A Lisbon story: short-term rental platforms and the housing market

Throughout Europe, many mayors have argued that house rental platforms such as Airbnb price locals out of city housing. Lisbon is an interesting case study on how to regulate this market. The median real estate price per square meter in the city increased more than 70% between the first quarter of 2016 and the last quarter of 2019. The number of overnight stays in Lisbon reached more than 11 million in 2019, about 20 times its resident population. João Pereira dos Santos writes about the causal impact of short-term rental regulations on the housing market and suggests policy implications

Compensação digital de distorções da fibra em sistemas de comunicação óticos de longa distância

The continuous increase of traffic demand in long-haul communications motivated the network operators to look for receiver side techniques to mitigate the nonlinear effects, resulting from signal-signal and signal-noise interaction, thus pushing the current Capacity boundaries. Machine learning techniques are a very hot-topic with given proofs in the most diverse applications. This dissertation aims to study nonlinear impairments in long-haul coherent optical links and the current state of the art in DSP techniques for impairment mitigation as well as the integration of machine learning strategies in optical networks. Starting with a simplified fiber model only impaired by ASE noise, we studied how to integrate an ANN-based symbol estimator into the signal pipeline, enabling to validate the implementation by matching the theoretical performance. We then moved to nonlinear proof of concept with the incorporation of NLPN in the fiber link. Finally, we evaluated the performance of the estimator under realistic simulations of Single and Multi- Channel links in both SSFM and NZDSF fibers. The obtained results indicate that even though it may be hard to find the best architecture, Nonlinear Symbol Estimator networks have the potential to surpass more conventional DSP strategies.O aumento contínuo de tráfego nas comunicações de longo-alcance motivou os operadores de rede a procurar técnicas do lado do receptor para atenuar os efeitos não lineares resultantes da interacção sinal-sinal e sinal-ruído, alargando assim os limites da capacidade do sistema. As técnicas de aprendizagem-máquina são um tópico em ascenção com provas dadas nas mais diversas aplicações e setores. Esta dissertação visa estudar as principais deficiências nas ligações de longo curso e o actual estado da arte em técnicas de DSP para mitigação das mesmas, bem como a integração de estratégias de aprendizagem-máquina em redes ópticas. Começando com um modelo simplificado de fibra apenas perturbado pelo ruído ASE, estudámos como integrar um estimador de símbolos baseado em ANN na cadeia do prodessamento de sinal, conseguindo igualar o desempenho teórico. Procedemos com uma prova de conceito perante não linearidades com a incorporação do ruído de fase não linear na propagação. Finalmente, avaliamos o desempenho do estimador com simulações realistas de links Single e Multi canal tanto em fibras SSFM como NZDSF. Os resultados obtidos indicam que apesar da dificuldade de encontrar a melhor arquitectura, a estimação não linear baseada em redes neuronais têm o potencial para ultrapassar estratégias DSP mais convencionais.Mestrado em Engenharia Eletrónica e Telecomunicaçõe

Establishing a high titer transient gene expression process in conditioned media for CHO-DG44 cells

Dissertação para obtenção do Grau de Mestre em BiotecnologiaTransient gene expression (TGE) allows for fast protein production in mammalian cells and has become a very important technology in the product development pipeline of biopharmaceuticals. Polyethylenimine (PEI) mediated, high-density transfections have allowed for transient processes exceeding ~300mg/L in CHO-DG44 cells. As such, the bottleneck of TGE is no more in the titers, but in the scale-up to volumes higher than 1L, because of the need for a medium exchange before transfection. It is known that if the transfection is done in a running culture, without a medium exchange (i.e in conditioned medium), the yields obtained are very low (~5 mg/L). In CHO-DG44 cells, this problem was explored from the point of view of transfection efficiency, gene delivery and transcription. A new insight is presented in this work: The low productivities are not due to a deficient gene delivery, but instead, to lower mRNA levels that we hypothesize to be related to a lower gene accessibility of the transfected plasmid. Further, the yields were improved from ~5mg/L to ~90mg/L (18-fold) by optimizing the conditions for transfecting in conditioned medium and utilizing sodium butyrate as a transcription enhancer. These results are expected to open paths for the successful scale-up of TGE

A simulation model for lean, agile, resilient and green supply chain management: practices and interoperability assessment

Dissertação para obtenção do Grau de Mestre em Engenharia e Gestão IndustrialIn today’s global market, the environment of unpredictable events has imposed a competitiveness improvement that requires a greater coordination and collaboration among Supply Chain (SC) entities, i.e., an effective Supply Chain Management (SCM). In this context, Lean, Agile, Resilient and Green (LARG) strategies emerged as a response. However, interoperability issues are always presents in operations among SC entities. From the Information Technology (IT) perspective, among all the multi-decisional techniques supporting a logistics network, simulation appears as an essential tool that allow the quantitative evaluation of benefits and issues deriving from a co-operative environment. The present work provides a SC simulation model for analysing the effect of the interoperability degree of LARG practices in the SC performance, through Key Performance Indicators (KPI’s) such as cost, lead time and service level. The creation of two scenarios with a different point of view about the LARG practices allowed to analyse which one contributes to the best SC performance. Since some of the inputs were assumed, it was made a sensitivity analysis to validate the output of the simulation model. Based on the creation of six types of math expressions, it was possible to establish the connection between the effect of the interoperability degree of LARG practices and the SC performance. This analysis was applied on a case study that was conducted at some entities of a Portuguese automotive SC. The software used to develop the simulation model is Arena, which is considered a user-friendly and dynamic tool. It was concluded that SCM, interoperability and simulation subjects must be applied together to help organisations to achieve overall competitiveness, focusing their strategies on a co-operative environment

A Study with Benfica, Porto, and Sporting

The various existing social media platforms aim at interaction and connectivity between users within online communities through the production and sharing of content. Similar to sports, social media allows users to obtain experiences that often stirs emotion. This empirical study combines the football component with social media, in which, through multiple linear regression, the performance of posts on social networks, Facebook, Instagram and Twitter, of the three biggest Portuguese clubs, is evaluated: Benfica, Porto and Sporting. This research reviews the literature of sports fanaticism, the structure and content of posts, combined with a bibliometric analysis of social media, which allows the understanding of this vast theme in four components: Social media engagement, User Generated Content, Online Communities, and Content Marketing. Through the testing of the hypotheses written for this research, assertive conclusions were obtained about the performance of social media posts in the sports field, such as, the relevance of visual posts, compared to textual posts; the effectiveness of posts that refer to the nostalgia of the supporter; and the determination of the social network most suitable for the accompaniment of a live football match.As várias plataformas de social media existentes, têm como objetivo a interação e conectividade entre utilizadores, dentro de comunidades online através de produção e partilha de conteúdo, desta forma, semelhante ao mundo do desporto, social media permite aos utilizadores obterem experiências que muitas vezes mexem com a emoção. Este estudo empírico alia a componente do futebol ao social media, em que, através de uma regressão linear múltipla, avalia-se a performance de posts nas redes sociais, Facebook, Instagram e Twitter, dos três maiores clubes portugueses: Benfica, Porto e Sporting. Esta investigação revê a literatura do fanatismo desportivo, da estrutura e conteúdo de posts, aliada a uma análise bibliométrica sobre social media, que permite a compreensão deste vasto tema em quatro compontentes: Social media engagement, User Generated Content, Comunidades Online, e Marketing de Conteúdo. Através da testagem das hipóteses redigidas para esta investigação, foram obtidas conclusões assertivas sobre a performance de posts de social media no âmbito desportivo, tais como, a relevância de posts visuais, face a posts textuais; a eficácia de posts que remetem à nostalgia do adepto; e a determinação da rede social mais indicada para o acompanhamento de um jogo de futebol a decorrer ao vivo

Movimentos autárquicos não-partidários. O caso da Guarda e o movimento “A Guarda Primeiro”

ResPublica : Revista Lusófona de Ciência Política, Segurança e Relações InternacionaisEste estudo visa conhecer as circunstâncias em que foi criado o Movimento “A Guarda Primeiro” para as eleições autárquicas de 2013, o seu impacto na geografia política do concelho e as suas consequências no interior do sistema de partidos e do sistema de poder municipal. Insere-se num estudo mais vasto sobre quinze movimentos autárquicos não-partidários (MANPs) que tem como objectivo central fazer o diagnóstico do estado de saúde do sistema de partidos em Portugal, precisamente a partir do observatório privilegiado dos MANPs. Palavras-chave: Movimentos Autárquicos Não-Partidários, Sistema de Partidos, Sondagens, Eleições Autárquicas.This study aims at understanding how the Movement “A Guarda Primeiro” has emerged for the 2013 local elections, the impact in the local scenario, its consequences within the party system and in the local power system. It is part of a wider study encompassing fifteen non-partisan local movements specifically aiming at understanding the portuguese party system and taking the non-partisan local movements as a privileged observatory

The effect of Brexit on British workers living in the EU

The effect of Brexit is an important topic in the European and British political agendas. This study examines the perspective of the EU countries, with regards how British citizens working in an EU country reacted to the end of free movement of workers. Employing synthetic control methods and using data from Portugal, we estimate how the behaviour of UK citizens working in Portugal would have evolved if the Remain vote had won the referendum. Our results suggest that the Brexit referendum reduced the number of UK citizens working in Portugal, particularly in the case of non-university educated, male individuals with temporary employment contracts. This reduction is explained by the decrease in the number of incomers. We also find that those UK citizens who were already working in Portugal before Brexit are less likely to leave the country.info:eu-repo/semantics/publishedVersio

Revenue-based financing

This dissertation has the purpose to introduce the concept of Revenue-based Financing to the academic literature and to assess its characteristics by studying the existent capital structure theories and comparing it with traditional financing options. This type of firm funding has been used in diverse industries but has not been widely available for use. In recent years there has been an increase in the firms providing this financing instrument. It is thus important to understand if this instrument is important to improve the access to financing and support the growth of certain firms. Existent literature and data have proved that it is not desirable for all firms to choose between equity and debt due to ownership and control issues or even due to different costs. Also in terms of access of financing, mainly for SMEs, revenue-based financing can be an instrument improving it by closing the gap between equity and debt financing enabling firms to take rapidly investment opportunities and bolster their growth. The real cases studied in this dissertation vary substantially in the terms agreed such as the collateral needed, the incidence of the costs of financing or other requirements made by the investors. Hence, it is very difficult to develop a unique framework for this type of financing, as each firm is a unique case. My research leads to the conclusion that Revenue-based financing should be used as a complementary tool and that, in fact, there is a need for this type of financing.Esta dissertação tem como objectivo introduzir o conceito de financiamento baseado nas vendas à literatura académica e avaliar as suas características. Isto será feito através do estudo das teorias de estrutura de capital existentes e elaborando uma comparação com as opções de financiamento tradicionais. Este tipo de financiamento empresarial tem sido utilizado em diversas indústrias porém o seu uso não está disponível em muitos países. Nos últimos anos tem vindo a aumentar o número de empresas no mercado a fornecer este instrumento, tornando-se assim importante perceber se este instrumento é importante para melhorar o acesso das empresas a financiamento como também ajudar no seu crescimento. A literatura existente tem provado que não é ideal para todas as empresas escolher entre capital próprio ou dívida, devido a problemas com o controle ou posse da empresa. Em relação ao acesso a financiamento, principalmente para PMEs, o financiamento baseado em vendas pode ser um instrumento que melhora este acesso, reduzindo a lacuna entre financiamento através de divida e capitais próprios ajudando estas a aproveitar oportunidades de investimento instantaneamente. Os casos reais observados nesta dissertação variam consideravelmente nos termos acordados como: a necessidade de colateral, incidência dos custos do financiamento ou outras exigências feitas pelos investidores. Consequentemente, é bastante difícil desenvolver um único modelo para este tipo de financiamento porque cada empresa é um caso único. A minha investigação leva à conclusão que este tipo de financiamento deverá ser utilizado como um instrumento complementar e que há uma necessidade para este tipo de financiamento