Factors influencing cranial variation between prehistoric Japanese forager populations.

Understanding the factors shaping human crania has long been a goal of biological anthropology, and climate, diet, and population history are three of the most well-established influences. The effects of these factors are, however, rarely compared within a single, variable population, limiting interpretations of their relative contribution to craniofacial form. Jomon prehistoric foragers inhabited Japan throughout its climatic and ecological range and developed correspondingly varied modes of subsistence. We have previously demonstrated that a large sample of Jomon crania showed no clear climatic pattern; here, we examine variation in Jomon crania in more detail to determine if dietary factors and/or population history influence human intrapopulation variation at this scale. Based on well-established archaeological differences, we divide the Jomon into dietary groups and use geometric morphometric methods to analyse relationships between cranial shape, diet, and population history. We find evidence for diet-related influences on the shape of the neurocranium, particularly in the temporalis region. These shape differences may be interpreted in the context of regional variation in the biomechanical requirements of different diets. More experimental biomechanical and nutritional evidence is needed, however, to move suggested links between dietary content and cranial shape from plausible to well-supported. In contrast with the global scale of human variation, where neutral processes are the strongest influence on cranial shape, we find no pattern of population history amongst individuals from these Jomon sites. The determinants of cranial morphology are complex and the effect of diet is likely mediated by factors including sex, social factors, and chronology. Our results underline the subtlety of the effects of dietary variation beyond the forager/farmer dichotomy on cranial morphology and contribute to our understanding of the complexity of selective pressures shaping human phenotypes on different geographic scales. Supplementary Information: The online version contains supplementary material available at 10.1007/s12520-023-01901-6.

Arrangement of high-energy neutron irradiation field and shielding experiment using 4 m concrete at KENS.

An irradiation field of high-energy neutrons produced in the forward direction from a thick tungsten target bombarded by 500 MeV protons was arranged at the KENS spallation neutron source facility. In this facility, shielding experiment was performed with an ordinary concrete shield of 4 m thickness assembled in the irradiation room, 2.5 m downstream from the target centre. Activation detectors of bismuth, aluminium, indium and gold were inserted into eight slots inside the shield and attenuations of neutron reaction rates were obtained by measurements of gamma-rays from the activation detectors. A MARS14 Monte Carlo simulation was also performed down to thermal energy, and comparisons between the calculations and measurements show agreements within a factor of 3. This neutron field is useful for studies of shielding, activation and radiation damage of materials for high-energy neutrons, and experimental data are useful to check the accuracies of the transmission and activation calculation codes.

Incidence of the concrete scalp deformity associated with deep scalp donor sites and management with the Unna cap.

The scalp has become a popular donor site for split-thickness skin grafts. This donor site does, however, have complications, including the concrete scalp deformity, which consists of hairs embedded in a thick, desiccated, exudative crust. This article presents our burn unit's experience with this complication. Fifty-six patients underwent scalp skin graft harvesting between 1984 and 1996. All grafts were quite thick and were used for resurfacing facial burns. Thirty-eight donor sites were treated with medicated gauze, and 18 were treated with the Unna cap, which is an Unna dressing applied over Aquaphor gauze (Beiersdorf, Norwalk, Conn). Eighteen of the 38 patients (32%) treated with medicated gauze developed the concrete scalp deformity. None of the patients treated with the Unna cap developed the deformity. Although useful, the deep scalp donor site has complications, including the concrete scalp deformity. However, with use of the Unna cap dressing, we have had no occurrences of this problem.