1,721,113 research outputs found
An application of Fuzzy Decision Theory: to cost-benefit analysis of pest management strategies
No full textMetapopulation model as useful tools for management in a fragmented habitat. Ambiente, risorse e sviluppo
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The dialectics of sustainability
No full textMost approaches to sustainability are rooted in general system thinking. In this framework, linkage patterns are key factors for understanding the dynamics of the systems and whose knowledge is fundamental to search for trajectories that guide our society toward greater sustainability. Nevertheless, multiple linkages do not merely transmit impacts and allow greatly separated components to communicate. They also allow opposites to manifest in their dynamic consequences, and they become the locus for explanation of the whole-and-part relationship. I show here, by using Levins’ loop analysis, that these dialectical attributes emerge in the context of sustainability and that they can bring about practical implications
Using dominator trees to catch secondary extinction in action
No full textIn ecosystems a single extinction event could eventually precipitate in a mass extinction, involving species that may be several connections away from the target of the perturbation. To forecast the effects of a species removal one can use an algorithm that unfolds a complex food web into a topologically simpler scheme, called dominator tree. This structure has revealed simple. elegant, and highly informative. Aim of this research is to test the dominator tree model in cases where secondary extinction has been observed
A hundred years of food web aggregation: the case study of the Barents Sea
No full textThe difference between various food web aggregation approaches is discussed. We review the history of food web aggregation (e.g. using trait combinations), lumping data (e.g. temporal food webs) and the biological relevance of food web resolution (e.g. larval stages). The effects of aggregation approaches on food web structure (e.g. the number of links between species at intermediate trophic levels) and the needs for standards (e.g. testing predictions) are briefly discussed. Finally, a case study of the Barents Sea food web is used for illustration, where we compare the outcome of biological and mathematical approaches to food web aggregation. Future research directions are also suggested and discussed, including the role of experimental food web research and better relating interaction networks to co-occurrence networks
Competitive factors of the agro-food E-commerce
No full textIn the new economy small and medium enterprises face new challenges in their business-to-consumers transactions, such as the use of new information and communication technologies. Electronic commerce may represent a competitive strategy to make enterprises of the agro-food sector more visible to consumers, if usability is adequately taken into account. The main barrier to the development of successful e-commerce business is represented by websites not meeting basic accessibility and usability features. To tackle this issue, heuristic evaluation and the gap analysis approach was adopted. The parameters taken into account stemmed from international Web recommendations and from previous surveys in the literature. Web site usability issues have been measured by a panel of consumers assessing a selected Web site each. Potential e-consumers simulated an online purchase, thereby allowing them to acquire insights on the importance and satisfaction on each of the usability issues taken into consideration. The success factors for e-commerce mainly involve efficiency of navigation (useful navigation tools or sequence of navigation), accuracy in content and supplied information. Consumers are more conduced to purchase by easy structure of Web sites than design and style. Additional information underlining the connection of producers to their territory enhances end-consumers' feel in supply chain identification. The adoption of e-commerce, as an innovative communication challenge in rural development and in regional identity is a crucial issue of dynamic food chains
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