Analysis of Age‐at‐Death Estimation Through the Use of Pubic Symphyseal Data*
ABSTRACT The question of whether age parameters derived from an American population will reliably estimate age-at-death for East European skeletal populations is important since the ability to accurately estimate an individual’s age-at-death hinges on what standard is used. A reference sample of identified individuals with known ages-at-death from the regions of the Former Yugoslavia (n = 861) is used to determine the age structure of victims and serves as the prior in the Bayesian analysis. Pubic symphyseal data in the manners of Todd (Am J Phys Anthropol, 3 , 285; Am J Phys Anthropol, 4 , 1) and Suchey-Brooks (Am J Phys Anthropol, 80 , 167) were collected for n = 296 Balkan males and females and for n = 2078 American males and females. An analysis of deviance is calculated using an improvement chi-square to test for population variation in the aging processes of American and East European populations using proportional odds probit regression. When males and females are treated separately, there is a significant association among females and the population (df = 1, chi-square likelihood ratio = 15.071, p = 0.001). New age estimates for Balkan populations are provided and are based on the calculated age distribution from the Gompertz-Makeham hazard analysis and the ages-of-transition. To estimate the age-at-death for an individual, the highest posterior density regions for each symphyseal phase are provided.
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ABSTRACT: Despite the recent increase in studies that involve the experimental burning of human remains and analysis of heat-induced change both taphonomic and traumatic, research focused on the analysis of thoroughly cremated or calcined bone is rare. The intent of the current study is to add to the existing literature and augment methodologies for the interpretation of severely burned fragmentary remains such as those from mass fatality contexts in which explosions or fire destroy the traditional means for identification. Earlier commercial cremains research focused on mechanically pulverized or processed cremains, post-cremation weights, differences between sexes and molecular composition. In contrast, this research studies human remains cremated in a commercial crematory retort without pulverization that yielded observations of recognizable skeletal elements that survived the firing process. Therefore, this commercial cremains research can be better applied to forensic fire contexts. The unprocessed cremains of 19 individuals were carefully inventoried and analyzed macroscopically. This study focused on the skeletal elements that lend themselves to the determination of biological profile (e.g. mastoid process, supraorbital ridge, greater sciatic notch) and included the degree of preservation of such elements. A 5-point completeness scoring system was developed to better reflect the variable preservation throughout the sample. Estimates of sex, age-at-death and ancestry were made when preservation permitted. However, the marked destruction of the facial skeleton did not allow for the observation of nonmetric traits necessary for ancestry estimation and the estimation of stature was beyond the scope of the current study. Sex was estimated correctly in 88% of the 18 cases in which preservation allowed for an estimate. Age-at-death estimation was correct in only 68% of the 16 cases for which the survival of the auricular surface and pubic symphyses allowed for the generation of an age range. The successful application of traditional anthropological techniques such as auricular surface aging and metric sexing of the postcranial skeleton, to the calcined remains in the current study demonstrates that valuable information can still be gleaned from a human body that has undergone sustained exposure to temperatures exceeding 870˚C(1600˚F). These findings are encouraging because they suggest that the concept of burned beyond recognition is a myth rather than the inevitable result of fire acting upon human remains.Theses and Dissertations-Anthropology. 01/2010;
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ABSTRACT: Gompertz-related distributions have dominated mortality studies for 187 years. However, nonrelated distributions also fit well to mortality data. These compete with the Gompertz and Gompertz-Makeham data when applied to data with varying extents of truncation, with no consensus as to preference. In contrast, Gaussian-related distributions are rarely applied, despite the fact that Lexis in 1879 suggested that the normal distribution itself fits well to the right of the mode. Study aims were therefore to compare skew-t fits to Human Mortality Database data, with Gompertz-nested distributions, by implementing maximum likelihood estimation functions (mle2, R package bbmle; coding given). Results showed skew-t fits obtained lower Bayesian information criterion values than Gompertz-nested distributions, applied to low-mortality country data, including 1711 and 1810 cohorts. As Gaussian-related distributions have now been found to have almost universal application to error theory, one conclusion could be that a Gaussian-related distribution might replace Gompertz-related distributions as the basis for mortality studies.The Journals of Gerontology Series A Biological Sciences and Medical Sciences 12/2012; · 4.31 Impact Factor
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ABSTRACT: Despite the prominent use of the Suchey-Brooks (S-B) method of age estimation in forensic anthropological practice, it is subject to intrinsic limitations, with reports of differential interpopulation error rates between geographical locations. This study assessed the accuracy of the S-B method to a contemporary adult population in Queensland, Australia and provides robust age parameters calibrated for our population. Three-dimensional surface reconstructions were generated from computed tomography scans of the pubic symphysis of male and female Caucasian individuals aged 15-70 years (n = 195) in Amira® and Rapidform®. Error was analyzed on the basis of bias, inaccuracy and percentage correct classification for left and right symphyseal surfaces. Application of transition analysis and Chi-square statistics demonstrated 63.9 and 69.7% correct age classification associated with the left symphyseal surface of Australian males and females, respectively, using the S-B method. Using Bayesian statistics, probability density distributions for each S-B phase were calculated, providing refined age parameters for our population. Mean inaccuracies of 6.77 (±2.76) and 8.28 (±4.41) years were reported for the left surfaces of males and females, respectively; with positive biases for younger individuals (<55 years) and negative biases in older individuals. Significant sexual dimorphism in the application of the S-B method was observed; and asymmetry in phase classification of the pubic symphysis was a frequent phenomenon. These results recommend that the S-B method should be applied with caution in medico-legal death investigations of Queensland skeletal remains and warrant further investigation of reliable age estimation techniques. Am J Phys Anthropol, 2013. © 2013 Wiley Periodicals, Inc.American Journal of Physical Anthropology 01/2013; · 2.48 Impact Factor