Científico de Acesso Aberto da ULisboa

University of Lisbon Institutional Repository

About the ULisboa Open Access Scientific Repository

The Open Access Scientific Repository of the University of Lisbon (ULisboa) is ULisboa's institutional repository, part of the RCAAP Project (Open Access Scientific Repositories of Portugal). This resource is essential for the dissemination and preservation of the academic and scientific production of the university community.

In the repository, users can access a wide variety of documents, in all fields of knowledge, resulting from the research activities carried out at ULisboa, including:

Doctoral theses and master's dissertations;
Publications in national and international scientific journals;
Communications at congresses and conferences;
Technical reports;
Books and book chapters;
Author's editions;
Patents;
Academic progression tests;
Evidence of teaching ability.

Through this repository, ULisboa promotes free access to knowledge and the global sharing of scientific information.

For more information or to explore the repository, visit https://repositorio.ulisboa.pt/.

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Email repositorio@ulisboa.pt

Recent Submissions

Ocean-atmosphere interactions : the case of Marine Heatwaves in the North Atlantic

Publication . Lopes,Beatriz Pereira; Department of Geographic Engineering, Geophysics and Energy; Gouveia,Célia Marina Pedroso; Oliveira,Ana Patrícia Pires Marques

Excessive greenhouse gas emissions are placing severe pressure on the oceans, which play a very important role in climate regulation. Consequently, the oceans are experiencing an exacerbated warming, leading to an increase in the occurrence of extreme events, such as Marine Heatwaves (MHWs). MHWs are characterized as prolonged periods of anomalously high sea surface temperatures (SSTs). Quantitatively, they are identified when SST anomalies exceed the 90th percentile of a reference climatology for at least five consecutive days. Understanding the occurrence of MHWs is challenging due to their rarity (less than 10 per cent of the surface temperature values, as the 90th percentile indicates) and the limited availability of consistent long-term observational data (last four decades). However, it is now known that they can be modulated by oceanic or atmospheric factors or a combination of both, affecting the ocean's ability to absorb incident solar radiation and dissipate it through currents and the mixing layer, leading to its warming. This study focused on large-scale atmospheric factors driving the MHW occurrence and characteristics in the North Atlantic (an area relatively understudied, especially when compared with the Mediterranean or with the Tasman Seas) from 1982 to 2022, with the objectives of (i) identifying spatial-temporal trends of MHWs, (ii) determining the atmospheric factors contributing to their occurrence, and (iii) exploring their relationship with prevalent climate variability modes. MHWs were identified using ESA Copernicus Climate Change Initiative Sea Surface Temperature data and Hobday et al. (2016)'s method. An event dataset generated using a new event detection algorithm developed by the team at +ATLANTIC CoLAB was used, with the events ranked by severity. Atmospheric data were obtained from ERA 5 reanalysis, including sea-level pressure, geopotential height, temperature, heat fluxes, solar radiation, and wind components. The study also analysed the North Atlantic Oscillation (NAO) index to examine its influence on MHWs. The results show positive trends in MHW frequency, duration, and intensity, especially since 1995, with regional variability. High-pressure systems with weak pressure gradients and associated reduced wind speeds, and increased solar radiation seem to be crucial for the formation of the analysed events. The annual NAO appears to modulate the spatial distribution of MHWs, with its positive phase favouring MHWs in mid-latitude regions, while the negative phase impacts subpolar and tropical regions.

2025Master thesis

Open access

Study of central and exclusive production of charged Higgs boson pairs with forward proton tagging at the LHC, and projections for the HL-LHC

Publication . Batista,Pedro Miguel Carvalho; Department of Physics; Pires,João Ramalho; Hollar,Jonathan Jason

Beyond the Standard Model (BSM) scenarios suggest the existence of new particles or interactions to address some of the fundamental questions left unanswered by the Standard Model (SM). The majority of these scenarios suggest the existence of a charged Higgs boson, and its observation would directly imply the existence of BSM physics. With this in mind, this project focused on studying the central and exclusive production (CEP) of a single pair of charged Higgs bosons at the Large Hadron Collider (LHC) Run 3, including projections for the High-Luminosity LHC (HL-LHC) Phase-2, both at a centerof-mass energy of √ s = 13.6 T eV . Additionally, CEP processes are advantageous to study due to the lower number of competing background processes, but also because it’s possible to perform proton tagging with the Precision Proton Spectrometer (PPS) installed at the Compact Muon Solenoid (CMS). This project also takes advantage of the first CMS jet matching High Level Trigger (HLT) designed for studying processes with a four-jet system in the final states. This study used events simulated with the tools MadGraph5 aMC@NLO, Pythia8, and Delphes. This study started with the calculation of the cross sections for the signal and background events. The next part of the analysis focused on the detector configurations for the LHC Run 3 and the HL-LHC Phase-2, and several studies were performed on the impact of pileup interactions, on the acceptance of the PPS detector, on the efficiency of the HLT, and on the statistical sensitivity to exclude the signal process. A comparison between the LHC Run 3 and HL-LHC Phase-2 configurations was also made to highlight the key differences in event analysis. Lastly, remarks were made on possible HLT improvements for the HL-LHC Phase-2, as well as on future studies that could enhance event analysis.

2025Master thesis

Open access

Extracting n-ary Relations from Biomedical Literature using Deep-Learning Techniques

Publication . Fernandes,João Lucas Matias; Department of Chemistry and Biochemistry; Couto,Francisco José Moreira

The rapid growth of biomedical literature makes it challenging for researchers to stay up-to-date. Text mining has become essential for efficiently extracting knowledge from unstructured texts. Abstracts offer a focused alternative to full-text articles, but extracting meaningful insights remains difficult. Key tasks such as Named Entity Recognition (NER) and Named Entity Linking (NEL) face issues like ambiguous terminology, entity variability, and incomplete knowledge bases, especially when handling novel or NIL (not-in-lexicon) entities. Relation Extraction (RE) systems also face challenges, including limited scope, lack of interpretability, and a focus on binary relations that do not fully capture complex biomedical interactions. This thesis introduces a small gold-standard dataset created by expanding 31 abstracts from the 600-document BioRED corpus. The dataset adds CellTypeOrAnatomicalConcept and NIL entities, serving as a resource to test and improve the Biomedical Entity Annotator (BENT) tool for NER and NEL. It also enables the extension of relation extraction from binary to n-ary relations, starting with ternary relations. Compared to BioRED, NER performance was generally lower across most entity types, while NEL showed particularly low scores for GeneOrGeneProduct, CellTypeOrAnatomicalConcept, and NIL entities, reflecting the challenges of novel entity annotation. For n-ary relation extraction, the K-RET system, built on BERT-based models, was employed with SciBERT and BioMedBERT. In the binary setting, the system achieved an F1-score of 0.775 compared to BioRED’s 0.7562. Ternary relations were evaluated against BioRex, a state-of-the-art study, yielding F1- scores of approximately 0.65. Despite being lower than BioRex, the results provide a promising baseline for n-ary relation extraction across a broader set of entity types.

2025Master thesis

Open access

Morfologia urbana e emoções : uma análise correlativa e comparativa para os períodos anterior, durante e pós COVID-19

Publication . Alexandra Rodrigues Santos,Sara; Instituto de Geografia e Ordenamento do Território; Sousa,Paulo Alexandre Morgado

Este estudo analisa a relação entre emoções e variáveis urbanas, a partir de uma abordagem multidisciplinar baseada em Sistemas de Informação Geográfica (SIG). Para o efeito, foram utilizadas variáveis espaciais como o uso do solo, pontos de interesse, caminhabilidade, índice de vegetação (NDVI), ruído, edifícios em estado de degradação, altura dos edifícios, vulnerabilidade ao calor e temperatura, complementadas por dados emocionais extraídos do Twitter e por 61 inquéritos aplicados a cidadãos. A nível metodológico, recorreu-se a uma análise de correlação de Spearman, à realização de uma análise de regressão linear (OLS), a análises bivariadas e à realização de mapas de calor através de uma Kernel Density Estimation para identificar padrões estatísticos e espaciais entre variáveis urbanas e emoções. Os resultados revelaram a existência de correlações estatisticamente fracas, mas consistentes, sugerindo que fatores como a cobertura vegetal, o conforto térmico e a qualidade do edificado têm impacto na perceção emocional. A análise espacial evidenciou ainda que a expressão emocional se concentra em áreas de centralidade urbana, sociabilidade e lazer. Os inquéritos reforçaram estes resultados, destacando a relevância dos espaços verdes para o sentimento de segurança e o impacto do ruído no bem-estar emocional. Apesar das limitações do estudo, nomeadamente a impossibilidade de integrar métricas de Space Syntax e a reduzida dimensão amostral, os resultados sublinham a importância de considerar a relação entre cidade, ambiente e emoções no planeamento urbano contemporâneo.

2025Master thesis

Open access

Um olhar crítico sobre os transportes : O trabalho de campo na aprendizagem dos transportes em Geografia no 11ºano

Publication . Marques Gandum,Gonçalo; Instituto de Geografia e Ordenamento do Território; Costa,Nuno Manuel Sessarego Marques da; Martins,Ana Isabel Matias Louro

Este trabalho centra-se na implementação de modelos colaborativos de avaliação no ensino da Geografia, com foco nos conteúdos relacionados com o tema dos transportes no 11.º ano de escolaridade. Inserido num contexto de inovação pedagógica, o estudo visa repensar a avaliação e as metodologias de ensino, promovendo a centralidade do aluno e o desenvolvimento de competências essenciais, conforme o Perfil do Aluno à Saída da Escolaridade Obrigatória. Face ao desgaste do ensino tradicional, assinalado pelo afastamento entre a escola e o mundo real, adotaram-se práticas mais envolventes, participativas e contextualizadas, procurando formar cidadãos críticos, autónomos e reflexivos. Este estudo baseia-se na Carta da Educação Geográfica e em diretrizes nacionais e europeias, que valorizam as infraestruturas de transporte como elementos chave para a coesão territorial e o desenvolvimento económico, sublinhando a integração de Portugal nas redes transeuropeias. Foram analisadas as redes rodoviárias, ferroviárias, aéreas e portuárias, recorrendo a dados estatísticos e institucionais para avaliar o impacto dos investimentos na redução das desigualdades regionais, no crescimento económico e na modernização da logística. A abordagem pedagógica privilegiou metodologias ativas, nomeadamente ludificação, trabalho colaborativo, trabalho de campo autónomo e o uso de ferramentas digitais como Google Maps e Kahoot, incentivando a participação, criatividade e responsabilidade dos estudantes. O professor assumiu um papel de facilitador e mediador, estimulando a aprendizagem autónoma. Destaca-se a realização do trabalho de campo em Geografia, concebido para ser realizado autonomamente pelos alunos, presencialmente no quotidiano e em formato virtual, ultrapassando limitações logísticas e económicas, assegurando a participação de todos e fortalecendo a ligação crítica e prática ao território e às redes de transporte. Ao longo do percurso, registou-se uma melhoria significativa na motivação, participação e desenvolvimento de competências transversais como a análise crítica, autonomia, argumentação e colaboração, valorizando a integração dos saberes e a experiência local dos alunos.

2025Master thesis

Open access