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
Polar form of the Dirac equation formula_11 vanish simultaneously, the spinor field is called regular, and in this case it is always possible to find a local frame in which the regular spinor field acquire the form up to a transformation of the type formula_15 and up to the reversal of the third axis. Therefore, a regular spinor can, in general, be written according to where formula_17 is called module and formula_18 is called Yvon-Takabayashi angle, and where formula_19 is the generic complex representations of the Lorentz transformation that is needed to obtain the generic spinor in its most reduced form as is written above. When