Family researchers and policy makers are giving increasing attention to the consequences of immigration for families. Immigration affects the lives of family members who migrate as well as those who remain behind and has important consequences for family formation, kinship ties, living arrangements, and children's outcomes. We present a selective review of the literature on immigrant families in the United States, focusing on key research themes and needs. A summary of secondary data sets that can be used to study immigrant families is presented as well as suggestions for future research in this increasingly important area of family research and policy.
The quotient ratio (QR) method, a new quantitative method for enantiomeric determination by mass spectrometry, is presented. The method is illustrated by the case in which a chiral analyte (A) and a chiral reference compound (ref*) are simultaneously coordinated to a transition metal ion (e.g., Cu2+ or Zn2 ) to form a singly charged deprotonated cluster ion in the course of electrospray ionization. The trimeric complex ion (three chiral ligands-2 mol of the analyte and 1 mol of the reference compound) is collisionally activated and undergoes dissociation by competitive loss of either a neutral reference or a neutral analyte. The ratio of the product ion branching ratios measured when pure chiral reference compounds (ref*D and ref*L) are employed in separate experiments is related via the kinetic method to the enantiomeric composition of the chiral mixture. This quotient ratio is logarithmically related to enantiomeric purity. In contrast to the previous single ratio method (Tao, W. A.; Zhang, D.; Wang, F.; Thomas, P. D.; Cooks, R. G. Anal. Chem. 1999, 71, 4427), the QR method reported here requires only one sample of the analyte with known optical purity to allow construction of a calibration curve. Accurate determinations of enantiomeric excess for amino acids and the chiral drug DOPA are demonstrated.
Accurate quantification of the optical isomers in a ternary mixture of D-, L-, and meso-tartaric acids is achieved using electrospray ionization tandem mass spectrometry for in-situ metal complex formation and a three-point calibration method to quantify the dissociation kinetics.
teenagers living in [mother/boyfriend] cohabiting families fare worse, on average, than those living with single mothers.This series presents findings from the National Survey of America's Families (NSAF). First administered in 1997, the NSAF is a survey of 44,461 households with and without telephones that are representative of the nation as a whole and of 13 selected states (
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