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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Three-dimensional image technology in forensic anthropology: assessing the validity of biological profiles derived from CT-3D images of the skeleton

Garcia de Leon Valenzuela, Maria Julia 12 March 2016 (has links)
This project explores the reliability of building a biological profile for an unknown individual based on three-dimensional (3D) images of the individual's skeleton. 3D imaging technology has been widely researched for medical and engineering applications, and it is increasingly being used as a tool for anthropological inquiry. While the question of whether a biological profile can be derived from 3D images of a skeleton with the same accuracy as achieved when using dry bones has been explored, bigger sample sizes, a standardized scanning protocol and more interobserver error data are needed before 3D methods can become widely and confidently used in forensic anthropology. 3D images of Computed Tomography (CT) scans were obtained from 130 innominate bones from Boston University's skeletal collection (School of Medicine). For each bone, both 3D images and original bones were assessed using the Phenice and Suchey-Brooks methods. Statistical analysis was used to determine the agreement between 3D image assessment versus traditional assessment. A pool of six individuals with varying experience in the field of forensic anthropology scored a subsample (n = 20) to explore interobserver error. While a high agreement was found for age and sex estimation for specimens scored by the author, the interobserver study shows that observers found it difficult to apply standard methods to 3D images. Higher levels of experience did not result in higher agreement between observers, as would be expected. Thus, a need for training in 3D visualization before applying anthropological methods to 3D bones is suggested. Future research should explore interobserver error using a larger sample size in order to test the hypothesis that training in 3D visualization will result in a higher agreement between scores. The need for the development of a standard scanning protocol focusing on the optimization of 3D image resolution is highlighted. Applications for this research include the possibility of digitizing skeletal collections in order to expand their use and for deriving skeletal collections from living populations and creating population-specific standards. Further research for the development of a standard scanning and processing protocol is needed before 3D methods in forensic anthropology are considered as reliable tools for generating biological profiles.
2

Estimation of body mass index from the metrics of the first metatarsal

Dunn, Tyler Edward 12 March 2016 (has links)
Estimation of the biological profile from as many skeletal elements as possible is a necessity in both forensic and bioarchaeological contexts; this includes non-standard aspects of the biological profile, such as body mass index (BMI). BMI is a measure that allows for understanding of the composition of an individual and is traditionally divided into four groups: underweight, normal weight, overweight, and obese. BMI estimation incorporates both estimation of stature and body mass. The estimation of stature from skeletal elements is commonly included into the standard biological profile but the estimation of body mass needs to be further statistically validated to be consistently included. The bones of the foot, specifically the first metatarsal, may have the ability to estimate BMI given an allometric relationship to stature and the mechanical relationship to body mass. There are two commonly used methods for stature estimation, the anatomical method and the regression method. The anatomical method takes into account all of the skeletal elements that contribute to stature while the regression method relies on the allometric relationship between a skeletal element and living stature. A correlation between the metrics of the first metatarsal and living stature has been observed, and proposed as a method for valid stature estimation from the boney foot (Byers et al., 1989). Body mass estimation from skeletal elements relies on two theoretical frameworks: the morphometric and the mechanical approaches. The morphometric approach relies on the size relationship of the individual to body mass; the basic relationship between volume, density, and weight allows for body mass estimation. The body is thought of as a cylinder, and in order to understand the volume of this cylinder the diameter is needed. A commonly used proxy for this in the human body is skeletal bi-iliac breadth from rearticulated pelvic girdle. The mechanical method of body mass estimation relies on the ideas of biomechanical bone remodeling; the elements of the skeleton that are under higher forces, including weight, will remodel to minimize stress. A commonly used metric for the mechanical method of body mass estimation is the diameter of the head of the femur. The foot experiences nearly the entire weight force of the individual at any point in the gait cycle and is subject to the biomechanical remodeling that this force would induce. Therefore, the application of the mechanical framework for body mass estimation could stand true for the elements of the foot. The morphometric and mechanical approaches have been validated against one another on a large, geographically disparate population (Auerbach and Ruff, 2004), but have yet to be validated on a sample of known body mass. DeGroote and Humphrey (2011) test the ability of the first metatarsal to estimate femoral head diameter, body mass, and femoral length. The estimated femoral head diameter from the first metatarsal is used to estimate body mass via the morphometric approach and the femoral length is used to estimate living stature. The authors find that body mass and stature estimation methods from more commonly used skeletal elements compared well with the methods developed from the first metatarsal. This study examines 388 `White' individuals from the William M. Bass donated skeletal collection to test the reliability of the body mass estimates from femoral head diameter and bi-iliac breadth, stature from maximum femoral length, and body mass and stature from the metrics of the first metatarsal. This sample included individuals from all four of the BMI classes. This study finds that all of the skeletal indicators compare well with one another; there is no statistical difference in the stature estimates from the first metatarsal and the maximum length of the femur, and there is no statistical between all three of the body mass estimation methods. When compared to the forensic estimates of stature neither of the tested methods had statistical difference. Conversely, when the body mass estimates are compared to forensic body mass there was a statistical difference and when further investigated the most difference in the body mass estimates was in the extremes of body mass (the underweight and obese categories). These findings indicate that the estimation of stature from both the maximum femoral length and the metrics of the metatarsal are accurate methods. Furthermore, the estimation of body mass is accurate when the individual is in the middle range of the BMI spectrum while these methods for outlying individuals are inaccurate. These findings have implications for the application of stature and body mass estimation in the fields of bioarchaeology, forensic anthropology, and paleoanthropology.
3

Nonmetric cranial trait expression in pre-contact Southwest Native Americans and modern Asians

Atkinson, Megan Lynn 09 October 2019 (has links)
Traditionally, pre-contact Native Americans have served as a biological reference for identifying modern Asian individuals in aspects of the biological profile due to their distantly shared genetic history, although this assumption remains largely untested. This study explores the craniomorphic variability between Asian and Asian-derived groups to ascertain whether they can be differentiated using population-specific models. Cranial and mandibular nonmetric trait data were recorded on pre-contact Native Americans (n=150) and compared within a statistical framework to cranial trait data for modern Thai (n=150) and Japanese (n=150) individuals. Chi-square analyses indicate that the groups exhibit statistically significant differences in their trait expressions. Of the 35 traits analyzed, 31 differ significantly between the groups. Binary logistic regression equations for differentiating the Japanese, Thai, and Native Americans are presented, and cross-validated correct classification rates range 60.0-90.0%. Further, the inclusion of sex into the logistic regression equations failed to improve their accuracies. The results indicate that the Native American and Asian groups are not skeletally homogenous due to divergent population histories, and that numerous cranial and mandibular nonmetric traits are resolute enough to detect differences within and between Asian and Asian-derived groups. Thus, this study highlights the utility of nonmetric traits in identifying individuals beyond the traditional African (“Black”), (“White”), and Asian groupings.
4

The overall biological profile of anatomized remains from the Winchester site

Borreson, Bailey 26 January 2024 (has links)
The following research examined the overall biological profile of an anatomized human skeletal assemblage discovered in Winchester, Massachusetts (Middlesex County) in 2020. This assemblage was discovered during construction of a private house in a suburban neighborhood. In addition, this project examined the history of medical teaching specimens and how this new collection connected to the anthropological understanding of this history. For centuries, marginalized individuals, including Black people, poor people, and criminals, were utilized as the cadaver supply for medical schools. The author examined the general biological profile, including sex, age, population affinity, and stature, of the Winchester assemblage. Since none of the fragmented postcranial bones were able to be matched to particular individuals, these estimations served as a profile for the general population of the Winchester assemblage. The skulls were the only parts of the sample that could be treated as specific individuals. Craniofacial nonmetric traits were observed as well as postcranial aspects of the skeleton. The total number (NISP) of adult remains was 14,469. The MNI of the adult remains was 35 based on the left femora. The author hypothesized that the majority of the remains would consist of male individuals, and the age profile would reflect the average age at death during the mid-1800s, which was about 20-40 years old. In addition, it was hypothesized that the majority of individuals would be of Black population affinity, which might indicate that the remains were robbed from Black cemeteries. The majority of the assemblage was indeed comprised of males. Specifically, 60.5% of the pubic symphyses and 58.8% of the greater sciatic notches analyzed were determined to be male. The general average age at death of the sample was 23 to 45 years old. Estimation of population affinity of the sample was attempted; however, the results were not compelling due to the fragmentation of the remains and limited ability to reconstruct crania. The stature of the remains was estimated to range from 58.1 to 69.9 inches or 4 feet 10 inches to 5 feet 10 inches. This biological profile was compared to the demographics of Middlesex County, Massachusetts, and the United States presented by the 1850 U.S. Census and data from the military during that time. The Winchester adult remains had more males than females, similar to the sex representation in Massachusetts’ poorhouses, penitentiaries, jails, and houses of correction during 1850. Unlike these institutions, the general population of Middlesex County had more females than males. The 1850 Census indicates that the majority of individuals in Massachusetts’ poorhouses, penitentiaries, jails, and houses of correction were 24 years and older, which aligns with the estimated aged range for the Winchester adult remains. White and Black individuals were the only population affinities compared in the 1850 Census, and there were significantly more White individuals. The average height of a White male in the US military was 63.7 inches, which aligned with the general stature interval of 58.1 to 69.9 inches for the adult Winchester remains. Future research, including DNA and isotope analyses, could provide further insights into the origins of these individuals discovered at this site.
5

A Paleodemographic Analysis of a Sample of Commingled Human Skeletal Remains at Ohio University

Kincer, Caroline D. 06 July 2018 (has links)
No description available.

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