In what specific ways do the following contribute to centripetal effects of social/economic areas

-transformation of building (renovations and low cost housing,

hi-tech and financial firms,

investments,

quality roads and transport,

commercial/industrial floor space buildings,

new jobs, land sold for redevelopment,

boboisation,

luxury housing near run down public housing areas,

companies forming into secondary CBD,

new business arrivals with jobs that require skills that local inhabitants do not have -