DefinitionsThe movement of ocean water is one of the twoprincipal sources of discrepancy between dead reckonedand actual positions of vessels. Water in motion is called acurrent; the direction toward which it moves is called set,and its speed is called drift.
Human RBC precursors are obtained by (i) separating glycophorin A(+) (gly A(+)) cells using a magnetic cell sorting (MACS) technique and by (ii) ex vivo expansion of precursors BFU-E (burst forming unit-erythroid) on methylcellulose semi-solid culture media from mononuclear cells of cord blood.
marrow, there is a population of erythropoietic stem cells. These are the precursors to RBCs, and they do have. nuclei (which get expelled before they leave the marrow) and the ability to respond to growth factors (in. particular, erythropoietin) by undergoing mitosis.