Importantly, the results of these analyses are fully consistent with increased local and global centrality and with lower constraint of CGPs, particularly for down-regulated CGPs (Additional file 6).
miR and miR* regions typically show the greatest constraint and hence the lowest rate of substitution, while the loop and stem regions, although important for processing, show lower constraint and hence a higher rate of substitution (Fahlgren et al. 2010).
To ensure that the estimated σ ^ u 2 is nonnegative it is necessary to specify a zero lower boundary constraint for σ ^ u 2. This can be accomplished using the lower b=value-list option of the parms statement of the MIXED procedure when using the SAS system.
However, our neutral divergence estimate for the X chromosome is slightly larger than for autosomes (supplementary table S5, Supplementary Material online) and hence cannot be held accountable for lower constraints in X-linked tRNAs but suggests that a lower Cx at paired and unpaired sites is indeed due to a higher number of fixed differences in tRNAs on the X chromosome.
Conversely, genes in the COGs "Coenzyme transport and metabolism", "Transcription", and "Signal transduction mechanisms" showed a tendency for lower codon bias (Table 2), possibly because these genes are not constitutively expressed and are not highly expressed in the cell, lowering the constraint for preferential codons usage [ 70- 72].
LR enables the development of lower bound constraints for both energy consumption (Eqs. 10 and 12) and delay constraint parameters on the optimal length of a constrained optimal path.
Node voltage and branch power must meet the following constrains: 1) Node voltage constraint U_{i,hbox{min} } le U_{i} le U_{i,hbox{max} } where ( U_{i,hbox{min} } ), ( U_{i,hbox{max} } ) are the upper and lower voltage constraints for node i, respectively.
However, it differs from studies done on a macroevolutionary timescale, which have consistently reported that accelerated evolutionary rates tend to happen at the periphery of the protein interaction network, likely due to the lower functional constraints for the peripheral proteins (Jeong et al. 2001; Fraser et al. 2002).
Based on presented diagram in Fig. 1, the lower bound constraint is violated for some points, almost high elevations.
