2 resultados para Hawksbill turtle
em AMS Tesi di Laurea - Alm@DL - Università di Bologna
Resumo:
The Adriatic Sea is considered a feeding and developmental area for Mediterranean loggerhead turtles, but this area is severely threatened by human impacts. In the Adriatic Sea loggerhead turtles are often found stranded or floating, but they are also recovered as by-catch from fishing activities. Nevertheless, information about population structuring and origin of individuals found in the Adriatic Sea are still limited. Cooperation with fishermen and a good network of voluntary collaborators are essential for understanding their distribution, ecology and for developing conservation strategies in the Adriatic Sea. In this study, a comparative analysis of biometric data and DNA sequence polymorphism of the long fragment of the mitochondrial control region was carried out on ninety-three loggerheads recovered from three feeding areas in the Adriatic Sea: North-western, North-eastern and South Adriatic. Differences in turtles body sizes (e.g. Straight Carapace Length) among the three recovery areas and relationship between SCL and the type of recovery were investigated. The origin of turtles from Mediterranean rookeries and the use of the Adriatic feeding habitats by loggerheads in different life-stages were assessed to understand the migratory pathway of the species. The analysis of biometric data revealed a significant difference in turtle sizes between the Southern and the Northern Adriatic. Moreover, size of captured turtles resulted significantly different from the size of stranded and floating individuals. Actually, neritic sub-adults and adults are more affected by incidental captures than juveniles because of their feeding behavior. The Bayesian mixed-stock analysis showed a strong genetic relationship between the Adriatic aggregates and Mediterranean rookeries, while a low pro¬portion of individuals of Atlantic origin were detected in the Adriatic feeding grounds. The presence of migratory pathways towards the Adriatic Sea due to the surface current system was reinforced by the finding of individuals bearing haplotypes endemic to the nesting populations of Libya, Greece and Israel. A relatively high contribution from Turkey and Cyprus to the Northwest and South Adriatic populations was identified when the three sampled areas were analyzed independently. These results have to be taken in account in a conservative perspective, since coastal hazards, affecting the population of turtles feeding in the Adriatic Sea may also affect the nesting populations of the Eastern Mediterranean with a unique genetic pattern.
Resumo:
Semantic Web technologies provide the means to express the knowledge in a formal and standardized manner, enabling machines to automatically derive meaning from the data. Often this knowledge is uncertain or different degrees of certainty may be assigned to the same statements. This is the case in many fields of study such as in Digital Humanities, Science and Arts. The challenge relies on the fact that our knowledge about the surrounding world is dynamic and may evolve based on new data coming from the latest discoveries. Furthermore we should be able to express conflicting, debated or disputed statements in an efficient, effective and consistent way without the need of asserting them. We call this approach 'Expressing Without Asserting' (EWA). In this work we identify all existing methods that are compatible with actual Semantic Web standards and enable us to express EWA. In our research we were able to prove that existing reification methods such as Named Graphs, Singleton Properties, Wikidata Statements and RDF-Star are the most suitable methods to represent in a reliable way EWA. Next we compare these methods with our own method, namely Conjectures from a quantitative perspective. Our main objective was to put Conjectures into stress tests leveraging enormous datasets created ad hoc using art-related Wikidata dumps and measure the performance in various triplestores in relation with similar concurrent methods. Our experiments show that Conjectures are a formidable tool to express efficiently and effectively EWA. In some cases, Conjectures outperform state of the art methods such as singleton and Rdf-Star exposing their great potential. Is our firm belief that Conjectures represent a suitable solution to EWA issues. Conjectures in their weak form are fully compatible with Semantic Web standards, especially with RDF and SPARQL. Furthermore Conjectures benefit from comprehensive syntax and intuitive semantics that make them easy to learn and adapt.