Osteological applications of high-resolution computed tomography: a prehistoric arrow injury

In comparison to conventional computed tomography (CT) and radiography, high-resolution CT is a superior means of visualizing and quantifying fine structures in a wide range of materials. Here the shape and size of a chert arrowhead lodged in a 700-year-old tibia from Norris Farms #36, Illinois, are identified, as are the bony response and the arrow's probable trajectory through the bone. The use of high-resolution CT – in this instance, to identify structures down to the level of individual trabeculae – can be used in other archaeological applications when fine details are important and specimens cannot be damaged by invasive (i.e., destructive) procedures.     

Endogenous Fractal Dynamics at Alpine Treeline Ecotones

Many of the hypotheses proposed to explain ecotones are based on an individualistic paradigm and are essentially static. While they include local feedbacks, they ignore the interactions between pattern and process across scales. These feedbacks in ecotones are nonlinear in nature and complicate the relations of pattern and process in vegetation, which, combined with observed fractal patterns, suggests a complexity science approach to investigate ecotone dynamics. A cellular automaton of alpine treeline, including nonlinear, local, positive, and negative feedbacks in tree establishment and mortality, as reported in field studies, is used as a model system. Fourier analysis of simulated alpine treelines shows fractal patterns across the treeline landscapes, which are created by patch development. The temporal evolution of the spatial pattern is also fractal. Landscape scale linear correlations between spatial pattern and the rate of advance of trees into tundra arise from localized nonlinear interactions. A tree-patch-landscape scale explanation of pattern–process interaction is proposed in which the endogenous feedbacks determine the spatial and temporal fractal properties of the ecotone. The simulated treeline advance exhibits self-organized complexity and may indicate a potential strategy for monitoring change.     

An Investigation of Ceramic Forming Method Using Reverse Engineering Techniques: The Case of Oinochoai from Dion, Macedonia, Greece

A method for investigating the forming technique of ancient ceramic vessels is presented. The recording, analysis, and comparison of the vessels' metrical properties by means of computer tomography, three-dimensional laser scanning, and solid-modeling software enables the identification of the applied manufacturing methods. A finite elements method-based simulation of the developed deformations during the vessels' manufacture offers significant insight into the applied shaping procedures. By making possible the exact recording of both the internal and external form of the vessels as well as the simulation of the forming procedure, the method represents a marked improvement to hitherto applied methods based on radiography. The method is applied on two early iron age ceramic jugs (oinochoai) found as offerings in tombs in excavations in Dion, Greece.