High-resolution sclerochronological analysis of the bivalve mollusk Saxidomus gigantea from Alaska and British Columbia: techniques for revealing environmental archives and archaeological seasonality

The butter clam, Saxidomus gigantea, is one of the most commonly recovered bivalves from archaeological shell middens on the Pacific Coast of North America. This study presents the results of the sclerochronology of modern specimens of S. gigantea, collected monthly from Pender Island (British Columbia), and additional modern specimens from the Dundas Islands (BC) and Mink and Little Takli Islands (Alaska). The methods presented can be used as a template to interpret local environmental conditions and increase the precision of seasonality estimates in shellfish using sclerochronology and oxygen isotope analysis. This method can also identify, with a high degree of accuracy, the date of shell collection to the nearest fortnightly cycle, the time of day the shell was collected and the approximate tidal elevation (i.e., approx. water depth and distance from the shoreline) from which the shell was collected.Life-history traits of S. gigantea were analyzed to understand the timing of growth line formation, the duration of the growing season, the growth rate, and the reliability of annual increments. We also examine the influence of the tidal regime and freshwater mixing in estuarine locations and how these variables can affect both incremental structures and oxygen isotope values. The results of the sclerochronological analysis show that there is a latitudinal trend in shell growth that needs to be considered when using shells for seasonality studies.Oxygen isotope analysis reveals clear annual cycles with the most positive values corresponding to the annual winter growth lines, and the most negative values corresponding to high temperatures during the summer. Intra-annual increment widths demonstrate clear seasonal oscillations with broadest increments in summer and very narrow increments or no growth during the winter months. This study provides new insights into the biology, geochemistry and seasonal growth of S. gigantea, which are crucial for paleoclimate reconstructions and interpreting seasonality patterns of past human collection.     

Excessive rightsizing? The interdependence of public school closures and population shrinkage

Shrinking cities have, by definition, lost population. Rightsizing is a strategic planning approach to mitigate the challenges of population loss by adjusting a municipality's services, amenities, or even footprint to fit a new demographic reality. While studies have documented the unacceptability and ineptitude of municipality-driven rightsizing, public school closures have proliferated and quietly become a noteworthy material manifestation of population change. However, as public schools are widely considered to be a foundational component of community cohesion, identity, and prosperity, it begs the question of whether their closure may accelerate the decline feedback mechanisms already present in many shrinking cities. Our study examines public school closures in Ontario, Canada, from 2011 to 2016 to determine the relationship between municipal population trajectories and size and public school closures, and to explore the prevalence of school closures and the community context in shrinking Ontario municipalities. We find that public school closures occurred disproportionately in shrinking and smaller municipalities. Furthermore, public school closure prevalence is associated with low income, low ethnoracial diversity, and low educational attainment.     

A Geometric Morphometric Study of Regional Craniofacial Variation in Mexico

Spanish speaking populations in the USA have long been categorised under the umbrella term ‘Hispanic’, which is a cultural construct. The term Hispanic ignores the unique ethnohistories and biological variation among Hispanic groups with various European, African and indigenous American influences. Considerable heterogeneity has been identified in pre‐contact America and has continued to influence the cultural and biological compositions of various regions today. The purpose of this research is to examine biological variation in Mexico, which was influenced by indigenous migration patterns and the Old World conquests of the Americans. Using multivariate statistics, this paper compares 16 three‐dimensional craniometric landmarks of samples from northern Central Mexico, northern Yucatan and western Mexico to examine the regional biological variation present in Mexico in both prehistoric and historic groups and also compares Mexican, Spanish and African American groups to examine patterns of Old World conquests. Multivariate statistics detected significant group differences for both size and shape (centroid size, p < 0.0001; shape, p < 0.0001) and showed that while significantly different, all the Mexican groups are more similar to one another except for one prehistoric inland‐western Mexican group, which is morphologically distinct from the other Mexican groups. Previous mtDNA research in these areas shows a low prevalence of African American admixture and a high indigenous component in the northern Mexican groups, which is consistent with the findings of this paper. The prehistoric and historic Mexican groups were the most similar indicating the retention of indigenous admixture after contact. The results from this analysis demonstrate that all groups are significantly different from one another supporting other findings that have shown that the indigenous populations of the New World are heterogeneous and that this variation may also contribute to the heterogeneity of contemporary populations. Copyright © 2013 John Wiley & Sons, Ltd.     

3D heritage visualisation and the negotiation of authenticity: the ACCORD project*

This article examines the question of authenticity in relation to 3D visualisation of historic objects and monuments. Much of the literature locates their authenticity in the accuracy of the data and/or the realism of the resulting models. Yet critics argue that 3D visualisations undermine the experience of authenticity, disrupting people’s access to the materiality, biography and aura of their historic counterparts. The ACCORD project takes questions of authenticity and 3D visualisation into a new arena – that of community heritage practice – and uses rapid ethnographic methods to examine whether and how such visualisations acquire authenticity. The results demonstrate that subtle forms of migration and borrowing occur between the original and the digital, creating new forms of authenticity associated with the digital object. Likewise, the creation of digital models mediates the authenticity and status of their original counterparts through the networks of relations in which they are embedded. The current pre-occupation with the binary question of whether 3D digital models are authentic or not obscures the wider work that such objects do in respect to the cultural politics of ownership, attachment, place-making and regeneration. The article both advances theoretical debates and has important implications for heritage visualisation practice.