Bubble pinch-off in turbulence.

Although bubble pinch-off is an archetype of a dynamical system evolving toward a singularity, it has always been described in idealized theoretical and experimental conditions. Here, we consider bubble pinch-off in a turbulent flow representative of natural conditions in the presence of strong and random perturbations, combining laboratory experiments, numerical simulations, and theoretical modeling. We show that the turbulence sets the initial conditions for pinch-off, namely the initial bubble shape and flow field, but after the pinch-off starts, the turbulent time at the neck scale becomes much slower than the pinching dynamics: The turbulence freezes.

Digestion of feed amino acids in the rumen and small intestine of dairy cows measured with nylon-bag techniques.

The disappearance of total N, non-protein-N and amino acid-N after washing, rumen incubation and intestinal passage of sugarbeet pulp, maize-gluten feed, maize feed meal, palm kernel meal, soyabean hulls, soyabean meal, grass silage, maize silage and concentrate was measured in four dairy cows using nylon-bag techniques. Disappearance of amino acid-N after washing varied between feedstuffs from 14 to 69% of feed amino acid-N, and was lower than disappearance of non-protein-N. For sugarbeet pulp, grass silage and maize silage, washing had a considerable effect on the amino acid profile.

Socioeconomic factors affecting fertility in the developing countries and of the developing population groups in South Africa.

"In the present paper...

Response stability in social research: lessons from a longitudinal study of the family-building process.

"Responses to questions, phrased to elicit identical answers from the same individuals over time, are compared. The questions were used in a South African longitudinal study on the family-building process. Although consistency for certain questions was high, consistency was particularly low for questions on family-planning methods used and desired number of children at the time of marriage.