Jan van Paradijs

Towards a Model for the Progenitors of Gamma-Ray Bursts In memory of Jan van Paradijs

We consider models for gamma-ray bursts in which a collimated jet expands either into a homogeneous medium or into a stellar wind environment, and calculate the expected afterglow temporal behavior. We show that (i) following a break and a faster decay, afterglows should exhibit a flattening, which may be detectable in both the radio and optical bands; (ii) Only observations at times much short...

Jan van Mill

De Groot proved that every group is the autohomeomorphism group of some metrizable space. A space is totally disconnected if every connected subset of it contains at most one point. We prove that every separable metrizable totally disconnected topological group is topologically isomorphic to the autohomeomorphism group of some separable metrizable space, when given the compact-open topology. It...

Jan A . van Gils Matthijs van der Geest Jutta Leyrer

Obituary for Jan Valentyn van der Merwe

Professor Jan Valentyn Van der Merwe passed away on Friday, 25 September, at the age of 71. Prof Jan’s illustrious career began after he completed a research fellowship at Duke University in the USA, and returned to South Africa as Head of the Department of Obstetrics and Gynaecology at Pretoria University. In this role, Prof Jan pioneered the establishment of an assisted reproduction unit in S...

Jan van der Noordaa (1934–2015);A Virologist Pur Sang

Our loyal friend and colleague, Jan van der Noordaa, passed away unexpectedly at the age of 80 on the evening of 17 June 2015. [...].