2 resultados para identity principle

em Repositório Científico da Universidade de Évora - Portugal


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Landscape, people and identity Landscape is about the interaction of a place or an area with people, which is reflected in the material interaction of people creating or shaping the landscape as well as in their mental perception, valuation and symbolic meaning of that landscape (Cosgrove 1998). This mutual and dynamic interaction forms the fundamental principle of the concept of landscape identity. Landscape identity has been described in scientific literature as a concept to bridge the physical, social and cultural aspects of landscapes. Also policy documents related with landscape and heritage (for example the UNESCO World Heritage Convention, the European Landscape Convention, the Faro Convention) are mentioning identity and landscape as key concepts. In those examples, landscape identity can refer to either the landscape itself - its features that makes the landscape unique (thus the landscape character), or to the social and personal construction. However, there is an interdependency between those two perspectives that needs to be conceptualised. Landscape identity is therefore defined as the multiple ways and dynamic relation between landscape and people (Loupa Ramos et al 2016).

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Knowledge of the chemical identity and role of urinary pheromones in fish is scarce, yet it is necessary in order to understand the integration of multiple senses in adaptive responses and the evolution of chemical communication [1]. In nature, Mozambique tilapia (Oreochromis mossambicus) males form hierarchies, and females mate preferentially with dominant territorial males, which they visit in aggregations or leks [2]. Dominant males have thicker urinary bladder muscular walls than subordinates or females and store large volumes of urine, which they release at increased frequency in the presence of subordinate males or preovulatory, but not postspawned, females [3–5]. Females exposed to dominant-male urine augment their release of the oocyte maturation-inducing steroid 17α,20β-dihydroxypregn-4-en-3-one (17,20β-P) [6]. Here we isolate and identify a male Mozambique tilapia urinary sex pheromone as two epimeric (20α- and 20β-) pregnanetriol 3-glucuronates. We show that both males and females have high olfactory sensitivity to the two steroids, which cross-adapt upon stimulation. Females exposed to both steroids show a rapid, 10-fold increase in production of 17,20β-P. Thus, the identified urinary steroids prime the female endocrine system to accelerate oocyte maturation and possibly promote spawning synchrony. Tilapia are globally important as a food source but are also invasive species, with devastating impact on local freshwater ecosystems [7, 8]. Identifying the chemical cues that mediate reproduction may lead to the development of tools for population control [9–11].