Age estimation techniques have utilized cranial suture closure, the sternal rib ends, the auricular surface, and the pubic symphysis, each with varying degrees of success. Although recent research has attempted to advance methodologies for age estimation, little progress has been made in discerning forensic age ranges that are beyond general estimates, especially in the old adult (50+) cohort. Since the accuracy of current aging methods decreases as chronological age increases, degenerative changes within the skeleton could potentially yield useful data for establishing and narrowing age estimates for older individuals, especially where only limited or fragmentary remains are recovered. The purpose of the present study was to conduct a visual examination of joint surfaces typically found to be affected by osteoarthritis (OA) by the fourth decade of life using a modified version of the OA scoring system proposed by Buikstra and Ubelaker (1994). According to archaeological, forensic, and clinical research, OA is most commonly found in the shoulder, hip, and knee, making these joints ideal for use in the present study. Within these three joints, ten osseous surfaces were examined: the acromial facet of the scapula, the glenoid fossa of the scapula, the lateral clavicle, the humeral head, the acetabulum of the os coxa, the femoral head, the medial and lateral femoral condyles, and the medial and lateral facets of the patella. Evidence of lipping, surface porosity, osteophyte formation, and eburnation were recorded on an ordinal scale, along with the percentage of the joint surface that was covered by each of the aforementioned traits. The data gathered from this examination were used to create a composite scoring system for age–at–death estimation using a modern North American sample of 206 White individuals from the W. M. Bass Donated Skeletal Collection and the Boston University Donated Osteological Collection. Significance testing indicated that sex differences were not present in the current analysis. A paired-sample t–test determined that the sample was affected with statistically significant levels of bilateral asymmetry. In addition, the current method is affected by low levels of intraobserver error, with only 5% of the sample being affected. Pearson's and Spearman's correlation coefficient were used to examine the relationship between a selected variable and age. The results of the present study indicate that OA has a positive correlation with age, although some joints show weaker associations than others. The right shoulder showed the highest correlation with age (r = 0.776, rs = 0.769; p < 0.01), followed closely by the left shoulder (r = 0.753, rs = 0.753; p < 0.01). The next highest correlation with age was observed for the left knee (r = 0.545, rs = 0.568; p < 0.01), followed by the right knee (r = 0.459, rs = 0.459; p < 0.01). The lowest correlation was observed in the left hip (r = 0.414, rs = 0.377; p < 0.01) and right hip (r = 0.476, rs = 0.377; p < 0.01). Data from multiple joint surfaces were combined for statistical analysis to create composite variables for each joint. The composite variables are combinations of traits for each joint that stepwise regression demonstrated as the best indictors for narrowing prediction intervals. This created a series of composite scores for the left shoulder, right shoulder, left hip, right hip, left knee and right knee. Individual prediction intervals at the 90% confidence interval were generated to create age ranges for each composite score. The mean age and frequency of each composite score was also recorded. This multifactorial approach demonstrated that the left and right shoulders provided the narrowest prediction intervals and also possessed the highest predictive power for estimating age-at-death. Relative predictive power was determined using R^2. The R^2 value for the right shoulder was the highest at 0.603, followed closely by the left shoulder with an R^2 value of 0.567. The R^2 value for all remaining variables was less than 0.3, indicating weak predictive power. The results of the present study were then compared to the four traditional macroscopic aging techniques: suture closure, morphology of the sternal rib ends, morphology of the auricular surface and the pubic symphysis. Sample distribution, correlation data, derived age ranges and error rates were compared between previous research and the results of the present study. All age estimation techniques demonstrated a positive correlation with age. Age ranges that were derived using Bayesian statistics or individual prediction intervals are more accurate at predicting actual age than those that were generated using confidence intervals of the mean, which provide information for mean age rather than actual age. In addition, the relationship between bone density and survivability of elements is discussed. It was determined that the skeletal elements utilized in traditional macroscopic aging are prone to breakage and loss based on their bone mineral density and location within the skeleton. In contrast, the proposed method utilized areas of the skeleton which are not typically examined for aging yet are likely to survive destruction from common taphonomic forces, making the use of OA in fragmentary or damaged contexts possible. Future research is needed to address the effects of ancestral variation and interobserver on the proposed method.

This research examined the behavior of avian scavenger bone dispersal in a New England environment. The furthest distance that avian species can carry bone elements can be used by search investigators by providing possible distances maximum dispersal. The sizes of bones dispersed by avian species provides context on how bone elements differing in size are transported from the initial site of deposition. The project utilized two locations with elements of varying sizes (large, intermediate, and small) with tracking tags attached to determine the distance and pattern of scavenger displacement. Scavenging was also recorded with motion-sensing game cameras that allowed for differentiation between which species scavenged on which elements, allowing for the distance carried to be associated with individual species. The most common avian scavengers were the northern cardinal (Cardinalis cardinalis), downy woodpecker (Dryobates pubescens), and blue jay (Cyanocitta cristata). The furthest element that was displaced and recovered was a pig rib approximately 62 meters from its initial placement location and it was moved by a crow (Corvus brachyrhynchos). The second furthest element displaced was a pig rib moved approximately 41.5 meters by a Cooper’s hawk (Accipiter cooperii). In addition, six other elements were removed from the platform by birds and not recovered due to possible displacement outside of the search radius and tracking application radius. Overall, 55.0% of elements were recovered within 1 meter of their initial placement location. For elements dispersed under 1 m, Rayleigh z-statistical tests (z =1.328; α = 0.05) for the site location in a wooded area indicated that directionality was not statistically significant, while the location in the wetlands was determined to be statistically significant (z = 20.656; α = 0.05). In addition, a Watson’s U2 Two-Sample Test of Homogeneity (U2 = 0.374) revealed the two groups of average directions are significantly different at α = 0.05. This indicates a difference in direction of displacement between the platforms. For Platform 1 (forested location), the results of the Mann-Whitney U-Test (z = -2.638) indicated that the distances of displacement between the spring and summer seasons are significantly different between the two seasons at α = 0.05. For Platform 2 (wetland location), the results of the Mann-Whitney U-Test (z = -0.859) indicate the distances of displacement between the two seasons were not significantly different between the two seasons at the α = 0.05 value. In addition, Kruskal-Wallis H tests revealed that there was no statistically significant difference between the platform location and the number of site visits for the majority of species. Only two species, cardinals (z = -2.04; α = 0.05) and song sparrows (z = -2.208; α = 0.05), were determined to have a statistically significant difference between the location and the number of site visits.

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With the evolution of forensic technology, methods for positive identification are vast and accurate. These methods allow for a corpse to be identified at almost any point of decomposition. The new technology and new methodology has led to a more creative and resourceful criminal. Although few cases have been documented where chemicals are the mode of disposal, this method provides a seemingly fool proof and effective approach to disposal. Several household chemicals contain harmful agents that when used may result in the masking of identity. The purpose of this study is to indicate which chemicals can be used in order to erode or dissolve the tissues making up the dentition and bone. Four chemicals, potassium hydroxide, sodium hydroxide, muriatic acid (hydrochloric acid) and sulfuric acid were chosen and tested on teeth and bone. The dentition and bone were exposed for a period of eight hours. Measurements including mass and caliper measurements were obtained at two-hour intervals. Of the common chemicals tested, muriatic acid (hydrochloric acid) was the most effective for destroying the tissues.

The present research examined whether the innominate acted as contextual information which resulted in a skewed scoring of skull morphological sex traits and pairs overall (both innominate and skull). Survey participants first assessed the sex of an innominate, then assessed the sex of a skull, using methods standard in the field. The sex of ten skulls and associated innominates, which served as contextual elements to introduce bias, were assessed in two surveys by 22 participants total. Male and female innominates and skulls were mixed and matched to test bias, though it was implied to participants that the paired elements were from the same individual. No significant bias was seen on the level of the skull. However, significant shifts in scores were seen on the level of the overall pair in three out of the five studied, indicating that the sex of the innominate was privileged over that of the skull. This is considered standard procedure in the field as the innominate is more reliable for sex estimation; thus, the findings of the present study are inconsistent with cognitive bias. However, the present study raises questions about the utility of the skull in the estimation of sex in human skeletal remains. While the innominate may be more reliable in sex estimation when both elements are present, this may lead to inattention to valuable information presented by the skull in particular contexts such as commingled burials.

Among the numerous taphonomic influences that can impact biological remains, agricultural activity has one of the most widespread effects. The present research examines the impacts of agricultural activities on buried skeletal remains, both in archaeological and medicolegal contexts. Juvenile pig (Sus scrofa) skeletons were utilized to simulate buried juvenile human aged 3 to 5 years to test the influence of original burial depths and different plowing intervals on the dispersal and the degree of damage caused by an offset disk plow. Ten juvenile pig skeletons were buried in relatively anatomical position, five at a bottom depth of 15 cmbs (cm below the surface) and five at 22 cmbs. They were subjected to different intervals of plowing with one burial at each depth subjected to a single, three, five, seven, or ten plow passes. The disturbed area was surveyed for surface material, and the plow furrows were excavated in 1 m by 1 m units. The excavated soil was screened using a ¼" mesh screen, except for two burials that were screened using a nested ¼" and ⅛" mesh screen to test the differences in recovery between the two screen sizes. The recovered skeletal material was inventoried and assessed for damage. The results of this research showed that while original burial depth had some effect on distribution of bone and the degree to which bone was damaged, the relationship was not statistically significant. The number of plowing intervals did have a significant effect on the distribution and degree of damage. The damage caused to bone by the offset disk plow would be distinguishable from perimortem trauma in dry bone. Comparison of the recovery rates of ¼" and ⅛" mesh found that ⅛" contributed to a higher recovery of juvenile remains at least 3 to 5 years of age in soil with a high gravel content.

This investigation explored the utility of mean osteon area, perimeter, and circularity as parameters for distinguishing between human and non-human bone. Although species of origin can be readily ascribed to undamaged remains, this evaluation can become difficult, if not impossible, when bone macrostructure has been obscured through taphonomic processes such as thermal alteration or extreme fragmentation. If mature Ovis aries, domestic sheep, and human osteon metrics area are significantly different, then osteon metrics can be useful parameters for distinguishing between these tissues and, thus, determining the species of origin for a bone sample of unknown provenience. This investigation consisted of histological analysis of cortical bone from 35 O. aries rib samples. O. aries samples were acquired from Riverslea Farm in Epping, New Hampshire (n = 30) and Cedar Ledge Farm in Somers, Connecticut (n = 5). Mean osteon area, perimeter, and circularity were assessed by manually tracing calibrated digital images of rib cross-sections using the ImageJ software from the National Institute of Health (NIH, Bethesda, MD). The results presented here indicate (1) that there are statistically significant histomorphometric differences between species, specifically goat and sheep, (2) that there are significant histomorphometric differences based on the anatomical, intra-rib sampling location, and (3) that the osteon metrics discussed here are may be poor parameters by which to ascribe the species of origin for remains with no known provenience, based on comparisons with findings from other publications.

Dental cementum is a mineralized tissue that coats the root of a tooth and anchors it into the alveolar socket via the periodontal ligament. Cementum is continuously deposited and mineralized throughout the life of a tooth, preserving the complex developmental processes of root formation in optically distinct histologic layers (Hillson, 1996; 2005). Analysis of these features has several anthropological applications, specifically the analysis of cementum increments and their utility in estimating age and season at death in humans for establishing a more specific post-mortem interval (PMI). Wedel (2007) conducted a pilot study to determine whether dental cementum increment analysis can be used to establish season of death in humans. Wedel (2007) hypothesized that by identifying the timing of the transition between the bands of arrested development and the bands of increased deposition, dental cementum increment analysis can be used to identify the season at death in humans. It was demonstrated that cementum increment analysis is 99% accurate in estimating whether an individual died in either a fall/winter or spring/summer season. The purpose of the present study was to estimate whether cementum bands could accurately be assigned to fall/winter, spring/summer seasons based on their optical properties as being light or dark. A total of 143 teeth of known age and known extraction date drawn from the Boston University Collection and the Antioquia Modern Skeletal Reference Collection in Medellín, Colombia were analyzed using recent protocols for preparation, sectioning, and observing increment lines in cementum. Dental cementum increment analysis was found to be between 61.54% and 71.15% successful in accurately correlating the nature of the last cementum increment to season at death using a combination of image evaluation and through focus evaluation methods on two distinct geographic samples. A through focus evaluation was found to be more successful at identifying the last band formed and is recommended for microscopic analyses estimating season at death using dental cementum increments. Geographic origin did not have a significant influence over the accuracy of the method to estimate season at death, however the results of this study suggest that teeth extracted from cadavers versus living individuals may have some influence on the accuracy of cementum increments to estimate season at death. No significant influence of sex, age, or tooth type on the identification and correlation of the last band formed were detected in this study. An interobserver analysis using digital images of a randomly selected sample of 45 sections found that interobserver agreement on the nature of the last band formed occurred in only 28.8% of the sample. Inconsistencies in the nature of the last band formed between multiple sections prepared from the same tooth were observed, which calls into question the validity of using cementum increments to estimate season at death. The potential limitations for the reliability of using dental cementum increment analysis to determine season at death in humans include the lack of a standardized method for preparing adequate sections for viewing cementum increments, and the subjectivity of identifying the last band in a given section. It is concluded that if the validity and reliability of dental cementum increment analysis as a method for age estimation can be established and configured to meet the criteria of the Daubert Standard, specifically in the adoption of a standardized protocol of analysis, then the validity of using this method for estimating season at death can be further considered.

The classic metaphyseal lesion (CML) is considered to be a strong indicator of physical abuse in infants. These fractures extend through the metaphysis of a long bone near the growth plate, disrupting the trabecular bone structure. The mechanism(s) behind this fracture type are not entirely understood. The present study investigated experimentally the possible loading conditions required to generate CMLs in pig models. Fifty hindlegs from stillborn pigs were tested in torsion using a mechanical testing machine and a digital torque wrench. Fractures to the metaphysis that resemble CMLs were produced during a combined loading event which applied torsion to the knee joint (distal femur, proximal tibia, and proximal fibula). A visual assessment of the physeal surface of each specimen was performed after testing, and classic metaphyseal lesions were identified by comparison with findings from Love et al. (2011). The only fractures seen in both the femora and tibiae were CMLs, with both bone types having 60% (30 of 50) total fractures. The frequency of total fractures on fibulae was less, with 42% (21 of 50). The frequency of CMLs in the fibulae, however, is lower than the frequency of total fractures (38%, n=50), as physeal fractures also presented in some of those bones. Thus, the CML was the most common type of fracture produced due to the torque applied to the bones during testing. When assessing the number of CMLs that occurred on each limb, nine limbs had only one CML present, while 28 limbs had one or more CMLs. Additionally, complete CMLs made up 51.9% (41 of 79) of the total number, while partial made up 48.1% (38 of 79). Out of the 150 bones tested, 79 (52.7%) showed fractures resembling CMLs in human infants. A fracture was 35% more likely to occur in a femur or a tibia than in a fibula, and multiple CMLs per specimen were more common than single CMLs. The physeal surfaces of the specimens recorded as having CMLs showed damage to the trabecular bone. Three physeal fractures were noted; one Type IV physeal fracture on a proximal tibia and one on a proximal fibula, and a Type II physeal fracture on a proximal fibula. No diaphyseal fractures of any kind were produced. Further investigation of these conditions is encouraged to gain more insight into the injury mechanism.

The accurate estimation of the postmortem interval (PMI) is one of the most important determinations in a forensic investigation of decomposing human remains. Forensic entomology has gained popularity in death investigation due to its reliability and precision in the estimation of the minimum postmortem interval (mPMI). Forensically significant insects are mainly necrophagous species, which feed only on decomposing animal matter, and the most common necrophagous insects are the blowflies (Diptera: Calliphoridae). Estimations of the mPMI by entomological methods are made using the known developmental rates of various species of blowfly and via the successional patterns of the carrion insect community in a given region. It is generally assumed that blowflies oviposit quickly after death, so in many cases this time may equate to the time since death. The precision of mPMI estimations based on the developmental rates of blowflies often relies on this assumption. Rainfall may effect decomposition by inhibiting access of insects to the cadaver or carcass for oviposition. The current study investigated the effects of rainfall on blowfly activity, behavior, and overall decomposition of decaying animal material in an outdoor environment in the northeastern United States, conducted at the Boston University Outdoor Research Facility (ORF). It was hypothesized that natural rainfall, typically light to moderate in the geographic area of study, will disturb initial blowfly activity by acting as a physical barrier, diminishing access to the remains, and creating a delay in colonization and subsequent larval development. This hypothesized delay would result in an underestimation of the mPMI by entomological methods when rainfall has occurred. Also examined were several questions about the nocturnal behavior of blowflies and their activity in heavy rain. In the experimental trial 12 pig (Sus scrofa) heads were exposed under normal conditions (N; no rain controls), and 15 pig heads were exposed under rainy conditions (R; rain treatment), split into uncovered (N, n=6; R, n=5), covered (NC, n=5; RC, n=5), and covered partially (RCP, n=5) treatments. Additionally, there were three pig heads used in a preliminary trial and three pig heads exposed in an active rain trial. Generally, the results show that while a negative correlation exists between the amount of rainfall experienced and the coded number of flies observed, the light to moderate rainfall typical of many rainy days in the northeastern Unites States will not totally inhibit blowfly activity or disturb established maggot masses. A one-way analysis of variance (ANOVA) determined that there was no statistically significant difference (p > 0.05) between the N, NC, R, RC, and RCP treatments in the number of days it took to reach the advanced decomposition stage. While constant, heavy rainfall may inhibit blowfly activity; the results suggest that the irregularity of natural rainfall would rarely produce the conditions necessary for this to make a significant impact estimation of the PMI by entomological methods, although further studies are needed to confirm this conclusion. The results show a positive correlation between solar radiation and the coded number of flies observed. Time of day as a function of the coded number of flies observed during the first 48 hours of exposure forms a bimodal bell curve, confirming that blowflies are diurnal in their natural environment. Additionally, evidence of scavenging by turkey vulture (Cathartes aura) and some unknown animal(s) was observed. The results of this study illustrate the complicated, multivariable nature of the process of decomposition. This study provides preliminary data on the effect of rainfall on blowfly activity and overall decomposition, while future studies will be required to determine the effects of the duration and the intensity of rainfall.