george modelski long cycle theory world politics hegemonic cycles sociology

joshua s. goldstein war cycles long waves international relations sociology

war cycles conflict recurrence international relations historical cycles sociology

tytler cycle political cycles democracy historical theory sociology

social cycle theory social change historical cycles sociological theory sociology

kondratiev wave long economic waves innovation cycles economic history sociology

dynastic cycle chinese history mandate of heaven political cycles sociology

cyclic process thermodynamic cycles heat engines state variables physics and geophysics

supercontinent cycle plate tectonics continental assembly geologic cycles geology and paleontology

phosphorus cycle phosphorus cycling nutrient cycles soil chemistry geology and paleontology

glaciation glacial cycles ice sheets paleoclimate geology and paleontology

aluminum cycle aluminium cycling geochemistry element cycles geology and paleontology

tide tidal cycles lunar gravity ocean dynamics cosmology and astronomy

sothic cycle ancient egyptian calendar sirius calendar cycles cosmology and astronomy

milankovitch cycles orbital forcing glacial cycles paleoclimate cosmology and astronomy