Stresse e competências psicológicas : estudo com jovens atletas

Orientação: Ângela LeiteO presente estudo, de caráter exploratório, objetiva conhecer e compreender as relações e interações entre as competências psicológicas e os processos de avaliação cognitiva na emergência e na resposta de stresse aos estímulos e situações do contexto desportivo. 107 jovens atletas do sexo masculino, com idades compreendidas entre os 10 e os 16 anos, de diversas modalidades e escalões competitivos, participaram no presente estudo. A todos os participantes foi administrado um protocolo de avaliação psicológica que incluía: Questionário Sociodemográfico e Desportivo, Inventário de Competências Psicológicas para o Desporto e Escala de Avaliação Cognitiva da Competição Desportiva – Perceção de Ameaça. Os resultados do estudo demonstraram que as competências psicológicas desempenham um papel importante na avaliação cognitiva de ameaça, uma vez que, as competências psicológicas evidenciaram estar negativamente correlacionadas com a perceção de ameaça e também revelaram predizer negativamente os níveis de perceção de ameaça experienciados pelos jovens atletas durante a competição desportiva. O estudo contribui para a identificação dos principais conteúdos de perceção de ameaça em jovens atletas, bem como para a identificação das principais dificuldades apresentadas ao nível das competências psicológicas. Por último, este estudo evidenciou a existência de diferenças nas competências psicológicas em função da modalidade praticada, da idade de início da prática da modalidade e das horas semanais de prática desportiva. Desta forma, o estudo permitiu concluir quanto à importância das relações e interações entre diversas variáveis e processos psicológicos interdependentes na explicação da experiência de stresse em contextos desportivos. A informação disponibilizada no presente estudo pretende contribuir para a implementação de intervenções psicológicas mais eficazes na redução dos níveis de stresse experienciados pelos jovens atletas.This exploratory study aims to know and understand the relationships and interactions between psychological skills and cognitive appraisal processes in emergency and stress response to stimuli and situations in the context of sports. 107 young male athletes , aged between 10 and 16 years, of different competitive levels and sport modalities , participated in the study. A psychological assessment protocol was applied to all participants which included: Sociodemographic and Sports Survey, Psychological Skills Inventory for Sports and Cognitive Appraisal Scale in Sport Competition – Threat Perception. The results of the study demonstrated that psychological skills play an important role in cognitive appraisal of threat, since psychological skills seem to be negatively correlated with threat perception and they also seem to negatively predict the perception threat levels experienced by young athletes during sport competition. The study contributes to the identification of the main contents of threat perception in young athletes, as well as to identify the main difficulties presented at the level of psychological skills. Finally, this study showed the existence of differences in psychological skills depending on the practiced sport modality, the age of onset of the practice modality and the weekly hours of sports. Thus, the study allowed to conclude upon the importance of relationships and interactions between different variables and interdependent psychological processes in explaining the stress experience in the context of sports. The information available in the present study aims to contribute to the implementation of more effective psychological interventions in reducing stress levels experienced by young athletes

Diplomacy in the Fifteenth-Century Monarchical State: A Baronial Pursuit? (Portugal, 1416-1449)

En 1438 Pedro, duque de Coimbra, era el segundo en la línea de sucesión al trono portugués. La muerte de su hermano mayor Duarte había dejado la corona vacante y Pedro, un poderoso magnate de mediana edad fue elegido como regente del hijo de Duarte, Alfonso, el niño de seis años sobre quien recaía el reinado. Primero como corregente y después en solitario, Pedro gobernó Portugal y sus élites durante una década marcada a veces por la satisfacción y a veces por la agitación, así como por las luchas cortesanas entre facciones aristocráticas. En 1449, entre acusaciones de lesa majestad y de favorecer a su propia persona, Pedro encontraría un amargo final en el campo de batalla, a manos de su joven sobrino, el rey Alfonso V, igualmente manipulado por una influente camarilla de enemigos del regente. El artículo examinará la actuación de Pedro de Coimbra y de algunos de sus hombres durante su carrera política (c. 1416-1449), particularmente la de aquellos empleados como «diplomáticos» en el extranjero. Se trazarán tres etapas diferentes en la trayectoria de Pedro –como infante, como consejero del rey y finalmente como regente del reino portugués– para conocer hasta qué punto un magnate destacado del siglo XV podía proyectar su influencia política en colaboración, o contra, el poder real. Finalmente, el artículo destaca la coexistencia, y también la superposición, entre las ambiciones diplomáticas reales y no reales y las tensiones y desafíos que causaban en la política y la diplomacia de Portugal durante dicho período.In 1438 Pedro, Duke of Coimbra, was second-in-line to the Portuguese throne. The death of his elder brother Duarte had left the royal seat vacant and Pedro, a middle-aged, powerful magnate was elected as regent for Duarte’s son Afonso, the boy of six to whom the crown fell. First as the coregent and then single-handedly, Pedro governed over Portugal and its elites during a decade marked in turn by contentment and upheaval, as much as by courtly struggles between aristocratic factions. In 1449, amidst accusations of lese-majesty and of favouring his own, Pedro would meet a bitter end in the field of battle, at the hands of his young nephew, King Afonso V, seemingly manipulated by an influential clique of enemies to the regent. This paper will examine Pedro of Coimbra and some of the men surrounding him during his political career (c. 1416 to 1449), in particular those employed as «diplomats» in foreign service. It will trace three different stages in Pedro’s trajectory — as a prince in the making, as the king’s counsellor, and finally as regent of the Portuguese kingdom — in order to question the extent to which a leading magnate of the fifteenth century was able to project his political influence in tandem with, or in reaction to, royal power. Ultimately, the paper highlights the co-existence, and indeed the overlap, between royal and non-royal diplomatic ambitions and the strains and challenges that it caused in the politics and diplomacy of Portugal in this period

Evaluating Recommender Systems Qualitatively: A survey and Comparative Analysis

Dissertation presented as the partial requirement for obtaining a Master's degree in Data Science and Advanced Analytics, specialization in Business AnalyticsRecommender systems have improved users' online quality of life by helping them find interesting and valuable items within a large item set. Most recommender system validation research has focused on accuracy metrics, studying the differences between the predicted and actual user ratings. However, recent research has found accuracy to underperform when systems go live, mainly due to accuracy’s inability to validate recommendation lists as a single entity, and shifted to evaluating recommender systems using "beyond-accuracy" metrics, like novelty and diversity. In this dissertation, we summarize and organize the leading research regarding the definitions and objectives of the beyond-accuracy metrics. Such metrics include coverage, diversity, novelty, serendipity, unexpectedness, utility, and fairness. The behaviors and relationships of these metrics are analyzed using four different models, two concerning the items characteristics (item-based) and two regarding the user behaviors (user-based). Furthermore, a new metric is proposed that allows the comparison of different models considering their overall beyond-accuracy performance. Using this metric, a reraking approach is designed to improve the performance of a system, aiming to achieve better recommendations. The impact of the reranking technique on each metric and algorithm is studied, and the accuracy and non-accuracy performance of each system is compared. We realized that, although the reranking technique can increase most beyond-accuracy metrics, the accuracy of that system starts to worsen due to the negative correlation between these two dimensions. We also found that item-based models tend to achieve much lower values of coverage and diversity than userbased models

A mortality & longevity study : the portuguese case

Mestrado em Actuarial ScienceEste trabalho foi desenvolvido com três objetivos principais: (i) fazer o survey da situação atual, no que diz respeito à mortalidade/longevidade no nosso país; (ii) desenvolver um estudo breve sobre os progressos registados na mortalidade em Portugal, com base num projeto semelhante apresentado por Assia Billing, no encontro da Primavera do Mortality Working Group da International Actuarial Association (Berlim, 2018) - grupo que se dedica ao estudo da mortalidade a nível mundial, dando particular atenção ao impacto que esta tem sobre o sector segurador, nomeadamente o ramo de Vida e Pensões; (iii) servir como suporte ao primeiro Country Report português, a ser divulgado pelo Mortality Working Group. No decorrer do trabalho, e tendo em vista os três objetivos estabelecidos, irão ser primeiramente analisados indicadores demográficos, como a evolução da população residente portuguesa, a sua pirâmide populacional, o índice de envelhecimento e a esperança de vida. Numa segunda parte, o foco incidirá sobre o sector segurador português, com a análise de indicadores como a produção ou a composição dos portfolios de investimento. Seguidamente, faz-se a análise dos produtos mais vendidos em Portugal, por tipo de contrato. No que diz respeito às tábuas de mortalidade, merecem destaque as que são publicadas anualmente pelo INE, bem como as que são mais utilizadas nas seguradoras que operam no território nacional. Finalmente, desenvolver-se-á a análise dos progressos registados mais recentemente a nível da mortalidade no país, na senda de estudos similares desenvolvidos para outros países.This work was developed with three main objectives: (i) to survey the current situation, regarding mortality/longevity in Portugal; (ii) to develop a brief study on the progress of mortality in the country, based on a similar project presented by Assia Billing in the Spring Meeting (Berlin 2018) of the International Actuary Association Mortality Working Group ? a group that is dedicated to the study of mortality worldwide, paying particular attention to the impact it has on the insurance sector, namely on Life and Pensions ; (iii) to serve as support for the first Portuguese Country Report to be released by the Mortality Working Group,. In the course of the study, demographic indicators, such as the evolution of the Portuguese resident population, the population pyramid, the aging index and the life expectancy, will be analyzed first. Then, the focus will be set on the Portuguese insurance sector, with the analysis of indicators such as the production or the composition of investment portfolios. Next, we analyze Portugal?s mostly sold insurance products, by type of contract. Regarding the mortality tables, it is worth mentioning those published annually by INE, as well as those that are most used by insurers operating in the national territory. Finally, an analysis of the most recent progress in mortality in the country will be performed, following similar studies developed for other countries.info:eu-repo/semantics/publishedVersio

Aplicação de métodos estatísticos em economia e finanças

Dissertação de mestrado em Estatística (área de especialização em Séries Temporais)Neste trabalho são descritos métodos estatísticos para a modelação e previsão de taxas de juro em economia. Concretamente, são usados os modelos ARMA-GARCH, incluindo os modelos sGARCH e IGARCH, para a análise de juros de obrigações emitidas pelo Banco Central Europeu com uma maturidade fixada. Após a seleção do modelo que melhor se adequa aos dados selecionados, é feita a previsão pontual e intervalar. A previsão intervalar é calculada através da técnica de bootstrap. As previsões obtidas sugerem algumas tendências na dinâmica das taxas de juro que podem ser interessantes para os decisores económicos.In this work, statistical methods are described for modelling and forecasting interest rates in economics. In particular, the models ARMA-GARCH are used, including the models sGARCH and IGARCH, for the analysis of the interest rates of bonds emitted by the European Central bank, for a fixed maturity. After choosing the model which best fits the data, a pointwise and interval forecasting is performed. The interval forecasting is calculated through the bootstrap technique. The forecasts obtained suggest some patterns for the dynamics of interest rates which might be of interest for economic decision-makers

Interactions Between Ultrashort Pulses and Laser-Produced Tin Plasmas

Inside commercial EUV nanolithography sources, micrometer-sized droplets of liquid tin are irradiated by a high-power CO2 laser, creating a plasma which emits the desired 13.5 nm light. However, small dense liquid spheres are an inefficient target shape for EUV production. To solve this, each droplet is irradiated by two laser pulses. Firstly, a low-energy pre-pulse irradiates the initially-spherical droplet, deforming it via hydrodynamic expansion into a shape more favourable for EUV production. Afterwards, a time-delayed high-energy main pulse irradiates this deformed droplet. Typically, pre-pulses with nanosecond durations are used to deform the target from a sphere into a thin disk. An alternative approach involves using pre-pulses with picosecond or femtosecond durations. These shorter pulses create an intense shock wave on the droplet surface, which propagates through the droplet focusing at its center, where a bubble is formed through a process called cavitation. This bubble rapidly expands, rupturing the droplet, which then breaks up into fine particles. These “cloud” targets have in some cases shown higher conversion efficiencies than disk targets, with the drawback of additional debris created by the violent transformation process. To study the dynamics of cloud targets, we designed and built a laser system capable of producing laser pulses with durations ranging from 220 fs to 100 ps. The system includes a 1064 nm source based on Nd:YVO4 and Nd:YAG, producing pulses with durations between 15 and 100 ps and energies of up to 180 mJ. This system can be used as a standalone source or as a pump for a 1.55 μm KTA-based optical parametric chirped pulse amplifier, producing pulses with durations from 220 fs to 10 ps, with energies up to 10.5 mJ. Ultrashort mJ-level pulses from the OPCPA were used to study the effects of pulse energy and duration on microdroplet deformation. The velocities of the cavitation expansion and of the ablated material are found to decrease for longer pulses, indicating shorter pulses lead to faster, more violent dynamics. Using linearly-polarized pulses, cylindrically-asymmetric shock waves were produced, leading to novel asymmetric target shapes which show good qualitative agreement with smoothed-particle hydrodynamics simulations, highlighting the role of shock waves in the laser-driven deformation dynamics. Charge-state-resolved ion energy spectra were recorded using an electrostatic analyzer to study the processes that shape the energy of the ions emitted by the plasma. For lower laser energies we observe a linear relation between the mean ion energy of each charge state and its ionization number, a trend consistent with the typical electrostatic-driven ion acceleration model. For higher laser energies this relation becomes nonlinear, hinting at effects beyond the simple electrostatic acceleration model. Using the 1064 nm amplifier to irradiate droplet targets with a pair of 50-ps laser pulses, comprising a weaker first pulse with variable energy in the μJ range followed by a more energetic 5 mJ pulse, we produced novel target shapes which were keenly dependent on the energy of the first pulse and the time delay between the pulses. Furthermore, the addition of a small first pulse led to a significant reduction in the kinetic energy of the ions emitted by the plasma, with a 30-fold reduction in the most extreme case. Charge-state-resolved measurements show a reduction of ion kinetic energy for every charge state and a pronounced reduction in the yield of higher-charge-state ions, which are the most energetic. In certain pulse-pair configurations, it becomes possible to completely suppress higher charge states above Sn2+. This suppression of faster ions holds practical significance in extending the lifetime of optical components inside EUV sources when paired with ion mitigation techniques which are most effective for lower-energy ions

Fostering Innovation by Promoting Entrepreneurship: From Education to Intention

AbstractIn the past decades, entrepreneurship has become one of the top concepts in the business field. Its relevance has increased since 2009 due to the global economic crisis. The literature associates entrepreneurship with the ability to innovate and create new products, services and projects, whether considering entrepreneurship as a new business initiative or as an innovation and marketing practice within organizations.Despite its relevance, there is no empirical evidence on the enabling factors of entrepreneurship and their contribution to the development of a marketing innovation centered culture. Our model therefore identifies these enabling factors. The data gathered covers four countries: names. I test the framework, keeping in mind each country has its own national education policies.The findings indicate that entrepreneurship education is common in three of the four countries and therefore is a main contributor to entrepreneurial intention. Moreover, there were no distinguishing in propensity regarding age and gender, but the combined country and education affects entrepreneurship propensity. Our analysis poses questions that will guide future paths of research

Importance of size-selective particle measuring for assessing occupational exposures: a case study “from field to fork”

Sampling the total air concentration of particulate matter (PM) only provides a basic estimate of exposure that normally not allows correlating with the observed health effects. Therefore is of great importance to recognize the particles size distribution and, particularly, the exposure to fine particles (≤ 2.5 μm). This particles dimension corresponds to the respirable fraction, the one that can implicate local and systemic effects due to particle deposition and clearance from the lungs and transport within the organism. This study intended to describe occupational exposure to PM2.5 in three units related with swine production and consumption, namely: feed production, swine production and swine slaughterhouse. A size-selective particle measuring in five to six workplaces of each unit was performed. Measurements of PM were done using a portable direct-reading hand-held equipment (Lighthouse, model 3016 IAQ). Data showed slaughterhouse unit with higher values, with values ranging from 0.030 to 0.142 mg/m3 (0.073 + 0.043), being the cutting room the workplace with higher values. In feed production unit, values were between 0.026 and 0.033 mg/m3 (0.028 + 0.003) with the warehouse of pharmacy products as the workplace with higher values. Finally, in swine unit values ranged from 0.006 to 0.048 mg/m3 (0.023 + 0.017) with the batteries area presenting the higher values. PM can be rich in fungi and bacteria and their metabolites, such as endotoxins and mycotoxins. Previous publications already showed high contamination in these occupational settings and particles can have an important role in exposure since can easily act as carrier of these agents. Data acquired allow not only a better prediction of particle penetration into respiratory regions of the respiratory tract, but also a better estimation of PM health effects. Moreover, data permit to identify the workplaces where investment should be made to prevent and reduce exposure

Stress e Engagement em situações de pressão. O caso do Centro de Tropas Comandos

A saúde mental dos subordinados é cada vez mais uma preocupação dos comandantes. É neste pressuposto que assenta esta investigação, mais especificamente, nos assuntos relacionados com o stress, engagement, felicidade subjetiva e desempenho. Posto isto, decidimos focalizar o nosso estudo em dois cursos de Comandos e em militares comandos que se encontram no ativo perfazendo um total de 144 militares participantes no estudo. Estes militares responderam a um inquérito por questionário com o objetivo de perceber qual o impacto do curso de Comandos nos militares em estudo e em particular nos níveis do stress, engagement, felicidade subjetiva e desempenho por eles sentidos. Verifica-se que os militares que terminaram com sucesso o curso de Comandos apresentavam níveis mais altos de vigor e dedicação e níveis mais baixos de preparação militar no momento em que iniciaram o curso do que no final. É também possível perceber que os militares que terminaram com sucesso o curso apresentavam níveis mais altos de vigor e dedicação que os militares que desistiram do curso. No decorrer do nosso estudo verificou-se ainda a existência de relações baixas e moderadas mas com níveis de significância aceitáveis da variável stress com o vigor, dedicação, absorção, felicidade e preparação militar. Não poderia ser descorado do nosso estudo o rendimento dos militares tendo em vista perceber como o poderíamos aumentar, assim verificamos que existem relações moderadas do rendimento militar com o vigor, dedicação, absorção e preparação física. O comandante é a pessoa que mais se preocupa com o bem-estar dos seus subordinados. Com base neste pressuposto decidimos incluir também no nosso estudo a variável felicidade podendo concluir-se que se relaciona a um nível moderado/alto com o vigor, dedicação, absorção, rendimento militar e preparação física.Abstract The mental health of the subordinates is increasingly a concern of commanders. This investigation lies on that assumption, more specifically, on issues related to stress, engagement, happiness and performance. That said, we have decided to focus our study on two Comando courses and on comando soldiers still in active duty, in a total of 144 soldiers taking part in our study. These soldiers answered a questionnaire survey that aimed to understand the impact of the Comando course on the soldiers in question, and the level of stress, engagement and subjective happiness and performance they felt. We have found that the soldiers who have successfully completed their Comando course showed higher levels of vitality and dedication, and lower levels of military preparedness at the time they started the course than at the end. We have also realized that those who successfully completed the course showed higher levels of vitality and dedication than those who dropped out. In the course of our study, we also found low and moderate level relationships, but with acceptable levels of the variable stress, with vitality, dedication, assimilation, happiness and military preparedness. Our study could not have ignored the yield of soldiers since our aim was also to find ways of increasing it. We have found evidence that military yield is moderately related to vitality, dedication, assimilation and physical condition. Based on the assumption that the commander is the person who cares most about the well-being of its subordinates, we have decided to include in our study the variable happiness. We can conclude that the relationship between this variable and vitality, dedication, assimilation, military yield and physical condition is moderate/high

Integration in MASCEM of the Joint Dispatch of Energy and Reserves Provided by Generation and Demand Resources

The provision of reserves in power systems is of great importance in what concerns keeping an adequate and acceptable level of security and reliability. This need for reserves and the way they are defined and dispatched gain increasing importance in the present and future context of smart grids and electricity markets due to their inherent competitive environment. This paper concerns a methodology proposed by the authors, which aims to jointly and optimally dispatch both generation and demand response resources to provide the amounts of reserve required for the system operation. Virtual Power Players are especially important for the aggregation of small size demand response and generation resources. The proposed methodology has been implemented in MASCEM, a multi agent system also developed at the authors’ research center for the simulation of electricity markets