BACKGROUND Preterm infants fed fortified human milk (HM) grow more slowly than those fed preterm formulas. These differences could be related to the variability in the macronutrient composition of expressed HM, resulting in inadequate nutrient intake in relation to the estimated needs of the preterm infants. OBJECTIVES The aim of this article was to show the variability in HM composition from...

Bimodal distributions of protein activities in signaling systems are often interpreted as indicators of underlying switch-like responses and bistable dynamics. We investigate the emergence of bimodal protein distributions by analyzing a less appreciated mechanism: oscillating signaling systems with varying amplitude, phase and frequency due to cell-to-cell variability. We support our analysis b...

Some of the assumptions underlying estimates of DNA and protein sequence divergence are examined. A solution for the variance of these estimates that allows for different mutation rates and different population sizes in each species and for an arbitrary structure in the initial population is obtained. It is shown that these conditions do not strongly affect estimates of divergence. In general, ...