Modular Decomposition and the Reconstruction Conjecture

We prove that a large family of graphs which are decomposable with respect to the modular decomposition can be reconstructed from their collection of vertex-deleted subgraphs.Comment: 9 pages, 2 figure

Activity-dependent adenosine release may be linked to activation of Na+-K+ ATPase : an in vitro rat study

In the brain, extracellular adenosine increases as a result of neuronal activity. The mechanisms by which this occurs are only incompletely understood. Here we investigate the hypothesis that the Na+ influxes associated with neuronal signalling activate the Na+-K+ ATPase which, by consuming ATP, generates intracellular adenosine that is then released via transporters. By measuring adenosine release directly with microelectrode biosensors, we have demonstrated that AMPA-receptor evoked adenosine release in basal forebrain and cortex depends on extracellular Na+. We have simultaneously imaged intracellular Na+ and measured adenosine release. The accumulation of intracellular Na+ during AMPA receptor activation preceded adenosine release by some 90 s. By removing extracellular Ca2+, and thus preventing indiscriminate neuronal activation, we used ouabain to test the role of the Na+-K+ ATPase in the release of adenosine. Under conditions which caused a Na+ influx, brief applications of ouabain increased the accumulation of intracellular Na+ but conversely rapidly reduced extracellular adenosine levels. In addition, ouabain greatly reduced the amount of adenosine released during application of AMPA. Our data therefore suggest that activity of the Na+-K+ ATPase is directly linked to the efflux of adenosine and could provide a universal mechanism that couples adenosine release to neuronal activity. The Na+-K+ ATPase-dependent adenosine efflux is likely to provide adenosine-mediated activity-dependent negative feedback that will be important in many diverse functional contexts including the regulation of sleep

CO2-dependent opening of an inwardly rectifying K+ channel

CO2 chemosensing is a vital function for the maintenance of life that helps to control acid–base balance. Most studies have reported that CO2 is measured via its proxy, pH. Here we report an inwardly rectifying channel, in outside-out excised patches from HeLa cells that was sensitive to modest changes in PCO2 under conditions of constant extracellular pH. As PCO2 increased, the open probability of the channel increased. The single-channel currents had a conductance of 6.7 pS and a reversal potential of –70 mV, which lay between the K+ and Cl– equilibrium potentials. This reversal potential was shifted by +61 mV following a tenfold increase in extracellular [K+] but was insensitive to variations of extracellular [Cl–]. The single-channel conductance increased with extracellular [K+]. We propose that this channel is a member of the Kir family. In addition to this K+ channel, we found that many of the excised patches also contained a conductance carried via a Cl–-selective channel. This CO2-sensitive Kir channel may hyperpolarize excitable cells and provides a potential mechanism for CO2-dependent inhibition during hypercapnia

Strategies to Support Employer-Driven Initiatives to Recruit and Retain Employees with Disabilities

Across the United States, a growing number of employers have established initiatives to increase the participation of workers with disabilities within their companies. These employers typically establish partnerships with local workforce and disability service organizations to source for talent. Coordinated by a single agency (or small number of agencies), employers are provided assistance and support services for recruitment, training, and job retention for employees with disabilities. This research brief presents four profiles that highlight innovative practices among employers operating warehouse distribution centers in the U.S

Tidal Stresses and Energy Gaps in Microstate Geometries

We compute energy gaps and study infalling massive geodesic probes in the new families of scaling, microstate geometries that have been constructed recently and for which the holographic duals are known. We find that in the deepest geometries, which have the lowest energy gaps, the geodesic deviation shows that the stress reaches the Planck scale long before the probe reaches the cap of the geometry. Such probes must therefore undergo a stringy transition as they fall into microstate geometry. We discuss the scales associated with this transition and comment on the implications for scrambling in microstate geometries.Comment: 22 pages, 1 figur