The survival of organic matter in bone: a review

If bone is considered as a composite of collagen (protein) and bioapatite (mineral), then three pathways of diagenesis are identified: (1) chemical deterioration of the organic phase; (2) chemical deterioration of the mineral phase; and (3) (micro) biological attack of the composite. The first of these three pathways is relatively unusual and will only occur in environments that are geochemically stable for bone mineral. However, because rates of biomolecular deterioration in the burial environment are slow, such bones would yield useful biomolecular information. In most environments, bones are not in thermodynamic equilibrium with the soil solution, and undergo chemical deterioration (path 2). Dissolution of the mineral exposes collagen to biodeterioration, and in most cases the initial phase of dissolution will be followed by microbial attack (path 3). Biological attack (3) also proceeds by initial demineralization; therefore paths 2 and 3 are functionally equivalent. However,in a bone that follows path 3 the damage is more localized than in path 2, and regions equivalent to path 1 may therefore exist outside these zones of destruction. Other biomolecules, such as blood proteins, cellular lipids and DNA, exist within the physiological spaces within bone.For these biomolecules, death history may be particularly important for their survival.     

Quantifying histological changes in archaeological bones using BSE–SEM image analysis

Recent years have seen rapid developments in the understanding of diagenetic changes to archaeological bones. In particular, the degradation or preservation of proteins and other biomolecules has been explored using an increasingly sophisticated battery of analytical techniques. Problems remain, however, in correlating these parameters with physical changes to bone that may be observed microscopically. This is due, in part, to the problems in reproducibly quantifying histological changes to archaeological bone. This paper introduces a novel method for the accurate quantification of these changes employing image analysis of SEM images. Self–consistency of results was tested using measurements of total calcium content at different magnifications. The term ‘bioerosion index’ is suggested for the measured parameter.     

ROAD INVESTMENTS,SPATIAL SPILLOVERS,AND DEFORESTATION IN THE BRAZILIAN AMAZON*

ABSTRACT Understanding the impact of road investments on deforestation is part of a complete evaluation of the expansion of infrastructure for development. We find evidence of spatial spillovers from roads in the Brazilian Amazon: deforestation rises in the census tracts that lack roads but are in the same county as and within 100 km of a tract with a new paved or unpaved road. At greater distances from the new roads the evidence is mixed, including negative coefficients of inconsistent significance between 100 and 300 km, and if anything, higher neighbor deforestation at distances over 300 km.     

Quantitative non-destructive analysis of metals in artefacts

Work on corroded lead-iron shot from the Mary Rose led to the development of two non-destructive techniques which can be employed to determine quantitatively the amounts of metals in a bimetallic artefact. The methods are described, equations produced and experiments conducted to authenticate the data produced. Both methods are relatively simple and need little equipment.