Three essays on the term structure of interest rates

A PhD Dissertation, presented as part of the requirements for the Degree of Doctor of Philosophy from the NOVA - School of Business and Economics

Three essays on the market for CEOs

A PhD Dissertation, presented as part of the requirements for the Degree of Doctor of Philosophy from the NOVA - School of Business and Economics

Three essays on economics of predictability of stock returns

A PhD Dissertation, presented as part of the requirements for the Degree of Doctor of Philosophy from the NOVA - School of Business and Economics

Three essays on game theory and bargaining

A PhD Dissertation, presented as part of the requirements for the Degree of Doctor of Philosophy from the NOVA - School of Business and Economics

Three essays on structural breaks

A PhD Dissertation, presented as part of the requirements for the Degree of Doctor of Philosophy from the NOVA - School of Business and Economics

Mirror on the wall, am I attracting people as beautiful as me?

This paper analyzes whether a company’s image affects its capability of attracting young employees. To do so, the process that leads to the creation of a company’s image by young professionals and the relevance they attribute to companies’ websites were addressed. By using the websites of 20 companies and conducting 12 semi structured interviews near recent graduates, it was possible to conclude that companies and young professionals seek different sources when it comes to form an image of a company and hence, what is perceived by companies as relevant to be communicated, is disregarded by young professionals given its indistinctiveness.

Three essays in risky behaviors

A PhD Dissertation, presented as part of the requirements for the Degree of Doctor of Philosophy from the NOVA - School of Business and Economics

Biological colonization on majolica glazed tiles: biodeterioration, bioreceptivity and mitigation strategies

The impact of microbial activity on the deterioration of cultural heritage is a well-recognized global problem. Glazed wall tiles constitute an important part of the worldwide cultural heritage. When exposed outdoors, biological colonization and consequently biodeterioration may occur. Few studies have dealt with this issue, as shown in the literature review on biodiversity, biodeterioration and bioreceptivity of architectural ceramic materials. Due to the lack of knowledge on the biodeteriogens affecting these assets, the characterization of microbial communities growing on Portuguese majolica glazed tiles, from Pena National Palace (Sintra, Portugal) and another from Casa da Pesca (Oeiras, Portugal) was carried out by culture and molecular biology techniques. Microbial communities were composed of microalgae, cyanobacteria, bacteria and fungi, including a new fungal species (Devriesia imbrexigena) described for the first time. Laboratory-based colonization experiments were performed to assess the biodeterioration patterns and bioreceptivity of glazed wall tiles produced in laboratory. Microorganisms previously identified on glazed tiles were inoculated on pristine and artificially aged tile models and incubated under laboratory conditions for 12 months. Phototrophic microorganisms were able to grow into glaze fissures and the tested fungus was able to form oxalates over the glaze. The bioreceptivity of artificially aged tiles was higher for phototrophic microorganisms than pristine tile models. A preliminary approach on mitigation strategies based on in situ application of commercial biocides and titanium dioxide (TiO2) nanoparticles on glazed tiles demonstrated that commercial biocides did not provide long term protection. In contrast, TiO2 treatment caused biofilm detachment. In addition, the use of TiO2 thin films on glazed wall tiles as a protective coating to prevent biological colonization was analysed under laboratorial conditions. Finally, conservation notes on tiles exposed to biological colonization were presented.

Firing and training costs and labour market segmentation

This dissertation consists of three essays on the labour market impact of firing and training costs. The modelling framework resorts to the search and matching literature. The first chapter introduces firing costs, both liner and non-linear, in a new Keynesian model, analysing business cycle effects for different wage rigidity degrees. The second chapter adds training costs in a model of a segmented labour market, accessing the interaction between these two features and the skill composition of the labour force. Finally, the third chapter analyses empirically some of the issues raised in the second chapter.