2 resultados para Temporal variability

em Biblioteca Digital da Produção Intelectual da Universidade de São Paulo (BDPI/USP)


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Changes in species composition is an important process in many ecosystems but rarely considered in systematic reserve site selection. To test the influence of temporal variability in species composition on the establishment of a reserve network, we compared network configurations based on species data of small mammals and frogs sampled during two consecutive years in a fragmented Atlantic Forest landscape (SE Brazil). Site selection with simulated annealing was carried out with the datasets of each single year and after merging the datasets of both years. Site selection resulted in remarkably divergent network configurations. Differences are reflected in both the identity of the selected fragments and in the amount of flexibility and irreplaceability in network configuration. Networks selected when data for both years were merged did not include all sites that were irreplaceable in one of the 2 years. Results of species number estimation revealed that significant changes in the composition of the species community occurred. Hence, temporal variability of community composition should be routinely tested and considered in systematic reserve site selection in dynamic systems.

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Previous studies have documented a subjective temporal attraction between actions and their effects. This finding, named intentional binding, is thought to be the result of a cognitive function that links actions to their consequences. Although several studies have tried to outline the necessary and sufficient conditions for intentional binding, a quantitative comparison between the roles of temporal contiguity, predictability and voluntary action and the evaluation of their interactions is difficult due to the high variability of the temporal binding measurements. In the present study, we used a novel methodology to investigate the properties of intentional binding. Subjects judged whether an auditory stimulus, which could either be triggered by a voluntary finger lift or be presented after a visual temporal marker unrelated to any action, was presented synchronously with a reference stimulus. In three experiments, the predictability, the interval between action and consequence and the presence of action itself were manipulated. The results indicate that (1) action is a necessary condition for temporal binding; (2) a fixed interval between the two events is not sufficient to cause the effect and (3) only in the presence of voluntary action do temporal predictability and contiguity play a significant role in modulating the effect.These findings are discussed in the context of the relationship between intentional binding and temporal expectation. (C) 2010 Elsevier B.V. All rights reserved.