Last week, President Obama became the latest to fail to put on what people in the television business call "neutral face," a warm but flat expression that betrays no hint of whatever feelings might be simmering inside.
He had reason to rejoice, of course, and yet, in the image, he wears a flat, uneasy expression — a fitting reflection of a moment that opens an uncertain new chapter.
The resulting PIRS was minimized for genes that exhibit both flat expression as a function of time and low variance in observed expression at each time point.
The expression response curve for the gene could be vertically shifted upward by introducing additional copies of the gene under the control of a constitutive (unregulated) promoter, as this would contribute a flat baseline expression rate.
They may have a flat facial expression, or exhibit exaggerated experiences.
The MdP was distinguished by a dramatic increase in the expression levels of Thbs4 (GeneID: 21828) compared with the other prominences, but relatively flat expression of Sdc2 (GeneID: 15529).
On average, tissue-specific genes (τ ≈ 1) had about equal expression in males and females, whereas genes with close to flat expression profiles showed about two times higher expression in males than in females (fig. 1).
In all cases, the genes selected by our metric show flat expression with low variation, whereas genes that rank poorly show high variation both within and between time points (compare Figure 1, Figure 2, and Figure 3 to Figure S4).
Details, including compliance with MIQE guidelines [ 14], are available in Additional files 2 and 3. Flat expression patterns across samples in the derivation dataset were filtered out by excluding genes with standard deviations ≤ 0.1.
