Human reproductive ecology to aid infant survival and growth. Lactational strategies vary cross-culturally, but can typically be defined by sibling sets and sex ratios, frequency of nursing, entire lactational duration, and milk composition. Milk is composed of my bioconstituents, but only a few will be outlined here. In the first days of puerperium, the first milk is thick and yellowish, also called colostrum. For weeks after that, mature milk is expressed and it has been shown that fetal-mammary gland signaling occurs even before birth in determining milk type and concentrations based on the fetus sex. Colostrum plays an important role in establishing the
Prenex normal form Prenex normal form A formula of the predicate calculus is in prenex normal form if it is written as a string of quantifiers and bound variables, called the prefix, followed by a quantifier-free part, called the matrix. Every formula in classical logic is equivalent to a formula in prenex normal form. For example, if formula_1, formula_2, and formula_3 are quantifier-free formulas with the free variables shown then is in prenex normal form with matrix formula_5, while is logically equivalent but not in prenex normal form. Every first-order formula is logically equivalent (in classical logic) to some formula in prenex normal