In the present paper, we have studied the impact of lactation upon fertility in the capuchin monkey, Cebus apella, under laboratory conditions. Nursing females (ten females, 12 postpartum periods) presented lactational amenorrhea (first menses at 159.2 +/- 9.0 vs 42.6 +/- 5.8 days postpartum in five non-nursing females, seven postpartum periods). Plasma estradiol and progesterone concentrations during lactational amenorrhea were lower than those during the follicular phase of the menstrual cycle. Prolactin was higher than in non-nursing females at 31-60 days postpartum. Interbirth interval, studied in three non-nursing (four intervals) and six nursing females (eight intervals) lasted for 349.5 +/- 11.8 and 613.4 +/- 30.8 days, respectively. In non-nursing females, early recovery of the menstrual cycle was followed by a residual infertility (mating but no pregnancy) lasting 152.8 +/- 7.9 days. In nursing females, recovery of the menstrual cycle was followed by an extended residual infertility of 301.5 +/- 22.7 days. Thus, in the capuchin monkey, nursing prolongs the interbirth interval by inducing lactational amenorrhea and extending the residual infertility period.

Resumen1 Esta investigación se plantea la necesidad de identificar el origen del modelo de subsidios a la vivienda social, orientados a la localización y contención urbana en Chile y México, analizando, desde una perspectiva crítica, los procesos de estructuración del marco normativo y de las políticas públicas de corte neoliberal, con la construcción del modelo de gestión territorial para el desarrollo. Para ello se plantea si es posible considerar a la política subsidiaria de vivienda social actual, como un modelo emulado por gobiernos latinoamericanos para materializar la desregulación del mercado del suelo urbano en la región. Específicamente analizan los marcos normativos e institucionales de la política habitacional chilena, con la implementación del sistema condicional de subsidios a la localización en México.