Percorrer por autor "Martins, Rute Sofia Tavares"
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- Analysis of the strategic leverage of sport dynamics of sport tourism events through a holistic approachPublication . Martins, Rute Sofia Tavares; Mascarenhas, MargaridaThis study focuses on the development of sport dynamics arising from the strategic leverage of sport events and encompassing the planning of tactics and actions conducive to its implementation. Therefore, the objective of this study aims to analyse the sport dynamic leveraging efforts of the event organizers of two non-mega international events. This investigation included the case study of international open water events hosted in Setúbal, Portugal. Data were collected through: (i) documentary analysis covering the period 2010–2022; (ii) field observation of the two events in 2022; and (iii) 14 post-event semi-structured interviews with representatives of the event organizers and a local partner of the events. The data were examined through content analysis using deductive data categorization. The results highlighted the importance of strategic planning of the benefits of sport events, considering both the increase in sport (active and passive) participation and the strengthening of sport organizational capacity. This expanded vision of the development of sport dynamics can maximize more benefits for the host community. The long-term perspective of leveraging local sport dynamics provided by the study of international sport events emphasized the need for a strategic vision that combines an asset-based approach and a community needs-based approach.
- Does the interrenal influence sex differentiation in sea bass, Dicentrarchus labrax?Publication . Martins, Rute Sofia Tavares; Canário, AdelinoSea bass Dicentrarchus labrax is one of the most important cultured species in Mediterranean aquaculture. This species remains sexually immature most of the first year of life, and at the time of marketing (2 years old), females are 18-40% heavier than males. However, in cultured populations, it is frequently reported skewed sex ratios in favour of males (reaching 70-99%), and thus, the acquisition of all-female stocks is an attractive option for sea bass aquaculture. The underlying hypothesis of this work is that in intensive culture, the sea bass interrenal tissue produces corticosteroids in response to stress, and together with them an excess of adrenal androgens shifting the normal androgen/ estrogen ratio and thus leading to gonadal masculinization. Thus, blocking cortisol production with an antagonist (Dexamethasone) during the androgen sensitive period would most likely decrease the androgen levels and thereby the sex ratios would be altered.
- 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.