However, in all of these cases the patterns of gene expression define a single segment periodicity, rather than the double segment periodicity observed in Strigamia and in Tribolium.
Two-segment periodicity is common in insects, but apart from Strigamia, a single segment periodicity is the rule in other arthropods and in vertebrates.
In some arthropods (for example, the myriapods Lithobius and Glomeris, the spider Cupiennius), this initial pattern appears to have a single segment periodicity, as defined by the subsequent expression of engrailed and other segment polarity genes in register with these primary stripes, and by the appearance of definitive segment morphology shortly afterwards [ 6- 8].
Such arrangements might have the effect (with potential advantage to the organism) of allowing a single underlying periodicity in some regions of the genome to constrain incremental sliding of nucleosomes in response to lateral forces, while potentially increasing nucleosome dissociation in response to such forces.
The power spectra of AL, GCA incidence rate and RA incidence rate have a secondary peak (periodicities) at 4 5 years, but the F10.7 power spectrum is dominated by a single frequency or periodicity.
The periodicity of the Kelvin cell enables calculation of the compressive response up to the limit stress with just a single fully periodic characteristic cell.
The periodicity of the Kelvin cell enables calculation of the initial elastic properties as well as the initiation stress with just a single fully periodic characteristic cell.
The approach presented is motivated by the observation, that stirred tank reactors operated in batch, semi-batch, continuous, or even periodically forced mode can be subsumed by a single optimization model with periodicity constraints and suitably chosen model equations and decision variables.
While there is widespread agreement that birth weight shows seasonal fluctuations [ 2, 3], there is a lack of between-location agreement about features such as: (a) the timing (or phase) of maximum weight, and (b) the presence of a single peak (unimodal, 12 month periodicity) or two peaks (bimodal, 6 and 12 month periodicities).
