background: the aim of this study was to compare the skeletal and dental changes of a toothborne (hyrax) and a bone-borne (smile distractor) expansion devices using three-dimensional model of a human skull. materials and methods: a finite element model of human skull was generated using data from 3-d ct scans of an 11-year-old female child. then a hyrax expander (tooth-borne appliance) and smil...

Urban megaregions have emerged as a new urbanized form. However, previous studies mostly focused on urban expansion at the city scale, particularly for large cities. Understanding urban expansion at the regional scale including cities having different sizes is important for extending current knowledge of urban growth and its environmental and ecological impacts. Here, we addressed two questions...