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.     

Troubled kids? Locational disadvantage,opportunity structures and social exclusion

ABSTRACT

Young people growing up in poverty often have restricted access to out-of-school enrichment activities that are important for generating the soft skills that support post-school transitions. This paper compares young Australians’ accounts of their opportunity structures – their engagement with enrichment activities, their post-school aspirations, and their knowledge of routes to achieve them – in two suburb types – improver suburbs (close to the median on many indicators) and isolate suburbs (severely disadvantaged on most indicators). While young people in improver suburbs felt able to access facilities and networks in equally or more affluent neighbouring suburbs, young people in isolate suburbs felt excluded from neighbouring suburbs, and experienced more restricted opportunity structures than young people living in improver suburbs, even those who were themselves economically disadvantaged. The paper argues that this geographical experience of exclusion prevents many economically disadvantaged young people from accumulating knowledge and skills valued in post-school settings.