Is X-ray diffraction able to distinguish between animal and human bones?

The possibility of determining the human or animal origin of bones from the lattice parameters of their inorganic bioapatite phase, when subjected to a high temperature treatment using the powder X-ray diffraction (XRD) technique, has been explored on a wide number of specimens. Forty-two animal bones were treated in a furnace at 1100 °C for 36 min and compared to 53 cremated human bones from a range of ancient necropolises. The X-ray diffraction patterns of bioapatite were simulated using both monoclinic P21/b and hexagonal P63/m structures to verify any occurrence of phase transformation and any difference in the lattice parameters due to the model. It was determined that the differences between the a-axis and c-axis of the monoclinic and hexagonal lattice were unimportant. Some outlying values were revealed to be caused by the presence of chlorine ions diffused into the apatite structure increasing its average unit cell values. Nevertheless, our results clearly show that in terms of lattice parameters the variability of human specimens are completely overlapped by the non-human variability making the use of XRD in order to distinguish animal from human bones questionable.     

Italy and Africa: how to forget colonialism

Abstract

The debate on colonialism places great emphasis on the composite set of transformations put in motion by colonialism fully to give birth to what became the post-colonial state in independent Africa. Many authors suggest that Italian colonialism in the Horn of Africa was too weak to perform this task. The present article intends to review the influence and effects of the Italian colonial experience for state making in the Horn of Africa. This also brings about one of the main anomalies of the Horn of Africa, where colonialism ended without a process of true decolonization, in the sense of a confrontation between colonized and colonizers in the transfer of power from metropolitan rule to African representatives. The present Italian foreign policy in Africa is similarly conditioned by its colonial history: besides its focus on the Horn of Africa, which was the centre of Italy's colonial expansion as well as the only post-Second WorldWar administration (Italian Trust Administration of Somalia – AFIS), the relations between Italy and Africa reflect the many inconsistencies and uncertainties of the colonial experience.     

A new calibration of the XRD technique for the study of archaeological burned human remains

A new calibration of human bones as a function of programmed temperature (200–1000 °C) and time (0, 18 and 60 min) is presented and discussed in order to investigate the issues related to the study of cremated bone remains by using the powder X-ray diffraction approach. The experimental results confirm the growth of hydroxylapatite crystallites as a function of the applied temperature, with a sigmoid behaviour that has been parameterized to the experimental data points. Particularly, it was observed that the thermal treatments for 60 min anticipate of about 100 °C the effects that are otherwise observed after the treatments for 0 min. The developed procedure was subsequently applied to cremated remains of various archaeological sites of Spain and supplied precise information not only about the temperature reached during the funerary rites, but also on the presumed duration for the cremation.     

An X-ray Diffraction (XRD) and X-ray Fluorescence (XRF) investigation in human and animal fossil bones from Holocene to Middle Triassic

We examined by Rietveld refinement of X-ray Diffraction patterns a series of 61 human and animal fossil bones in an age range from present time to Middle Triassic (around 245 Ma). This approach, supplemented by elemental analysis according to X-ray Fluorescence, has permitted to obtain a quantitative evaluation of the mineralogical phases in the specimens, thus allowing to reconstruct the mineralization process involved. Concerning the apatite phase, after adopting a monoclinic geometry for the unit cell, the method permits to determine with fair degree of precision the unit cell volume, which is found to decrease in relatively short geological times as a function of the fluorine substitution process for the hydroxyl group –OH. After excluding the role of a high-temperature fire treatment to the bones, it is found that a certain linear correlation may exist over the geological time scale involved between the age of the specimen and the average crystallite size. This observation permits to use the XRD pattern as an evaluation of the age of the fossil, although the stratigraphic observations, where available, remain as the main reliable source for dating such biomaterials. The uncertainty related to this age estimation may be hardly better than 15–20% in absolute, because of various assumptions involved in the XRD methodology used and in the variability of the burial environment that may be subjected to discontinuous changes over the very long time of deposition.     

A study by thermal treatment and X-ray powder diffraction on burnt fragmented bones from tombs II,IV and IX belonging to the hypogeic necropolis of “Sa Figu” near Ittiri,Sassari (Sardinia,Italy)

In the course of an anthropological investigation of three tombs of the hypogeic necropolis of “Sa Figu” (near the village of Ittiri in North Sardinia, Italy), numerous burnt bone fragments were collected. In particular, from the whole necropolis we selected a tenth of long bones from tomb IV, a small fragment of femur from tomb II and four fragments belonging to tomb IX. The aim of this work is to determine a temperature range to which the bone fragments were heated, in order to assess a funerary cremation which was presumably used at that time to quickly and hygienically eliminate the flashy parts of deceased people rather than a purification rite with fires inside the sepulchres. We attempted to evaluate the range of temperature to which the bones were likely subjected, making a joint use of thermal treatment and powder X-ray diffraction investigations. From our X-ray line broadening results carried out with a modern approach (Rietveld method), it emerged that a group of five fragmented burnt bones (one specimen belonging to tomb IV, the other four from tomb IX) were subjected to a heat treatment in a temperature range from 600 and 750 °C. Conversely another group of bones (belonging to tombs II and IV) turned out to be subjected to temperatures not higher than 250 °C.