Publications (17)21.47 Total impact
- [Show abstract] [Hide abstract] ABSTRACT: In April 2011, human skeletons were exposed to heavy storms at the outdoor Anthropology Research Facility (ARF) in Knoxville, Tennessee. Of the approximate 125 skeletons at the ARF in April 2011, 30 donations exhibited postmortem damage that could be attributed to the storms. At least 20 of the affected donations exhibit postmortem damage clearly associated with hailstones due to the oval shape and similar small size of the defects observed. The irregular shape and larger size of other defects may be a product of other falling objects (e.g., tree branches) associated with the storms. Storm-related damage was observed throughout the skeleton, with the most commonly damaged skeletal elements being the scapula and ilium, but more robust elements (i.e., femora and tibiae) also displayed characteristic features of hailstone damage. Thus, hailstone damage should be considered when forensic practitioners observe unusual postmortem damage in skeletal remains recovered from the outdoor context.
- [Show abstract] [Hide abstract] ABSTRACT: This study aims to develop Korean-specific equations for stature estimation and compare their performance to existing techniques. Due to a lack of appropriate reference samples in Korea, equations were generated using a hybrid method on 113 Korean unknown skeletons. In this approach, estimates using the anatomical method  were regarded as actual stature. Results revealed that new equations produced more accurate and precise estimates than previous techniques. In addition, due to consistent body proportions of Korean populations through time and space, new equations are applicable to Korean skeletons regardless of their temporal and geographic origins. For obtaining statures at death, particularly in a forensic context, an age correction factor, 0.0426cm/year, should be applied.
- [Show abstract] [Hide abstract] ABSTRACT: Although raccoons are known as one of the most common scavengers in the U.S., scavenging by these animals has seldom been studied in terms of forensic significance. In this research, the seasonal pattern of raccoon scavenging and its effect on human decomposition was investigated using 178 human cadavers placed at the Anthropological Research Facility (ARF) of the University of Tennessee, Knoxville (UTK) between February 2011 and December 2013. The results reveal that (i) the frequency of scavenging increases during summer, (ii) scavenging occurs relatively immediately and lasts shorter in summer months, and (iii) scavenging influences the decomposition process by hollowing limbs and by disturbing insect activities, both of which eventually increases the chance of mummification on the affected body. This information is expected to help forensic investigators identify raccoon scavenging as well as make a more precise interpretation of the effect of raccoon scavenging on bodies at crime scenes.
- [Show abstract] [Hide abstract] ABSTRACT: Postmortem succession of human-associated microbial communities ("human microbiome") has been suggested as a possible method for estimating postmortem interval (PMI) for forensic analyses. Here we evaluate human gut bacterial populations to determine quantifiable, time-dependent changes postmortem. Gut microflora were repeatedly sampled from the proximal large intestine of 12 deceased human individuals as they decayed under environmental conditions. Three intestinal bacterial genera were quantified by quantitative PCR (qPCR) using group-specific primers targeting 16S rRNA genes. Bacteroides and Lactobacillus relative abundances declined exponentially with increasing PMI at rates of Nt = 0.977e(-0.0144t) (r(2) = 0.537, p < 0.001) and Nt = 0.019e(-0.0087t) (r(2) = 0.396, p < 0.001), respectively, where Nt is relative abundance at time (t) in cumulative degree hours. Bifidobacterium relative abundances did not change significantly: Nt = 0.003e(-0.002t) (r(2) = 0.033, p = 0.284). Therefore, Bacteroides and Lactobacillus abundances could be used as quantitative indicators of PMI. © 2015 American Academy of Forensic Sciences.
Conference Paper: The Forensic Anthropology Research Facility: Past and present research
- [Show abstract] [Hide abstract] ABSTRACT: The Anthropological Research Facility allows actualistic studies evaluating human decomposition to be conducted in a controlled, scientific setting. These studies have had significant ramifications for forensic investigations. Donated cadavers are used to study the precise nature and timing of decomposition events. More than 1,000 bodies have been donated, and more than 2,000 individuals are registered for donation on their death. Initial studies using cadavers focused on gross morphological changes of human decomposition, while more recent research has delved into biochemical analyses. This research has contributed to the accuracy of time since death estimations, which may be critical in criminal investigations. Furthermore, the donated cadavers contribute to the unprecedented diversity of the William M. Bass Donated Skeletal Collection, which allows for a wide range of skeletal-based research. The continuous supply of human cadavers is essential for these research endeavors, and the Forensic Anthropology Center strives to ensure that donor wishes are fulfilled and to assure donors that their invaluable gift will serve the scientific community for years to come.
- [Show abstract] [Hide abstract] ABSTRACT: Few accurate methods exist currently to determine the time since death (postmortem interval, PMI) of skeletonized human remains found at crime scenes. Citrate is present as a constituent of living human and animal cortical bone at very uniform initial concentration (2.0 ± 0.1 wt %). In skeletal remains found in open landscape settings (whether buried or not), the concentration of citrate remains constant for a period of about 4 weeks, after which it decreases linearly as a function of log(time). The upper limit of the dating range is about 100 years. The precision of determination decreases slightly with age. The rate of decrease appears to be independent of temperature or rainfall but drops to zero for storage temperature <0°C.
- [Show abstract] [Hide abstract] ABSTRACT: Trotter and Gleser's (1-3) stature equations, conventionally used to estimate stature, are not appropriate to use in the modern forensic context. In this study, stature is assessed with a modern (birth years after 1944) American sample (N = 242) derived from the National Institute of Justice Database for Forensic Anthropology in the United States and the Forensic Anthropology Databank. New stature formulae have been calculated using forensic stature (FSTAT) and a combined dataset of forensic, cadaver, and measured statures referred to as Any Stature (ASTAT). The new FSTAT-based equations had an improved accuracy in Blacks with little improvement over Ousley's (4) equations for Whites. ASTAT-based equations performed equal to those of FSTAT equations and may be more appropriate, because they reflect both the variation in reported statures and in cadaver statures. It is essential to use not only equations based on forensic statures, but also equations based on modern samples.
Chapter: The Anthropology Research Facility
- [Show abstract] [Hide abstract] ABSTRACT: Sex determination is one of the essential steps in personal identification of an individual from skeletal remains. Most elements of the skeleton have been subjected to discriminant function analysis for sex estimation, but little work has been done in terms of the patella. This paper proposes a new sex determination method from the patella using a novel automated feature extraction technique. A dataset of 228 patellae (95 females and 133 males) was amassed from the William M. Bass Donated Skeletal Collection from the University of Tennessee and was subjected to noninvasive high resolution computed tomography (CT). After the CT data were segmented, a set of features was automatically extracted, normalized, and ranked. The segmentation process with surface smoothing minimizes the noise from enthesophytes and ultimately allows our methods to distinguish variations in patellar morphology. These features include geometric features, moments, principal axes, and principal components. A feature vector of dimension 45 for each subject was then constructed. A set of statistical and supervised neural network classification methods were used to classify the sex of the patellar feature vectors. Nonlinear classifiers such as neural networks have been used in previous research to analyze several medical diagnosis problems, including quantitative tissue characterization and automated chromosome classification. In this paper, different classification methods were compared. Classification success ranged from 83.77% average classification rate using labels from a Fuzzy C-Means (FCM) clustering step, to 90.3% for linear discriminant classification (LDC). We obtained results of 96.02% and 93.51% training and testing classification rates, respectively, using feed-forward backpropagation neural networks (NN). These promising results using newly developed features and the application of nonlinear classifiers encourage the usage of these methods in forensic anthropology for identifying the sex of an individual from incomplete skeletons retaining at least one patella.
- [Show abstract] [Hide abstract] ABSTRACT: Five craniofacial variables (glabella-occipital length, basion-bregma height, maximum cranial breadth, nasion-prosthion height, and bizygomatic breadth) were used to examine secular change in morphology from the mid-19(th) century to the 1970s. The 19(th) century data were obtained from the Terry and Hamann-Todd anatomical collections, and the 20(th) century data were obtained from the forensic anthropology databank. Data were available for Blacks and Whites of both sexes. Secular change was evaluated by regressing cranial variables on year of birth. Two analyses were conducted, one using the original variables and one using size and shape. Size is defined as the geometric mean of the cranial variables, and shape is the ratio of each variable to size. The results show remarkable changes in the size and shape of the cranial vault. Vault height increases in all groups in both absolute and relative terms. The vault also becomes longer and narrower, but these changes are less pronounced. Face changes are less than the vault changes, but to the extent that they occur, the face becomes narrower and higher. Overall cranial vault size has increased, but shape changes are greater than size changes. The magnitude of secular change in vault height exceeds that for long bones over a comparable time period, but follows a similar course, which suggests that vault height and bone length respond to the same forces. Changes in vault dimensions must occur by early childhood because of the early development of the vault. Am. J. Hum. Biol. 12:327-338, 2000. Copyright 2000 Wiley-Liss, Inc.
- [Show abstract] [Hide abstract] ABSTRACT: The Cambridge Encyclopedia of Human Growth and Development. Edited by Stanley J. Ulijaszek, Francis E. Johnson, and Michael A. Preece. Cambridge, UK: Cambridge University Press. 1998. 497 pp. ISBN 0-521-56046-2. $95.00 (cloth).
- [Show abstract] [Hide abstract] ABSTRACT: We examine secular change in long bone lengths and allometry of Americans dating from the mid-19th century to the 1970s. Skeletal samples were derived from the Huntington Collection, Terry Collection, World War II casualties, and the Forensic Anthropology Data Bank. Regression of bone length on year of birth allowed evaluation of the secular change in bone length. Size was computed as the geometric mean of all bone lengths, and shape as the ratio of each bone to size. These variables were then regressed on year of birth, allowing evaluation of allometric secular change. The results revealed a pattern of change that can be summarized as follows: male secular change is stronger than female, lower limb bone secular change is more pronounced than upper limb bone change, and distal bones change more than proximal bones, particularly in the lower limb. In males, white changes are uniformly higher than black but these differences do not rise to the level of statistical significance. Environmental forces, such as nutrition and disease, are the usual causes of secular changes in overall size. This paper shows that long bone proportions also respond to these same environmental factors. Moreover, the changes in body proportion are likely to be due to allometric consequences of growth changes that occur early in life. Am J Phys Anthropol 110:57-67, 1999.
- [Show abstract] [Hide abstract] ABSTRACT: Many applied problems in physical anthropology involve estimation of an unobservable quantity (such as age at death or stature) from quantities that are observable. Two of the more disparate subdisciplines of our discipline, paleoanthropology and forensic anthropology, routinely make use of various estimation methods on a case-by-case basis. We discuss the rationales for making estimations on isolated cases, taking stature estimation from femoral and humerus lengths as an example. We show that the entirety of our discussion can be placed within the context of calibration problems, where a large calibration sample is used to estimate an unobservable quantity for a single skeleton. Taking a calibration approach to the problem highlights the essentially Bayesian versus maximum likelihood nature of the question of stature estimation. On the basis of both theoretical arguments and practical examples, we show that inverse calibration (regression of stature on bone length) is generally preferred when the stature distribution for a reference sample forms a reasonable prior, while classical calibration (regression of bone length on stature followed by solving for stature) is preferred when there is reason to suspect that the estimated stature will be an extrapolation beyond the useful limits of the reference sample statures. The choice between these two approaches amounts to the decision to use either a Bayesian or a maximum likelihood method.
- [Show abstract] [Hide abstract] ABSTRACT: Many applied problems in physical anthropology involve estimation of an unobservable quantity (such as age at death or stature) from quantities that are observable. Two of the more disparate subdisciplines of our discipline, paleoanthropology and forensic anthropology, routinely make use of various estimation methods on a case-by-case basis. We discuss the rationales for making estimations on isolated cases, taking stature estimation from femoral and humerus lengths as an example. We show that the entirety of our discussion can be placed within the context of calibration problems, where a large calibration sample is used to estimate an unobservable quantity for a single skeleton. Taking a calibration approach to the problem highlights the essentially Bayesian versus maximum likelihood nature of the question of stature estimation. On the basis of both theoretical arguments and practical examples, we show that inverse calibration (regression of stature on bone length) is generally preferred when the stature distribution for a reference sample forms a reasonable prior, while classical calibration (regression of bone length on stature followed by solving for stature) is preferred when there is reason to suspect that the estimated stature will be an extrapolation beyond the useful limits of the reference sample statures. The choice between these two approaches amounts to the decision to use either a Bayesian or a maximum likelihood method. Yrbk Phys Anthropol 41:65–92, 1998. © 1998 Wiley-Liss, Inc.
The University of Tennessee Medical Center at KnoxvilleKnoxville, Tennessee, United States