The traits of the pubis described by Phenice (Am J Phys Anthropol 30 (1969) 297-302) have been used extensively by physical anthropologist for sex estimation. This study investigates all three of Phenice's characteristics in an approach similar to Walker's (Am J Phys Anthropol 136 (2008) 39-50) study using observations from the cranium and mandible. The ventral arc, the subpubic contour, and the medial aspect of the ischio-pubic ramus were scored on a five-point ordinal scale from a sample of 310 adult, left innominates of known ancestry and sex from the Hamann-Todd Human Osteological Collection and the W.M. Bass Donated Skeletal Collection. Four observers with varying levels of experience blindly scored each trait using new descriptions and illustrations adapted from those originally created by Phenice. The scores were then analyzed with ordinal logistic regression. Using all three traits for sex classification, the mean correct classification rate was 94.5% cross-validated for experienced observers. Intra- and interobserver error in trait scoring was low for all three traits and agreement levels ranged from moderate to substantial. Tests of the method on an independent validation sample provided a classification accuracy of 86.2%. This revision of the Phenice (Am J Phys Anthropol 30 (1969) 297-302) technique is a reliable and valid method of sex estimation from the human innominate that meets the Daubert criteria for court admissibility.
Birds such as the cowbird that lay their eggs in the nests of other birds have evolved strategies to disguise their chicks and not just their eggs. María De Mársico and her colleagues at the University of Buenos Aires observed eggs or hatchlings from the screaming cowbird (Molothrus rufoaxillaris; pictured left) or the shiny cowbird (Molothrus bonariensis) that were placed or laid in the nests of the baywing (Agelaioides badius; right), and measured the fledglings' survival rates. The researchers found
One of the many difficulties associated with identifying undocumented border crossers stems from an inability to narrow down the search area for the region of origin and family members to obtain family reference samples for DNA comparison. While the geography of regions of origins is wide, the biological profiles of the undocumented border crossers often show strong similarities, young and male. The isotopic composition of human bones, teeth, and hair has been demonstrated to be useful biomarkers for tracing locations and movements of individuals and for aiding in the identification of human remains. Data obtained from human remains can be compared to and aligned with various reference sources, such as soils and bedrock, archaeological remains, or cultural data. Here, the spatial deficiency in isotopic reference data for Mexico, specifically for oxygen (δ18O) isotopes in tap water, is being addressed through the collection and analysis of over 150 water samples and explored with tooth enamel isotopic values from recently identified Mexican nationals. The isoscape was developed using a Spine with Barriers interpolation method and shows sufficient detail to narrow down the regions where specific isotopic values are represented. The individuals were plotted on the developed isoscape using conditional correlations. The methodology was successful in assigning the correct regions of origin for the two individuals, which shows the tremendous potential of the developed isoscape. Nonetheless, there is more research needed to further improve upon this geolocation method, including analysis of multiple isotopes in different tissues, and the development of new isotopic methods.
The forensic literature suggests that when adolescents fall onto edged and pointed surfaces, depressed fractures can occur at low energy levels. This study documents impact biomechanics and fracture characteristics of infant porcine skulls dropped onto flat, curved, edged, and focal surfaces. Results showed that the energy needed for fracture initiation was nearly four times higher against a flat surface than against the other surfaces. While characteristic measures of fracture such as number and length of fractures did not vary with impact surface shape, the fracture patterns did depend on impact surface shape. While experimental impacts against the flat surface produced linear fractures initiating at sutural boundaries peripheral to the point of impact (POI), more focal impacts produced depressed fractures initiating at the POI. The study supported case-based forensic literature suggesting cranial fracture patterns depend on impact surface shape and that fracture initiation energy is lower for more focal impacts.
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