Although sputum pre-treatment appeared to be effective, this meta-analysis could not separate the effect of chemicals (e,g, bleach) from the various physical methods (e,g, centrifugation) used.
Comparing dN, dS, and ω (dN/dS) to species-richness of clades allows us to separate the effect of mutation rate on net diversification from the effect of selection and effective population size.
The authors acknowledge that it is difficult to separate the effect of breast-feeding from childbirth itself.
The challenge was to separate the effect of cushioning from every other factor.
But that's no different from trying to separate the effect of an athlete's speed from the effect of his strength.
To be sure, it becomes hard to separate the effect of political change on the arts from the kind of vocal evolution that has been happening worldwide anyway.
For instance, in the Maine math study, it is hard to separate the effect of the laptops from the effect of the teacher training.
Mr. Manning said that he believes so, although it is difficult to separate the effect of local ads from the national ads with the tagline and the equally famous milk mustache.
To separate the effect of these factors from the effect of the name, Dr. Figlio compared children within the same family: a sibling with one of these names versus a sibling with a more conventional name.
It is necessary to separate the effect of nonlinear refraction from that of the nonlinear absorption.
We were able to separate the effect of DNIC on the peak pain and on TS.
