Opening Pousada da Serra da Estrela in Covilhã: A two-way impact - studying the value chain

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

Reconceptualising public spaces of (IN)equality: sensing and creating layers of visibility

Tese apresentada para cumprimento dos requisitos necessários à obtenção do grau de Doutor em Geografia e Planeamento Territorial - Especialidade: Geografia Humana

CMOS indoor light energy harvesting system for wireless sensing applications

Dissertação para obtenção do Grau de Doutor em Engenharia Electrotécnica e de Computadores

Control system for actuation and sensing in digital microfluidics devices

Digital Microfluidics (DMF) is a second generation technique, derived from the conventional microfluidics that instead of using continuous liquid fluxes, it uses only individual droplets driven by external electric signals. In this thesis a new DMF control/sensing system for visualization, droplet control (movement, dispensing, merging and splitting) and real time impedance measurement have been developed. The software for the proposed system was implemented in MATLAB with a graphical user interface. An Arduino was used as control board and dedicated circuits for voltage switching and contacts were designed and implemented in printed circuit boards. A high resolution camera was integrated for visualization. In our new approach, the DMF chips are driven by a dual-tone signal where the sum of two independent ac signals (one for droplet operations and the other for impedance sensing) is applied to the electrodes, and afterwards independently evaluated by a lock-in amplifier. With this new approach we were able to choose the appropriated amplitudes and frequencies for the different proposes (actuation and sensing). The measurements made were used to evaluate the real time droplet impedance enabling the knowledge of its position and velocity. This new approach opens new possibilities for impedance sensing and feedback control in DMF devices.

Indexing and active fund management: International evidence

Author's pre-print

Characterization of molecular damage induced by UV photons and carbon ions on biomimetic heterostructures

The study of the effect of radiation on living tissues is a rather complex task to address mainly because they are made of a set of complex functional biological structures and interfaces. Particularly if one is looking for where damage is taking place in a first stage and what are the underlying reaction mechanisms. In this work a new approach is addressed to study the effect of radiation by making use of well identified molecular hetero-structures samples which mimic the biological environment. These were obtained by assembling onto a solid support deoxyribonucleic acid (DNA) and phospholipids together with a soft water-containing polyelectrolyte precursor in layered structures and by producing lipid layers at liquid/air interface with DNA as subphase. The effects of both ultraviolet (UV) radiation and carbon ions beams were systematically investigated in these heterostructures, namely damage on DNA by means vacuum ultraviolet (VUV), infrared (IR), X-Ray Photoelectron (XPS) and impedance spectroscopy. Experimental results revealed that UV affects furanose, PO2-, thymines, cytosines and adenines groups. The XPS spectrometry carried out on the samples allowed validate the VUV and IR results and to conclude that ionized phosphate groups, surrounded by the sodium counterions, congregate hydration water molecules which play a role of UV protection. The ac electrical conductivity measurements revealed that the DNA electrical conduction is arising from DNA chain electron hopping between base-pairs and phosphate groups, with the hopping distance equal to the distance between DNA base-pairs and is strongly dependent on UV radiation exposure, due loss of phosphate groups. Characterization of DNA samples exposed to a 4 keV C3+ ions beam revealed also carbon-oxygen bonds break, phosphate groups damage and formation of new species. Results from radiation induced damage carried out on biomimetic heterostructures having different compositions revealed that damage is dependent on sample composition, with respect to functional targeted groups and extent of damage. Conversely, LbL films of 1,2-dipalmitoyl-sn-Glycero-3-[Phospho-rac-(1-glycerol)] (Sodium Salt) (DPPG) liposomes, alternated with poly(allylamine hydrochloride) (PAH) revealed to be unaffected, even by prolonged UV irradiation exposure, in the absence of water molecules. However, DPPG molecules were damaged by the UV radiation in presence of water with cleavage of C-O, C=O and –PO2- bonds. Finally, the study of DNA interaction with the ionic lipids at liquid/air interfaces revealed that electrical charge of the lipid influences the interaction of phospholipid with DNA. In the presence of DNA in the subphase, the effects from UV irrladiation were seen to be smaller, which means that ionic products from biomolecules degradation stabilize the intact DPPG molecules. This mechanism may explain why UV irradiation does not cause immediate cell collapse, thus providing time for the cellular machinery to repair elements damaged by UV.

Nanostructuring silicon probes via electrodeposition: characterization of electrode coatings for acute in vivo neural recordings

Understanding how the brain works will require tools capable of measuring neuron elec-trical activity at a network scale. However, considerable progress is still necessary to reliably increase the number of neurons that are recorded and identified simultaneously with existing mi-croelectrode arrays. This project aims to evaluate how different materials can modify the effi-ciency of signal transfer from the neural tissue to the electrode. Therefore, various coating materials (gold, PEDOT, tungsten oxide and carbon nano-tubes) are characterized in terms of their underlying electrochemical processes and recording ef-ficacy. Iridium electrodes (177-706 μm2) are coated using galvanostatic deposition under different charge densities. By performing electrochemical impedance spectroscopy in phosphate buffered saline it is determined that the impedance modulus at 1 kHz depends on the coating material and decreased up to a maximum of two orders of magnitude for PEDOT (from 1 MΩ to 25 kΩ). The electrodes are furthermore characterized by cyclic voltammetry showing that charge storage capacity is im-proved by one order of magnitude reaching a maximum of 84.1 mC/cm2 for the PEDOT: gold nanoparticles composite (38 times the capacity of the pristine). Neural recording of spontaneous activity within the cortex was performed in anesthetized rodents to evaluate electrode coating performance.

Autonomia funcional em idosos : caracterização multidimensional em idosos utentes de um centro de saúde urbano

RESUMO: Tivemos como objectivo do presente trabalho avaliar a capacidade funcional, e factores eventualmente a ela associados, numa amostra de 152 idosos ambulatórios, sem doenças agudas ou graves, utentes de um centro de saúde urbano. Cada avaliação consistiu numa entrevista, mediante um inquérito sobre capacidade funcional, morbilidade, estado mental e aspectos sociais, e no estudo da composição corporal. As perguntas referentes às variáveis estudadas foram por nós desenvolvidas e estruturadas com base em escalas internacionais validadas e de utilização comum na avaliação de idosos, excepto para as variáveis em que não encontrámos escalas com essas características. Os seus quesitos foram incluídos como perguntas e respostas estruturadas e pré-codificadas, permitindo a atribuição de uma pontuação a cada variável e a sua posterior divisão dicotómica. Aplicámos as escalas de Katz e de Lawton para a avaliação das actividades de autonomia física e instrumental da vida diária, a escala de Grimby para a avaliação da actividade física, a escala de Hamilton e o teste de Folstein para a avaliação do estado mental nas vertentes afectiva e cognitiva e a escala de Graffar para caracterizar a classe social, e perguntas sobre locomoção, autoavaliação da saúde, queixas de saúde presentes e rede social. Fizemos o registo da morbilidade segundo a International Classification of Primary Care - ICPC. A avaliação antropométrica constou da medição do peso, da altura, dos perímetros do braço, da cintura, da anca e proximal da coxa, e das pregas bicipital, tricipital, sub-escapular e supra-ilíaca. Foi também feita a estimativa da composição corporal por cálculos derivados de índices antropométricos e de bioimpedância eléctrica corporal total, o doseamento de algumas proteínas plasmáticas e a quantificação da força de preensão. Analisámos os resultados obtidos por grupos quanto ao sexo e à idade, dividida nos escalões etários 65 a 74 anos e mais do que 74 anos. Por regressão linear múltipla, foi testado o efeito do sexo e da idade sobre os valores medidos, para cada uma das variáveis e cada uma das suas pontuações parciais, sendo considerado como evidência de um efeito estaticamente significativo um valor “p” inferior a 0,05.Resumimos do seguinte modo os dados obtidos e a sua comparação com os dos estudos que seleccionámos como referência: A média de idades da amostra foi de 74 anos, sendo um terço destes do sexo masculino. Na sua maioria eram independentes em locomoção e funcionalidade, praticavam alguma actividade física, classificavam a sua saúde como razoável ou boa, apresentavam sintomatologia activa, não tinham depressão ou demência, tinham quem os acompanhasse embora cerca de metade apresentasse algum grau de isolamento, eram de baixa classe social, tinham excesso de peso, valores elevados de massa gorda, parâmetros plasmáticos proteicos compatíveis com ausência de doenças agudas ou graves e considerável força muscular de preensão. Na análise descritiva por grupos quanto ao sexo e/ou à idade, verificou-se que as mulheres e os mais idosos apresentavam maior isolamento social e os valores mais baixos de massa magra, hemoglobina e força de preensão. As mulheres tinham maior prevalência de dependência em autonomia física, depressão e valores mais baixos de transferrina. Os mais idosos apresentavam maior dependência em funcionalidade, menor actividade física, maior prevalência de demência, índice de massa corporal menos elevado, e valores mais baixos de albumina. Não se verificou prevalência de piores resultados dicotómicos nos homens nem no escalão etário menos idoso. Não teve relação com o sexo ou a idade o compromisso em autonomia instrumental, a presença de morbilidade ou a baixa classe social, assim como a não perturbação da locomoção e dos níveis de somatomedina-C. A análise comparativa com estudos multidimensionais em idosos portugueses e europeus ambulatórios revelou que a nossa amostra apresentava muitas características semelhantes às desses idosos. Assim, tinham elevada independência em locomoção, considerável independência em autonomia física e menor independência em autonomia instrumental; prática de actividade física ligeira, as mulheres dentro e os homens fora de casa; maior prevalência de morbilidade a nível dos aparelhos locomotor e cardiocirculatório, nos nossos idosos com pouca flutuação na autoavaliação de saúde; pequena prevalência de depressão e de demência; maior isolamento social nas mulheres e nas mais idosas; factores de classe social de baixo nível, diferindo apenas em relação aos idosos do norte da Europa que apresentavam elevada escolaridade e profissões mais diferenciadas; características biométricas sobreponíveis às dos idosos portugueses e às dos do sul da Europa, com tendência para o excesso de peso e proporção elevada de massa gorda; e doseamentos plasmáticos proteicos e força muscular de preensão compatíveis com ausência de doenças agudas ou crónicas graves. A comparação com os referidos estudos em relação ao risco de dependência, revelou semelhanças na associação entre dependência funcional e idade avançada, morbilidade, alteração do estado mental e isolamento social. Na amostra que estudámos não obtivemos associação entre dependência e o sexo feminino, facto que se verificou no estudo nacional de Almeida et al. e nos estudos multicêntricos europeus, ou o grau de escolaridade, como no estudo francês. Podemos concluir que, com o instrumento de avaliação que utilizámos, foi possível detectar e caracterizar perturbações numa amostra de idosos ambulatórios, a maioria funcionalmente independentes, sem alterações do estado mental, mas apresentando morbilidade activa, tendência para a obesidade, e actividade física ligeira. Nos que apresentaram alterações, estas foram mais frequentes no sexo feminino e nos indivíduos com mais de 74 anos. A escala de funcionalidade desenvolvida foi sensível aos efeitos da idade e permitiu o cálculo do risco de dependência em relação às outras variáveis estudadas, sendo mais marcante a associação com baixa actividade física, presença de queixas de saúde, demência e índice de massa corporal elevado. Consideramos que a metodologia que empregámos poderá contribuir para a avaliação de capacidades, cujo conhecimento sistemático nos idosos se impõe. ------------- ABSTRACT: The main objective of the present work was to evaluate functional capacity and related factors, in a sample of 152 ambulatory elderly, free from acute or serious disease, attending an urban health centre. Each evaluation included an interview, with a questionnaire about functional capacity, morbidity, mental health and social aspects, and the study of body composition. The questions were developed and structured in accordance with international validated scales usually applied in the evaluation of the elderly, whenever there were scales for that purpose. Their items were included as structured pre-coded questions and answers, so that each variable could have its own quotation and be dichotomised. We employed Katz and Lawton scales for basic and instrumental activities of daily living, Grimby scale for physical activity, Hamilton scale for depression, Folstein’s Mini Mental State Examination for cognitive ability and Graffar scale for social class, and questions about walking, health perception, active complaints and social network. The symptoms register was done according to the International Classification of Primary Care - ICPC. The anthropometric exam involved the determination of height and weight, arm, waist, hip and proximal thigh circumferences, and biceps, triceps, subscapular and suprailiac skinfolds. For the body composition calculation we employed equations derived from anthropometric indices, and from measurement of total body bioelectric impedance. We also measured some plasma proteins and handgrip strength. The analysis of results was done by sex and age groups, separating those with 65 to 74 years from those older than 74 years. The effects of sex and age were tested by linear multiple regression, for each variable and its components. Presented "p" values being considered statistically significative if less than 0,05. The results we obtained and their comparison with the studies we choose as reference can be summarised as follows: Mean age of the sample was 74 years and about one third were men. Most of them were independent in gait and functionality, practised some physical activity, rate their health as fair or good, had physical complaints, had not depression or dementia, had some companionship although almost half of them with stigmas of isolation, belonged to low social class, were in the range of overweight, had raised values of fat mass, plasma proteins in accordance with no acute or serious disease, and considerable handgrip strength. The analysis of groups by sex and age revealed that women and the eldest had the greater social isolation and the lowest values of free fat mass, haemoglobin and handgrip strength. Women had the higher dependence in basic activities of daily living, more depression and lower levels of transferrin. The eldest were more dependent in functionality, had greater prevalence of dementia, less physical activity, less raised body mass index and lower levels of albumin. Men alone and the age range of 65 to 74 did not show any prevalence of the worse dichotomised results. There was no relationship between sex or age and instrumental activities of daily living, morbidity or low social class, and unaffected gait or somatomedin-C levels. The comparison of results with multidimensional studies in portuguese and european ambulatory elderly showed that our sample had many similarities with theirs. They were independent in gait and activities of daily living; practiced light physical activity, women indoors and men outdoors; had greater morbidity at locomotor and cardiovascular systems, with small latitude in health evaluation; low prevalence of depression and dementia; social isolation predominantly in older women; and low social class factors, witch is only different from those of north Europe who had higher education levels and professional carriers; biometric characteristics similar to other portuguese and south Europe elders, with tendency for overweight and high proportion of fat mass; and plasma protein levels and handgrip strength in accordance with no acute or chronic serious disease. The comparison to the referred studies in relation to dependency risk, showed similarities in the association of dependency and age, morbidity,altered mental state and social isolation. We did not find association between dependency and sex, as it was found in the portuguese study of Almeida et al. and the european multicentric studies, or the education level, as in the french study. We conclude that, with the evaluation battery we employed, it was possible to detect and characterise alterations in a sample of ambulatory elderly, most of whom were functionally independent and had no alterations in mental state, but had active morbidity, tendency to obesity, and only light physical activity. Those that had some alteration, were more frequently women and the eldest. The functionality scale we developed showed to be sensitive to age effects and suitable for the calculation of risk of dependency, being more important the association with low physical activity, active complaints, dementia and high body mass index. We consider that the methodology we applied can contribute to the evaluation of capabilities that should be systematically sought for in the elderly.

A abolição da dupla incriminação no mandado de detenção europeu

This essay presents the European Arrest Warrant and its relationship with the principle of double criminality, which was abolished in 2002 with the new Framework Decision (FD). This instrument was essential to implement the principle of mutual recognition and strengthen the police and judicial cooperation in criminal matters in the newly created space of freedom, security and justice. It was urgent to create mechanisms to combat cross-border crime, that alone States have struggled to counter. An analysis of the FD No 2002/584/JHA is made. The execution of warrants and the non-mandatory and optional grounds of refusal are studied in detail. As it is the implementation issue. The role of mutual recognition in practice is studied as well. The procedure is to introduce the principle of double criminality, to explain the concept and its abolition, warning for the consequences derived from them, related to the principle of legality and fundamental rights. The analysis of the European Arrest Warrant in practice in Portugal and in comparison with other Member States allows the measurement of the consequences from the abolition of dual criminality and the position of States on this measure. With the abolition of double criminality, the cooperation in judicial and criminal matters departs from what was intended by the European Council of Tampere. And without cooperation, fundamental rights of citizens are unprotected, so the states have to adopt measures to remedy the "failures" of the European Law.

Measuring the impact of short and lending practices using the DGTW benchmarks

Mutual fund managers increasingly lend their holdings and/or use short sales to generate higher returns for their funds. This project presents a first look into the impact these practices on performance using the performance measures: i) Characteristic Selectivity (CS), the ability of the fund's managers to choose stocks that outperform their benchmarks; ii) Characteristic Timing (CT), the ability of the manager to time the market; iii) and Average Style (AS), the returns from funds systematically holding stocks with certain characteristics. These returns are computed through the DGTW benchmarks. The effect of other variables that have also been shown to impact fund’s returns – total net assets under management, investment styles, turnover and expense ratios – will also be analyzed. I find that managers who use short-sales do not exhibit better stock picking abilities than those who do not, while mutual funds that lend do present higher CS returns. In addition, while lending is not significant for the total performance of a fund, the employment of short-sales and of both short-sales and lending has a negative impact on the fund’s performance.

The flow-performance relationship around the world

We use a new dataset to study how mutual fund flows depend on past performance across 28 countries. We show that there are marked differences in the flow-performance relationship across countries, suggesting that US findings concerning its shape do not apply universally. We find that mutual fund investors sell losers more and buy winners less in more developed countries. This is because investors in more developed countries are more sophisticated and face lower costs of participating in the mutual fund industry. Higher country-level convexity is positively associated with higher levels of risk taking by fund managers.

Fabrication and characterization of transparent conductive oxide surface sensors for electrocorticography – TrECoG

Understanding how the brain works has been one of the greatest goals of mankind. This desire fuels the scientific community to pursue novel techniques able to acquire the complex information produced by the brain at any given moment. The Electrocorticography (ECoG) is one of those techniques. By placing conductive electrodes over the dura, or directly over the cortex, and measuring the electric potential variation, one can acquire information regarding the activation of those areas. In this work, transparent ECoGs, (TrECoGs) are fabricated through thin film deposition of the Transparent Conductive Oxides (TCOs) Indium-Zinc-Oxide (IZO) and Gallium-Zinc-Oxide (GZO). Five distinct devices have been fabricated via shadow masking and photolithography. The data acquired and presented in this work validates the TrECoGs fabricated as efficient devices for recording brain activity. The best results were obtained for the GZO- based TrECoG, which presented an average impedance of 36 kΩ at 1 kHz for 500 μm diameter electrodes, a transmittance close to 90% for the visible spectrum and a clear capability to detect brain signal variations. The IZO based devices also presented high transmittance levels (90%), but with higher impedances, which ranged from 40 kΩ to 100 kΩ.

Control of a white organic light emitting diode’s emission parameters using a single doped RGB active layer

White Color tuning is an attractive feature that Organic Light Emitting Diodes (OLEDs) offer. Up until now, there hasn’t been any report that mix both color tuning abilities with device stability. In this work, White OLEDs (W-OLEDs) based on a single RGB blend composed of a blue emitting N,N′-Di(1-naphthyl)-N,N′-diphenyl-(1,1′-biphenyl)-4,4′-diamine (NPB) doped with a green emitting Coumarin-153 and a red emitting 4-(Dicyanomethylene)-2-methyl-6-(4-dimethylaminostyryl)-4H-pyran (DCM1) dyes were produced. The final device structure was ITO/Blend/Bathocuproine (BCP)/ Tris(8-hydroxyquinolinato)aluminium (Alq3)/Al with an emission area of 0.25 cm2. The effects of the changing in DCM1’s concentration (from 0.5% to 1% wt.) allowed a tuning in the final white color resulting in devices capable of emitting a wide range of tunes – from cool to warm – while also keeping a low device complexity and a high stabilitty. Moreover, an explanation on the optoelectrical behavior of the device is presented. The best electroluminescense (EL) points toward 160 cd/m2 of brightness and 1.1 cd/A of efficiency, both prompted to being enhanced. An Impedance Spectroscopy (IS) analysis allowed to study both the effects of BCP as a Hole Blocking Layer and as an aging probe of the device. Finally, as a proof of concept, the emission was increased 9 and 64 times proving this structure can be effectively applied for general lighting.

Improving silicon probe performance through layer-by-layer coating

Fully comprehending brain function, as the scale of neural networks, will only be possi-ble with the development of tools by micro and nanofabrication. Regarding specifically silicon microelectrodes arrays, a significant improvement in long-term performance of these implants is essential. This project aims to create a silicon microelectrode coating that provides high-quality electrical recordings, while limiting the inflammatory response of chronic implants. To this purpose, a combined chitosan and gold nanoparticles coating was produced allied with electrodes modification by electrodeposition with PEDOT/PSS in order to reduce the im-pedance at 1kHz. Using a dip-coating mechanism, the silicon probe was coated and then charac-terized both morphologically and electrochemically, with focus on the stability of post-surgery performance in anesthetized rodents. Since not only the inflammatory response analysis is vital, the electrodes recording degradation over time was also studied. The produced film presented a thickness of approximately 50 μm that led to an increase of impedance of less than 20 kΩ in average. On a 3 week chronic implant, the impedance in-crease on the coated probe was of 641 kΩ, compared with 2.4 MΩ obtained for the uncoated probe. The inflammatory response was also significantly reduced due to the biocompatible film as proved by histological tests.

Field-effect transistors based on Zinc oxide nanoparticles

This work reports the development of field-effect transistors (FETs), whose channel is based on zinc oxide (ZnO) nanoparticles (NPs). Using screen-printing as the primary deposition technique, different inks were developed, where the semiconducting ink is based on a ZnO NPs dispersion in ethyl cellulose (EC). These inks were used to print electrolyte-gated transistors (EGTs) in a staggered-top gate structure on glass substrates, using a lithium-based polymeric electrolyte. In another approach, FETs with a staggered-bottom gate structure on paper were developed using a sol-gel method to functionalize the paper’s surface with ZnO NPs, using zinc acetate dihydrate (ZnC4H6O4·2H2O) and sodium hydroxide (NaOH) as precursors. In this case, the paper itself was used as dielectric. The various layers of the two devices were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier Transform Infrared spectroscopy (FTIR), thermogravimetric and differential scanning calorimetric analyses (TG-DSC). Electrochemical impedance spectroscopy (EIS) was used in order to evaluate the electric double-layer (EDL) formation, in the case of the EGTs. The ZnO NPs EGTs present electrical modulation for annealing temperatures equal or superior to 300 ºC and in terms of electrical properties they showed On/Off ratios in the order of 103, saturation mobilities (μSat) of 1.49x10-1 cm2(Vs)-1 and transconductance (gm) of 10-5 S. On the other hand, the ZnO NPs FETs on paper exhibited On/Off ratios in the order of 102, μSat of 4.83x10- 3 cm2(Vs)-1and gm around 10-8 S.