The Old and the New: Qualifying City Systems in the World with Classical Models and New Data

Zipf's rank‐size rule, lognormal distribution, and Gibrat's urban growth models are considered as summarizing fundamental properties of systems of cities. In this article, they are used as statistical benchmarks for comparing the shapes of urban hierarchies and evolutionary trends of seven systems of cities in the world including BRICS, Europe, and United States. In order to provide conclusions that avoid the pitfalls of too small samples or uncontrolled urban definitions, these models are tested on some 20,000 urban units whose geographically significant delineations were harmonized in each country over 50 years between 1960 and 2010. As a result, if the models appear not always statistically valid, their usefulness is confirmed since the observed deviations from empirical data remain limited and can often be interpreted from the geohistorical context of urbanism proper to each world region. Moreover, the article provides new free software which authorizes the reproducibility of our experiments with our data bases as well as with complementary data.     

Ultrathin sectioning techniques

Epoxy mixtures incorporating Araldite available in Australia have been used to embed Recent organisms, fossils and sedimentary rocks. Resultant sections of embedded material may be less than 10 micrometres thick and give increased resolution of fine structures. Mixtures used and sectioning techniques are described.     

Sclerochronological analysis of archaeological mollusc assemblages: methods,applications and future prospects

Accreting skeletal tissues found in bone, teeth, otoliths and molluscan shell act as sensitive recorders of local environmental and climatic conditions. Owing to their robust nature, ubiquity and abundance in the archaeological record as well as the potential for high-resolution data acquisition, the accreting skeletal tissues of archaeological molluscs are increasingly employed as palaeoenvironmental proxies. Researchers have chiefly utilised such proxies to extend instrumental records of environmental conditions through palaeoenvironmental reconstruction and explore the impact of environmental and climatic change on human populations. However, the use of environmental proxies from the archaeological record can be hampered by a number of methodological challenges including inadequate sampling strategies, appropriate calibration, the use of inappropriate proxies and the broad extrapolation of localised results. This paper reviews the use of molluscan shell from archaeological contexts as palaeoenvironmental proxies. We focus on the application of sclerochronology—a suite of high-resolution physical and geochemical data recovery methods widely used in conjunction with molluscan shell. This paper presents an overview of the potential of these techniques in approaching more nuanced understandings of human-environment interactions and how they can be more successfully incorporated into archaeological research.     

Development of a systems model to visualise the complexity of children's independent mobility

Substantial changes to the built environment, urbanisation patterns, and societal norms have contributed to limiting children's opportunities for being independently mobile. Several linear causal pathway models have been developed to understand the influences on children's independent mobility; however feedback loops between and within the various levels of influence cannot be modelled using such an approach. The purpose of this paper is to refine the interrelationships of factors related to children's independent mobility, taking into account earlier models, broader contextual factors, recent children's geographies literature, and feedback loops. Systems model components were informed by attributes known to influence children's independent mobility, related qualitative findings, and the development of a framework that could lend itself to multilevel modelling approaches. This systems model may provide a useful structure for identifying how best to develop and monitor interventions to halt the declining rates of children's independent mobility.