2 resultados para signature splitting

em Repositório Científico da Universidade de Évora - Portugal


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A corrosion product rarely reported in the literature has been found on the copper support of three miniature paintings of the 17th and 18th centuries. This product, which has been identified as dicoppertrihydroxyformate (Cu2(OH)3HCOO), is an unusual basic copper formate found on copper artifacts. The identification and characterization of dicoppertrihydroxyformate was carried out directly over the corroded surface of the objects, using a nondestructive approach, which combines the integrated use of various microanalytical techniques. Using this approach, it was possible to obtain a set of new reference data about the natural form of Cu2(OH)3HCOO, that will enable its unambiguous identification in other similar objects. In this work, the probable causes that may have contributed to its formation are also discussed.

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In the last three decades, the range of the Egyptian mongoose (Herpestes ichneumon) has increased in the Iberian Peninsula. A panel of microsatellites was used to confront the patterns of genetic diversity of the species with the scenario of its recent northward expansion in its Iberian range. Evidence of substructure and significant genetic differentiation within the studied population were recorded, with a central-northern subpopulation (CNorth) and a southern subpopulation (S). Northward range expansion was supported by the observed allelic frequencies, diversity parameters, and observed heterozygosity of the studied loci, with S showing a higher allelic diversity and a higher number of private alleles than CNorth. Patterns of isolation-by-distance and isolation-by-barrier as a result of the Tagus River were demonstrated, suggesting that the river acted as a semi-permeable barrier, possibly leading to genetic differentiation of the studied population. The observed individuals from CNorth in southern locations and individuals from S in central/northern areas might comprise evidence for long range dispersals across the studied range. A bottleneck event after population expansion was supported by a significant heterozygosity deficiency in CNorth, which is in agreement with a scenario of founder events occurring in recently colonized areas after the crossing of the Tagus River.