Studies of secondary osteons in ribs have provided a great deal of what is known about remodeling dynamics. Compared with limb bones, ribs are metabolically more active and sensitive to hormonal changes, and receive frequent low-strain loading. Optimization for calcium exchange in rib osteons might be achieved without incurring a significant reduction in safety factor by disproportionally increasing central canal size with increased osteon size (positive allometry). By contrast, greater mechanical loads on limb bones might favor reducing deleterious consequences of intracortical porosity by decreasing osteon canal size with increased osteon size (negative allometry). Evidence of this metabolic/mechanical dichotomy between ribs and limb bones was sought by examining relationships between Haversian canal surface area (BS, osteon Haversian canal perimeter, HC.Pm) and bone volume (BV, osteonal wall area, B.Ar) in a broad size range of mature (quiescent) osteons from adult human limb bones and ribs (modern and medieval) and various adult and subadult non-human limb bones and ribs. Reduced major axis (RMA) and least-squares (LS) regressions of HC.Pm/B.Ar data show that rib and limb osteons cannot be distinguished by dimensional allometry of these parameters. Although four of the five rib groups showed positive allometry in terms of the RMA slopes, nearly 50% of the adult limb bone groups also showed positive allometry when negative allometry was expected. Consequently, our results fail to provide clear evidence that BS/BV scaling reflects a rib versus limb bone dichotomy whereby calcium exchange might be preferentially enhanced in rib osteons.

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Abstract. Molecular-based characterizations of Andean peoples are traditionally conducted in the service of elucidating continental-level evolutionary processes in South America. Consequently, "western" Andean population genetic variation is often represented in relation to "eastern" variation among Amazon and Orinoco River Basin populations. This west-east contrast in patterns of population genetic variation is typically attributed to large-scale phenomena, such as dual founder colonization events and/or differing long-term microevolutionary histories.However, alternative explanations that consider the nature and causes of population genetic diversity within the Andean region remain underexplored.Here we examine population genetic diversity in the Peruvian Central Andes using mtDNA HVI and Y-chromosome STR data from 17 newly sampled 3 populations combined with published samples. Using this geographically comprehensive data set, we first re-assess the currently accepted pattern of western vs. eastern population genetic structure, which our results ultimately reject: mtDNA population diversities were lower, rather than higher, within Andean versus eastern populations, and only highland Y-chromosomes exhibited significantly higher within-population diversities compared to eastern groups.Multiple populations, including several highland samples, exhibited low genetic diversities for both genetic systems. Second, we explore whether the implementation of Inca state and Spanish colonial policies starting at about A.D. 1400 could have substantially restructured population genetic variation, and consequently constitute a primary explanation for the extant pattern of population diversity in the Peruvian Central Andes. Our results suggest that Peruvian Central Andean population structure cannot be parsimoniously explained as the sole outcome of combined Inca and Spanish policies on the region's population demography: Highland populations differed from coastal and lowland populations in mtDNA genetic structure only; highland groups also show strong evidence of female-biased gene flow and/or effective sizes relative to other Peruvian ecozones. Taken together, these findings indicate that population genetic structure in the Peruvian Central Andes is considerably more complex than previously reported and that characterizations of, and explanations for, genetic variation may be best pursued within more localized regions and defined time periods. 4Since at least the 1960s, characterizations of Andean peoples from a molecular perspective have been conducted peripherally, as part of larger investigative efforts in South America as a whole. These efforts have had two main goals: first, to inform debates on the peopling of South America and of the Americas writ large; second, to contribute to broad understandings of human micro-to macroevolutionary change. Both goals were vitalized by the work of James V. Neel, Francisco M. Salzano, and associated colleagues among tribal groups in Venezuela and Brazil. Thus, from the 1960s into the ...

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Dental casts are invaluable research tools. There are a variety of molding compounds available, all having temperature, humidity, and timing guidelines to ensure a precise replica of dentition. However, not all field research conditions allow for adherence to environmental guidelines requiring longer wait times prior to pouring epoxy for casting. This study, tests a common molding compound in extreme environments and over varying time intervals, testing the integrity of the dental molds in producing precise replicas of original teeth. 580 molds were created under three varying environments: room temperature, hot/humid, and cold/dry. Molds were removed from these environments in two-week intervals over twelve weeks. The resulting casts were measured to determine timing limitations for producing accurate dental casts under varying environments. Molds stored at room temperature retained their shape and size for the complete twelve weeks.  Molds kept in a hot and humid environment, however, only maintained their shape and size up to four weeks, whereas molds in a cold and dry environment showed significant changes by the end of the second week. These findings provide additional tools for researchers working in a variety of field conditions allowing casts to be taken of specimens that cannot be transported off site.