Local Indicator of Spatial Agglomeration between Newly Opened Outlets and Existing Competitors on a Street Network

Distance from competitors is a key factor in retail site selection and profitability. To understand the locational tendency that each newly opened outlet locates close to or far from existing competitors in a target area, a specific method is needed. Hence, this study aims first to develop a statistical method to discover the local spatial associations between newly opened and existing point-like outlets on a street network. We achieve this objective by extending the network local cross K function. The second objective is to evaluate the practicality of the proposed method by applying it to restaurants in a trendy district in Tokyo. Specifically, this study focuses on answering two questions: first, whether each newly opened restaurant is closely located to existing ones or not and, second, whether each existing restaurant attracts newly opened restaurants or not. The results show that the method is useful for revealing the location tendencies of retail outlets toward competitors.     

Strontium isotope analysis to reveal migration in relation to climate change and ritual tooth ablation of Jomon skeletal remains from western Japan

A gradual population increase accompanying climate cooling has been evinced as having occurred in western Japan during the Middle (ca. 5000–4000 years BP) to Late-Final Jomon period (ca. 4000–2300 years BP). We test the hypothesis that this population change paralleled increasing human migration. We also test the archaeological hypothesis that types of ritual tooth ablation can be used to distinguish between locals and immigrants during the Late-Final Jomon period. We measured strontium isotope ratios in human skeletal remains from the Middle Jomon Ota and the Late-Final Jomon Tsukumo sites located in the Sanyo region of western Japan. Tooth enamel and bone were analyzed, and modern plant samples were collected in the areas surrounding the two sites to make a map of environmental strontium isotope ratios. The biosphere strontium isotope ratios correlated well with the underlying geology, enabling us to put forth a hypothesis of immigrants’ origins. There were no migration pattern differences between the Middle and Late-Final Jomon groups, indicating that the gradual population increase was caused by an increase in the indigenous population. All the Tsukumo individuals are locals, and this finding indicates that types of tooth ablation did not distinguish between locals and immigrants. Alternative hypotheses for the presence of different tooth ablation types in the Jomon society should be explored.