A mixed tideâtwo uneven tides a day, or one high and one lowâis also possible. Tides vary on timescales ranging from hours to years due to a number of factors. To make accurate records, tide gauges at fixed stations measure water level over time.
Top 10 facts about the world. Oligodendrocytes, also known as oligodendroglia, are a type of brain cell in the central nervous system that belongs to the glial cell family. The main purpose of glial cells is maintenance and support of nervous system cells.
Oligodendroglia, types of glial cells, arise during development from oligodendrocyte precursor cells, which can be identified by their expression of a number of antigens, including the ganglioside GD3, the NG2 chondroitin sulfate proteoglycan, and the platelet-derived growth factor-alpha receptor subunit (PDGF-alphaR).