Monte Carlo studies of phase transitions and adsorption : application to n-6 Lennard-Jones, C60 and zeolite systems

The solid-fluid transition properties of the n - 6 Lennard-Jones system are studied by means of extensive free energy calculations. Different values of the parameter n which regulates the steepness of the short-range repulsive interaction are investigated. Furthermore, the free energies of the n < 12 systems are calculated using the n = 12 system as a reference. The method relies on a generalization of the multiple histogram method that combines independent canonical ensemble simulations performed with different Hamiltonians and computes the free energy difference between them. The phase behavior of the fullerene C60 solid is studied by performing NPT simulations using atomistic models which treat each carbon in the molecule as a separate interaction site with additional bond charges. In particular, the transition from an orientationally frozen phase at low temperatures to one where the molecules are freely rotating at higher temperatures is studied as a function of applied pressure. The adsorption of molecular hydrogen in the zeolite NaA is investigated by means of grand-canonical Monte Carlo, in a wide range of temperatures and imposed gas pressures, and results are compared with available experimental data. A potential model is used that comprises three main interactions: van der Waals, Coulomb and induced polarization by the permanent electric field in the zeolite.

Treatment of aqueous effluents contaminated with ionic liquids

Ionic liquids are a class of solvents that, due to their unique properties, have been proposed in the past few years as alternatives to some hazardous volatile organic compounds. They are already used by industry, where it was possible to improve different processes by the incorporation of this kind of non-volatile and often liquid solvents. However, even if ionic liquids cannot contribute to air pollution, due to their negligible vapour pressures, they can be dispersed thorough aquatic streams thus contaminating the environment. Therefore, the main goals of this work are to study the mutual solubilities between water and different ionic liquids in order to infer on their environmental impact, and to propose effective methods to remove and, whenever possible, recover ionic liquids from aqueous media. The liquid-liquid phase behaviour of different ionic liquids and water was evaluated in the temperature range between (288.15 and 318.15) K. For higher melting temperature ionic liquids a narrower temperature range was studied. The gathered data allowed a deep understanding on the structural effects of the ionic liquid, namely the cation core, isomerism, symmetry, cation alkyl chain length and the anion nature through their mutual solubilities (saturation values) with water. The experimental data were also supported by the COnductor-like Screening MOdel for Real Solvents (COSMO-RS), and for some more specific systems, molecular dynamics simulations were also employed for a better comprehension of these systems at a molecular level. On the other hand, in order to remove and recover ionic liquids from aqueous solutions, two different methods were studied: one based on aqueous biphasic systems, that allowed an almost complete recovery of hydrophilic ionic liquids (those completely miscible with water at temperatures close to room temperature) by the addition of strong salting-out agents (Al2(SO4)3 or AlK(SO4)2); and the other based on the adsorption of several ionic liquids onto commercial activated carbon. The first approach, in addition to allowing the removal of ionic liquids from aqueous solutions, also makes possible to recover the ionic liquid and to recycle the remaining solution. In the adsorption process, only the removal of the ionic liquid from aqueous solutions was attempted. Nevertheless, a broad understanding of the structural effects of the ionic liquid on the adsorption process was attained, and a final improvement on the adsorption of hydrophilic ionic liquids by the addition of an inorganic salt (Na2SO4) was also achieved. Yet, the development of a recovery process that allows the reuse of the ionic liquid is still required for the development of sustainable processes.

Describing vocal performance of Portuguese cantadeiras of Alto Minho

Portugal has strong musical traditions, which have been perpetrated by decades through folkloristic activities. In folk groups from Alto Minho (north of Portugal), folk singing is mostly performed by cantadeiras, amateur female solo singers who learn this style orally. Their vocal characteristics are distinctive when compared with other regions of the country; however, deep understanding of these vocal practices is still missing. The present work aims at studying Alto Minho cantadeira’s vocal performance in a multidimensional perspective, envisioning social, cultural and physiological understanding of this musical style. Thus, qualitative and quantitative data analyses were carried out, to: (i) describe current performance practices, (ii) explore existent perceptions about most relevant voice features in this region, (iii) investigate physiological and acoustic properties of this style, and (iv) compare this style of singing with other non-classical singing styles of other countries. Dataset gathered involved: 78 groups whose members were telephone interviewed, 13 directors who were asked to fill in a questionnaire on performance practices, 1 cantadeira in a pilot study, 16 cantadeiras in preliminary voice recordings, 77 folk group members in listening tests, and 10 cantadeiras in multichannel recordings, including audio, ELG, air flow and intra-oral pressure signals. Data were analysed through thematic content analysis, descriptive and inferential statistics, hierarchical principal components, and multivariate linear regression models. Most representative voices have a high pitched and loud voice, with a bright timbre, predominance of chest register without excessive effort, and good text intelligibility with regional accent. High representativeness levels were obtained by few cantadeiras; these sing with high levels of subglottal pressure and vocal fold contact quotient, predominance of high spectrum energy and vocal loudness, corroborating indications of prevalence of pressed phonation. These vocal characteristics resemble belting in musical theatre and share similarities with country (USA) and ojikanje (Croatia) singing. Strategies that may contribute to the preservation of this type of singing and the vocal health of current cantadeiras are discussed, pointing at the direction of continuous education among folk groups, following practices that are already adopted elsewhere in Europe.

A importância dos processos físicos no controlo da eutrofização em estuários

Muitos dos problemas tróficos existentes nos estuários e zonas costeiras têm origem no excesso de nutrientes, em particular Azoto (N) e Fósforo (P), resultante do sucessivo enriquecimento dos rios durante o seu percurso até ao mar e também de descargas directas nestes sistemas. Nixon (1995) definiu eutrofização como o aumento da quantidade de matéria orgânica disponível na massa de água. Esta é uma definição assumida neste estudo, considerando que a eutrofização é o primeiro, de uma sequência de fenómenos resultantes do sobre-enriquecimento de nutrientes, que inclui a alteração de espécies dominantes e o aumento dos níveis de turbidez da água.

DPSIR framework application supported by integrated watershed modeling for irrigation from Alqueva dam (Portugal) on Guadiana river estuary

Dissertação de mest., Gestão da Água e da Costa, Faculdade de Ciências e Tecnologia, Universidade do Algarve, 2009

The function and future of the LOICS basins approach in promoting integrated coastal zone & watershed management with an emphasis on developing countries

Dissertação de Mestrado, Gestão da Água e da Costa, Faculdade de Ciências e Tecnologia, Universidade do Algarve, 2010

Ante-projecto de uma unidade de tratamento de águas residuais oleosas, no porto de Cádis

Dissertação de mest., Engenharia do Ambiente, Faculdade de Ciências do Mar e do Ambiente, Universidade do Algarve, 2008

Filogeografia de Brachidontes puniceus (Gmelin, 1791) no arquipélago de Cabo Verde

Dissertação mest., Biologia Marinha, Universidade do Algarve, 2009

Efeito do cloro no desenvolvimento e na tiróide da Tilápia Moçambicana (Oreochromis mossambicus)

Dissertação mest., Biotecnologia, Universidade do Algarve, 2009

A análise conjunta na medição das preferências por eventos culturais e desportivos: uma contribuição para a gestão da procura em pavilhões multiusos

Dissertação mest., Gestão Empresarial, Universidade do Algarve, 2008

Simulation of economic benefits achieved by water quality improvement for recreational and professional users, within the SPICOSSA SSA (SPICOSSA System Approach) 11 - Guadiana estuary ecosystem sic

Dissertação de Mestrado, Gestão da Água e da Costa, Faculdade de Ciências e Tecnologia, Universidade do Algarve, 2010

Utilização de macroalgas verdes como biorremediadores em efluentes de indústrias agroalimentares: dinâmica das vias metabólicas relacionadas com os compostos azotados

Dissertação de mest., Tecnologia de Alimentos, Instituto Superior de Engenharia, Univ. do Algarve, 2013

A influência do perfeccionismo parental, dos estilos parentais e dos padrões de vinculação no desenvolvimento do perfeccionismo em jovens adultos

As conceções clássicas sobre as origens do perfeccionismo e os principais modelos explicativos do seu desenvolvimento assentam no pressuposto de que a relação parental constitui um importante fator na compreensão deste traço de personalidade nos filhos. Apesar do suporte teórico e conceptual, os resultados da investigação empírica são parciais e pouco conclusivos. Neste contexto, definimos como objetivos principais analisar a influência do Perfeccionismo parental no desenvolvimento do Perfeccionismo dos filhos jovens adultos e compreender o papel dos Estilos Parentais e dos Padrões de Vinculação. Procurou-se ainda averiguar se o efeito destas variáveis era moderado pelo sexo do progenitor ou pelo sexo do filho. Os resultados encontrados permitem um conhecimento mais aprofundado sobre o papel destes fatores parentais. A perceção de um Estilo Parental Autoritário e de uma Vinculação pouco Segura aos pais parece contribuir marcadamente para o desenvolvimento do Perfeccionismo Desadaptativo. Por outro lado, um Estilo Parental Democrático e uma Vinculação Segura parecem apenas influenciar uma parte do Perfeccionismo o Adaptativo. O estudo do contributo diferencial de cada um dos progenitores no desenvolvimento do perfeccionismo em função do sexo do filho permitiu testar as duas hipóteses descritas na literatura sobre o papel moderador do sexo. Os dados sugerem que os filhos desenvolvem tendências perfeccionistas pela identificação com o progenitor do mesmo sexo (hipótese do cuidador do mesmo sexo), enquanto a componente desadaptativa do perfeccionismo parece desenvolve-se tanto nos filhos do sexo masculino como nas filhas quando a mãe manifesta também níveis elevados de Perfeccionismo Desadaptativo (hipótese do cuidador principal). Os resultados apoiam ainda o Modelo da Aprendizagem Social e o Modelo das Expectativas Sociais formulados por Flett, Hewitt, Oliver e Macdonald (2002). Por último, são discutidas as implicações destes resultados na prevenção e na intervenção psicológica com pais e filhos e apontadas algumas das limitações do presente trabalho que poderão ser colmatadas em futuras investigações.

The effect of conservation measures on the spatial and temporal variation of rocky fish assemblages in the Arrábida Marine Park

Marine protected areas (MPAs) have been widely proposed for conservation purposes and as a tool for fisheries management. The Arrábida Marine Park is the first MPA in continental Portugal having a management plan, fully implemented since 2009. The main objective of this study was to evaluate the effect of protection measures on rocky reef fish assemblages and target invertebrates through before-after and control-effect (no-take vs. fished areas) underwater visual surveys and analysis of landings trends. Second, we used surveys before, during and after implementation of the management plan to understand fishers‟ preferences for fishing grounds and adaptation to the new rules, and evaluated the reserve effect through analysis of both ecological responses and fishing effort density. Third, we identified the main oceanographic drivers influencing the structure of reef fish assemblages and predicted the community structure for the last 50 years, in light of climatic change. Overall results suggest positive responses in biomass but not yet in numbers of some commercial species, with no effects on non-target species. The reserve effect is reinforced by the increase in landings of commercial species, despite increased fishing effort density in some areas, especially with octopus traps. Fishing grounds are mainly chosen based on the distribution of target species and associated habitats, but distance to port, weather conditions and safety also influence fishers‟ choices. Moreover, different fisheries respond differently to the protection measures, and within each fishery, individual fishers show distinct strategies, with some operating in a broader area whereas others keep preferred territories. Our results also show that wind stress and temperature are the main oceanographic drivers for rocky reef fish assemblages, with tropicalization of assemblages and polewards movements of species over the last 50 years consistent with temperature trends. We believe this study provides significant lessons for marine conservation and management of coastal systems.

Ecological niche modeling, cytogenetics and phylogeography of the genera Geomalacus and Letourneuxia (Gastropoda, Pulmonata) from the Iberian-Moroccan region

First described more that 150 years ago, the systematics of the genera Geomalacus and Letourneuxia (Arionidae, Gastropoda, Pulmonata) is still challenging. The taxonomic classification of arionid species is based on extremely labile characters such as body size or color that depends both on diet and environment, as well as age. Moreover, there is little information on the genetic diversity and population structure of the Iberian slugs that could provide extra clues to disentangle their problematic classification. The present work uses different analytical tools such as habitat suitability (Ecological Niche Modeling - ENM), cytogenetic analysis and phylogeography to establish the geographical distribution and evolutionary history of these pulmonate slugs. The potential distribution of the four Geomalacus species was modeled using ENM, which allowed the identification of new locations for G. malagensis, including a first report in Portugal. Also, it was predicted a much wider distribution for G. malagensis and G. oliveirae than previously known. Classical cytogenetic analyses were assayed with reproductive and a novel use of somatic tissues (mouth and tentacles) returning the number of chromosomes for the four Geomalacus species and L. numidica (n = 31, 2n = 62) and the respective karyotypes. G. malagensis and L. numidica present similar chromosome morphologies and karyotypic formulae, being more similar to each other than the Geomalacus among themselves. We further reconstructed the phylogeny of the genera Geomalacus and Letourneuxia using partial sequences of the mitochondrial cytochrome oxidase subunit I (COI) and the nuclear ribosomal small subunit (18S rRNA), and applied an independent evolutionary rate method, the indicator vectors correlation, to evaluate the existence of cryptic diversity within species. The five nominal species of Geomalacus and Letourneuxia comprise 14 well-supported cryptic lineages. Letourneuxia numidica was retrieved as a sister group of G. malagensis. G. oliveirae is paraphyletic with respect to G. anguiformis. According to our dating estimates, the most recent common ancestor of Geomalacus dates back to the Middle Miocene (end of the Serravallian stage). The major lineage splitting events within Geomalacus occurred during the dry periods of the Zanclean stage (5.3-3.6 million years) and some lineages were confined to more humid mountain areas of the Iberian Peninsula, which lead to a highly geographically structured mitochondrial genetic diversity. The major findings of this are the following: (1) provides updated species distribution maps for the Iberian Geomalacus expanding the known geographic distribution of the concerned species, (2) unravels the cryptic diversity within the genera Geomalacus and Letourneuxia, (3) Geomalacus oliveirae is paraphyletic with G. anguiformis and (4) Letourneuxia numidica is sister group of G. malagensis.