Browsing by Issue Date, starting with "2022-10-18"
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- A influência dos tweets de Elon Musk no retorno das ações da Tesla: um estudo de eventosPublication . Alves, Joana Beatriz Pinto; Cunha, António Manuel Pereira RodriguesTechnological progress in recent decades has brought a new reality and changed the way people contact each other. That revolution was essentially marked by the introduction and subsequent affirmation of social networks, which spread among the population like a pandemic. These initially took on a strictly personal character. However, they quickly began to be seen as a professional channel. Among the numerous advantages for the entities, the ease with which any information is dispersed worldwide stands out. It is therefore a tool that has quickly established itself in the business world, especially among the most visible CEOs. The notoriety of this medium of information communication has led to several questions being raised regarding the influence of interactions on stock prices. Often, this hypothesis is raised about Elon Musk, CEO of Tesla, for his influence on the medium and the way he interacts on the social network Twitter. Using the Events Study methodology, it was feasible to ascertain its impact.It was not possible to reject the hypothesis that Elon Musk's tweets had no impact on Tesla stock price returns.
- Impacto das práticas de corporate governance na estrutura de capital das empresas cotadas na Euronext Lisbon: o efeito moderador da diversidade de géneroPublication . Torres, Catarina Filipa Oliveira; Machado, Ricardo André Cabral de Carvalho BahiaThe intrinsic role that corporate governance practices may play in the constitution of decisions related with the capital structure of companies is a relevant factor for the success of an organization. As such, the main objective of this work is to investigate the direct relationship between corporate governance practices and debt decisions of Portuguese companies listed on Euronext Lisbon, as well as to investigate whether the previous relationship is affected by the existence of a moderating effect of gender diversity. To carry out this study, a panel database of 36 Portuguese companies listed on Euronext Lisbon was collected, for a period between 2015 and 2020. In order to analyze the purpose of this study, several econometric models were formulated, until the most adequate model, the Fixed Effects model, was obtained. The results show that all the explanatory variables of the study, such as board size, independence of administracion board and CEO duality, have a significant influence on the debt decisions of Portuguese listed firms. Moreover, the results indicate that the impact that board independence has on firms' debt level changes from positive to negative under conditions of a high level of gender diversity. This paper contributes to help companies introduce and contextualize new practices that lead to better governance and help them attract better resources to achieve an optimal capital structure. It’s also, to our knowledge, the first study to analyze the effect of the moderating role of gender diversity on the relationship between corporate governance and capital structure for Portuguese listed companies.
- TEM study of the oxidation resistance and diffusion processes in a multilayered TiSiN/TiN(Ag) coating designed for tribological applicationsPublication . Bondarev, Andrey; Al-Rjoub, Abbas; Bin Yaqub, Talha; Polcar, Tomas; Fernandes, FilipeThis work investigates the structure evolution of a multilayered TiSiN/TiN(Ag) coating with heating, oxide scale growth, diffusion processes occurring during oxidation, and changes in the structure and chemical composition of the non-oxidized zone. The coatings have a multilayered structure with a bilayer periodic thickness of ~40 nm. The TiN(Ag) layer consists of fcc TiN and Ag crystalline phases, where Ag nanocrystallites are homogenously distributed at the TiN grain boundaries. The TiSiN layer consists of fcc Ti–Si–N solid solution grains and an amorphous a-SiNx phase which segregates at the Ti–Si–N grain boundaries. In-situ hot-XRD analysis shows that the first signs of oxidation occur at 800 ◦C, when rutile-TiO2 starts to form. The oxidized part of the coating is Ag depleted, except the top layer terminating the structure, which contains some 1–3 nm Ag clusters. Ag diffuses towards the surface from oxidized zones. The cross-sectional analysis also shows no signs of recrystallization and structural changes, except for stress relaxation in the non-oxidized part after annealing at 800 ◦C. No Ag redistribution or diffusion is found in the non-oxidized part, even close to the interface with the oxide layer, which suggest effectiveness of the multilayered design to mitigate uncontrolled Ag migration towards the surface.