Browsing by Issue Date, starting with "2019-10-09"
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- Education matters: cumulative advantages and disadvantages amongst Portuguese older menPublication . Vilhena, Carla; Valadas, Sandra T.; Almeida, António Fragoso deOur paper sought to analyse the influence of the educational background over various dimensions of the lives of Portuguese older men (age 60+) across the life course. Drawing on the theory of cumulative advantages and disadvantages we used biographical research, namely narrative interviews with men from different educational background: men with a very low educational background and men with a medium/high educational background. Our results show the influence of educational background in the life course, and how it can contribute to accumulation of advantages/disadvantages that explain their biographies and the very different situations in which they live today.
- Satisfação e lealdade em função do perfil de cliente bancário (segmento empresa) na região do AlgarvePublication . Duarte, Carla Filipa Ramos; Ferreira, Eugénia Maria Dores MaiaO aumento da competitividade entre os Bancos, aliado a uma maior exigência por parte dos clientes, fruto da crescente globalização dos mercados e dos novos avanços tecnológicos, leva a que seja cada vez mais difícil agradar os clientes, sejam eles particulares ou empresas. As empresas são, cada vez mais, um segmento no qual os Bancos querem estar presentes, não apenas por se tratarem do pilar da economia, como por se afigurarem como um segmento rentável. Justifica-se, assim, realizar um estudo que permita compreender quais os fatores inerentes à satisfação e lealdade de clientes bancários, particularmente os clientes empresa. O presente estudo, de natureza exploratória, visa estudar o impacto da gestão da relação em clientes bancários do segmento empresa, através da análise da satisfação e da lealdade. A recolha de dados foi efetuada com um questionário aplicado a empresas da Região do Algarve, tendo posteriormente sido utilizado o programa Statistical Package for Social Sciences (SPSS), versão 25.0, no tratamento dos dados recolhidos, que possibilitou a realização de diversas análises estatísticas com vista a discutir objetivos específicos, definidos à priori, que permitiram ir de encontro ao objetivo geral do estudo. Através da aplicação dos métodos Nonlinear Canonical Correlation Analysis (OVERALS), clusters hierárquicos e CHi-squared Automatic Interaction Detection (CHAID), confirmou-se que uma gestão eficiente da imagem do banco, das expetativas dos clientes e da qualidade dos produtos e serviços prestados, a par de gestão focada nas componentes relacionais, são fatores-chave para satisfação e lealdade de clientes bancários empresas. Esta investigação assume particular relevância, na medida em que poderá representar um contributo à implementação e/ou aperfeiçoamento de estratégias de gestão que visem melhorar a imagem do banco e a relação comercial entre as empresas e o banco, permitindo aos bancos uma diferenciação competitiva que lhes permita permanecer e singrar no mercado competitivo em que atuam.
- Cryopreservation of zebrafish germ cells: technological improvements and methodological standardization for gene banking and managementPublication . Diogo, Patricia Alexandra Cavaleiro; Gavaia, Paulo; Cabrita, ElsaDue to the increasing number of zebrafish (Danio rerio) mutant and transgenic lines, there is a high demand for assisted reproductive techniques to support facility management. Efficient zebrafish sperm cryopreservation is a pressing necessity to manage and preserve the valuable zebrafish genetic resources. Although zebrafish sperm cryopreservation was first attempted more than 30 years ago, protocols still lack standardization, which translates into high variability in post-thaw sperm quality and in vitro fertilization success. Therefore, the present thesis aims to improve the current methodologies used for zebrafish sperm cryopreservation and broodstock management towards the standardization of procedures in this species. The introductory context of the present thesis is approached in chapter 1. In this chapter the relevance of zebrafish model is discussed as well as this species sperm cryopreservation usefulness. The main factors affecting sperm quality and the application of reliable quality analysis are discussed in this chapter. The final objective of sperm cryopreservation is to obtain high quality offspring and therefore in vitro fertilization, early development and offspring quality analysis are important tools for the optimization of sperm cryopreservation methodologies. The current knowledge in sperm cryopreservation fundamentals is approached in this chapter, as well as the main advances and bottlenecks in zebrafish sperm cryopreservation. In chapter 2, the zebrafish sperm motility activation was assessed under different conditions of water temperature and conductivity. The environmental conditions present in the fertilization microenvironment are responsible for the mechanism of spermatozoa motility activation and metabolic modulation that influence the probability of fertilization success. Zebrafish is commonly reared at 28°C, but with variable water conductivity conditions among facilities. However, sperm motility analysis is routinely performed with distilled water at room temperature. We aimed to understand the effect of water temperature and conductivity on sperm motility and fertilization ability. Water at 28°C with lower water conductivity (0 and 700 μS/cm) improve sperm motility parameters. Standardization of the water conditions (of system water and activation médium used for motility analysis) among facilities is highly relevant to improve the reproducibility of sperm quality analysis and thus, to predict with higher accuracy fertilization ability. Successful cryopreservation depends on high quality sperm, which depends on the quality of breeders. Consequently, broodstock selection and management is a priority to improve sperm cryopreservation. The broodstock diet has a preponderant effect on gamete quality, particularly in phospholipids and antioxidants content which are known to promote spermatogenesis. Therefore, in chapter 3 we aimed to determine the effects of a tailor-made purified diet supplemented with phosphatidylcholine (PC) or phosphatidylethanolamine (PE) on the zebrafish reproductive performance, gamete quality and larval skeletal malformations. Both dietary supplementations with phospholipids improved sperm motility and eggs quality, however PC increased the incidence of skeletal malformations on the offspring, as previously observed in other teleosts. Although dietary phospholipids classes have a role in the ossification process of the vertebral column in teleosts, its mechanisms are still to be understood. Therefore, the development and use of a standardized diet for zebrafish broodstock is essential to reduce the variability of the reproductive performance among facilities. In chapter 4, the selection of optimal age and minimum sperm collection frequency was evaluated, since these factors are essential to obtain high quality samples. Our results indicate that young males (6-8 months) showed higher sperm quality and require a minimum of 14 days between sperm collections to recover sperm plasma membrane viability. An important bottleneck in cryopreservation is the liquid nitrogen requirement for storage. Therefore, it was established in chapter 5 a new cryopreservation method using an electric ultrafreezer (-150°C) as an alternative to liquid nitrogen, for the first time in a teleost species. This protocol reaches a fast cooling rate (-66°C/min) in one single step and yields higher sperm viability and DNA integrity in comparison to the traditional methods (-20°C/min in liquid nitrogen). The synergy obtained by the combination of cryoprotectants is a successful cryopreservation strategy that can be beneficial in the optimization of zebrafish sperm cryopreservation. Therefore, it was selected the most adequate cryoprotectant combination that generates offspring with normal skeletogenesis. Data show that 15% of DMF with 50 mM of bicine or 10% of egg yolk is beneficial for the quality of zebrafish offspring sired by cryopreserved sperm. To the best of our knowledge, this is the first report on skeletal development of zebrafish offspring sired by cryopreserved sperm performed with different extender compositions. Zebrafish is especially useful to investigate some of the most prominent human diseases such as diabetes. Among other consequences, diabetes (type I and II) causes disturbances in the male reproductive system, since glucose metabolism is an important event not only in spermatogenesis but also in mature spermatozoa metabolism. In chapter 6 we aimed to validate zebrafish as a useful model organism to investigate male reproductive dysfunctions mechanisms caused by type I diabetes. In this chapter, sperm cryopreservation was applied to a relevant zebrafish model of type I diabetes. The transgenic zebrafish under diabetic conditions shows higher levels of insulin a (insa), insulin receptor a (inra) and glucose carrier 2 (slc2a2) transcripts in spermatozoa when compared to the controls. This is because gametogenesis occurred under diabetic conditions, changing transcription in the germline. Consequently, spermatozoa carry the imprinted transcripts that will be transmitted during fertilization. Sperm quality (motility, viability and DNA integrity) was lower in the transgenic fish under (transient) diabetic state as observed in human and mouse model. Sperm cryopreservation affects sperm quality of fish both under diabetic and non-diabetic conditions. However, diabetic conditions were detrimental in sperm freezability, which can be explained by the lower initial sperm quality. In this chapter zebrafish was validated as a useful model organism to investigate male reproductive dysfunctions mechanisms caused by type I diabetes. Relevant differences between different zebrafish lines are evidenced in terms of sperm quality and susceptibility to damage, which suggests that it is an important factor to consider while establishing sperm cryopreservation protocols. This thesis offers new insights and a set of guidelines on breeder’s management and sperm cryopreservation to improve zebrafish husbandry practices. Keywords: Zebrafish, sperm quality, cryopreservation, ultrafreezer, sperm motility activation, diet, type I diabetes
- Postos à prova: um olhar sociológico sobre as práticas familiares de pessoas idosas em tempos de crise e de austeridadePublication . Coelho, Patrícia Marina Paulo Correia Calças Severino; São José, José; Martins, João EduardoO combate à crise introduziu a austeridade em Portugal e em vários países da União Europeia (UE). O objetivo desta investigação é compreender, aprofundadamente, como a “sociedade de austeridade” (Ferreira, 2011; Ferreira 2012a, 2012b) se tem manifestado nas vidas das pessoas idosas, em especial nas suas práticas familiares e perceber até que ponto estas manifestações, os seus significados e as suas consequências são moldadas pelo curso de vida e pela interseção do género, da idade e da classe social. A expressão generalizada dos efeitos da crise e da austeridade faz pensar que se tenham manifestado nas vidas das pessoas idosas, não só um rol de mudanças nas práticas familiares, mas também na saúde, no bem-estar e na qualidade de vida. Ainda se sabe muito pouco sobre esta problemática e, em Portugal, o conhecimento é muito escasso. Em termos metodológicos, é seguida uma abordagem biográfica/narrativa e a amostra é composta por vinte e oito entrevistas em profundidade a pessoas idosas, com idades entre os 69 e os 92 anos de idade, residentes em Faro e inseridas em diferentes estruturas sociais, por forma a captar a maior diversidade possível de experiências biográficas marcadas pela crise e austeridade. Os resultados concluem que, apesar do carácter transversal das mudanças nas práticas familiares, os contornos destas mudanças variam em função dos perfis sociológicos das pessoas idosas, encontrando-se os contornos mais graves entre as pessoas idosas com um perfil socialmente desvantajoso. Também as práticas familiares das pessoas idosas registaram mudanças significativas, e na saúde e no bem-estar, os efeitos da crise e da austeridade foram particularmente negativos.