When the Border Crossed Me

The category of generalized crossed modules

In the definition of a crossed module $(T,G,rho)$, the actions of the group $T$ and $G$ on themselves are given by conjugation. In this paper, we consider these actions to be arbitrary and thus generalize the concept of ordinary crossed module. Therefore, we get the category ${bf GCM}$, of all generalized crossed modules and generalized crossed module morphisms between them, and investigate som...

Who will care for me when I get sick?

Who will do an ERCP on me when I'm retired?

To the Editor: In South Africa (SA) it is widely accepted that subspecialties such as gastroenterology (GE) are not functioning adequately, [1] as was highlighted in the SAMJ in 2004. [2] Fewer trainees are able to choose to subspecialise in GE. Indeed, all specialties are faced with a lack of training facilities. The National Department of Health (NDoH) plans to run the academic hospitals, whe...

Follow-Me Cloud: When Cloud Services Follow Mobile Users

The trend towards the cloudification of the 3GPP LTE mobile network architecture and the emergence of federated cloud infrastructures call for alternative service delivery strategies for improved user experience and efficient resource utilization. We propose Follow-Me Cloud (FMC), a design tailored to this environment, but with a broader applicability, which allows mobile users to always be con...

Dangerous bifurcation at border collision: when does it occur?

It has been shown recently that border collision bifurcation in a piecewise smooth map can lead to a situation where a fixed point remains stable at both sides of the bifurcation point, and yet the orbit becomes unbounded at the point of bifurcation because the basin of attraction of the stable fixed point shrinks to zero size. Such bifurcations have been named "dangerous bifurcations." In this...