Using accumulated degree-days to estimate the postmortem interval from decomposed human remains.

Forensic anthropologists often rely on the state of decomposition to estimate the postmortem interval (PMI) in a human remains case. The state of decomposition can provide much information about the PMI, especially when decomposition is treated as a semi-continuous variable and used in conjunction with accumulated-degree-days (ADD). This preliminary study demonstrates a supplemental method of determining the PMI based on scoring decomposition using a point-based system and taking into account temperatures in which the remains were exposed. This project was designed to examine the ways that forensic anthropologists could improve their PMI estimates based on decomposition by using a more quantitative approach. A total of 68 human remains cases with a known date of death were scored for decomposition and a regression equation was calculated to predict ADD from decomposition score. ADD accounts for approximately 80% of the variation in decomposition. This study indicates that decomposition is best modeled as dependent on accumulated temperature, not just time.

Reconsidering the auricular surface as an indicator of age at death.

Using standards established by Lovejoy et al. to estimate age at death from auricular surface morphology, 266 individuals of documented age, sex, and ancestry from the Terry and Bass Donated Collections were scored. Analysis of covariance (ANCOVA) indicates that for the factors that could be controlled, age is the sole influence on auricular surface morphology. Ancestry and sex had no significant effect on auricular phase expression. No evidence of secular changes was detected when comparing the Terry Collection (early 20th century) to the Bass Collection (later 20th century). Pearson correlations reveal that several of the subcomponents of the auricular surface (superior and inferior demifaces, left and right sides, transverse organization, texture) correspond with age equally well, although a combined scoring of all features performs slightly better than any one indicator taken alone. Not surprisingly, only 33% of the sample was correctly aged when using the 5-year age ranges provided by Lovejoy et al., suggesting that the published ranges are much too narrow to be used in forensic contexts. To assess the variation in age per phase, standard descriptive statistics and error ranges were calculated and can be employed by forensic anthropologists when estimating the age of an unidentified decedent. Because the mean ages of some of the eight phases did not differ significantly from one another, a modified six-phase system is presented. The auricular surface performs as well as any other single skeletal indicator of adult age. This research suggests that a statistically-informed approach should be taken in order to fully understand the drawbacks and limitations of any aging method.

Variation in midfacial tissue thickness of African-American children.

Forensic anthropologists use facial reconstruction to develop a likeness of an unknown individual in order to generate public interest that may lead to a positive identification. Tissue thicknesses of the face from living persons or cadavers are an essential part of the reconstruction method. The purpose of this study is to add to the growing database of tissue thicknesses along the facial midline of African-American children and to begin to examine the possibility of geographic differences between children of the same ancestral group. Results indicate that significant differences do not exist between males and females or between African-American females from the Midwest and Southeast U.S. Only age was determined to have a significant effect on mean tissue thickness variation, in our sample, with the majority of change occurring in the facial region.