Browsing by resource type "doctoral thesis"
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- 1948-1965: o declínio do paradigma clássico e a emergência do maneirismo de HollywoodPublication . Carrega, Jorge Manuel Neves; Tavares, MirianO presente trabalho, investiga as origens históricas e as características formais do maneirismo de Hollywood, através de uma análise da produção cinematográfica dos estúdios de Hollywood, entre o final da década de 1920 e o fim do chamado studio system (em meados da década de 1960). Tal como o maneirismo histórico, o maneirismo hollywoodiano constitui um fenómeno artístico complexo e contraditório, cujas origens remontam ao estilo germânico introduzido no cinema dos estúdios em final dos anos vinte, por cineastas europeus como F.W. Murnau, Paul Leni, Rouben Mamoulian e James Whale. Tendo eclodido no final da II Guerra Mundial, período que assinala o início crise do sistema social, cultural e industrial que havia originado o cinema clássico, o maneirismo de Hollywood nasceu de uma consciência do cinema em relação ao seu passado. Obrigado a concorrer com a chamada “modernidade” cinematográfica europeia e com a ficção televisiva (que se apropriara do modelo clássico), o cinema de Hollywood explorou novos temas e géneros cinematográficos e investiu na exibição da técnica e do aparato tecnológico, forçando os limites do paradigma clássico, através de uma retórica de efeitos maneiristas que, não implicando um corte radical com o classicismo, representou uma clara tentativa de renovação formal, levada a cabo por cineastas como Alfred Hitchcock, Vincente Minnelli, Douglas Sirk, Stanley Donen e Jerry Lewis. A coexistência de varias correntes estéticas no cinema do pós-guerra (1945-1968), período em que, a par das últimas grandes obras clássicas, o maneirismo enquanto manifestação estética emergiu como modelo dominante, permite-nos concluir que o chamado cinema “clássico” (do estúdios de Hollywood) incluiu também, desde cedo, um cinema maneirista.
- Abordagem motivacional à exploração vocacional e à tomada de decisão de carreiraPublication . Paixão, Olímpio Manuel Lino Brás; Gamboa, Vítor Manuel PachecoO trabalho desenvolvido nesta tese de doutoramento assenta numa linha de investigação que procura analisar o lugar que os processos motivacionais ocupam nas teorias e modelos explicativos da carreira. Com base na teoria da autodeterminação, os três estudos empíricos que compõem este trabalho procuram articular e operacionalizar variáveis motivacionais e da carreira, com o intuito de enriquecer a discussão relativa à importância de se contemplar o estudo da qualidade da motivação e o seu impacto na explicação dos comportamentos vocacionais. O primeiro estudo procura alargar o trabalho de validação da escala de autonomia para a tomada de decisão de carreira, recorrendo à técnica de análise fatorial confirmatória, numa amostra de alunos de ensino secundário. Globalmente, os resultados revelam valores de ajustamento sofríveis, apesar de não apresentarem problemas a nível dos pesos fatoriais e da variância explicada e suportando a estrutura de quatro dimensões que representam os quatro tipos de motivação propostos pelo modelo teórico. O segundo estudo testa um modelo integrativo que explora a capacidade preditora da motivação autónoma e controlada na indecisão de carreira, considerando os efeitos de mediação dos comportamentos de exploração vocacional. O modelo final apresenta bons valores de ajustamento, tendo sido encontrados dois mediadores e três efeitos indiretos significativos. Por fim, no terceiro estudo recorremos à elaboração de agrupamentos (análise de clusters), com base em perfis motivacionais, analisando como se diferenciam relativamente aos níveis de suporte parental percebido, exploração vocacional e indecisão de carreira. Foram encontrados três perfis motivacionais: alunos autodeterminados, não-autodeterminados e externamente regulados. No geral, a teoria da autodeterminação apresenta qualidades que contribuem para o enriquecimento da explicação das razões subjacentes ao envolvimento nas atividades relacionadas com a tomada de decisão, bem como para a organização de intervenções de carreira que têm como objetivo a internalização dos processos vocacionais.
- Acclimation and adaptation of invasive seaweeds - a case study with the brown alga Sargassum muticumPublication . Serebryakova, Alexandra; Serrão, Serrão, Ester; Viard, Fréderique; Engelen, AschwinNon-indigenous seaweeds impact natural communities worldwide, affecting biodiversity, ecosystem functioning, and ecosystem services, resulting in significant economic and social consequences. Among major impacts are the displacement of native species, a threat to endangered species, and effects on ecological and evolutionary processes within the invaded communities. While critical to predict the fate of introduced species, understanding the mechanisms of acclimation and adaptation following introduction represents a great challenge in seaweeds. In this thesis, we investigated some acclimation processes, with an emphasis on the role of associated microbiota, and examined their effects with Sargassum muticum as a model species. This brown seaweed native to Asia, is an emblematic invader among seaweeds, with a distribution now ranging from Mexico to Alaska in America and from Morocco to Norway in Europe. We first reviewed the competitive advantages and traits that may contribute to its invasiveness. In addition, we provided an overview of putative underlying mechanisms of acclimation and adaptation and highlighted their role in seaweed invasions. We then examined the effects of ocean acidification on the microbiome of S. muticum and revealed that it does not have significant effects on the seaweed-associated microbiota despite certain changes in the microbial community. We further investigated the seasonal changes in the seaweed-associated microbiota and revealed significant differences between seasons and geographic locations. Finally, we applied ecological niche modelling, but innovatively accounting for phenology, to project the distribution of S. muticum under two future climate change scenarios. According to our projections, by 2100 the distribution of S. muticum is expected to shift northwards along its European, North American and Asian distributions with a partial retreat from the currently occupied areas.
- Acoustic-oceanographic data fusion for prediction of oceanic acoustic eldsPublication . Martins, Nelson Estêvão; Jesus, S. M.Maritime rapid environmental assessment exercises became rather important. An underlying objective is to predict the evolution of the acoustic eld due to an underwater target. Main contributions to this end have relied on accurate models of acoustic propagation, which receive baseline properties and ocean forecasts as input. Intuitively, the most accurate oceanographic forecast should imply the most accurate acoustic forecast. This can fail, due to at least two reasons: 1) the full set of (space-time-variant) environmental properties are rarely known with enough accuracy; 2) even the most sophisticated propagation model cannot handle the full environmental detail in solving propagation equations, forcing the experimenter to reduce complex environmental features to a simpli ed representation. Acoustic modeling errors appear then as inevitable. Little possibility of error minimization exists, if the propagation model is simply run in a `forward' manner. The results presented in this work show that the acoustic error can be minimized, if the propagation model is fed with an environmental parameter vector containing two distinct sets: one, xed and formed by the environmental parameters with uncontrolled errors; the other, variable and with errors determined in a controlled way, adapted to the errors in the rst subset. Here, the second set is treated as a distinct quantity, labeled as \equivalent model". It can be determined by acoustic inversion. The equivalent model is employed for two objectives: to estimate the acoustic eld at a given present time (nowcast), and a given future time (forecast). Synthetic acoustic elds, and oceanographic measurements and predictions (with the Navy Coastal Ocean Model) obtained for the Maritime Rapid Environmental Assessment 2003 sea trial, drive the simulations. For the problem of nowcast, the equivalent model is determined at sparse transect points, and interpolated to points with no acoustic measurements. For the problem of forecast, the equivalent model is furthermore `extrapolated' to future time. The `extrapolation' consists of a mapping between sound speed pro le and equivalent model. When providing an estimate of the future sound speed at the mapping input, the estimate of the future equivalent model is obtained. The proposed method led to a decrease of 3{5 dB in transmission loss estimation error, as compared to standard procedures.
- Activated carbon adsorption of cyanotoxins from natural watersPublication . Costa, Helena Cristina Reis; Rosa, Maria João; Teixeira, Margarida Ribau; Menaia, José António Gomes FerreiraActivated carbon adsorption of cyanotoxins from natural waters
- Activie vision in robot cognitionPublication . Saleiro, Mário Alexandre Nobre; du Buf, J. M. H.; Rodrigues, J. M. F.As technology and our understanding of the human brain evolve, the idea of creating robots that behave and learn like humans seems to get more and more attention. However, although that knowledge and computational power are constantly growing we still have much to learn to be able to create such machines. Nonetheless, that does not mean we cannot try to validate our knowledge by creating biologically inspired models to mimic some of our brain processes and use them for robotics applications. In this thesis several biologically inspired models for vision are presented: a keypoint descriptor based on cortical cell responses that allows to create binary codes which can be used to represent speci c image regions; and a stereo vision model based on cortical cell responses and visual saliency based on color, disparity and motion. Active vision is achieved by combining these vision modules with an attractor dynamics approach for head pan control. Although biologically inspired models are usually very heavy in terms of processing power, these models were designed to be lightweight so that they can be tested for real-time robot navigation, object recognition and vision steering. The developed vision modules were tested on a child-sized robot, which uses only visual information to navigate, to detect obstacles and to recognize objects in real time. The biologically inspired visual system is integrated with a cognitive architecture, which combines vision with short- and long-term memory for simultaneous localization and mapping (SLAM). Motor control for navigation is also done using attractor dynamics.
- Adding value to performance measurement by using system dynamics and multicriteria analysisPublication . Santos, Sérgio Pereira dosMeasuring performance either formally or informally is a common practice in most organisations. It is well established that performance measurement plays a critical role in organisations, signalling how well they are succeeding in achieving their objectives and identifying where improvement efforts are required. In an attempt to respond to the assessment needs of organisations, several performance measurement frameworks have been developed over the years. However, in spite of the remarkable progress that has been made in the development of better integrated, balanced and strategically driven performance measurement frameworks, there are issues which deserve further research if these frameworks are to provide a stronger basis from which to manage effectively for improvement. Informed by the literature review and conceptual experimentation, this thesis aims to show that the use of system dynamics (SD) and multiple criteria decision analysis (MCDA), individually and in an integrated manner, can address some of these issues and bring new insights to inform and support the different stages of the performance measurement and management process. To this purpose, a framework incorporating the integrated use of SD and MCDA is suggested and its conceptual coherence and practical relevance is discussed. The conceptual coherence is illustrated by a simple but realistic application in the health care sector. The practical relevance of the framework is assessed in an organisational setting, taking the form of three in-depth case studies. Several conclusions are drawn regarding the potential role of SD and MCDA to add value to the performance measurement and management process, including an assessment of their suitability, limitations, and implementation issues associated with this particular context.
- Adversidade psicossocial, recursos de resiliência e qualidade de vida na adolescência: um estudo comparativo entre adolescentes portugueses e imigrantesPublication . Martinho, Selma Regina Gonçalves; Lemos, IdaO estudo dos processos psicológicos que norteiam a adolescência tem merecido nas últimas décadas particular atenção por parte da comunidade científica. Esse interesse tem-se expandido para além dos determinantes de natureza individual, considerando-se igualmente importantes a estrutura e o funcionamento da família, e as dinâmicas que a ela se associam. Por sua vez, nas últimas duas décadas, dada a relevância dos movimentos migratórios e o seu impacto na economia dos países, a investigação em Psicologia tem mostrado interesse pelos processos de adaptação e de integração psicossocial dos imigrantes. Na presente investigação definimos como objetivo principal o estudo das relações entre fatores psicológicos, psicossociais e socioeconómicos e familiares, enquanto fatores com influência na qualidade de vida e nos resultados desenvolvimentais positivos na adolescência. Pretendemos assim, compreender de que forma acontecimentos de vida considerados stressantes podem influenciar o bem-estar relacionado com a saúde na adolescência em adolescentes imigrantes. Mais especificamente, propusemo-nos analisar se estes adolescentes estão em maior risco para o desenvolvimento de problemas psicopatológicos e psicossociais, por comparação com adolescentes nativos portugueses. Para responder aos objetivos colocados participaram no presente estudo 742 adolescentes de ambos os sexos, residentes no Algarve: 390 imigrantes e 352 nativos, com idades compreendidas entre os 11 e 18 anos. Com vista à prossecução destes objetivos procedemos à adaptação de duas escalas psicométricas: a Escala de Estilos Educativos (Delgado, Jiménez, Sánchez-Queija & Gaviño, 2007) (Estudo 1) e a Escala de Avaliação da Coesão e da Adaptabilidade Familiares-III (Olson, Portner & Lavee, 1985) (Estudo 2). Para a avaliação de sintomas psicopatológicos recorremos às escalas Perturbação do Comportamento, Depressão Major, Perturbação de Ansiedade Generalizada, Perturbação Pós-Stresse Traumático, Problemas Académicos e Problemas de Autoconceito da Escala de Psicopatologia do Adolescente de Reynolds (2000), e para a análise dos recursos internos de resiliência utilizámos a Escala Healthy Kids Resilience Assessment Module (Versão 6.0) de Constantine, Bernard e Diaz (1999). Para aferir da perceção de qualidade de vida relacionada com a saúde nos adolescentes recorremos ao Kidscreen-52 (Ravens-Sieberer, 2006) (Estudo 3). Relativamente aos estudos de validação dos instrumentos, os dados obtidos relativos à EEE (Delgado et al., 2007), permitiram concluir que a escala apresenta boas propriedades psicométricas, revelando coeficientes de alfa de Cronbach satisfatórios, quer na escala total, quer nas suas subescalas. Os resultados da análise fatorial exploratória com rotação Varimax foram igualmente satisfatórios, corroborando as dimensões propostas pelos autores da versão original da EEE, confirmando assim a validade da escala enquanto instrumento com viabilidade de utilização em investigação com amostras de adolescentes portugueses. Igualmente a análise da consistência interna da escala FACES-III revelou coeficientes de alfa de Cronbach satisfatórios e a análise fatorial exploratória com rotação Varimax confirmou a estrutura fatorial do original do instrumento, atestando a possibilidade de utilização do mesmo em contextos de investigação, clinico e de intervenção. No que se refere ao Estudo 3, os resultados da análise comparativa entre adolescentes imigrantes e nativos, sugerem que os adolescentes nativos se percecionam como mais autónomos e com melhor comunicação e relacionamento com a família e grupo de pares. Por outro lado, os adolescentes imigrantes apresentam índices mais elevados ao nível Estado de Humor Geral e Papéis, comparativamente com os nativos portugueses. De entre os imigrantes, os adolescentes de origem brasileira relataram maior Controlo Comportamental por parte dos pais. Finalmente, não se evidenciaram diferenças significativas entre os dois grupos no que respeita à Qualidade de Vida Relacionada com a Saúde. Estes resultados são discutidos com base numa abordagem desenvolvimental-ecológica da adolescência.
- Aeroportos e turismo residencial. Do conhecimento às estratégiasPublication . Almeida, Claudia; Ferreira, Ana Maria Alves Pedro; Costa, CarlosO problema da nossa pesquisa resultou de uma ampla revisão de literatura que visava cruzar quatro áreas distintas, a gestão do conhecimento, as parcerias estratégicas, os aeroportos e o turismo residencial. Estas áreas permitiram-nos avaliar o quão diversificados podem ser os estudos turísticos e estabelecer relações de proximidade entre as diferentes temáticas. O objectivo do problema definido visava estabelecer uma relação entre a gestão integrada do conhecimento e o trabalho conjunto dos aeroportos com outras entidades do sector público e privado e a forma como esta podia contribuir de forma favorável para a delineação adequada de estratégias de negociação de rotas com as companhias aéreas, potenciando o desenvolvimento de novos segmentos de mercado turístico, como é o caso do turismo residencial, e originar alterações na procura turística de uma região. A metodologia adoptada para dar resposta à nossa investigação insere-se numa matriz desenvolvida no processo de elaboração do estudo. A matriz EGIC (espiral da gestão integrada do conhecimento) abrange diferentes métodos e técnicas de investigação, que passam pela aplicação de questionários (procura e oferta), entrevistas com especialistas e painel de debate, permitindo reunir dados para caracterizar o segmento de mercado do turismo residencial no Algarve. Esta matriz tem como objectivo reunir informação que permita sustentar o conhecimento de um segmento de mercado turístico e criar uma plataforma de apoio ao seu desenvolvimento futuro na região em estudo. Os resultados obtidos nas várias técnicas utilizadas permitiram-nos caracterizar este segmento de mercado e identificar quais as principais lacunas de informação existentes e sobre as quais é necessário incidir no futuro. Numa fase final do estudo apresentamos uma hipótese de estrutura de uma plataforma de apoio ao desenvolvimento integrado do turismo residencial, assim como as principais actividades que esta deveria integrar de modo a fazer face às necessidades da região algarvia.
- Afecto e identidade nacional: a contribuição teórica das representações sociais para o estudo de uma imagem persistente em PortugalPublication . Rosado, Maria de Fátima Vieira; Gil, José; Jesuíno, Jorge Correia
- Afecto: oscilógrafo do sentidoPublication . Vasconcelos, Soraya; Reia-Baptista, VítorÉ objectivo deste projecto teórico-prático produzir um corpo de trabalho artístico e desenvolver paralelamente uma dissertação teórica em torno de processos envolvidos na criação. É presumível que a visão particular que um artista tem sobre a arte num sentido amplo (a sua teoria), e o seu particular fazer artístico (a sua práxis), derivem um do outro e se contaminem, existindo uma relação próxima entre as ideias sobre as quais reflecte através da sua obra e a sua visão ontológica da arte. Considera-se o objecto fulcral da arte algo que vive não apenas de uma apropriação inteligente da realidade, mas também de um entendimento afectivo – de um sentir para além de um raciocinar. O afecto, enquanto experiência de sentido é condição essencial para o artista que o veícula no seu trabalho; é na sua obra que o artista modela uma coisa sentida para a devolver como coisa dada a sentir. Dada a natureza irredutível dos objectos que resultam da prática artística, a possibilidade de comunicar o sentido da arte através de códigos (palavra, discurso, linguagem) consensualmente entendidos é, no entanto, posta em causa. Trata-se de um processo que se posiciona no limite da razão, tornando-se necessário pensar outros mecanismos para alcançar esse sentido para além daqueles usados geralmente para compreender matérias comprováveis.
- Aims of education and well-being as absence of disorderPublication . Pereira, Rui Lopes Penha; Haydon, GrahamThis thesis offers an original account of what personal well-being can be. Any account of education, it is believed, has to do with and aims at personal well-being. I approach this view on well-being not in a positive but in a negative way. I put forward some items that in certain circumstances can be taken by and called sources or forms of disorder. In the absence of such forms or sources of disorder, I assume that a certain order, prudential or moral, takes place and that constitutes the well-being of the person. The concept of ‘absence of disorder’ is introduced and argued as an educationally appropriate view of personal well-being which is the central educational aim. Therefore, ‘absence of disorder’ is positioned as the central aim of education. This concept is illuminated, for practical reasoning, by a list of seven possible forms of disorder: Comparison, Corruption, Dependency, Division, Fear, Self-disintegration and Violence. As a view of personal well-being, ‘absence of disorder’ is initially rooted in informed desire satisfaction, via the introduction of the concept of entropy. Prudentially, the agent’s informed desire is satisfied by living a life with low build up of entropy or disorder. But, in a second move such a base is also provided by the Levinasinian concept of ‘disinterest’ as a root for ‘what is to be a human’. Such ‘disinterest’ is related to the concepts of love and of ‘action for its own sake’. It is at this final approach that an attempt is made towards the approximation of the ethical and the prudential aspects of social practices. Even if only to some extent successful, the argument is directed to the following conclusion: an education aiming at ‘absence of disorder’ may promote prudential well-being and give us some confidence in simultaneously favouring moral education.
- Airbnb stakeholders´ perceptions and behavioral intentions: the case of Airbnb in VietnamPublication . Thuc, Do Thi Mai Doan; Silva, João Albino; Pereira, Luís NobreResearch on Airbnb accommodation providers and consumers’ perception and behavioral intention has received much scholarly attention within the sharing economy literature in the recent decade. From the literature on consumer side, despite growing interest in studying the effect of electronic word-of-mouth (eWOM) on Airbnb customers’ perception and behavioral intentions through online review mining techniques, limited Airbnb related research was conducted as an empirical study to provide insight into how Airbnb customers with different personal characteristics adopt eWOM, and what are the drivers of their intention to spread positive WOM after the stay experience. In addition, it is worth noting that this study overlapped with the period of the global pandemic, COVID-19 - which has impacted this short-term rental platform seriously, however, less is known about Airbnb customers’ eWOM adoption process and Airbnb hosts’ decision making process in a health-related crisis. Moreover, the large proportion of the existing studies focus on the matured Airbnb markets, while cultural and situational factors were found to hold a great importance on influencing Airbnb stakeholders’ perception and their subsequent behaviours. Thus, this study aims to explore the perception and eWOM related behavioral intentions of Airbnb consumers; and to study the antecedents of Airbnb hosts’ continuance intention with the sharing platform in an emerging sharing economy market – Vietnam, especially in the setting of the global pandemic. Guided by the positivism paradigm, this research is a combination of four scientific papers which tend to achieve the aforementioned general objectives. More specifically, the first paper of this study utilized the Cognitive appraisal – Emotional response – Coping Behaviour model to re-examine the most commonly confirmed antecedents of consumers’ perceived values towards Airbnb and broadening the comprehension of how these perceived value affect Vietnamese Airbnb consumers’ satisfactions, and electronic and traditional word-of-mouth ((e)WOM) intention. The findings confirmed the significant role of perceived functional benefits, monetary values, and hedonic benefits on encouraging Airbnb consumers’ positive (e)WOM intention directly or indirectly via satisfaction with their stay experience. Results also revealed that the relationships among social interaction, novelty, sustainability, and customer satisfaction were not significant in the Vietnamese Airbnb market. These contradictory findings provide stronger evidence on the critical influence of cultural values in Airbnb customers’ perception and behavioral intentions. Moreover, the novelty of this study lies in the confirmation of the impact of traditional WOM intention on eWOM intention from the message communicators’ perspective, in which this finding has not been discussed until now in any research context. Second, through extending the Stimuli – Organism – Response model, the next paper of this research expands our understanding of the determinants of Airbnb customer loyalty beyond the well-established contribution of customer satisfaction, since it identified the influential role of perceived enjoyment on Airbnb customers’ intention to spread positive comments towards this accommodation sharing platform. Moreover, the theoretical contribution of this study is also related to the investigation of the moderating role of Airbnb customers’ sociodemographic and tripographic characteristics in the associations among perceived enjoyment, its antecedents (home benefits, social interaction, authenticity and monetary value) and consequences (eWOM intention). The results revealed that these relationships remain unchanged among the different groups of customers, except business travellers, which offer a foundation for the empirical comprehension of this emerging Airbnb target market segment. To achieve the research objectives of the first two studies, an online survey-based questionnaire using a non-probabilistic sampling method was applied to collect data on a sample of Vietnamese customers who had experienced Airbnb accommodation within a year before the period of data collection. A total of 352 questionnaires were collected, from which 163 and 162 eligible Airbnb users in Studies 1 and 2 respectively were retained for data analysis by the application of the Partial Least Square approach to SEM (PLS-SEM). Third, guided by the conclusion of customers’ distinct eWOM adoption in the literature, this part of the research aims to provide an empirical evidence on explaining the contradictory findings regarding the effect of eWOM on Airbnb consumers’ behavioral intentions through considering the moderating role of consumers’ sense of power and perceived psychological risk towards COVID-19. Furthermore, this work also takes into account the importance of cultural differences in Airbnb customers’ behavioral intentions by carrying out a cross-national study among Italy, Portugal and Vietnam. More particularly, this study expanded the Model of Goal directed Behavior (MGB) to investigate how eWOM influences Airbnb existing and prospective customers’ desire to book Airbnb accommodation indirectly through attitude, subjective norms, perceived behavioral control, anticipated emotions, and trust in hosts which consequently lead to their purchase intention. In order to test the proposed hypotheses, an electronic survey was conducted in these three countries which resulted in a total sample of 1,849 respondents (including 1,146 Italian, 262 Portuguese and 441 Vietnamese Airbnb users and non-users). Airbnb non-users are defined as those who are aware of the Airbnb platform but have never experienced it before. The collected data were later analysed by also using PLS-SEM. The findings found the different moderating role of sense of power and psychological risk in Airbnb customers’ eWOM adoption process across these three research contexts, which confirmed the significance of cultural and situation factors in studying eWOM and Airbnb customers’ behavioral intentions. Furthermore, desire to book the shared accommodation was found as the most influential factor in customers’ purchase intention, which confirmed the suitability of the MGB in studying Airbnb customers’ behavioral intentions in the uncertain situation brought by a global pandemic. Fourth, the final part of this research shifts the focus to Airbnb accommodation service provider – Airbnb hosts in order to examine the antecedents of their continuance intention with the platform during the COVID-19 pandemic. Airbnb hosts are usually considered as micro-entrepreneurs that are not professionally trained in hotel management. Grounded on the Theory of Planned Behavior (TPB), this study proposes a conceptual framework integrating TPB constructs including Airbnb hosts’ attitude, subjective norms and perceived behavioral control, and a dedication-based factor, so called trust towards Airbnb to study their loyalty intention along with the moderating effect of Superhost badge on the modeled relationships. A sample of 160 Vietnamese Airbnb hosts was observed through an electronic survey and data were later analyzed with PLS-SEM. Findings showed that Airbnb hosts’ attitude, perceived behavioral control and trust towards Airbnb significantly impact their intent to continue listing the assets on the platform. Last but not least, findings confirmed the existence of the moderating role of Airbnb hosts’ status in their decision-making process during an unprecedented pandemic. Thus, this study subsequently enriches the literature on the accommodation sharing industry from the lens of different types of accommodation service providers and contributes to advancing the theory in the field of micro-entrepreneurs’ response towards crises. This research provides practical implications in two specific ways. First, the findings of this study shed light on Airbnb platform management and Airbnb hosts’s understanding of Vietnamese Airbnb customers’ perceived values, their perception towards the shared accommodation and subsequent eWOM related behavioral intentions. Second, these results also support the platform management company and local authorities in setting up effective management strategies to reduce Airbnb guests and hosts’ perceived risks of the crisis, enhance their mutual trusts and trust towards the platform which finally increase their satisfaction and loyalty in the setting of COVID-19 or similar crises in future.
- A alegoria histórica nos filmes de viagem de Manoel de OliveiraPublication . Santos, Wiliam Pianco dos; Soares, Ana IsabelEsta investigação defende que uma análise temática, formal e conceitualmente centrada sobre O Sapato de Cetim (1985), Non, ou a Vã Glória de Mandar (1990), Viagem ao Princípio do Mundo (1997), Palavra e Utopia (2000), Um Filme Falado (2003) e Cristóvão Colombo – O Enigma (2007), títulos da autoria do cineasta português Manoel de Oliveira, pode sustentar a configuração desse conjunto fílmico enquanto corpus. À seleção em causa propõe-se a denominação filmes de viagem de Manoel de Oliveira. Os filmes de viagem de Manoel de Oliveira são caracterizados por enredos que abordam episódios passados da história global, com ênfase sobre a história portuguesa, para que, por meio do uso da alegoria histórica como recurso narrativo, possam refletir acerca da atualidade geopolítica mundial, com especial atenção sobre o contemporâneo nacional. Nos títulos que compõem os filmes de viagem de Manoel de Oliveira, sustenta-se, há recorrentemente a presença de narrativas de viagem, nas quais destaca-se a interação entre a crítica da imagem eurocêntrica como modo de compreensão da história (nacional ou mundial) e a defesa dos feitos portugueses como contribuição fundamental para a globalização planetária. O presente trabalho argumenta que o discurso narrativo dos filmes de viagem de Manoel de Oliveira está constituído filme a filme, em diálogo permanente e complementar entre os enredos em causa, em razão de uma mensagem alegórica que relaciona passado e presente, bem como a partir do proveito de narrativas de viagem e do embate entre a crítica ao discurso eurocêntrico e o elogio à diferença portuguesa.
- Algarve artificial reefs fish assemblages and trophic ecology: implications for the local near shore fisheriesPublication . Miguel de Sousa Leitão, Francisco; Santos, M. N.; Erzini, Karim
- Alterações ambientais na costa algarvia durante o holocénico: um estudo com base em diatomáceasPublication . Gomes, Ana Isabel de Sousa Horta Dias; Boski, T.; Moura, Delminda; Szkornik, Katie; Witkowski, AndrzejA sensibilidade das diatomáceas às alterações físico-químicas do meio aquático em que vivem, torna estas algas unicelulares indicadores paleoambientais de alto potencial interpretativo. O presente estudo caracteriza as condições de vida das diatomáceas em zonas de transição oceano-continente do Algarve e assim cria um análogo modeno para interpretações paleoambientais do registo sedimentar. A investigação descrita abrangeu os sedimentos superficiais, a água superficial dos estuários de rios Arade e Guadiana e as diatomáceas associadas aos sedimentos. Tal permitiu: (i) definir associações de diatomáceas e, complementarmente, a concentração dos estomatocistos de crisofíceas ao longo das zonas intermareais dos dois estuários e, (ii) concluir que os parâmetros ambientais que condicionam a distribuição das diatomáceas nestes estuários são principalmente a textura do sedimento, o tempo de inundação e a salinidade da água intersticial do sedimento. Além disso, o fraco gradiente de salinidade observado no estuário do Arade permitiu aprofundar o conhecimento das associações presentes em ambientes de água salobra, enquanto que a análise da distribuição das associações de diatomáceas no estuário do Guadiana contribuiu para aumentar o conhecimento adquirido no estuário do Arade, relacionando a composição das associações com o gradiente completo de salinidade entre o meio marinho e fluvial. Adicionalmente, verificou-se que em ambos os estuários existem espécies que não foram descritas até ao momento. Assim, foi ainda identificado e proposto formalmente um novo género e espécie de diatomácea, a Syvertsenia iberica. A aplicação dos conhecimentos adquiridos no presente trabalho à interpretação dos paleoambientes sedimentares do Plistocénico terminal e Holocénico, nos estuários do Arade e Guadiana, através do desenvolvimento de funções de transferência e do estudo do registo fóssil das diatomáceas e dos estomatocistos de crisofíceas, resultou numa reconstrução mais pormenorizada da evolução das referidas zonas estuarinas, em função da subida do nível médio do mar após o Último Máximo Glacial.
- Aluminum bioaccumulation and tolerance in Plantago algarbiensis Samp. and Plantago almogravensis Franco, assessed by using in vitro cultures and micropropagated plantsPublication . Martins, Neusa; Romano, AnabelaThis thesis aims to understand the aluminum (Al) bioaccumulation capacity, toxicity effects and tolerance mechanisms in two rare species endemic from Portugal, Plantago algarbiensis Samp. and Plantago almogravensis Franco. Firstly, two protocols were developed to propagate in vitro these species (Chapter 2). Afterwards it was investigated the influence of low pH on in vitro growth (Chapter 3). The seed germination requirements and the effects of Al on the germination and early development of seedlings were then evaluated in Chapters 4 and 5, respectively. The impact of low pH and Al on physiological responses, oxidative stress status and capacity for Al accumulation in micropropagated shoots and plantlets was investigated in the subsequent chapters (Chapters 6, 7 and 8). Finally, in Chapter 9 the possible implications of organic acids in Al detoxification were evaluated. Both species were successfully micropropagated showing high shoot multiplication rates and rooting frequencies and the micropropagated shoots of both species were able to tolerate and grow in low pH conditions. The seeds of both species germinate readily at 15 ºC and Al showed no impact on the germination percentage in either species but oxidative stress during early seedling development was detected. Although, both species accumulated considerable Al amounts and showed to be moderately tolerant to low pH and Al, P. almogravensis appeared to be more able to manage the oxidative stress and, therefore, adapted to maintain cellular physiology and growth under these stress conditions. Results suggested that Al detoxification in P. almogravensis implies both secretion of organic acids from roots and Al intracellular chelation by organic acids, while in P. algarbiensis only the internal mechanism seems to be involved. This research contributes to the understanding of the mechanisms underlying P. algarbiensis and P. almogravensis adaptation to acidic Al-rich conditions.
- Alumni in a relationship marketing perspective: the alumni-alma mater commitment relationshipPublication . Pedro, Ilda Maria Horta; Mendes, Júlio; Pereira, Luís NobreFostering relationships with alumni has consisted of framing strategies to increase competitiveness amongst higher education institutions (HEIs) in Europe and particularly in Portugal. This thesis aims to understand the alumni-alma mater commitment relationship, through the identification of its drivers, indicators, and alumni patterns leading to an intention to commit. The work was developed at the University of Algarve (UAlg) through qualitative and quantitative research methods. Results are embodied in three papers. The first study draws upon alumni opinions regarding four main dimensions: academic experience, current situation, commitment indicators and the HEI’s commitment. The information was obtained through three focus groups (paper one). A structural equation modelling approach was used to investigate the relationship between a set of latent variables, identified in the qualitative research and supported by the literature, and the commitment relationship. To this end, a sample of 2,008 alumni was obtained through an online survey (paper two). The obtained results helped in the development of the last phase of the work, in which was applied a cluster analysis to segment the alumni and a binomial regression model to identify determinants of the intention to collaborate (paper three). The results show that the affective, cognitive and HEI’s commitment directly influence the commitment relationship. Alumni stress their intention to recommend, share their experience with current students, and give their help when it is necessary as ways to give back. Furthermore, they also recognise the importance of benefits and advantages in this relationship. Five segments of alumni were identified through clustering analysis, revealing valuable information for decision-making, particularly regarding an expressed willingness to participate in fundraising campaigns, which is relevant in a context where these campaigns are not very common. Results of the regression model showed that predictors of intention to collaborate comprised participation in extracurricular activities, sense of belonging, and elements considered in HEI’s commitment (solicitation, communication, and quality). HEI’s responsibility is underlined as a true catalyst in the commitment relationship process. The general conclusions of this thesis are in line with the literature, but they also add value in the context of European higher education, particularly in Portugal, where the alumni culture is starting to make small steps.
- Amino acid requirements of white seabream (Diplodus sargus) larvae: effects on growth and performancePublication . Saavedra, Maria Margarida Alves da Silva de Almeida; Dinis, Maria Teresa; Conceição, L. E. C.Diplodus sargus is a potential species for aquaculture. Constraints to its production are a high incidence of skeletal deformities and stagnation of the growth rate in juvenile stage, possibly caused by dietary imbalances. This thesis is focused on the amino acid (AA) requirements of Diplodus sargus larvae, on the formulation of diets with AA supplementation and also identifies larvae skeletal deformities patterns (Chapter 2). D. sargus AA requirements were estimated using the AA profiles from larval carcass. It was observed that the AA profiles were relatively constant during larval ontogeny, and dietary imbalances were identified in rotifers and Artemia (Chapter 3). Tyrosine, lysine, tryptophan and arginine supplementation was tested by tube feeding and lower gut absorptions efficiencies were observed for these AA. Also, these AA do not seem to be limiting D. sargus growth (Chapter 4 and 5). Based on the results from Chapter 3, a microencapsulated casein diet with a balanced AA profile was formulated and was compared to an unbalanced AA diet and to a live feed diet (control) (Chapter 6). Results showed lower ammonia excretion and less skeletal deformities in larvae fed a balanced diet. Tryptophan supplementation in the diet was tested because of its involvement in skeleton ossification (Chapter 7). However, a decrease on larval growth and no effect on skeletal deformities were observed. The effect of tyrosine and phenylalanine supplementation on D. sargus larvae was tested and a higher survival to a temperature stress test was observed in larvae fed a tyrosine supplementation (Chapter 8). Larvae given a phenylalanine supplementation had a decreased incidence on vertebral compressions. In conclusion, an AA balanced diet reduces skeletal deformities and improves nitrogen utilization. Skeletal deformities do not seem related to tryptophan deficiency. Supplementation of phenylalanine and tyrosine lead to a decrease on skeletal deformities and better resistance to a stress test, respectively. From the AA studied; tryptophan, lysine, phenylalanine, arginine and tyrosine; none seems to be limiting D. sargus larval growth
- Amor, liberdade e sabedoria - dialética de uma construção visualPublication . Barata, Alexandre Nuno Serrão Fialho Alves; Tavares, Mirian; Santos, António Pedro Cabral dosInvestigação para desenvolvimento de projeto artístico no domínio das artes visuais, partindo da análise de obras de minha autoria, sob o nome artístico de Xana. No processo exploratório inicial sistematizei as questões conceptuais e construtivas presentes, nomeadamente: as ideias e obsessões, as atitudes operativas e os valores éticos. Na fase de execução projetual realizei uma deriva entre essa reflexão e a prática artística, num processo experimental que relacionou ideias/formas visuais, imaginação, ética e os novos lugares e contextos de intervenção. Com esta estratégia desenvolveu-se um discurso pessoal, enunciouse a postura crítica à sociedade contemporânea e exerceu-se intervenção cultural. As obras criadas neste projeto são dispositivos ativos que se relacionam com as pessoas, com o espaço, numa poética em que acontece a propagação não linear da expressão visual numa pesquisa necessariamente idiossincrática, complexa e subjetiva. Talvez, por isso, foi decidido experimentar nos trabalhos finais a ideia de labirinto. Esta investigação situa-se no âmbito da especulação analítica e da prática das artes visuais, num processo de procura do belo dialogal e convulsivo que nos permita prosseguir a construção de uma “obra aberta”, de que já falava Umberto Eco, com uma ética estética alicerçada sobre os valores do amor, da liberdade e da sabedoria.