The experiment starts when CA has reached
its steady state. The experimental clock is set to
t = 0. The time unit is one day.
Max age =140. Cells older than 140 days die. The image below
depicts CA-1 and its age distribution. Then comes CA-2 and its age distribution.
The different shades of gray are proportional to cell age. White represents
age = 0, and black,
age = 140. The vertical line indicates where the age of the oldest
cell has reached age max, whereupon its age is set to 0 (white). CA-2
ages faster than CA-1 and cells reach age max earlier.
Below are three distributions observed at = 50. Since CA-2 ages faster than CA-1, its ages at t = 50 are higher, and so is its mean aging vrlocity. The third distribution depicts average acceleration of CA-2 relative to CA-1. The lowest figure depicts aging of the cell at position 47 in the two CA. Their mean difference rises linearly, indicating that age acceleration fluctuates about a constant value.
In the last experiment acceleration was proportional to cell position. Cells at position 40 accelerated slower than those at position 60. The mean aging acceleration distribution is skewed.
Chapters 11, and 12 describe the nature of biological age. Processes in our body age at different velocities, which is most conspicuous in tissues. In the previous chapter cells aged at a constant velocity (acceleration = 0). In the present experiments acceleration > 0. Age acceleration may fluctuate between positive and negative values. When studying our aging body we apply physical (chronological) time. In this framework aging is constant. Each year we age by one year. Acceleration = 0
zygote -> effect[1, 1000]; go; restoreparams; age[] += 1.5 a[]; effect[no, 140]; go; restoreparams ; Do[age[[2, i]]+= (1 + 0.01 i) a[[2, i]]]; effect[no, 140]; go ;