Estimation of skeletal age at death is based on the premise that osseous tissue undergoes predictable and patterned changes through the life of the individual that can be quantified and accurately correlated with skeletal age. The utility of any method of estimating skeletal age at death is dependent on two basic principles. First, the descriptive parameters of the method must account for the range of phenotypic variation observed at the skeletal site. Second, the method must be accurate when applied to an unknown individual, regardless of the individual's unique life history. This study examines the reliability and accuracy of the sternal end of the fourth rib method for the determination of skeletal age at death and explores whether chronic substance abuse alters the pattern of change at the sternal end of the fourth rib. Additional variables considered include gender, race and the presence of thoracic disease. One hundred and fifty five sets of ribs, obtained during forensic autopsy, are examined and age at death determined in two separate trials. All antemortem data, with the exception of gender, are collected following completion of rib examination in order to prevent biasing the observer. Reliability (intra-observer error) and accuracy are computed utilizing the kappa statistic. The results suggest that the sternal end of the fourth rib is a reliable but not an accurate method of determining skeletal age at death. The variables of sex, race, and thoracic disease all influence the accuracy of the method. Chronic substance abuse appears to influence both the reliability and the accuracy of the method.

Thesis--Oslo. / Includes bibliographical references (p. 257-271).

Thesis--Copenhagen. / Summary in Danish. Bibliography: p. 123-126.

Thesis--Copenhagen. / Summary in Danish. Bibliography: p. 123-126.

Thesis--Oslo. / Includes bibliographical references (p. 257-271).

Up to 70% of modern humans experience problems with their third molars, whether it is failure of proper eruption (impaction) or not erupting at all (agenesis). Thus, it is a commonly used example for explaining why humans are still evolving and the relevance of evolutionary medicine. Agenesis dates back to at least early Homo erectus, and is seen with greater frequency during the evolution of later Homo. However, there are currently few data that support any of the three hypotheses (agenesis as selection against impaction, developmental delay, and the probable mutation effect) proposed to explain the evolution of agenesis and impaction. Furthermore, while most researchers associate changes in the physical properties of food with an increased frequency of third molar pathologies, it is unclear whether these changes took place during the advent of agriculture, the beginning of industrialization or both. Considerable variation exists among modern human populations in the rate of agenesis and impaction, but there are inconsistencies in reports of how modern variation partitions among sex, population, and morphological traits. Thus, this study first aims to explain modern variance in agenesis and impaction, then to use morphological data to assess how the third molar pathologies of four different populations from Serbia, Egypt, Japan and SE USA changed with the adoption of agriculture and the beginnings of industry. This will lead to an understanding of the evolution of third molar agenesis and impaction that will help understand the evolutionary origins of an important condition affecting modern humans. First, we aimed to consolidate all available data on worldwide third molar agenesis frequencies, with a particular emphasis on exploring the factors leading authors to find contradictory results for the demographic and morphological predictors of this anomaly. A total of 12,376 studies were originally identified, then narrowed down to 1,312 for title/abstract screening. Based on our inclusion and exclusion criteria, we selected 92 studies, containing 100 effect sizes and 63,314 subjects, for systematic review and meta-regression. The worldwide rate of agenesis was found to be 22.63% (95% CI: 20.64%-24.76%), though the estimates ranged from 5.32% to 56.0%. Our subgroup analyses revealed that females are 14% more likely to have agenesis of one or more third molars than males and that maxillary agenesis was 36% more likely than mandibular agenesis in both sexes. Further, we found that having agenesis of one or two molars was most common, while agenesis of three molars was least common. Finally, we found large differences among agenesis frequency depending on geographic region. This information is expected to be of use not only to clinicians and patients but also to policy makers, given the implications for third molar extraction protocols. Next, we performed a meta-analysis to synthesize the abundant existing literature on third molar impaction frequencies worldwide. A total of 7,936 records were originally identified, then narrowed down to 864 for title/abstract screening. Based on our inclusion and exclusion criteria, we selected 49 studies, containing 83,484 subjects, for systematic review and meta-regression. The worldwide rate of impaction was found to be 24.40% (95%CI: 18.97%-30.80%), though the estimates ranged from 3.08% to 68.60%. Our subgroup analyses revealed that mandibular impaction was 57.58% more likely than maxillary impaction, while we did not detect any difference in impaction frequency between males and females. In addition, we found that mesioangular impaction was most common, followed by vertical impaction, with distoangular and horizontal impaction less frequent. Further, we found that having impaction of one or two third molars was most common, while impaction of three or four third molars was least common. Finally, we found small differences among impaction frequency depending on geographic region. Given the rich debate surrounding third molar treatment policy, understanding demographic and morphological differences in impaction rates is an important first step in assessing appropriate treatment protocols. Finally, we applied the results of these analyses to explore the evolutionary origins of third molar agenesis and impaction. Humans are unique in having high frequencies of pathological third molars, including impacted molars that fail to erupt and agenesis, or missing, molars. Many researchers attribute an increased prevalence of third molar agenesis and impaction to highly processed modern diets. Three competing hypotheses exist to explain the evolution of third molar agenesis: 1) agenesis as the result of selection against impaction, 2) agenesis as developmental delay, and 3) the probable mutation effect. These hypotheses, however, remain untested. Here we test these hypotheses using data from four populations sampled before, during and after the transitions to agriculture and two populations before, during, and after the transition to industry. We found the selection against impaction hypothesis contributed to the rise in third molar agenesis at the end of the industrial transition, but impaction remained at such low frequencies during the agricultural transition that this mechanism is unlikely to have been a causative force. Furthermore, we found a negative relationship between dental arch space and third molar agenesis in the industrial transition, but a positive relationship between these two variables in the agricultural transition. Overall, these data suggest that two different mechanisms influenced the prevalence of human third molar agenesis: one operating since the time of Homo erectus and one with much more recent origins. / Human Evolutionary Biology

The purpose of this study is to explore the world of anatomical gifts, specifically whole body donations for anatomical dissection, and to examine the relationship between laboratory cadavers and anatomy students. This relationship is rooted in the "anatomical gift" of a body to science. As a result of this gift, the physical remains of a dead person are transformed into a liminal artifact—one that possesses characteristics of both person and thing—whose purpose is to be cut apart for scientific study. Two inherently anthropological concepts that can help us to understand the cadaver and its relationships are "the gift" and the body as material culture. Anthropology has traditionally divided the world in such a way as to separate mind, body, and material things. Yet the gift to science of a dead human body occupies material, biological, and cultural domains—and as such both challenges and sheds light on subdisciplinary boundaries. What sort of people donate their bodies "to science," and why do they do it? How do anatomy students respond to working with cadavers? What is the nature of the relationship between cadaver and student? To address these questions, I focus on the experiences of prospective body donors and occupational and physical therapy students in western Massachusetts. I combine quantitative and qualitative data, drawn from survey questionnaires completed by a self-selected sample of prospective donors and by three cohorts of OT and PT anatomy students, to contribute to our understanding of the anatomical gift, the body as material culture, and subdisciplinary boundaries. As a result of this research, several points have emerged that may be of use to anatomy students, prospective donors, and body donor programs. To further the analysis of whole body donation for anatomical dissection, I propose three lines of more specifically focused research. Such continued research would make valuable contributions to the pedagogy of anatomy. At a broader and more theoretical level, it would also enhance our appreciation of the complex relationships between persons and things, and between the living and the dead, at the intersection of human biological, material, and cultural domains.

This study analyzes variation in WBC among participants in the Health, Aging and Body Composition study (Health ABC). First, white blood cell (WBC) counts are compared among African Americans and European Americans in the study, confirming a significant difference. These population-based differences in WBC are also described in literature as differing significantly between different African populations, Caribbean populations, Central and South American groups, Asian populations and Europeans (Bain et al., 1984; Saxena and Wong, 1990; Bain, 1996; Menard et al., 2003; Hsieh et al., 2007). Ancestry informative markers are used to estimate the individual ancestry of the African Americans in the study. There is a significant association of low WBC with a higher proportion of African ancestry. An admixture mapping approach is used to identify a novel locus [independently identified in a separate admixture scan in the Jackson Heart Study (JHS)] that influences WBC levels. The peaks of association in both studies localize to a region ~0.9 Mb centered on the Duffy Antigen Receptor for Chemokines gene (DARC [MIM 110700]). Second, the functionality at the DARC locus is determined by investigating associations between DARC and neutrophils, lymnphocytes, monocytes, basophils and eosinophils. This investigation shows a consistent genetic effect at this locus associated with all of these differential cell types. Third, the association of DARC with all marrow derived cell lineages and red blood cell levels is evaluated. It is shown that, in addition to known associations between the DARC gene and malarial resistance (Miller et al., 1976; Livingstone, 1984) often associated with red blood cells, the DARC gene is also associated with WBC levels (Nalls et al., 2008). Selective pressure at this genetic locus may be related to its effect on WBC that may have contributed to the fixation of the FY- allele in some populations. / Anthropology

Polymorphisms at four paternally-inherited loci (DYS287, SPY1, DYS199 and DXYS156) were surveyed in twenty-seven populations (n = 997) world-wide to trace the origins of Native Americans. One of the haplotypes (6) is found at relatively high frequencies in all seven Native American populations representing two of the major linguistic divisions in the New World. The same haplotype was found at low frequencies in Siberian Eskimos and was absent from eleven other Asian populations. A second haplotype (7) was present at high frequencies in all the Native American and several Siberian populations. It was present at moderate frequencies in European populations and at low frequencies in several Asian populations. These data best support the hypothesis of a single male-mediated migration wave for the early peopling of the Americas, although a multi-wave hypothesis is not rejected.

The purpose of this study was to reconstruct historical fire regimes along an elevation and vegetation gradient in the Sacramento Mountains, NM. I cross-dated fire-scarred specimens to reconstruct the fire history within two mixed-conifer, four ponderosa pine, and two pinon-juniper stands. Prior to Euro-American settlement, historical fire intervals were estimated at 6 years in ponderosa pine, 10 years in mixed-conifer, and 27 years in pinon-juniper forests. To evaluate whether Native Americans may have influenced historical fire regimes, I cross-dated scars from peeled trees found within the study area. Comparison between scar dates, historical records, and variations in fire frequencies did not show a regional effect on historical fire regimes by Mescalero, but suggested that they may have had a local impact on fire frequencies of the late 1700's. Following Euro-American settlement (ca. 1880) fire was nearly absent from the study area due to livestock grazing and fire suppression.