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47 results on '"Wagner-Wysiecka, Ewa"'

45. Investigating the degradation of Baltic amber

Author

Shashoua, Yvonne, Wagner-Wysiecka, Ewa, Szwedo, Jacek, Sontag, Elzbieta, Sobecka, Anna, Czebreszuk , Janusz, and Cwalinski, Mateusz

Subjects
FTIR spectroscopy, oxidation, yellowing, baltic amber, degradation
Abstract

A recent survey of the National Museum of Denmark’s (NMD) collections revealed more than 17,000 unique pieces of Baltic amber in the form of beads, jewelry and other decorative pieces, making it one of the largest collections of amber in Europe. After its use as jewelry or other decorative pieces in pre-history, amber is likely to be buried for many years in dry or wet, boggy soils or transported in seawater before discovery. The survey concluded that 45% of amber in NMD’s collections exhibited signs of deterioration, manifested by surface crazing, powdering and discoloration (see Fig.1). Based on surface appearance alone, the condition of the objects seemed to reflect the environments in which they were found. Only 4% of those amber pieces that were excavated from wet bogs or found in water exhibited a high degree of degradation compared with 40% of objects found in dry environments. Amber found in dry soils were frequently recognizable by their pale yellow, friable, surface crusts. By contrast, amber found in wet environments was dark brown in colour with cohesive surfaces. Because the amber collections reflect the economic, social, religious and other cultural beliefs prevalent in pre-historic Europe, it is essential that they are preserved for study and enjoyment by future generations.

Published
2018

46. A botanical view of the ‘Baltic amber forest’: new evidence from seed plants, lichens and fungi

Author

Alexander Schmidt, Eva-Maria Sadowski, Ulla Kaasalainen, Jouko Rikkinen, Ewa Wagner-Wysiecka, Ewa, Helsinki Institute of Sustainability Science (HELSUS), Botany, Viikki Plant Science Centre (ViPS), Plant Biology, Biosciences, Lichens, Finnish Museum of Natural History, and Teachers' Academy

Subjects
1181 Ecology, evolutionary biology
Abstract

Baltic amber forms the largest amber deposit on earth and it is particularly well-known for the plethora of arthropod inclusions. The floristic composition, habitat types and climate of its Eocene source area, however, are still controversial. The differing suggestions range from early Eocene tropical to late Eocene temperate environments, and from lowland to montane forests. We screened a large number of inclusions from historic collections and from recently discovered amber pieces and found many inclusions of seed plants, lichens and microfungi that provide important insights into habitat structure and climate.

47. Anion recognition by alpha-arylazo-N-confused calix[4]pyrroles.

Author

Gu R, Depraetere S, Kotek J, Budka J, Wagner-Wysiecka E, Biernat JF, and Dehaen W

Abstract

The first example of substitution reaction in the free alpha-position of N-confused calix[4]pyrroles is reported: azo-coupling with various arenediazonium salts. The obtained azocompounds were used for studies of their anion-binding properties by UV-Vis spectroscopy.

Published
2005
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