Search results for "pigments."
showing 3 items of 133 documents
MATERIALS AND ARTISTIC TECHNIQUES OF THE FLEMISH WOODEN ALTAR FROM DEPOSITS OF ABATELLIS PALACE MUSEUM (PALERMO, ITALY)
2022
In the frame of the restoration intervention on a 16th century wooden altar performed by the experts of the Gallery of Art for the Sicilian Region ‘Palazzo Abatellis’, a deep scientific investigation of the artwork has been made by a scientific team in order to individuate the constitutive materials and techniques. The outcomes from the multi-analytical analyses supported the scheduling and monitoring of the conservation treatments and revealed the pictorial materials and underdrawing techniques typical of the artistic production for this typology of work of art widespread between the 15th and 16th centuries in central and northern Europe.
Diversity in warning coloration: selective paradox or the norm?
2019
Aposematic theory has historically predicted that predators should select for warning signals to converge on a single form, as a result of frequency-dependent learning. However, widespread variation in warning signals is observed across closely related species, populations and, most problematically for evolutionary biologists, among individuals in the same population. Recent research has yielded an increased awareness of this diversity, challenging the paradigm of signal monomorphy in aposematic animals. Here we provide a comprehensive synthesis of these disparate lines of investigation, identifying within them three broad classes of explanation for variation in aposematic warning signals: …
Long-term changes in pigmentation of arctic Daphnia provide potential for reconstructing aquatic UV exposure
2016
Abstract Despite the biologically damaging impacts of solar ultraviolet radiation (UV) in nature, little is known about its natural variability, forcing mechanisms, and long-term effects on ecosystems and organisms. Arctic zooplankton, for example the aquatic keystone genus Daphnia (Crustacea, Cladocera) responds to biologically damaging UV by utilizing photoprotective strategies, including pigmentation. We examined the preservation and content of UV-screening pigments in fossil Daphnia remains (ephippia) in two arctic lake sediment cores from Cornwallis Island (Lake R1), Canada, and Spitsbergen (Lake Fugledammen), Svalbard. The aims were to document changes in the degree of UV-protective p…