Charged particle trajectories in a toroidal magnetic and rotation-induced electric field around a black hole

Trajectories of charged particle in combined poloidal, toroidal magnetic field and rotation-induced unipolar electric field superposed in Schwarzschild background geometry have been investigated extensively in the context of accreting black holes. The main purpose of the paper is to obtain a reasonably well insight on the effect of spacetime curvature to the electromagnetic field surrounding black holes. The coupled equations of motion have been solved numerically and the results have been compared with that for flat spacetime. It is found that the toroidal magnetic field dominates the induced electric field in determining the motion of charged particles in curved spacetime. The combined electromagnetic field repels a charged particle from the vicinity of a compact massive object and deconfines the particle from its orbit. In the absence of toroidal magnetic field the particle is trapped in a closed orbit. The major role of gravitation is to reduce the radius of gyration significantly while the electric field provides an additional force perpendicular to the circular orbit. Although the effect of inertial frame dragging and the effect of magnetospheric plasma have been neglected, the results provide a reasonably well qualitative picture of the important role played by gravitation in modifying the electromagnetic field near accreting black holes and hence the results have potentially important implications on the dynamics of the fluid and the radiation spectrum associated with accreting black holes.Comment: 18 pages, Latex, 8 figures, To appear in Int. J. Mod. Phys.

Women and Irrigation in Nepal: Context, Issues and Prospects

Occasional Papers in Sociology and Anthropology - Volume 9, 200

A novel tool for organisational learning and its impact on safety culture in a hospital dispensary

Incident reporting as a key mechanism for organisational learning and the establishment of a stronger safety culture are pillars of the current patient safety movement. Studies have suggested that incident reporting in healthcare does not achieve its full potential due to serious barriers to reporting and that sometimes staff may feel alienated by the process. The aim of the work reported in this paper was to prototype a novel approach to organisational learning that allows an organisation to assess and to monitor the status of processes that often give rise to latent failure conditions in the work environment, and to assess whether and through which mechanisms participation in this approach affects local safety culture. The approach was prototyped in a hospital dispensary using Plan-Do-Study-Act (PDSA) cycles, and the effect on safety culture was described qualitatively through semi-structured interviews. The results suggest that the approach has had a positive effect on the safety culture within the dispensary, and that staff perceive the approach to be useful and usable