A group is combable if it can be represented by a language of words satisfying a fellow traveller property; an automatic group has a synchronous combing which is a regular language. This paper gives a systematic analysis of the properties of groups with combings in various formal language classes, and of the closure properties of the associated classes of groups. It generalises previous work, i...

Over the past six decades, tourism has experienced continued expansion and diversification becoming one of the largest and fastest growing economic sectors in the world. Many new destinations have emerged alongside the traditional ones of Europe and North America. In the next years an increase of travelling is expected, and the number of related infections will also be higher (http://www.unwto....

This report describes a 21-year-old male patient who presented to a UK hospital with mild symptoms of fever, malaise and arthralgia. He had just returned from Hoga Islands (Indonesia) where he had spent six weeks. While examination was unremarkable, his blood showed a significant rise in liver function tests and a steady drop in white cells as well as platelets. Dengue serology was later found ...

Rapid urban growth is resulting into increase in travel demand and private vehicle ownership in urban areas. In the present scenario the existing infrastructure has failed to match the demand that leads to traffic congestion, vehicular pollution and accidents. With traffic congestion augmentation on the road, delay of commuters has increased and reliability of road network has decreased. Four s...