Postcollision multifragmentation in fullerene-surface impact: Microscopic insights via molecular dynamics simulations.

Postcollision multifragmentation which we have recently observed experimentally in C60 (-)-surface impact is the phenomenon of a delayed multiparticle breakup of a highly collisionally vibrationally excited large molecule/cluster (the precursor species) into several polyatomic fragments, after leaving the surface. In this paper, we show that the molecular dynamics simulations of near-grazing C60 collisions with a gold surface at 300 eV impact energy (very similar to the experimental conditions) successfully reproduce the experimentally observed characteristics of the postcollision multifragmentation process. The calculated mass resolved kinetic energy distributions and the time dependent yield curves of the Cn fragments revealed a precursor mediated, velocity correlated, delayed fragmentation event along the outgoing trajectory, far away from the surface.

Parent relationship quality and infant-mother attachment.

This project examined interrelations between father-mother conflict, father support of mother, maternal behavior, and infant-mother attachment within a sample of 79 African American families living in a highly stressed urban community. Father support of mother was not related to maternal parenting behavior or infant attachment. Conflicted mother-father relationships were associated with problematic maternal behavior, low maternal sensitivity, infant attachment insecurity, and infant attachment disorganization.

Mothers' representations of their infants and parenting behavior: Associations with personal and social-contextual variables in a high-risk sample.

Associations between mothers' psychological distress, experiences of verbal and violent relational conflict, representations of the relationships with their infants, and parenting behavior were examined in 100 African American mothers of 17- to 20-month-old infants. Maternal representations of infants were assessed via the Working Model of the Child Interview (WMCI; Zeanah, Benoit, Hirshberg, & Barton, 1986). Results showed that mothers who experienced more conflict with their own mothers had increased odds of having disengaged representations of the relationship with their infants.

Mother expectation of bother and infant attachment behaviors as predictors of mother and child communication at 24 months in children of methadone-maintained women.

This study used a transactional model of development (Sameroff, 1975) to test whether methadone exposure, mother's expectation of her future infant's degree of bother during pregnancy, infant attachment behaviors assessed at 12 months, and mother and child communication assessed at 24 months reciprocally influence each other in a sample of 30 full-term, African American toddlers exposed in utero to methadone and 42 comparison toddlers. Toddlers were videotaped at 24 months communicating with their mothers in eight scripted situations and at 12 months participating in a separation-reunion procedure to assess attachment behaviors. Mothers in both groups were comparable on race, education, age, SES, parity, IQ, and marital status.