Haematopoiesis refers to the commitment and differentiation processes that lead to the formation of all blood cells from haematopoietic stem cells. In adults, haematopoiesis occurs mainly in the bone marrow (medullary), but it can also occur in other tissues such as the liver, thymus and spleen (extramedullary).

Haematopoiesis is the process of formation of blood cellular components derived from derived from hematopoietic stem cells. These hematopoietic stem cells present in bone marrow and have the capability to form different mature blood cells and tissues. This process is necessary in order to maintain steady state levels in the blood circulation. Open access to the scientific literature means the removal of barriers (including price barriers) from accessing scholarly work. There are two parallel “roads” towards open access: Open Access articles and self-archiving. Open Access articles are immediately, freely available on their Web site, a model mostly funded by charges paid by the author (usually through a research grant). The alternative for a researcher is “self-archiving” (i.e., to publish in a traditional journal, where only subscribers have immediate access, but to make the article available on their personal and/or institutional Web sites (including so-called repositories or archives)), which is a practice allowed by many scholarly journals. Open Access raises practical and policy questions for scholars, publishers, funders, and policymakers alike, including what the return on investment is when paying an article processing fee to publish in an Open Access articles, or whether investments into institutional repositories should be made and whether self-archiving should be made mandatory, as contemplated by some funders.