Browsing by Issue Date, starting with "2024-07-29"
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- Somatostatin signalling coordinates energy metabolism allocation to reproduction in zebrafishPublication . Chen, Jie; Zhao, Wenting; Cao, Lei; Martins, Rute Sofia Tavares; Canario, AdelinoBackgroundEnergy allocation between growth and reproduction determines puberty onset and fertility. In mammals, peripheral hormones such as leptin, insulin and ghrelin signal metabolic information to the higher centres controlling gonadotrophin-releasing hormone neurone activity. However, these observations could not be confirmed in lower vertebrates, suggesting that other factors may mediate the energetic trade-off between growth and reproduction. A bioinformatic and experimental study suggested co-regulation of the circadian clock, reproductive axis and growth-regulating genes in zebrafish. While loss-of-function of most of the identified co-regulated genes had no effect or only had mild effects on reproduction, no such information existed about the co-regulated somatostatin, well-known for its actions on growth and metabolism.ResultsWe show that somatostatin signalling is pivotal in regulating fecundity and metabolism. Knock-out of zebrafish somatostatin 1.1 (sst1.1) and somatostatin 1.2 (sst1.2) caused a 20-30% increase in embryonic primordial germ cells, and sst1.2-/- adults laid 40% more eggs than their wild-type siblings. The sst1.1-/- and sst1.2-/- mutants had divergent metabolic phenotypes: the former had 25% more pancreatic alpha-cells, were hyperglycaemic and glucose intolerant, and had increased adipocyte mass; the latter had 25% more pancreatic beta-cells, improved glucose clearance and reduced adipocyte mass.ConclusionsWe conclude that somatostatin signalling regulates energy metabolism and fecundity through anti-proliferative and modulatory actions on primordial germ cells, pancreatic insulin and glucagon cells and the hypothalamus. The ancient origin of the somatostatin system suggests it could act as a switch linking metabolism and reproduction across vertebrates. The results raise the possibility of applications in human and animal fertility.
- Early Neolithic settlement and graves in Lisbon’s Historic CentrePublication . Cardoso, João Luis; Martins, FilipeIn recent years, information regarding the human presence during the Early Neolithic period in the Historic Center of Lisbon has increased, as a result of numerous preventive archaeological excavations carried out within the scope of mitigating impacts resulting from the recovery of old buildings or the construction of new ones. Such work, carried out by several Archeology companies that have worked in areas considered to be of greatest archaeological sensitivity within the city of Lisbon, have led to results of exceptional relevance for the knowledge of the first producing societies that occupied this territory from the last quarter of the 6th millennium BC. Thus, not only large settlements were identified, such as Encosta de Sant’Ana and Bairro Alto, integrating several loci, such as Palácio Ludovice. The first structured graves known in Portuguese territory at this time were also identified, in close association with the inhabited spaces, corresponding to individual depositions in the fetal position carried out at the bottom of small graves excavated in the geological substrate. The importance of these discoveries justified the presentation of this synthesis, which summarizes all the information published to date.
- Turismo cultural ao nivel no destino Algarve. Caso de estudo dos percursos pedonais nos Centros Históricos das Cidades de Portimão e LouléPublication . Rodrigues, Ana Filipa Rocha; Rosa, Maria Manuela Pires; Rebelo, Efigénio da LuzO conceito de Turismo Acessível evoluiu de um segmento promotor da acessibilidade segundo a abordagem do design universal, que atende às necessidades das pessoas com deficiência, a uma abordagem mais abrangente de Turismo de qualidade. As Rotas Turísticas visam a promoção do destino e da cultura local, possibilitando formas de estimular os visitantes à obtenção de experiências culturais, e.g, a observação da arquitetura local na paisagem urbana. A atual investigação tem como tema o Turismo Cultural Acessível no destino Algarve, pretendendo analisar as rotas turísticas pedonais existentes em dois centros históricos: “Rota Turística Acessível” de Portimão e os Itinerários Pedonais “Comércio” e “Património” de Loulé. Existe um gap na literatura sobre a satisfação dos consumidores das Rotas Culturais e a Acessibilidade percebida. O objetivo proposto neste estudo consiste em analisar a satisfação dos consumidores das referidas rotas, a partir de inquéritos realizados na Época Alta e na Época Baixa. A análise foi limitada pelos seus produtos, serviços e experiências culturais acessíveis. Através da análise estatística, Regressão Logística Binária, pretende-se verificar quais os determinantes da satisfação dos consumidores dos percursos pedonais culturais, ao nível da acessibilidade, bem como apurar quais os atributos do Turismo Cultural Acessível de um itinerário que podem ser benéficos e complementares para o outro e vice-versa. Os resultados apresentados indicam que existem boas práticas associadas ao Turismo Cultural Acessível e ao desenvolvimento sustentável do destino Algarve, podendo a acessibilidade ser um elemento contribuidor no planeamento e gestão sustentável dos destinos turísticos.