44 resultados para imprinting approaches


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The application of scientific-based conservation measures requires that sampling methodologies in studies modelling similar ecological aspects produce comparable results making easier their interpretation. We aimed to show how the choice of different methodological and ecological approaches can affect conclusions in nest-site selection studies along different Palearctic meta-populations of an indicator species. First, a multivariate analysis of the variables affecting nest-site selection in a breeding colony of cinereous vulture (Aegypius monachus) in central Spain was performed. Then, a meta-analysis was applied to establish how methodological and habitat-type factors determine differences and similarities in the results obtained by previous studies that have modelled the forest breeding habitat of the species. Our results revealed patterns in nesting-habitat modelling by the cinereous vulture throughout its whole range: steep and south-facing slopes, great cover of large trees and distance to human activities were generally selected. The ratio and situation of the studied plots (nests/random), the use of plots vs. polygons as sampling units and the number of years of data set determined the variability explained by the model. Moreover, a greater size of the breeding colony implied that ecological and geomorphological variables at landscape level were more influential. Additionally, human activities affected in greater proportion to colonies situated in Mediterranean forests. For the first time, a meta-analysis regarding the factors determining nest-site selection heterogeneity for a single species at broad scale was achieved. It is essential to homogenize and coordinate experimental design in modelling the selection of species' ecological requirements in order to avoid that differences in results among studies would be due to methodological heterogeneity. This would optimize best conservation and management practices for habitats and species in a global context.

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The application of luminescence dating to young volcanic sediments has been first investigated over three decades ago, but it was only with the technical innovations of the last decade that such analyses became viable. While current analytical procedures show promise for dating late Quaternary volcanic events, most efforts have been aimed at unconsolidated volcanic tephra. Investigations into direct dating of lava flows or of non-heated volcanoclastics like phreatic explosion layers, however, remain scarce. These volcanic deposits are of common occurrence and represent important chrono- and volcanostratigraphic markers. Their age determination is therefore of great importance in volcanologic, tectonic, geomorphological and climate studies. In this article, we propose the use of phreatic explosion deposits and xenolithic inclusions in lava flows as target materials for luminescence dating applications. The main focus is on the crucial criterion whether it is probable that such materials experience complete luminescence signal resetting during the volcanic event to be dated. This is argued based on the findings from existing literature, model calculations and laboratory tests.

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Hypereosinophilic syndromes are a heterogeneous group of uncommon disorders characterized by the presence of marked peripheral blood eosinophilia, tissue eosinophilia, or both, resulting in a wide variety of clinical manifestations. Although corticosteroids are the first-line therapy for many of these disorders, approaches to the treatment of patients who do not tolerate or are unresponsive to corticosteroids are poorly standardized. A multidisciplinary group of 37 clinicians and scientists participated in a workshop held in May 2005 in Bern, Switzerland to discuss current and future approaches to therapy for 3 eosinophil-mediated disorders: hypereosinophilic syndrome, Churg-Strauss syndrome, and eosinophil-associated gastrointestinal disease. The goal of the workshop was to summarize available data regarding treatment of these disorders to identify the most promising therapies and approaches for further study. There was consensus among all of the participants that the identification of markers of disease progression to assess treatment responses is a research priority for all 3 disorders. Furthermore, the need for newer therapeutic strategies and novel drugs, as well as multicenter trials to assess all treatment modalities, was emphasized.