Characterization of sol-gel matrices with entrapped cutinase

Dissertação para obtenção do Grau de Doutor em Engenharia Química e Bioquímica

Children consumer behaviour field lab: The Nestum consumer

A Work Project, presented as part of the requirements for the Award of a Masters Degree in Management from the NOVA – School of Business and Economics

Development of ion jelly thin films for electrochemical devices

Dissertação para obtenção do Grau de Doutor em Química Sustentável

Introducing Mobile Money in Rural Mozambique: Evidence from a Field Experiment*

The limitations of access to finance in Africa, together with the recent boom in cell phone use in that continent, created high expectations regarding the introduction of mobile money in many African countries. The success story of M-PESA in Kenya raised the bar further. We designed and conducted a field experiment to assess the impact of randomized mobile money dissemination in rural Mozambique. For this purpose we benefit from the fact that mobile money was only recently launched in the country, allowing for the identification of a pure control group. This paper reports on the first results of this ongoing project after the first wave of dissemination efforts in rural locations, which included the recruitment and training of mobile money agents, community meetings and theaters, as well as individual rural campaigning. Administrative and behavioral data both show clear adherence to the services in the treatment group. Financial literacy and trust outcomes are also positively affected by the treatment. We present behavioral evidence that the marginal willingness to remit was increased by the availability of mobile money. Finally, we observe a tendency for mobile money to substitute traditional alternatives for both savings and remittances.

Vitamin A Deficiency and Training to Farmers: Evidence from a Field Experiment in Mozambique

Vitamin A deficiency is a widespread public health problem in Sub-Saharan Africa. This paper analyzes the impact of a food-based intervention to fight vitamin A deficiency using orange-fleshed sweet potato (OFSP). We conducted a randomized evaluation of OFSP-related training to female farmers in Mozambique, in which the treatment group was taught basic concepts of nutrition, and OFSP-planting and cooking skills. We found encouraging evidence of changes in behavior and attitudes towards OFSP consumption and planting, and considerable increases in nutrition-related knowledge, as well as knowledge on cooking and planting OFSP.

Migrant Remittances and Information Flows: Evidence from a Field Experiment*

Do information flows matter for remittance behavior? We design and implement a randomized control trial to quantitatively assess the role of communication between migrants and their contacts abroad on the extent and value of remittance flows. In the experiment, a random sample of 1,500 migrants residing in Ireland was offered the possibility of contacting their networks outside the host country for free over a varying number of months. We find a sizable, positive impact of our intervention on the value of migrant remittances sent. Our results exclude that the remittance effect we identify is a simple substitution effect. Instead, our analysis points to this effect being a likely result of improved information via factors such as better migrant control over remittance use, enhanced trust in remittance channels due to experience sharing, or increased remittance recipients’ social pressure on migrants.

Development of an equipment to detect and quantify muscular spasticity

Dissertação para obtenção do Grau de Mestre em Engenharia Biomédica

Fast screening for diagnostic of heart ischemic episodes

Dissertação para obtenção do Grau de Doutor em Química Sustentável

Valuation of marine and coastal ecosystems: The role of ecological-economic modeling

A Work Project, presented as part of the requirements for the Award of a Masters Degree in Economics from the NOVA – School of Business and Economics

Vitamin A deficiency and training to farmers: Evidence from a field experiment in Mozambique

A Work Project, presented as part of the requirements for the Award of a Masters Degree in Economics from the NOVA – School of Business and Economics

Comparação entre os métodos de Ziehl-Neelsen modificado e Acid-Fast-Trichrome para a pesquisa fecal de Cryptosporidium parvum e Isospora belli

Devido a crescente importância dos coccídios intestinais (Cryptosporidium, Isospora e Cyclospora) como parasitos oportunistas, é fundamental para os laboratórios diferenciar morfologicamente estes protozoários; a técnica de Ziehl-Neelsen modificada (ZNm) é amplamente utilizada para este fim; recentemente, foi proposto um novo procedimento, a coloração combinada do ácido tricrômico (Acid-Fast-Trichrome - AFT). O objetivo do presente estudo foi comparar os processos AFT e ZNm para a detecção destes coccídios em amostras fecais de pacientes portadores do vírus VIH. Foram selecionados dois grupos de indivíduos, para inclusão no estudo, segundo a presença (n=60) ou ausência de diarréia (n=60). As amostras de fezes foram coletadas em solução de formalina 10% e os esfregaços fecais preparados i) diretamente das fezes e ii) após concentração prévia a 500xg (10 minutos), foram submetidos aos diferentes processos de coloração. Considerando-se a positividade por técnica (AFT e ZNm), verificou-se a superioridade do procedimento de ZNm (n=19; 100% dos casos positivos) sobre o de AFT (n=8; 42,1%). Ambos possibilitaram a identificação dos 101 casos verdadeiramente negativos. Coccidiose intestinal foi mais frequente entre os pacientes que apresentaram diarréia (26,6%) em comparação à positividade observada entre os indíviduos assintomáticos (5%) sendo que C. cayetanensis não foi detectada em ambos os grupos. Foi de nosso interesse avaliar a aplicabilidade da técnica AFT para a coloração deste protozoário. Devido à sensibilidade e especificidade obtida neste estudo (100%), conclui-se que o método de ZNm continua sendo o mais indicado para o diagnóstico da criptosporidiose e isosporose, principalmente quando associado ao procedimento de centrífugo-concentração (500xg, 10 minutos). Embora a coloração AFT tenha baixo custo, faz-se necessário o seu aperfeiçoamento pois este procedimento permite o diagnóstico simultâneo dos coccídios intestinais (C. parvum, I. belli e C. cayetanensis) e dos microsporídios.

Assessment of hydrogen sulfide removal from biogas using a field scale anoxic biotrickling filter.

Hydrogen sulphide is one of the most toxic and corrosive compound present in swine-derived biogas streams.In this study, afield scale biotrickling filter for the removal of hydrogen sulfide was investigated.A Biofilter packed with supporting biofilm materials was fed continuously with a proprietary nutrient solution and operatedfor over 73days. The system has been operating with a H2S inlet concentrations ranging from 1,000to 3,000 ppm.Significant removal efficiencies >95% was demonstrated. pH of the stock feeding solution decreased from 6.2 to as low as 3.5within couple days.The resulting drop in pH provided circumstantial evidence to support biological H2 Soxidation to sulphuric acid by sulfide-oxidizers. Sulfur precipitation was also observed to occur. The results suggested that H2S removal from biogas stream can be efficiently achieved using portable, low cost and maintenance free biotrickling filters.

Forecasts of relative performance in tournaments: Evidence from the field

This paper uses a field experiment to investigate the quality of individuals’ forecasts of relative performance in tournaments. We ask players in luck-based (poker) and skill-based (chess) tournaments to make point forecasts of rank. The main finding of the paper is that players’ forecasts in both types of tournaments are biased towards overestimation of relative performance. However, the size of the biases found is not as large as the ones often reported in the psychology literature. We also find support for the “unskilled and unaware hypothesis” in chess: high skilled chess players make better forecasts than low skilled chess players. Finally, we find that chess players’ forecasts of relative performance are not efficient.

Haptic robot-environment interaction for self-supervised learning in ground mobility

Dissertação para obtenção do Grau de Mestre em Engenharia Eletrotécnica e de Computadores

Green synthesis of 2-Oxazoline-based polymers with antimicrobial activity using scCO2

Using a green methodology, 17 different poly(2-oxazolines) were synthesized starting from four different oxazoline monomers. The polymerization reactions were conducted in supercritical carbon dioxide under a cationic ring-opening polymerization (CROP) mechanism using boron trifluoride diethyl etherate as the catalyst. The obtained living polymers were then end-capped with different types of amines, in order to confer them antimicrobial activity. For comparison, four polyoxazolines were end-capped with water, and by their hydrolysis the linear poly(ethyleneimine) (LPEI) was also produced. After functionalization the obtained polymers were isolated, purified and characterized by standard techniques (FT-IR, NMR, MALDI-TOF and GPC). The synthesized poly(2-oxazolines) revealed an unusual intrinsic blue photoluminescence. High concentration of carbonyl groups in the polymer backbone is appointed as a key structural factor for the presence of fluorescence and enlarges polyoxazolines’ potential applications. Microbiological assays were also performed in order to evaluate their antimicrobial profile against gram-positive Staphylococcus aureus NCTC8325-4 and gram-negative Escherichia coli AB1157 strains, two well known and difficult to control pathogens. The minimum inhibitory concentrations (MIC)s and killing rates of three synthesized polymers against both strains were determined. The end-capping with N,N-dimethyldodecylamine of living poly(2- methyl-2-oxazoline) and poly(bisoxazoline) led to materials with higher MIC values but fast killing rates (less than 5 minutes to achieve 100% killing for both bacterial species) than LPEI, a polymer which had a lower MIC value, but took a longer time to kill both E.coli and S.aureus cells. LPEI achieved 100% killing after 45 minutes in contact with E. coli and after 4 hours in contact with S.aureus. Such huge differences in the biocidal behavior of the different polymers can possibly underlie different mechanisms of action. In the future, studies to elucidate the obtained data will be performed to better understand the killing mechanisms of the polymers through the use of microbial cell biology techniques.