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.
Each chromosome is like a DNA library with two protective caps on the end known as telomeres. As telomeres become shorter, their structural integrity weakens, which causes cells to age faster and die younger. In human cells, telomeres are usually single-stranded DNA that contains several thousand repeats of a simple TTAGGG sequence.