Filling an Emulsion Drop with Motile Bacteria

We have measured the spatial distribution of motile Escherichia coli inside spherical water droplets emulsified in oil. At low cell concentrations, the cell density peaks at the water-oil interface; at increasing concentration, the bulk of each droplet fills up uniformly while the surface peak remains. Simulations and theory show that the bulk density results from a `traffic' of cells leaving the surface layer, increasingly due to cell-cell scattering as the surface coverage rises above $\sim 10\%$. Our findings show similarities with the physics of a rarefied gas in a spherical cavity with attractive walls.Comment: 5 pages, 4 figures, Supporting Information (5 pages, 5 figures

Comparing Skill Acquisition Under Varying Onsets of Differential Reinforcement: A Preliminary Analysis

The purpose of the current study was to evaluate the effect of implementing differential reinforcement at different times relative to the onset of teaching new skills to learners with autism spectrum disorder. Specifically, we first determined the most efficient differential reinforcement arrangement for each participant. Using the most efficient arrangement, we evaluated if differential reinforcement from the immediate onset, early onset, or late onset is the most efficient for learners to acquire a new skill. Three children diagnosed with autism spectrum disorder who have a history of receiving intervention based on the principles of applied behavior analysis participated in this study. The immediate onset of differential reinforcement resulted in the most efficient instruction in 6 of 7 comparisons. The results are discussed in light of previous studies and suggestions for future research are provided

Labour strategies, cross-border solidarity and the mobility of health workers : Evidence from five New Member States

Shortages of health workers in Western Europe have been addressed, in part, by recruitment from New Member States. In addition to concerns regarding social dumping and cohesion, the loss of human capital and subsequent deleterious impact on services poses a new challenge for trade unions. The aim of this article is to examine the strategies and interventions of health worker trade unions in five countries: Hungary, Latvia, Poland, Romania and Slovakia. Union capacity is analysed through the dimensions of structural power (ability to cause disruption through industrial action); institutional power (lobbying and negotiating with appropriate bodies); and coalitional power (mobilizing support across borders with labour and non-labour organizations). While structural power is generally weak, the deployment of institutional and coalitional power has been more varied across the five countries.Peer reviewe