Multiresponsive supramolecular systems for information processing at the molecular level

Dissertação para obtenção do Grau de Doutor em Química Sustentável

Watershed-scale runoff routing and solute transport in a spatially aggregated hydrological framework

Dissertation submitted in partial fulfillment of the requirements for the Degree of Master of Science in Geospatial Technologies

Flexible multivariate GARCH modeling with an application to international stock markets

This paper offers a new approach to estimating time-varying covariance matrices in the framework of the diagonal-vech version of the multivariate GARCH(1,1) model. Our method is numerically feasible for large-scale problems, produces positive semidefinite conditional covariance matrices, and does not impose unrealistic a priori restrictions. We provide an empirical application in the context of international stock markets, comparing the nev^ estimator with a number of existing ones.

Search-for-yield in Portuguese fixed-income mutual funds and monetary policy

This paper studies the effects of monetary policy on mutual fund risk taking using a sample of Portuguese fixed-income mutual funds in the 2000-2012 period. Firstly I estimate time-varying measures of risk exposure (betas) for the individual funds, for the benchmark portfolio, as well as for a representative equally-weighted portfolio, through 24-month rolling regressions of a two-factor model with two systematic risk factors: interest rate risk (TERM) and default risk (DEF). Next, in the second phase, using the estimated betas, I try to understand what portion of the risk exposure is in excess of the benchmark (active risk) and how it relates to monetary policy proxies (one-month rate, Taylor residual, real rate and first principal component of a cross-section of government yields and rates). Using this methodology, I provide empirical evidence that Portuguese fixed-income mutual funds respond to accommodative monetary policy by significantly increasing exposure, in excess of their benchmarks, to default risk rate and slightly to interest risk rate as well. I also find that the increase in funds’ risk exposure to gain a boost in return (search-for-yield) is more pronounced following the 2007-2009 global financial crisis, indicating that the current historic low interest rates may incentivize excessive risk taking. My results suggest that monetary policy affects the risk appetite of non-bank financial intermediaries.

Momentum risk: An approach following the correlations between active stocks

The momentum anomaly has been widely documented in the literature. However, there are still many issues where there is no consensus and puzzles left unexplained. One is that strategies based on momentum present a level of risk that is inconsistent with the diversification that it offers. Moreover, recent studies indicate that this risk is variable over time and mostly strategy-specific. This work project hypothesises and proves that this evidence is explained by the portfolio constitution of the momentum strategy over time, namely the covariance and correlation between companies in the top and down deciles and across them.

Evolution of coauthorship networks: worldwide scientific production on leishmaniasis

Introduction Collaboration is one of the defining features of contemporary scientific research, and it is particularly important with regard to neglected diseases that primarily affect developing countries. Methods The present study has identified publications on leishmaniasis in the Medline database from 1945 to 2010, analyzing them according to bibliometric indicators and statistics from social network analysis. Examining aspects such as scientific production, diachronic evolution, and collaboration and configuration of the research groups in the field, we have considered the different types of Leishmania studied and the institutional affiliation and nationality of the authors. Results Seven-hundred and thirty-five authors participate in 154 prominent research clusters or groups. Although the most predominant and consolidated collaborations are characterized by members from the same country studying the same type of Leishmania, there are also notable links between authors from different countries or who study different clinical strains of the disease. Brazil took the lead in this research, with numerous Brazilian researchers heading different clusters in the center of the collaboration network. Investigators from the USA, India, and European countries, such as France, Spain, the United Kingdom, and Italy, also stand out within the network. Conclusions Research should be fostered in countries such as Bangladesh, Nepal, Sudan, and Ethiopia, where there is a high prevalence of different forms of the disease but limited research development with reference authors integrated into the collaboration networks.

Psychological safety, authentic leadership and social networks : A psycho-structural approach to the study of groups

Tese de Doutoramento em Psicologia na área de especialização de Psicologia das Organizações apresentada ao ISPA - Instituto Universitário

Study of the role of wall teichoic acids in the localization Staphylococcus aureus cell wall synthesis protein PBP4

The cell wall of Staphylococcus aureus is a highly complex network mainly composed of highly cross-linked peptidoglycan (PG) and teichoic acids (TAs), both important for the maintenance of the integrity and viability of bacteria. The penicillin binding proteins (PBPs), which catalyse the final stage of PG biosynthesis, are targets of β-lactam antibiotics and have been a key focus of antibacterial research. S. aureus has four native PBPs, PBP1-4 carried by both methicillin-sensitive (MSSA) and –resistant (MRSA) strains. PBP4 is required for the synthesis of the highly cross-linked PG and, as shown in recent studies, is essential for the expression of β-lactam resistance in community-acquired strains (CA-MRSA). This protein has a septal localization that seems to be spatially and temporally regulated by an unknown intermediate of the wall teichoic acids (WTA) biosynthesis pathway. Therefore, if WTA synthesis is compromised, PBP4 becomes dispersed throughout the entire cell membrane. The aim of this project was to identify the WTA precursor responsible for the septal recruitment of PBP4. In order to do so, inducible mutants of tarB and tarL genes in the background of NCTCPBP4-YFP were constructed allowing for the study of PBP4 localization in the presence and absence of these specific tar genes.With this work we were able to show that the absence of TarB or TarL leads to the delocalization of PBP4, indicating that TarL or a protein/WTA precursor whose localization/synthesis is dependent on TarL is responsible for the recruitment of PBP4.

Decisions of technology innovation: the role of indicators

This work presents research conducted to understand the role of indicators in decisions of technology innovation. A gap was detected in the literature of innovation and technology assessment about the use and influence of indicators in this type of decision. It was important to address this gap because indicators are often frequent elements of innovation and technology assessment studies. The research was designed to determine the extent of the use and influence of indicators in decisions of technology innovation, to characterize the role of indicators in these decisions, and to understand how indicators are used in these decisions. The latter involved the test of four possible explanatory factors: the type and phase of decision, and the context and process of construction of evidence. Furthermore, it focused on three Portuguese innovation groups: public researchers, business R&D&I leaders and policymakers. The research used a combination of methods to collect quantitative and qualitative information, such as surveys, case studies and social network analysis. This research concluded that the use of indicators is different from their influence in decisions of technology innovation. In fact, there is a high use of indicators in these decisions, but lower and differentiated differences in their influence in each innovation group. This suggests that political-behavioural methods are also involved in the decisions to different degrees. The main social influences in the decisions came mostly from hierarchies, knowledge-based contacts and users. Furthermore, the research established that indicators played mostly symbolic roles in decisions of policymakers and business R&D&I leaders, although their role with researchers was more differentiated. Indicators were also described as helpful instruments to conduct a reasonable interpretation of data and to balance options in innovation and technology assessments studies, in particular when contextualised, described in detail and with discussion upon the options made. Results suggest that there are four main explanatory factors for the role of indicators in these decisions: First, the type of decision appears to be a factor to consider when explaining the role of indicators. In fact, each type of decision had different influences on the way indicators are used, and each type of decision used different types of indicators. Results for policy-making were particularly different from decisions of acquisition and development of products/technology. Second, the phase of the decision can help to understand the role indicators play in these decisions. Results distinguished between two phases detected in all decisions – before and after the decision – as well as two other phases that can be used to complement the decision process and where indicators can be involved. Third, the context of decision is an important factor to consider when explaining the way indicators are taken into consideration in policy decisions. In fact, the role of indicators can be influenced by the particular context of the decision maker, in which all types of evidence can be selected or downplayed. More importantly, the use of persuasive analytical evidence appears to be related with the dispute existent in the policy context. Fourth and last, the process of construction of evidence is a factor to consider when explaining the way indicators are involved in these decisions. In fact, indicators and other evidence were brought to the decision processes according to their availability and capacity to support the different arguments and interests of the actors and stakeholders. In one case, an indicator lost much persuasion strength with the controversies that it went through during the decision process. Therefore, it can be argued that the use of indicators is high but not very influential; their role is mostly symbolic to policymakers and business decisions, but varies among researchers. The role of indicators in these decisions depends on the type and phase of the decision and the context and process of construction of evidence. The latter two are related to the particular context of each decision maker, the existence of elements of dispute and controversies that influence the way indicators are introduced in the decision-making process.

Good vibrations

The work reported in this thesis addresses the research question of when and how positive psychological states impact positive behavior and positive organizational development. We present two theoretical essays and three empirical studies to find possible answers to this question and we use a multitude of methodologies with different epistemological assumptions, including quantitative correlation analysis, social network analysis and qualitative grounded theory analysis. In the whole, our work shows that positive psychological states are fundamental to promote individual and organizational higher-levels of performance and well-being. It also points that the capability to induce positive psychological states in others (an “alter-positive” approach) is a powerful way to develop outstanding individuals and organizations. In a broader sense, it stresses the need to promote good vibrations as a fundamental route to create a better world.

On line pre-concentration for simultaneous determination of low molecular weight organic acids and inorganic anions in Amazonian river water samples employing ion chromatography with conductivity detection

An ion chromatography procedure, employing an IonPac AC15 concentrator column was used to investigate on line preconcentration for the simultaneous determination of inorganic anions and organic acids in river water. Twelve organic acids and nine inorganic anions were separated without any interference from other compounds and carry-over problems between samples. The injection loop was replaced by a Dionex AC15 concentrator column. The proposed procedure employed an auto-sampler that injected 1.5 ml of sample into a KOH mobile phase, generated by an Eluent Generator, at 1.5 mL min-1, which carried the sample to the chromatographic columns (one guard column, model AG-15, and one analytical column, model AS15, with 250 x 4mm i.d.). The gradient elution concentrations consisted of a 10.0 mmol l-1 KOH solution from 0 to 6.5 min, gradually increased to 45.0 mmol l-1 KOH at 21 min., and immediatelly returned and maintained at the initial concentrations until 24 min. of total run. The compounds were eluted and transported to an electro-conductivity detection cell that was attached to an electrochemical detector. The advantage of using concentrator column was the capability of performing routine simultaneous determinations for ions from 0.01 to 1.0 mg l-1 organic acids (acetate, propionic acid, formic acid, butyric acid, glycolic acid, pyruvate, tartaric acid, phthalic acid, methanesulfonic acid, valeric acid, maleic acid, oxalic acid, chlorate and citric acid) and 0.01 to 5.0 mg l-1 inorganic anions (fluoride, chloride, nitrite, nitrate, bromide, sulfate and phosphate), without extensive sample pretreatment and with an analysis time of only 24 minutes.

Mineralizações associadas a shear zone networking na vertente oriental da Serra de Arga (Minho, Portugal)

Dissertação de mestrado em Ordenamento e Valorização de Recursos Geológicos

Modelação, simulação e implementação de agitação acústica para aplicações em microfluídica

Tese de Doutoramento (Programa Doutoral em Engenharia Biomédica)

The role of IFNγ in higher brain function: in health and under chronic stress

Tese de Doutoramento em Ciências da Saúde

Discurso mediático e sociedade: repensar a Análise Crítica do Discurso

A análise do discurso jornalístico e do seu enraizamento social tem conhecido avanços significativos nas últimas duas décadas, especialmente devido ao surgimento e desenvolvimento da Análise Crítica do Discurso. No entanto, há três aspectos importantes que merecem mais investigação: o plano temporal na análise do discurso, as estratégias discursivas dos atores sociais, e os efeitos extra e supra-textual do discurso mediatizado. Em primeiro lugar, a compreensão da biografia dos assuntos públicos exige uma análise longitudinal dos textos mediatizados e dos seus contextos sociais, mas a maioria das formas de análise do discurso jornalístico não tem em conta a sequência temporal dos textos e as suas implicações. Em segundo lugar, como a representação mediática das questões sociais é, em grande medida, função da construção discursiva de eventos, problemas e posições por diferentes atores sociais, as estratégias discursivas que eles empregam numa variedade de arenas e canais ‘antes’ e ‘depois’ dos textos jornalísticos precisam de ser examinados. Em terceiro lugar, o facto de que muitos dos modos de operação do discurso são extra- ou supra-textuais requer que se tenha em consideração vários processos sociais ‘fora’ do texto. Este trabalho tem como objetivo produzir um contributo teórico e metodológico para a integração destas questões em análise do discurso, propondo um quadro analítico que combina uma dimensão textual com uma contextual.