The insight underlying this is that the notion of rigid displacement therefore of rigid coordinate system, and inertial frame imposes a priori a degree of uniformity, or symmetry, on spacetime; the displacement of bodies without change of dimension, and the transport of an ideal clock without distortion of time-intervals, requires a homogeneous space.
Figure 5 illustrates an ideal clock signal while triggering at the rising edge of the clock signal with the desired basal period.
Timelike world lines can be parameterized by a quantity, proper time, which is measured by ideal clocks following such world lines.
Einstein evidently was thinking that, in general relativity, coordinates, and coordinate transformations, no longer represent the possible displacements of rigid bodies or the transport of ideal clocks.
The metrical field has physical and metrical significance, and the metrical significance does not consist in the mere articulation of relations obtaining between, say, rigid rods or ideal clocks.
As Pauli puts it above, according to Weyl "the metric field must not be defined by means of information taken from these measuring instruments [rigid rods and ideal clocks]".
In contrast, an analogous fact was not known in the theory of electricity; consequently, it would seem that there was no compelling physical reason to think that rigid rods and ideal clocks would be under the universal influence of the electromagnetic field.
An ideal fast-clock gene will show significant variation throughout the 19 strains; one such gene, which encodes a PPE family protein, is easily identified by the color variation in the column (see Figure 3).
In genetic logic circuits, oscillation signal produced from a repressilator is not ideal as a clock for use in the kind of circuits relying on the change of rising or falling edge of the clock signal for state transition.
More ideal would be a clock that would allow the comparison of events recorded in the genome with events recorded in different genomes, or even with events in the geological record [ 36].
With a proper belt, it would be ideal for round-the-clock poolside meetings with chief financial officers, especially if I were 30 pounds heavier.
