Browsing by Subject "Forensic anthropology"
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Item Standardized decomposition rates of human remains in the West Texas area(Texas Tech University, 2004-08) Cavness, Gina DeeAnnRecent requests by law enforcement agents for accurate time since death analysis has led to the necessity for region specific data. This study focuses on the decomposition rate of human tissue for the West Texas environment. Fourteen human limbs were placed in wire rabbit hutches on the ground of the Texas Tech Native Rangeland. Data was collected on the type of animals and insects present and their impact on the decomposition process. Also collected were weather and climatic data for the months of March through September. This study shows that skeletalization of the remains is directly affected by environmental factors. Skeletalization first began two weeks after the study was started and became completed by the third month, in most specimens. Application of this study will contribute to an accurate estimation of time since death for human remains found in the West Texas area.Item The petrous portion of the human temporal bone: potential for forensic individuation(2009-06-02) Wiersema, Jason MatthewIn this dissertation I evaluate the potential of the morphology of the petrous portion of the human temporal bone as seen on axial CT scans of the head as a means to generate identifications of fragmentary human skeletal remains. The specific goals are threefold: (1) To investigate variability in the shape of the petrous portion of the human temporal bone using two-dimensional morphometric analysis; (2) to evaluate the reliability of the resultant method in forensic identification; and (3) to consider the results within the framework of Bayesian theory in light of recent rulings regarding the admissibility of forensic testimony. The data used in this research were collected from axial CT images of the cranium. Two sets of images were collected for each of the 115 individuals in the sample so that Euclidean distance comparisons could be made between images of the same individual and images from different individuals. I collected two-dimensional coordinate data from 36 landmarks on each of the CT images and calculated the distances between each of the coordinate points to generate the data used in the statistical analyses. I pared down this set of measurements using two different models (referred to as the biological and PCFA models). The measurement sets of both models were then compared to one another using nearest neighbor analysis, to test their relative efficiency in matching replicate images to one another. The results of both models were highly accurate. Three incorrect nearest neighbor matches resulted from the biological model and 5 from the PCFA model. The errors appear to have been the result of variation in the axial plane between the first and second scans. The results of the nearest neighbor comparisons were then considered within the context of Bayes' Theorem by calculating likelihood ratios and posterior probabilities. The likelihood ratios and posterior probabilities were very high for both models, indicating that: 1) there is significant individual variability in the measurements of the petrous portion used in this research, and 2) this variation represents a high level of potential accuracy in the application of this method in the identification of forensic remains.