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
Hasse invariant of a quadratic form Hasse invariant of a quadratic form In mathematics, the Hasse invariant (or Hasse–Witt invariant) of a quadratic form "Q" over a field "K" takes values in the Brauer group Br("K"). The name "Hasse–Witt" comes from Helmut Hasse and Ernst Witt. The quadratic form "Q" may be taken as a diagonal form Its invariant is then defined as the product of the classes in the Brauer group of all the quaternion algebras This is independent of the diagonal form chosen to compute it. It may also be viewed as the second Stiefel–Whitney class of "Q". The invariant may be computed for