The effects of PVAc treatment and organic solvent removal on δ13C, δ15N,and δ18O values of collagen and hydroxyapatite in a modern bone

The stable isotopic analysis of archaeological and paleontological bones has become a common method to examine questions of ecology, climate, and physiology. As researchers addressing such questions incorporate museum collections in their studies, it is necessary to understand the isotopic effects of common preservation techniques utilized in such collections to ensure the preservation of original isotopic values. This study examines the effects of PVAc glue (polyvinyl acetate) applied in acetone solution and the subsequent removal of PVAc using various organic solvents on the δ¹³C and δ¹⁵N values of extracted bone collagen, the δ¹³C and δ¹⁸O values of carbonate in bone hydroxyapatite, and the δ¹⁸O values of phosphate in hydroxyapatite. The data demonstrate that isotopic values in the collagen and phosphate are unaffected by any combination of PVAc treatment and solvent application. The carbonates show little variation in δ¹³C values, but exhibit variable δ¹⁸O values upon exposure to the PVAc solution. It is here suggested that δ¹⁸O values from carbonates in PVAc-treated bones do not retain an original isotopic value and should not be included in future studies.     

Movements upon movements: Refugee and activist struggles to open the Balkan route to Europe

ABSTRACT

In 2015–2016, 1.2 million refugees sought safety in Europe via the Balkan Route. How, in an era of securitized borders, did this unprecedented movement of people from the global south reach the global north? Ethnographic research from two post-Yugoslav nodes along the Route—Preshevë, Serbia and Ljubljana, Slovenia—offers answers that diverge from state-centric accounts, revealing that the relationships between movements, in the sense of both migration and activism, were integral to the dynamics of the Route.