Exploring Oyster (Crassostrea virginica) Habitat Collection via Oxygen Isotope Geochemistry and its Implications for Ritual and Mound Construction at Crystal River and Roberts Island,Florida

Research at Crystal River and Roberts Island Shell Mound Complex, on the western coast of Florida, USA, offers a quantitative assessment of the temporality of shell deposit construction, Native subsistence practices, and mobility patterns through stable oxygen isotope data from eastern oyster (C. virginica). The δ¹⁸O_water values of oysters vary synchronously with salinity, assuming relatively constant δ¹⁸O_water/salinity gradients since the time of occupation, allowing for an examination of shifts in oyster habitat exploitation over time. Our previous (Thompson et al. 2015) study indicated that midden accumulation occurred throughout the year, while oysters from mound deposits were collected in colder months. New data indicate that in addition to differential season of collection, habitat exploitation also varied. During early occupation at the site, oysters were collected primarily from lower saline habitats, while in later phases oysters were obtained from higher salinity waters; we relate this to a lower sea level and concomitant settlement shift seaward. Additionally, oyster from later mound contexts was collected from higher saline habitats relative to those in midden contexts; Native people may have targeted specific bioherms at certain times for the year for feasting-related mound construction.     

The social origins of cognition: A basis for reintegrating anthropology and psychology?

Wertsch, James V., ed. Culture, Communication and Cognition. New York: Cambridge University Press, 1985. x + 379 pp. including notes, bibliography, and indices. $42.50 cloth, $14.00 paper.

Rogoff, Barbara, and Jean Lave, eds. Everyday Cognition: Its Development in Social Context. Cambridge: Harvard Unversity Press, 1984. vi + 352 pp. including notes, bibliography, and index. $27.50 cloth.     

Investigating experimental knapping damage on an antler hammer: a pilot-study using high-resolution imaging and analytical techniques

Organic (bone, antler, wood) knapping tools were undoubtedly a component of early human tool kits since the Lower Palaeolithic. Previous studies have identified pitting and the occasional presence of embedded flint flakes as important features for recognizing archaeological bone and antler percussors. However, no systematic protocol of analysis has been suggested for the study of this rare archaeological material. Here we present qualitative and quantitative results of a preliminary analysis of an experimental knapping hammer, using a novel combination of microscopy (focus variation optical microscope and scanning electron microscope), micro-CT scanning and energy dispersive X-ray spectroscopy. These imaging and analytical techniques are used to characterize use-damage from the manufacture of handaxes. This paper highlights the strengths and weakness of each technique. Use-wear on the working area included attritional bone loss, micro-striations and compaction of the outer layer of the antler matrix from repeated hitting of the beam against the sharp edge of the handaxe during knapping. Embedded flint flakes were also identified in the pits and grooves. This combination of high-resolution imaging techniques is applicable to fragile archaeological specimens, including those encrusted by sediment or encased in matrix.     

The Fluidity of the ‘Farming Ladder’: The Experience of the Duffin Family,Yorkshire, 1870-1950

This article examines the nuances of the ‘farming ladder’ through a case study of the Duffin farming family. It explores the circumstances in which they flourished and faltered; the internal and external determinants affecting their ability to maintain a grip on the ‘farming ladder’; and the fluidity of the ladder. Drawing upon the personal archive of the family and complementary sources, the variable position of the family on the ‘farming ladder’ as they progress from agricultural labourers to farmers and then back to labourers is charted within wider historical and geographical frameworks. The social and spatial relationships forged are identified as being particularly important in the operation of the ‘farming ladder’.     

Solidarity Economy for Development and Women's Emancipation: Lessons from Bolivia

This article critically assesses the relationship between the solidarity economy (SE) and women's emancipation through a case study of SE groups in El Alto, Bolivia. It highlights the fact that the failure to harness the potential of SE as a development alternative and as a means for the emancipation of women can partly be attributed to the neglect of gender‐related issues in the study of SE. Following an examination of SE in the Bolivian context of class and ethnicity, the article deepens the analysis by focusing on gender. It shows that the significant participation of women in SE is a response to the double imperative imposed by the current processes of monetization of production and home‐based reproduction. Compared with their insertion into the market individually, participation in SE allows women to increase and smooth their income. In general, however, their income remains lower than that of men and also below the poverty line. This reflects a continuing gender asymmetry and points to the limitations to what solidarity among poor women can achieve. The article concludes with an assessment of the possibilities as well as the difficulties inherent in a new pathway to women's emancipation through SE, a pathway which would necessitate a reorganization of the social sphere of reproduction.     

Quantifying Interpolation Errors in Urban Airborne Laser Scanning Models

Airborne laser scanning (ALS) is becoming an increasingly popular data capture technique for a variety of applications in urban surface modeling. Raw ALS data are captured and supplied as a 3D point cloud. Many applications require that these data are interpolated onto a regular grid in order that they may be processed. In this article, we identify and analyze the magnitudes and spatial patterning of residuals from ALS models of urban surfaces, at a range of different scales. Previous research has demonstrated the effects of interpolation method and scale upon the nature of error in digital surface models (DSMs), but the size and spatial patterning of such errors have not hitherto been investigated for urban surfaces. The contribution of this analysis is thus to investigate the ways in which different methods may introduce error, and to understand the uncertainty that characterizes urban surface models that are devised for a wide range of applications. The importance of the research is shown using examples of how the different methods may introduce different amounts of error and how the uncertainty information may benefit users of ALS height models. Our analysis uses a range of validation techniques, including split-sample, cross-validation, and jackknifing, to estimate the error created in DSMs of urban areas.