Hunting for Brown Dwarfs in Corona Australis

Tese de mestrado, Física (Astrofísica e Cosmologia), Universidade de Lisboa, Faculdade de Ciências, 2022Brown dwarfs are substellar objects with masses ranging from 0.08 Solar masses at the high end, down to those overlapping with masses of giant exoplanets. The study of young brown dwarfs is key to understanding both planet- and star-formation processes. It helps constrain the low-mass regime of the Initial Mass Function which, for nearby star-forming regions, is well characterized down to ∼ 10 − 20 Jupiter masses but becomes loosely defined for lower mass values. Having in mind that young brown dwarfs are very faint sources, a complete census of brown dwarfs in nearby star-forming clouds, where they can be more easily detected, is imperative to improve our knowledge on both planetary and stellar formation models, as well as the shape of the substellar Initial Mass Function. The Corona Australis cloud is one of the closest star-forming regions to the Solar system, at a distance of ∼ 150 parsecs. In 2017, it was observed using the Suprime-Cam instrument at the Subaru telescope. These observations have a field-of-view of ∼ 0.255 deg2 , and result in the deepest optical photometric catalog of the region with magnitudes ranging down to 23 mags in the I-band, which is equivalent to ∼ 3 Jupiter masses at a distance of 150 pc (with no extinction) using the AMES-COND model. The work of this thesis consists of the data reduction of this dataset and of the selection of a list of candidate sources for future spectroscopic observations in Corona Australis. The PSF photometry has been performed using the Source-Extractor and PSFEx software and calibrated with the help of the DENIS I-band photometry, and colours were obtained by cross-matching the dataset with the VISTA Hemisphere Survey catalog. This resulted in an IJKs catalog of 21 133 sources. After photometry, we selected sources from our catalog which presented colours consistent with those of young objects. From the resulting list of sources, we made two further selections. One for the sources present in the Gaia EDR3 catalog, selecting those with proper motions and parallaxes similar to spectroscopically confirmed members of Corona Australis. This selection produced a list of 15 objects. For the other selection, below the Gaia limit, we use only colours. Most of the sources we are interested in are substellar objects and are, hence, very faint. Because of this, they were not detected by Gaia. As such, we selected sources which are below the Gaia limit (I ∼ 19 mag) and above 22 mag. This method resulted in a list of 313 sources, where 145 objects present colours for masses below 5 Jupiter masses, and with most of our candidates residing in the planetary-mass regime (if indeed confirmed as members of Corona Australis) according to the AMES-COND models. It should be stressed, however, that this selection method is expected to produce a large number of contaminants and therefore requires further confirmation through spectroscopy observations. The total list of candidates for follow up spectroscopy observations is then composed of 328 sources. During the Subaru observations, an Hα catalog was also produced. Hα information from this catalog was used to flag possible active accretors in our list of candidates, although only 3 sources from our list of 328 candidates present bright Hα emission. Using empirical models from Pecaut and Mamajek (2013), we built an extinction map of the observed field. This extinction map was used alongside the Besançon galaxy model to estimate the number of contaminants in our list of candidates for follow-up spectroscopy observations. We found a contamination rate of ∼ 90%, meaning we expect to confirm ∼ 30 new planetary mass brown dwarfs. Having only ∼ 100 of these objects been identified so far, our spectroscopy efforts may increase the current budget of known free-floating planetary mass objects by ∼ 30%. The preparatory work for the follow-up spectroscopy observations is also developed here. These observations will be done using the K-band Multi Object Spectrograph at the Very Large Telescope. Seven different fields are proposed encompassing 219 sources from our selection list. Using the Exposure Time Calculator, KMOS-dedicated software and the observation preparation tool p2, we estimate a full exposure time of six hours and twenty-five minutes.Anãs castanhas jovens são cruciais para percebermos os mecanismos por detrás da formação estelar e planetária. Elas ajudam-nos a caracterizar a Função de Massa Inicial que, para as regiões de formação estelar mais próximas, está bem definida até cerca de 10 − 20 Júpiters. Regiões de formação estelar são os lugares na Via Láctea onde a maior parte das estrelas e objectos sub-estelares são formados. Ao observar estas regiões, podemos detectar anãs castanhas quando estas ainda estão em estágios de formação e evolução. A Função de Massa Inicial é uma função que representa a distribuição de massas de objectos formados numa dada região. No entanto, para massas mais baixas, a Função de Massa Inicial ainda não tem uma definição bem estabelecida. Está melhor definida para massas maiores (objectos mais luminosos) e existe um debate sobre a universalidade desta função que ainda não obteve um consenso. Por isso, a detecção de anãs castanhas em regiões de formação estelar é importante para obtermos uma versão completa da Função de Massa Inicial e para obter conhecimentos à cerca dos mecanismos de formação tanto de estrelas como de planetas. Existem vários cenários hipotesizados para a formação de anãs castanhas. Diferentes observações ao longo dos anos têm favorecido certos cenários em prol de outros, mas ainda não existe um consenso para o mecanismo de formação dominante nem a frequência relativa com que cada cenário acontece. As anãs castanhas são objectos particularmente pouco brilhantes, por isso a sua detecção torna-se mais fácil para as regiões de formação estelar mais próximas. Corona Australis é uma destas regiões de formação estelar, a apenas uma distância de ∼ 150 pc do sistema Solar. Esta região foi primeiro identifacada na década de 1910s e tem sido extensivamente observada, mas estas observações direccionam-se maioritariamente aos objectos mais brilhantes desta região. As observações também tem sido direccionadas maioritariamente para o Coronet Cluster, um agregado de estrelas a Oeste da nuvem estelar onde se espera que grande parte da população da região estelar resida. Recentemente, esta associação foi observada por Bo Reipurth em Maio de 2017 usando o instrumento Suprime-Cam no telescópio Subaru. Estas observações produziram o catálogo óptico mais sensível desta região, tendo sido observada na banda I. O trabalho apresentado nesta tese consiste na redução destas observações e na selecção de objectos para observações espectroscópicas consequentes. Esta selecção é feita prioritizando objectos que apresentem propriedades cinemáticas semelhantes às de membros de Corona Australis espectroscopicamente confirmados e/ou cores características de fontes luminosas jovens. Com este fim, o catálogo foi calibrado em relação ao catálogo DENIS e foi feita uma correspondência cruzada com o catálogo VHSDR6 de forma a obtermos cores para estes objectos. Assim, construímos um catálogo de 21 133 objectos detectados nesta região. Depois, representámos a fotometria do nosso catálogo num diagrama cor-magnitude. Este diagrama permite identificar objectos jovens e prováveis membros da nuvem, já que estes vão apresentar cores avermelhadas características destes objectos. Desenhámos uma linha arbitrária no diagrama cor-magnitude e selecionámos objectos do nosso catálogo mais vermelhos que esta linha. Isto resultou numa lista de 650 objectos que foram redireccionados para o nosso processo de selecção baseado nas propriedades cinemáticas. As propriedades cinemáticas de alguns dos objectos neste catálogo foram obtidas do catálogo produzido pela missão Gaia. Utilizámos membros confirmados espectroscopicamente para determinar os valores cinemáticos característicos da nuvem. Objectos selecionados pelo diagrama cor-magnitude com valores cinemáticos semelhantes aos dos membros de Corona Australis foram selecionados. Esta selecção produziu uma lista de 15 candidatos com cores características de objetos jovens e propriedades cinemáticas semelhantes às dos membros da nuvem. Nem todos os objectos no nosso catálogo têm um par no catálogo Gaia por serem pouco brilhantes e, consequentemente, não terem sido detectados durante a missão Gaia. Atendendo a isto, uma lista de 313 candidatos foi produzida, onde objectos abaixo do limite da missão Gaia (I ∼ 19 mag) e acima de I = 22 mag, presentes na lista de selecção de objectos por cor-magnitude, foram seleccionados. 145 desses candidatos apresentam massas mais baixas que 5 Júpiters e a maior parte pertence ao regime planetário da função de massa (de acordo com o modelo AMES-COND). No total, a nossa lista de candidatos para observações espectroscópicas futuras é composta por 328 objectos. Durante as observações de Maio de 2017, Corona Australis também foi observada usando um filtro Hα. Como não existe um cátalogo público de Corona Australis para observações em Hα, não foi possível calibrar este catálogo. No entanto, não deixa de ser possível identificar os objectos mais brilhantes neste filtro. Isto é importante porque a emissão de Hα pode indicar a existência de acreção numa fonte luminosa, que é um sinal de juventude. No entanto, apenas 3 dos 328 candidatos apresenta uma forte emissão de Hα. Usando os modelos empíricos de Pecaut and Mamajek (2013), cálculamos a extinção presente em alguns dos objectos no nosso catálogo. Com estas extinções, conseguimos construir um mapa da extinção presente no campo observado pelo telescópio Subaru. Este mapa foi usado para estimar o número de contaminantes na nossa lista de candidatos. Estes contaminantes serão estrelas vermelhas ou galáxias por detrás da nuvem que são erroneamente identificadas como objectos jovens. Outras hipóteses incluem a presença de estrelas gigantes existentes no interior da nuvem, ou, menos provavelmente, objectos jovens entre nós e Corona Australis. Calculámos uma taxa de contaminação de 90%, o que significa que esperamos confirmar cerca de 30 anãs castanhas jovens com massa no regime planetário. Até agora, foram catalogados ∼ 100 objectos flutuantes de massa planetária, logo as nossas observações espectroscópicas poderão aumentar a amostra destes objectos por ∼ 30%. A preparação para as observações espectroscópicas futuras também é apresentada nesta tese. Estas observações vão ser feitas com o instrumento K-band Multi Object Spectrograph presente no Very Large Telescope. Vão ser executadas na banda H + K e são dispostas em sete campos diferentes que englobam 219 objectos da nossa lista de candidatos. A Exposure Time Calculator do European Space Observatory foi utilizada para determinar a melhor configuração para o número e duração de exposições. O resultado são dez exposições de 120 segundos cada. A combinação do programa KMOS Arm Allocator com a aplicação p2 tool permitiu-nos calcular o tempo total de observação para cada exposição, que resultou em 55 minutos para cada execução totalizando seis horas e vinte-e-cinco minutos de tempo de telescópio

A literature meta-analysis and integrative model

Baptista, G., & Oliveira, T. (2019). Gamification and serious games: A literature meta-analysis and integrative model. Computers in Human Behavior, 92, 306-315. DOI: 10.1016/j.chb.2018.11.030In recent years we have witnessed a growing number of companies and institutions embedding game mechanics and game design techniques in all types of information systems, applications, and services. Following this trend, it is possible to find an increasing number of publications studying these subjects. With this meta-analysis we synthesise and integrate all the earlier literature and information available on gamification and serious games, assessing the current state-of-the-art in the field, filling a literature gap on this subject. We calculated meta-analysis effects from a total of 54 studies and 59 datasets collected from the literature. Attitude, enjoyment, and usefulness are the most relevant predictors of intention to use gamification. Intention, enjoyment, and usefulness are the most relevant predictors of the brand attitude towards gamification. Our results allow us to present a theoretical model that will be of value to future gamification studies.authorsversionpublishe

The impact of negative interest rates on a firm’s financing costs

In this project we want to find out to what extent the adoption of negative interest rates (specifically the Deposit Facility Rate) by the European Central Bank has affected the financing costs of a non-financial firm, providing a real example. We compute two different interest rates – one contracted with the bank (theoretical) and one resulting from the balance sheet and income statement (practical), the former representing what the firm expects to pay over the loan, and the latter encompassing the indirect costs of borrowing – and compare them between periods. We set the break between periods on June 2014, when the European Central Bank cut its Deposit Facility Rate into negative grounds, and find that the contracted interest rate dropped, and the overall interest rate increased, with the increase being caused not only by an increase in risk exposure, but also by a generalized increase in taxes, commissions and fees.Queremos com este projeto descobrir qual o impacto da política de taxas de juro negativas impostas pelo Banco Central Europeu (nomeadamente a taxa de Facilidade Permanente de Depósito) sobre os custos de financiamento numa empresa não financeira. Calculámos duas taxas de juro diferentes – a contratada ao banco (teórica), e uma resultante do balanço e demonstração de resultados (prática), a primeira representando o que a empresa espera pagar sobre o empréstimo, e a segunda que engloba os custos indiretos do financiamento – e comparámo-las entre períodos. A divisão entre períodos é feita em Junho de 2014, altura em que o Banco Central Europeu baixou a sua taxa de Facilidade Permanente de Depósito para valores negativos, concluímos que a taxa contratada desceu, e a taxa prática subiu, sendo esta subida causada não só pelo aumento da exposição ao risco, mas também pelo aumento generalizado de impostos, taxas e comissões

Load Management in a Smart House

Since a couple years ago, studies have been done in order to minimize the energy consumption at home. With that in mind, algorithms were developed to predict the energy consumption at the house and study the behaviour of the loads with the goal of minimizing the energy costs. In this dissertation, the objective was to create a model for the space heating and water heating and study their behaviour and adjust their load model to reduce the energy consumption and energy bill, and find the best energy tariffs for each case.The models consider physical parameters of the house , so the model can be a better approximation from reality.However, the problem is not only, a Energy and bill reduction, but the algorithm has to focus on the comfort of the house habitants too.Since a couple years ago, studies have been done in order to minimize the energy consumption at home. With that in mind, algorithms were developed to predict the energy consumption at the house and study the behaviour of the loads with the goal of minimizing the energy costs. In this dissertation, the objective was to create a model for the space heating and water heating and study their behaviour and adjust their load model to reduce the energy consumption and energy bill, and find the best energy tariffs for each case.The models consider physical parameters of the house , so the model can be a better approximation from reality.However, the problem is not only, a Energy and bill reduction, but the algorithm has to focus on the comfort of the house habitants too

Energy and Environmental Impacts of Potential Application of Fully or Partially Electric Propulsion Vehicles: Application to Lisbon and São Miguel, Portugal

AbstractThe transportation sector has been one of the fastest growing sectors resulting in a high final energy consumption in Portugal (40% in 2011), with road transportation sector being responsible for 82% of that energy consumption. As a result, alternative vehicle technologies such as electric vehicles are becoming increasingly important since they may contribute to greater energy efficiency. However, their electric autonomy limitations influence the mobility paradigm, making their acceptance dependent on the location and context of driving. Thus, the objective of this study was to characterize mobility patterns and compare the potential application of fully or partially electric propulsion vehicles in two different Portuguese contexts: the Lisbon region (city pattern) and the Island of São Miguel, Azores, Portugal (rural pattern). This characterization was performed by on road monitoring of 9 drivers in Lisbon and 17 drivers in Sao Miguel. São Miguel drivers are those which have a more suitable pattern for using alternative vehicles comparably to the Lisbon region, since they travel about 47% less than the Lisbon population (33 km daily compared to 62 km per day) and, consequently, having a charging time availability about 30% higher. The São Miguel population also has greater presence in lower vehicle specific power (VSP) modes, with an average speed 25% lower than the Lisbon population. São Miguel drivers present greater efficiency in electricity consumption per kilometer (25% more efficient) than the Lisbon sample. Finally, the impacts of using alternative vehicles were quantified, concluding that the alternative technologies would reduce the Well-to-Wheel (WTW) energy consumption per kilometer between 37% and 68%

Noble metal nanoparticles applications in cancer

Nanotechnology has prompted new and improved materials for biomedical applications with particular emphasis in therapy and diagnostics. Special interest has been directed at providing enhanced molecular therapeutics for cancer, where conventional approaches do not effectively differentiate between cancerous and normal cells; that is, they lack specificity. This normally causes systemic toxicity and severe and adverse side effects with concomitant loss of quality of life. Because of their small size, nanoparticles can readily interact with biomolecules both at surface and inside cells, yielding better signals and target specificity for diagnostics and therapeutics. This way, a variety of nanoparticles with the possibility of diversified modification with biomolecules have been investigated for biomedical applications including their use in highly sensitive imaging assays, thermal ablation, and radiotherapy enhancement as well as drug and gene delivery and silencing. Here, we review the available noble metal nanoparticles for cancer therapy, with particular focus on those already being translated into clinical settings.publishersversionpublishe

Mobile banking and mobile payment acceptance

A thesis submitted in partial fulfillment of the requirements for the degree of Doctor in Information Management, specialization in Information and Decision SystemsTechnological advancements registered in the last three decades have revolutionized the financial industry, promoting major changes in the financial services provided. The spread of Internet-enabled phones, smart phones and tablets combined with fast and reliable communications networks, have encourage banks and service providers to provide a new set of self-service banking applications to mobile devices. These facts combined with the globalisation of business and systems are reinforcing the need to acquire a deeper understand on the impact of the acceptance of mobile services. With this dissertation we intend to contribute to a better understanding of the determinants of mobile banking and mobile payments services acceptance and use, at individual level. For this reason we developed a total of five different studies; four about mobile banking and one about the mobile payment. We started in chapter two with a mobile banking literature weight and meta-analysis. The impact of culture in the mobile banking acceptance in an African developing country is analysed in chapter three, trying to better identify how culture influences individual use behaviour. In chapter four we study the mobile payment, trying to identify the direct and indirect effects on the determinants of adoption and the intention to recommend this technology. In chapter five we return to mobile banking, intending to identify the potential impact of the utilization of game mechanics and game design techniques in the acceptance of these services. In the fifth and last study, presented in chapter six, we analyse data from three different countries in three distinct continents, combining acceptance with trust and risk, simultaneously capturing success and resistance factors towards mobile banking intention and use behaviour. In epistemological terms, we adopted a posture characteristic of positivism. With regard the theoretical framework, besides the weight and meta-analysis study, we use the extended unified theory of acceptance and use of technology (UTAUT2) (Venkatesh et al., 2012) in all the studies; namely combining it with (i) cultural moderators (Hofstede, 1980) in the third chapter, (ii) the innovation characteristics of the diffusion of innovations (DOI) (Rogers, 2003), the perceived technology security, and the intention to recommend constructs in the fourth chapter, (iii) a gamification impact construct in the fifth chapter, and (iv) trust and risk model (Bélanger & Carter, 2008) in the sixth chapter. This work provides several contributions for research and practice, contributing to the advancement of knowledge, exploring and discussing direct implications for banks, financial institutions, service providers, service managers, IT and marketing departments, users, and researchers. The innovative models that we use in our work combine the strengths and constructs from well-known theoretical models, providing a solid foundation to our studies. In summary, considering all studies and datasets used, the intention best drivers were (i) habit, found significant in three studies and five datasets and (ii) performance expectancy, found significant in all five studies and in six datasets, and in the use best drivers were (i) habit, found significant in three studies and five datasets and (ii) intention, found significant in two studies. Considering the studies individually, collectivism, uncertainty avoidance, short term, and power distance were found to be the most significant cultural moderators, providing new insights into factors affecting the acceptation and how culture influences individual use behaviour. In terms of mobile payment, the relevance of customer’s intention to recommend mobile payment technology in social networks and other means of communication was confirmed, supporting the recommendation to include it in social marketing campaigns and in future technology adoption studies. A direct and strong relationship between gamification and intention was also confirmed, showing that, when used and designed properly, gamification can help make banking activities more exciting, more interesting, and more enjoyable, and in turn increase customer acceptance, engagement and satisfaction. From the multi-group analysis between countries additional results were found, supporting services customization and marketing campaigns adaptations accordingly. For the intention to use mobile banking, (i) performance expectancy is a more important factor for Portuguese than Brazilian users, (ii) hedonic motivation is a more important factor for Mozambican users than Portuguese or Brazilian ones, and (iii) price value is significant and more important for Mozambican than Portuguese users. For the use behaviour, (i) behavioural intention is a more important factor for Mozambican than Portuguese or Brazilian users and (ii) the facilitating conditions is a more important factor for Mozambican than Portuguese or Brazilian users. A theoretical model based in the best intention and use predictors found in literature is presented, from the weight and meta-analysis’ results, supporting further and future studies in this area

Gestão sustentável de fluxos de passageiros num corredor interurbano através de soluções inteligentes de tarifário

O sistema de transportes é um dos principais emissores de GEE. Em sentido da neutralidade carbónica e do combate às alterações climáticas, este trabalho propõe uma metodologia, para o desenvolvimento de um sistema de apoio com foco na otimização de preços, quer das portagens, quer dos sistemas de transportes públicos, que assenta na internalização das externalidades do transporte ferroviário e rodoviário no corredor interurbano Aveiro - Coimbra, nomeadamente os GEE (CO₂), poluentes atmosféricos (NOₓ) e o congestionamento. A internalização é feita através dos rendimentos do Estado, sendo que são, no final, apresentadas duas propostas de melhoria. Sendo uma mais assente no ponto de vista dos transportes públicos sugerindo uma redução tarifária e de seguida verificar qual será o seu efeito no mercado através da alteração da procura, por exemplo, ao considerar com esta abordagem um valor de elasticidade de 0,332, são feitas várias iterações de redução do valor da tarifa do comboio em 25 % até obter um valor mínimo para a tarifa do comboio. Na outra abordagem foi feita a eliminação da portagem na autoestrada A1 e foi verificado o impacto desta decisão. Os resultados em cada solução são diferentes ao nível das emissões, externalidades, custos dos utilizadores e receita do Estado. Na primeira abordagem o impacto calculado foi uma redução no total das externalidades de 45 % na autoestrada e de 62 % na nacional. A nível das emissões obteve-se uma redução de emissões de CO₂ entre os 3 % e os 5 % e no NOₓ obteve-se uma variação entre os −1 % e os 2 % na autoestrada dependendo se se considera um veículo a diesel ou a gasolina. No IC2 registou-se uma redução entre os 1 % e os 15 % em todos os poluentes. A nível dos custos percecionados pelos utilizadores, registou-se uma redução entre os 8 % e os 17 % dependendo se o veículo é a diesel ou a gasolina, ou se circula na autoestrada ou no IC2, e obteve-se também uma redução entre os 26 % e os 30 % do ponto de vista da receita do Estado e/ou do concecionário das autoestradas. Para a ferrovia a nível das externalidades existe um aumento na ordem dos 160 % e uma diminuição dos custos dos utilizadores na ordem dos 10 %. Para a abordagem alternativa, registou-se um aumento no total das externalidades entre os 9 % e os 11 %, dependente se é na autoestrada ou na estrada nacional, respetivamente. A nível de emissões obteve-se um aumento em relação ao CO₂ na ordem de 1 % e uma redução entre os 1 % e os 3 % nas emissões de NOₓ. A nível dos custos pressentidos pelos utilizadores, registou-se uma redução de 12 % quer para um veículo a diesel como a gasolina na autoestrada; no IC2 regista-se uma diminuição de 17 % quer seja um veículo a diesel ou a gasolina. Do ponto de vista da receita do Estado ou do concecionário das autoestradas existe uma redução de 17 % na autoestrada A1, no IC2 obteve-se um aumento de 8 %. Para concluir, pode-se afirmar que a primeira abordagem é aquela que leva a uma redução generalizada das externalidades e emissões.The transport system is one of the main GHG emitters. In the sense of carbon neutrality and the fight against climate change, this paper proposes a methodology for the development of a support system focused on price optimisation, both for tolls and public transport systems, which is based on the internalisation of externalities of rail and road transport in the aveiro-coimbra long-distance corridor, namely GHGs (CO₂), pollutants (NOₓ) and congestion. The internalization is done through the income of the State, and two proposals for improvement are presented in the end. Being a more based on the point of view of public transport suggesting a reduction of tariff and then verifying what will be its effect on the market by changing demand, for example, when considering with this approach a value of elasticity of 0.332, several iterations are made to reduce the value of the train fare by 25 % until you get a minimum value for the train fare. In the other approach, the toll was eliminated on the A1 motorway and the impact of this decision was verified. The results in each solution are different in terms of emissions, externalities, user costs and state revenue. In the first approach the calculated impact was a reduction in total externalities of 45 % on the highway and 62 % on the national highway. Emissions were reduced by CO₂ between 3 % and 5 % and at NOₓ there was a variation between −1 % and 2 % on the freeway depending on whether you consider yourself a diesel or gasoline vehicle. In IC2 there was a reduction between 1 % and 15 % in all pollutants. In terms of the costs perceived by users, there was a reduction between 8 % and 17 % depending on whether the vehicle is diesel or gasoline, or if it circulates on the motorway or IC2, and there was also a reduction between 26 % and 30 % from the point of view of state and/or highway design. For the railway at the level of externalities there is an increase in the order of 160 % and a decrease in user costs in the order of 10 %. For the alternative approach, there was an increase in total externalities between 9 % and 11 %, depending on whether it is on the highway or on the national highway, respectively. Emissions increased from CO₂ in the order of 1 % and a reduction between 1 % and 3 % in NOₓ emissions. In terms of user-related costs, there has been a 12 % reduction for either a diesel vehicle such as petrol on the motorway; in IC2 there is a decrease of 17 % whether it is a diesel or gasoline vehicle. From the point of view of state revenue or the highway design, there is a 17 % reduction on the A1 motorway, an increase of 8 %. In conclusion, it can be said that the first approach is one that leads to a widespread reduction in externalities and emissions.Mestrado em Engenharia Mecânic

Portuguese health care providers’ knowledge, attitudes, and acceptability of HIV pre-exposure prophylaxis

Introduction: Evidence shows that pre-exposure prophylaxis (PrEP) is highly effective in preventing sexually acquired human immunodeficiency virus (HIV) infection. Whilst its implementation is limited to the US and some countries where demonstration projects have taken place, PrEP has recently been introduced in Portugal. Successful implementation of PrEP requires actively engaging and involving of health care providers (HCP) in Portugal, yet little is known about their knowledge, attitudes, and acceptability towards this novel intervention. Material and methods: An online survey of convenience-sampled Portuguese HCP was conducted in January 2016, prior to PrEP implementation, to determine their knowledge, attitudes, practices, and acceptability of PrEP. Results: A total of 96 respondents nationwide took part in the study, of whom the majority were females (60.3%), specialist physicians/junior doctors (39%/53%), working in the field of HIV for 1 to 5 years (42.3%). Over half (51%) considered having an average or high knowledge of PrEP, and this was more common amongst infectious diseases specialists. Major concerns regarding PrEP implementation included a rise in sexually transmitted infections and increased antiretroviral resistance. Despite only 31.3% being asked about PrEP in the future, the majority (75%) considered that PrEP should be made available in Portugal. The main barrier to PrEP implementation was the lack of knowledge and information to HCP. Conclusions: Portuguese HCP demonstrated variable degrees of knowledge around PrEP, yet most would support its introduction in the country. Concerns were raised about potential consequences of PrEP roll out as well as implementation challenges that ought to be addressed before PrEP introduction.info:eu-repo/semantics/publishedVersio