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AbstractEven though lithics in the Maya region have traditionally been relegated to appendices and tool-type lists, much has been done to move beyond this descriptive approach in the last decade. In this article we highlight general themes of lithic studies in the Maya region since 2011, including economic production and exchange, the role of lithics in ritual practice, and the use of previously understudied raw materials and lithic forms, such as ground stone. Employing a temporal scope that encompasses the Maya and their preceramic predecessors, we explore gendered patterns of research within lithic studies from a feminist perspective and discuss the impacts that gender disparities have on academic thought.

AbstractAlthough much research has been conducted on the Late Postclassic period Maya, there has been relatively less study of the role of economic activities in political management during this period. Many such studies focused on obsidian analysis and technology as proxies for trade and exchange. This article builds on that research, using a legacy collection of obsidian implements collected during archaeological surveys in the 1970s to examine Late Postclassic period (AD 1200–1524) economic networks in the K'iche’ region. Obsidian collections from the site of Q'umarkaj and the surrounding region were examined through technological and geochemical analyses. I find that during the Late Postclassic period, K'iche’ elites had more access to nonlocal obsidian sources than did non-elites, but that access to locally available sources was managed through independent and diverse acquisition networks. Thus, the K'iche’ elite were not dependent on local economies as a main source of political power.

•A novel application of pXRF on an understudied material.•Provides a detailed description of vitrophyre, a type of volcanic glass, used in artifact production.•Highlight the land-use patterns and social interactions between the Nimíipuuand the cultural groups of the Bitterroot region in the Northern Rockies and Plains.

Stone tool producers in the Maya Lowlands had several types of raw materials from which to choose. Limestone, chert, and obsidian are the most naturally abundant, whereas chert and obsidian outnumber limestone in archaeological contexts. The presence of flaked-stone tools made of limestone is typically attributed to the scarcity of more suitable raw materials. Nevertheless, in chert-rich areas, such as the upper Belize River valley, limestone bifaces and production debitage are present. To understand their presence, we examine limestone biface production and use at Buenavista del Cayo.

ABSTRACTObsidian flake tools are an important component of Early Horizon (ca. 800–400 B.C.) lithic assemblages in highland Peru. However, the functions of these tools have not been ascertained. In this paper, we present the results of an experimental project that tests the hypothesis that flake tools were used for shearing domesticated camelids (alpacas and llamas). A collection of 10 replicated flake tools were used to shear an alpaca over different amounts of time. Our results indicate that these implements provide an efficient means of shearing camelids, though their efficiency declines after prolonged use. Following the shearing experiment, optical light microscope (OLM) and scanning electron microscope (SEM) analyses were undertaken to determine what kinds of use-wear were present on the tools. We tentatively conclude that shearing does leave recognizable edge-wear, including micro-chipping, faint striations, and residues, which we believe could be visible in Peruvian archaeological lithic assemblages.

ABSTRACTIn lithic studies, much attention is devoted to analyses of production processes and finished tools while little attention is paid to production implements. Hammerstones present an interesting problem as many areas with readily available lithic raw material sources lack materials for high-quality hammerstones. This paper uses a case study from a chert-rich area, the upper Belize River valley of western Belize, to examine how the Late Classic Maya acquired material to be used as hammerstones. This paper finds that lithic producers used locally available poor-quality stone as well as imported materials, such as groundstone, as hammerstones, suggesting multiple acquisition networks existed through which lithic producers obtained percussion implements.

Examinations of landscape-level resources, particularly lithic raw material sources, are generally associated with hunter-gatherer and mobile societies; the distribution and source locations of such materials are used as proxies for mobility and territorial ranges. The variable locations of lithic raw material sources also affect sedentary societies, influencing the economic role of these materials and the administration of the raw material sources. This paper addresses the effect of uneven resource distributions across the landscape in sedentary societies, specifically the Late to Terminal Classic Maya (670–890 CE), through a case study of chert resources from the Mopan Valley, Belize. This paper discusses the role of the localness and commonality of lithic raw material sources in influencing individuals' access to source areas and involvement in lithic production, illustrating that not only the local or non-local nature of the source area, but also the frequency of source areas within a region, influence the economic organization of lithic resource extraction and production.

AbstractBackground:While breastfeeding rates have been increasing in the United States, they remain below targets set by multiple public health organizations. Lower rates are associated with certain demographic groups. We performed a retrospective chart review to examine rates of breastfeeding at the time of postpartum follow-up in a mixed-race urban cohort.Objective:This study was conducted to examine the proportion of women who were breastfeeding at 6–8 weeks postpartum and to determine if these proportions differed by race and insurance status.Materials and Methods:We identified women who delivered singleton term infants at an urban university hospital between July and December 2013. Self-reported breastfeeding status at 6–8 weeks postpartum was abstracted for all women who completed postpartum follow-up visits. Data were analyzed with logistic regression to compare rates of any or exclusive breastfeeding between women with Medicaid and private insurance.Results:Charts of 656 women were reviewed; 405 women completed postpartum follow-up within 8 weeks. The Medicaid population had significantly lower rates of breastfeeding even after accounting for interaction and confounding by demographic factors (any breastfeeding odd ratio [OR] 0.53, confidence interval [CI] 0.04–0.31; exclusive breastfeeding OR 0.48, CI 0.33–0.85). When stratified by race, white women on Medicaid had the lowest probability of breastfeeding of all groups (p< 0.01).Conclusions:Among patients delivering at an urban academic hospital, women on Medicaid were significantly less likely to breastfeed than those with private insurance. The greatest differential by insurance was seen among white women. Efforts to improve breastfeeding should focus on low-income women of all races.

ABSTRACTArchaeological analyses of European lithic technologies in North America are often discussed anecdotally within the context of other material evidence of European occupations. In North America, the presence of gunflints manufactured in Europe, generally England (which became part of Great Britain in 1707) or France, is used as a marker for the influence of these European powers and as a reflection of from whom residents obtained their material culture. Gunflints were made in Europe and in North America (north of the Rio Grande) from the early 1600s to the late 1800s. Thus, gunflints from sites such as the Natchez Fort, Louisiana (AD 1729–1731) provide a unique avenue of analysis for understanding both continuity in lithic technologies and the interactions between indigenous and introduced technologies. We address methodological concerns in typifying historic lithic collections, specifically eighteenth-century gunflints, particularly as these concern sourcing and the implications of sourcing for eighteenth-century colonial interactions in the southeastern United States.

Analysis of the structure and function of native thick (myosin-containing) filaments of muscle has been hampered in the past by the difficulty of obtaining a pure preparation. We have developed a simple method for purifying native myosin filaments from muscle filament suspensions. The method involves severing thin (actin-containing) filaments into short segments using a Ca2+-insensitive fragment of gelsolin, followed by differential centrifugation to purify the thick filaments. By gel electrophoresis, the purified thick filaments show myosin heavy and light chains together with nonmyosin thick filament components. Contamination with actin is below 3.5%. Electron microscopy demonstrates intact thick filaments, with helical cross-bridge order preserved, and essentially complete removal of thin filaments. The method has been developed for striated muscles but can also be used in a modified form to remove contaminating thin filaments from native smooth muscle myofibrils. Such preparations should be useful for thick filament structural and biochemical studies.

Polyethylene glycol (PEG) is gaining interest as an alternative green solvent in chemical synthesis and processing. This report presents density and viscosity data from 293.15 K to 358.15 K as well as self-diffusion coefficient data from 298.15 K to 358.15 K for oligomers of PEG from di- to nonaethylene glycol. The results were obtained by extrapolation from measurement series where water, the most common impurity in PEGs, was intentionally added in several increments. The obtained results are carefully compared to literature data, which are widely available only for density and viscosity, and only for the lower oligomers. Densities are found to be linearly dependent on temperatures for all studied oligomers. The temperature dependence of viscosity and self-diffusion coefficients show only slight deviations from the Arrhenius equation over the investigated temperature range. The activation energies obtained from the viscosity data agree well with the activation energies from the self-diffusion coefficient data and appear to be linearly dependent with respect to the number of ethylene oxide repeat units in the PEG oligomer. This linearity combined with the observation that the pre-exponential factor appears to be the same for all studied oligomers may serve as a tool to estimate viscosities and self-diffusion coefficients for higher oligomers within the investigated temperature range. The densities of the oligomers all fall within a rather narrow range without a clear trend in homologous series.

Considering the importance of nucleosome position with regard to how regulatory factors recognize their binding sites in chromatin, we have investigated the inherent nucleosome positioning properties of a transcriptional enhancer of the albumin gene. In the liver, where the albumin gene is highly expressed, the enhancer exists in an array of precisely positioned, nucleosome-like particles with transcription factors bound. In the absence of specific binding factors, such as in non-liver tissues or in polynucleosome arrays assembled in vitro, nucleosomes are randomly positioned over the enhancer. Herein we investigate the intrinsic nucleosome positioning properties of the central enhancer sequence assembled into mono-nucleosome core particles in vitro. We find that the enhancer DNA prefers three translational positions, each of which utilizes different rotational settings on the nucleosome core. We conclude that DNA binding factors that position nucleosomes may do so by stabilizing one configuration out of several that can be adopted by the underlying DNA, and that the potential exists for different positions to be stabilized at different stages of development.