The application of IMM normalization to this pair of samples results in a normalization factor of 0.989 (-0.016 on l o g2 scale; shown by the red line in Additional file 1: Figure S12) after excluding some genes.
On the other hand, the application of advanced normalization has provided some improvement of the detection of T-C in comparison with the approach where no signal enhancement has been applied.
These negative correlations remained significant with the application of global normalization in the reanalysis (P < 0.001).
We demonstrate that the application of loess normalization to the spikes' signal decreases significantly the major source of variability.
Another distinction was the application of cDNA normalization to the construction of the U. vulgaris transcriptome but not the U. gibba transcriptome.
For this purpose, we speculated that the application of a normalization process during library construction could reduce the proportion of highly expressed genes, and contribute to the efficient collection of genes from samples.
These positive correlations were statistically significant both in the entire subject group and in the subgroup with schizophrenia (Supplementary Table 5) and they remained significant with the application of global normalization in the reanalysis (P < 0.05).
The application of a normalization procedure (z-transformation), therefore, represents a useful method to account for the individual differences in absolute physiological responsivity (e.g., Kreibig et al., 2007; Stemmler, 1989).
