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
Invariant of a binary form the form itself of degree 1 and order 1. The algebra of invariants of the quadratic form "ax" + 2"bxy" + "cy" is a polynomial algebra in 1 variable generated by the discriminant "b" − "ac" of degree 2. The algebra of covariants is a polynomial algebra in 2 variables generated by the discriminant together with the form "f" itself (of degree 1 and order 2). The algebra of invariants of the cubic form "ax" + 3"bx""y" + 3"cxy" + "dy" is a polynomial algebra in 1 variable generated by the discriminant "D" = 3"b""c" + 6"abcd" − 4"b""d" −