Browsing by Issue Date, starting with "2016-07-07"
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- Role of spawning synchrony on hybridization barriers in sympatric intertidal fucoid algae - when and whyPublication . Monteiro, Carla Alexandra da Silva; Pearson, Gareth; Serrão, Ester; Valero, MyriamIn sympatric assemblages of congeners with incomplete reproductive barriers, the synchrony within species and asynchrony between species may be under strong selection, reinforcing prezygotic reproductive isolation and reducing hybridization. Interspecific asynchrony and gametic incompatibility are considered the two most important prezygotic mechanisms reinforcing assortative mating and acting against hybridization. However, divergence of reproductive strategies in closely related species might also contribute to reproductive isolation. The main goal of this thesis was to investigate hypotheses concerning the mechanisms that act against hybridization in sympatric species with external fertilization, including the asynchrony of gamete release, mating system variations and gametic incompatibility. As a model we used sympatric Fucus species with different reproductive modes, hermaphroditic (selfing) and dioecious (obligate outcrossing). The results show a clear relationship between patterns of gamete release and tidal/circadian cycles that contributes to interspecific variation in spawning time between hermaphroditic and dioecious species. The data support the hypothesis that asynchronous egg release acts as a prezygotic barrier to hybridization between hermaphroditic and dioecious species, and therefore, that mating system variation between congeners plays important role against hybridization. We also provide evidence that gametic incompatibility is an incomplete prezygotic barrier between Fucus species. Results show the potential of interspecific fertilization, and the potential growth and survival of hybrids relative to the parental lineage.
- Biological and chemical strategies for the recovery of precious and rare metals as nanoparticlesPublication . Assunção, Ana; Costa, Maria ClaraThe present work explored the potential of chemical (solvent extraction) and biological (using anaerobic bacterial community) technologies, aiming the removal/recovery of precious metals from aqueous solutions. Solvent extraction or liquid-liquid extraction was used to find a suitable platinum and palladium extractant, to be applied to the treatment of aqueous solutions containing these metals. Thus, N,N’-dimethyl-N,N’-dicyclohexyltetradecylmalonamide (DMDCHTDMA), N,N’-dicyclohexyl-N,N’-dimethylsuccinamide (DMDCHSA) and N,N’-dimethyl-N,N’-diphenylsuccinamide (DMDPHSA) were tested and proved to be efficient at extracting platinum (IV) from HCl solutions. Platinum (IV) was then successfully stripped from DMDCHTDMA using 1 M HCl solution, and from DMDCHSA and DMDPHSA, using seawater. These extractants proved to be less efficient for palladium (II) removal, thus, for this metal, biological strategies were tested. A palladium (II)-resistant bacterial community, able to biorecover palladium from solutions, was found. The phylogenetic analysis showed that this community was mainly composed by bacteria close to Clostridium species, however, bacteria affiliated to genera Bacteroides and Citrobacter were also identified. The potentialities of combining solvent extraction and the use of bacterial communities for palladium and platinum recovery were also demonstrated. Pd(II) and Pt(IV) in aqueous phases were efficiently extracted to organic phases. The metals were then stripped with seawater, precipitated and recovered using a filtered solution from bacterial growth. The successful precipitation of palladium (II) and platinum (IV), as nanosized PdS and PtS2 particles, was accompanied by sulphide concentration decrease in the bacterial growth solution. Biological processes, using effluents from an acid mine drainage bioremediation treatment system, were tested for gold recovery from aqueous solutions. The use of these effluents, with dissolved biogenic sulphide, proved to be an excellent alternative for Au(III) recovery as Au(0) nanoparticles (NPs). Finally, biogenic sulphide, from the effluents tested before, was also used to successfully synthesize Ag2S NPs and Ag2S/TiO2 nanocomposite. The Ag2S NPs and Ag2S/TiO2 nanocomposite obtained have semiconductor properties and can theoretically be used for radiation based applications.
- Hotel Vila Galé LagosPublication . Guerreiro, Miguel da Luz; Correia, Marisol B.; Sousa, CarlosO presente relatório refere-se a um estágio curricular desenvolvido no âmbito do Mestrado em Direção e Gestão Hoteleira, lecionado na Escola Superior de Gestão, Hotelaria e Turismo da Universidade do Algarve. O estágio decorreu entre 8 de agosto de 2014 e 8 de abril de 2015 e englobou os departamentos de Food & Beverage (Bar, Economato e Restaurante), Alojamento (Receção e Housekeeping) e Direção / Administrativos. O primeiro objetivo do presente relatório consiste em apresentar informação detalhada sobre a cadeia hoteleira Vila Galé e a unidade de acolhimento, o Hotel Vila Galé Lagos, e descrever a experiência vivenciada num período de oito meses. O segundo propósito, relacionado com o projeto de investigação, prende-se com a elaboração de um estudo de análise de dados da unidade, baseado numa amostra das 15 nacionalidades com maior taxa de ocupação durante o ano de 2014. Este estudo visa aferir as preferências dos hóspedes relativamente a consumos nos estabelecimentos de restauração e bebidas e Spa, tipologias de quarto, regimes de alojamento e agências de viagem/operadores turísticos, examinando igualmente estatística univariada das despesas com o alojamento e os consumos no hotel no ano de 2014. O presente artigo tenciona igualmente ser uma referência para o setor da hotelaria em matéria de previsão de vendas, receitas, ocupação e encomendas de mercadoria. A partir da análise e interpretação dos resultados obtidos do estudo, foi possível verificar que, apesar de Portugal ser a nacionalidade com maior número de hóspedes na unidade em 2014, os lusitanos despenderam menos do que os germânicos no que toca aos estabelecimentos de restauração e bebidas e Spa. Todavia, os hóspedes nacionais foram os clientes mais assíduos do Restaurante Inevitável no último quadrimestre do ano, e terão, efetivamente, efetuado maiores despesas com o alojamento e respetivos regimes em todo o ano civil.