Acute hunger of rat pups elicits increased kyphotic nursing and shorter intervals between nursing bouts: implications for changes in nursing with time postpartum

Earlier findings, based on limited behavioral observations, indicate that nursing behavior in rats declines dramatically in duration over time postpartum-despite increasing ingestion of milk by rat pups to meet their growth and metabolic needs-although hungry pups elicit more nursing than do well-nourished pups. The authors compared the nursing pattern in detail for 6 hr on Days 7 and 14 and induced hunger in pups acutely with mammary-duct-ligated dams unable to provide milk. Compared with Day 7, on Day 14, supine nursing and the interval between nursing bouts increased, whereas hovering over pups and kyphotic nursing decreased. When pups were increasingly hungry, these age-related changes were counteracted. Thus, the ingestive motivation of pups largely regulates the nursing pattem over time.     

Changes in older Dutch adults’ role networks after moving

Using the convoy model (R. L. Kahn & T. C. Antonucci, 1980), this study examined the differential impact of relocation, depending on the distance moved, on the size of 3 types of role networks. A total of 890 Dutch nonmovers and 445 movers (aged 55–86 years) were selected from the Longitudinal Aging Study Amsterdam. Results of analyses of variance showed that the neighbor networks changed most after relocation. Long‐distance movers discontinued the largest number of relationships with fellow club members. As expected, moving did not affect coworker networks. The findings show that, consistent with the convoy model, role networks proved to be unstable. Older adults, however, restored their partial networks at the second observation by starting new relationships.