Physical fitness : identifiers of sport participation and bone health in youth

Physical fitness (PF) assessment is a key tool in monitoring sports performance and health indicators in young people, mainly because PF is related to indicators of both sporting potential and performance, used in signalization, recruitment and surveillance, and bone health. Therefore, this tool may be considered of valuable use to both sport and health professionals. However, there is not a single standardised protocol able to assess the several attributes of PF among young athletes from different sport backgrounds and non-athletes. In this context, this dissertation presents four investigations developed in two major research areas in the evaluation of PF: sports performance and bone health. Regarding sports performance, the reliability of the PF tests, in young athletes from different competitive levels and sports backgrounds were tested. The battery of the FITescola® program proved to be applicable in young athletes of both sexes, constituting a reliable instrument of simple application in the field of sports performance. The discriminatory power of each FITescola® test for signalling young people with sport potential, in consolidated sport organization models, according to gender and age was also analysed. The results showed that PF tests are a valid instrument for signalling young people with sport potential, and that the discriminatory power of the tests varied according to gender and age. In the area of bone health, one investigation was conducted to analyze the relationship between different PF tests and speed of sound (SoS) values in the radius and tibia of young athletes and non-athletes. Different degrees of association were observed between the several PF tests and the radial and tibial SoS values. The degrees of association varied according to gender and athlete status of the participants. The results of this investigation indicate that, for the purpose of monitoring bone health, different PF tests XIX should be applied depending on whether or not young people were athletes. Another analyzed, for the first time, the relationship between vigorous physical activity and SoS in the radius and tibia and whether this relationship was mediated by different PF tests and fatness. The results suggested that some of the effects of vigorous physical activity on radial and tibial SoS were mediated by cardiorespiratory fitness in girls, while the upper and lower muscle strength, speed of displacement and fat mass (%) were found to be mediators in boys. The mediating effect of a PF tests and fat mass (%) on the association of vigorous physical activity with bone health outcomes differed between boys and girls. In summary, this dissertation provides observational scientific evidence on the importance and applicability of PF assessment in the context of competitive sport and, simultaneously, for monitoring bone health among young athletes and non-athletes. These findings may be relevant for present and future interventions in competitive sport as well as in public health.A avaliação da aptidão física é um instrumento fundamental para a monitorização do rendimento desportiva e da saúde, principalmente devido ao facto da aptidão física estar associada a indicadores de potencial desportiva, utilizados no processo de sinalização e recrutamento de jovens, bem como a indicadores de saúde óssea. Desta forma, este instrumento pode ser considerado como uma mais-valia para profissionais da área do desporto e saúde. Todavia, não existe um único protocolo estandardizado capaz de avaliar os vários atributos da aptidão física entre jovens atletas de diferentes modalidades e não atletas. No âmbito do rendimento desportivo, foi testada a reprodutibilidade e a fiabilidade dos testes de aptidão física em jovens atletas de diferentes níveis competitivos. A bateria do programa FITescola® demonstrou ser aplicável em jovens atletas de ambos os sexos, constituindo um instrumento fiável de aplicação simples no âmbito do rendimento desportivo. Adicionalmente, foi analizado o poder discriminativo de cada teste do FITescola® para sinalizar jovens com potencial desportivo, em função do sexo e da idade. Os resultados demonstraram que os testes de aptidão física são um instrumento válido para a sinalização de jovens com potencial desportivo e que o poder discriminatório dos testes variou de acordo com o sexo e a idade. Na área da saúde óssea, foi conduzido uma investigação para analisar a relação entre os diferentes testes de aptidão física e os valores da velocidade do som no rádio e na tíbia, em jovens atletas e não atletas. Os graus de associação variaram em função do sexo e da condição de atleta dos participantes. Os resultados desta investigação indicam que, para efeitos de monitorização da saúde óssea, diferentes testes de aptidão física devem ser aplicados, em função da condição de atleta. Outra XXI investigação analisou, pela primeira vez, a relação entre a atividade física vigorosa e a velocidade do som no rádio e na tíbia, e se esta relação era mediada por diferentes testes de aptidão física e pela massa gorda (%). Os resultados sugerem que nas raparigas, uma parte dos efeitos da atividade física vigorosa na velocidade do som no rádio e na tíbia ere mediada pela aptidão cardiorrespiratória, enquanto, nos rapazes, a força muscular superior e inferior, a velocidade de deslocamento e a massa gorda (%) foram identificados como mediadores desta relação. A presente dissertação fornece evidência científica observacional sobre a importância e aplicabilidade da avaliação da aptidão física tanto no contexto competitivo, como na monitorização da saúde óssea em jovens atletas e não atletas. Estes resultados podem ser relevantes para intervenções presentes e futuras no âmbito do desporto de competição e da saúde pública

The unphysical character of dark energy fluids

It is well known that, in the context of general relativity, an unknown kind of matter that must violate the strong energy condition is required to explain the current accelerated phase of expansion of the Universe. This unknown component is called dark energy and is characterized by an equation of state parameter $w=p/\rho<-1/3$. Thermodynamic stability requires that $3w-d\ln |w|/d\ln a\ge0$ and positiveness of entropy that $w\ge-1$. In this paper we proof that we cannot obtain a differentiable function $w(a)$ to represent the dark energy that satisfies these conditions trough the entire history of the Universe.Comment: 8 pages, 1 figur

Understanding the role of influencers’ credibility in social media and its impact on consumers’ purchase intentions

Digital media and the internet, in particular, have developed into a massive vehicle for consumer-generated communications. In these contexts, consumers are no longer only passive subjects in the marketing exchange process. Else than consuming content, they increasingly create, share and distribute information to other consumers through digital platforms. The fast growth of social media over the last decades has boosted the adoption of influencer marketing. This type of marketing brought companies new opportunities to expose themselves and strengthen relationships with customers. However, there is some lack of knowledge regarding the drivers that influence the effects of the influencer. In this sense, the current dissertation intents to understand how the characteristics of digital influencers, concerning various dimensions of credibility, affect the consumers' purchase intentions, comparing low and high product involvement. The present study was developed in an exploratory and quantitative way, in which a survey was conducted with 1924 valid responses obtained. The final results indicate that, for low-involvement products, all the credibility related characteristics, namely expertise, trustworthiness, attractiveness and popularity, influence consumers' purchasing intentions. Moreover, it was confirmed that an increase in the influencer’s credibility might increase the user’s purchase intentions. Contrarily, for high-involvement products, only trustworthiness and attractiveness affect purchase intentions, and increases in the credibility of the influencer might not have such a significant impact on purchase intentions.Mídia digital e a internet, em particular, transformaram-se num veículo massivo para as comunicações geradas pelos consumidores. Nestes contextos, os consumidores deixaram de ser apenas agentes passivos no processo de troca no marketing. Mais do que consumir conteúdo, eles cada vez mais criam, partilham e distribuem informações através das plataformas digitais. O rápido crescimento das redes sociais nas últimas décadas impulsionou a adoção do marketing de influência. Este tipo de marketing trouxe novas oportunidades para as empresas se exporem e fortalecerem relações com os seus clientes. No entanto, existe alguma falta de conhecimento sobre os drivers que influenciam os efeitos dos influenciadores. Neste sentido, a presente dissertação foi desenvolvida com o intuito de compreender de que forma as características dos influenciadores digitais, no que diz respeito a várias dimensões de credibilidade, afetam as intenções de compra dos consumidores, comparando baixo e alto envolvimento com o produto. O estudo atual foi desenvolvido de forma exploratória e quantitativa, no qual foi realizado um inquérito com 1924 respostas válidas obtidas. Os resultados finais indicam que, para produtos de baixo envolvimento, todas as características relacionadas com a credibilidade, nomeadamente perícia, fidedignidade, atratividade e popularidade, influenciam as intenções de compra dos consumidores. Além disso, foi confirmado que um aumento na credibilidade do influenciador poderá aumentar as intenções de compra dos consumidores. Pelo contrário, para produtos de alto envolvimento, apenas a fidedignidade e atratividade afetam as intenções de compra, e um aumento da credibilidade do influenciador poderá não ter um impacto significativo nas intenções de compra

Event-based tracking of human hands

This paper proposes a novel method for human hands tracking using data from an event camera. The event camera detects changes in brightness, measuring motion, with low latency, no motion blur, low power consumption and high dynamic range. Captured frames are analysed using lightweight algorithms reporting 3D hand position data. The chosen pick-and-place scenario serves as an example input for collaborative human-robot interactions and in obstacle avoidance for human-robot safety applications. Events data are pre-processed into intensity frames. The regions of interest (ROI) are defined through object edge event activity, reducing noise. ROI features are extracted for use in-depth perception. Event-based tracking of human hand demonstrated feasible, in real time and at a low computational cost. The proposed ROI-finding method reduces noise from intensity images, achieving up to 89% of data reduction in relation to the original, while preserving the features. The depth estimation error in relation to ground truth (measured with wearables), measured using dynamic time warping and using a single event camera, is from 15 to 30 millimetres, depending on the plane it is measured. Tracking of human hands in 3D space using a single event camera data and lightweight algorithms to define ROI features (hands tracking in space)

Water vapor pressure deficit in Portugal and implications for the development of the invasive African citrus psyllid trioza erytreae

African citrus psyllid (Trioza erytreae (Del Guercio)) is a vector insect of the bacterium Candidatus Liberibacter africanus, the putative causal agent of Huanglongbing, the most devastating citrus disease in the world. The insect was found on the island of Madeira in 1994 and in mainland Portugal in 2015. Present in the north and center of the country, it is a threat to Algarve, the main citrus-producing region. Trioza erytreae eggs and first instar nymphs are sensitive to the combination of high temperatures and low relative humidity. Daily maximum air temperature and minimum relative humidity data from 18 weather stations were used to calculate the water vapor pressure deficit (vpd) from 2004 to 2018 at various locations. Based on the mean vpd and the number of unfavorable days (vpd < 34.5 and vpd < 56 mbar) of two time periods (February to May and June to September), less favorable zones for T. erytreae were identified. The zones with thermal and water conditions like those observed in the Castelo Branco and Portalegre (Center), Beja (Alentejo), Alte, and Norinha (Algarve) stations showed climatic restrictions to the development of eggs and first instar nymphs of African citrus psyllid. Effective control measures, such as the introduction and mass release of Tamarixia dryi (Waterson), a specific parasitoid, and chemical control are necessary in favorable periods for T. erytreae development, such as in spring and in areas with limited or no climate restrictions.info:eu-repo/semantics/publishedVersio

Monitoring Portugal’s Recovery in the COVID-19 Pandemic and Post-Pandemic Context. A Conceptual Model and Methodology for Monitoring the Economic and Social Recovery

The Research Project 'Monitoring Recovery - Proposal of a Conceptual Model and Methodology for Monitoring the Economic and Social Recovery of Portugal in the COVID-19 Pandemic and Post- Pandemic Context' was carried out by the Public Policy Monitoring Unit [UMPP] of the University of Évora between October 1, 2021 and October 1, 2022 and was funded by the Technical Assistance Operational Program [POAT] of the Partnership Agreement Portugal 2014-2020 [PT2020]. The results achieved by this Research Project are divided into a set of documents and specific studies, which, as a whole and in an integrated manner, aimed to formalise a concrete guidance proposal - albeit conceptual - for the design, operationalization and implementation of a Monitoring System to support pursuit of the 'Portugal 2030 Strategy' and the mix of public policy instruments contributing to its achievement. In this context, a roadmap for action structured around six key components is presented: 1) Definition of Objectives and Scope of the Monitoring System; 2) Mobilization of Stakeholders and Definition of the Governance Model; 3) Systematization of the Public Intervention’s Rationale; 4) Identification of Information Needs; 5) Definition of Indicators and Methods for Information Collection; 6) Design of Communication Products and Dissemination of Results.Funded by the Technical Assistance Operational Program [POAT] of the Partnership Agreement Portugal 2014-2020 [PT2020]

Plantas invasoras no sul de Portugal: uma abordagem biogeográfica

As espécies invasoras são uma das principais ameaças à biodiversidade causando impactes ecológicos, económicos e nos serviços dos ecossistemas. O conhecimento conjunto da dinâmica das séries de vegetação e da ecologia das plantas invasoras é uma ferramenta útil na recuperação ecológica de áreas invadidas e na prevenção de invasões. Este trabalho tem como objectivo principal averiguar a relação entre a distribuição das plantas invasoras e as comunidades vegetais terrestres do Sul de Portugal. Para tal, fez-se corresponder a distribuição de nove plantas invasoras selecionadas com as séries de vegetação e territórios biogeográficos, em 60 quadrículas com 1 Km2. A Província Lusitana-Andaluza Costeira revelou-se a mais invadida, com predomínio de Acacia dealbata, Acacia longifolia e Opuntia maxima no potencial climatófilo de sobreiral psamófilo; A. longifolia dominou no potencial edafoxerófilo de zimbral de Juniperus turbinata e A. dealbata e Arundo donax no potencial edafo-higrófilo de freixial. Com base nos resultados, estabeleceram-se áreas prioritárias para intervenção; INVASIVE PLANTS IN SOUTHERN PORTUGAL A BIOGEOGRAPHICAL APPROACH Abstract: Invasive species are one of the main threats to biodiversity worldwide and are responsible for negative impacts at ecological, economic and ecosystem services level. Complementarity between vegetation series dynamics and invasive plants ecology knowledge is essential to address ecological restoration and to prevent invasions. The main goal of this work is to investigate the relationship between invasive plants distribution and terrestrial plant communities of Southern Portugal. Fieldwork was conducted in 60 1 Km2 sampling plots and a correspondence was made between nine selected invasive plants and the vegetation series and the biogegraphic units The Andalusian-Lusitanian Coastal province was the most invaded biogeographic unit and revealed the dominance of Acacia dealbata, Acacia longifolia and Opuntia maxima in the cork oak psammophilous series; A. longifolia dominated in the maritime turbinate juniper edapho-xerophilous series and A. dealbata and Arundo donax in the ash edaphohygrophilous groves potential. Based on the results, priority areas for intervention were defined