The size of poly(A)-containing RNAs in Drosophila melanogaster embryos.

The size range of poly(A)-containing RNA from Drosophila melanogaster embryos has been estimated by hybridization with 3H-labeled poly(U) and subsequent fractionation on sucrose gradients. The median size of nuclear poly(A)-containing RNA is about 30 S (6000 nucleotides), and the median size of cytoplasmic poly(A)-containing RNA is about 17 S (1800 nucleotides). The relationship of these sizes to messenger RNA needed to code for protein and to the length of DNA contained in a chromomere is discussed.

Parent-infant interaction in 8-month-olds.

Twenty 8-month-olds were observed interacting with their parents in a structured laboratory situation. Their responses to separations from each parent and the entrance of a strange adult were recorded. These events did not result in the predicted intensification of parental preferences.

Borderline hypertension discovered during screening: effect of twelve months' treatment.

The frequency of borderline hypertension (diastolic BP 95 to 109 mm Hg) is described in 5,877 men and 1,125 women attending a screening clinic. Borderline hypertension is more frequent in each 5-year age group in men than women. The results of the initial 12 months treatment show a greater fall in mean systolic and diastolic pressures in those on active treatment in comparison with placebo.

Relationship between linguistic performance and memory deficits in retarded children.

Performance of retarded children was measured on four tests of linguistic ability and two memory tests. Subjects were 50 retarded children: 10 each at mental ages 3, 4, 5, 6, and 7. The relationship between linguistic performance and memory was assessed by correlational analysis.

The sociability of two-year-olds with their mothers and fathers.

Twenty-one two-year-olds were observed interacting with their parents in a laboratory playroom. Previously reported analyses had found that they displayes no preferencd for interaction with either parent. The present analysis found that there was a high degree of correlation between the sociability of the cild with his mother and his sociability with his father.