A debt-to-GDP ratio of 60% is quite often noted as a prudential limit for developed countries. This suggests that crossing this limit will threaten fiscal sustainability. For developing and emerging economies, 40% is the suggested debt-to-GDP ratio that should not be breached on a long-term basis.
1 Telomerase is found in high levels in germline cells (egg and sperm) and stem cells. 2  In these cells telomere length is maintained after DNA replication and the cells do not show signs of ageing. 3  Telomerase is also found in high levels in cancer cells.
Cancer cells are immortal because they produce telomerase. In the human body, only two kinds of body cells are immortal, able to divide without limit. Cancer cells are one. The other kind of immortal cell is the embryonic stem cell. More on Telome...