Confluent with the single dimension of time, breach of time-reversal symmetry is usually perceived as a one-dimensional concept. In its ultimate realization–the one-way guiding device–it allows optical propagation in one direction, say +z, and forbids it in the opposite direction, −z. Hence, in studies of time-reversal asymmetry the mapping t 7→ −t is naturally associated with z 7→ −z. However,...

We investigate the problem of secure message transmission in the presence of a ‘fully generalised’ adversary, who disrupts and listens to separate sets of communication wires. We extend previous results by considering the case when these sets may have arbitrary size, providing necessary and sufficient conditions for both one-way and two-way communication.

This study assessed goal-setting and task performance among Nigerian managers. Data were collected from 521 subjects including 176 Yoruba, 147 Igbo and 198 Hausa/Fulani managerial employees in Lagos, Nigeria. The relevant scales of the 57-item questionnaire designed by Mendonca and Kanungo (1994) were used to obtain measures of the dependent variables. Mean scores in goal setting and performanc...

Recent e-Government literature has highlighted Government 2.0 (Gov 2.0) as a vehicle for greater citizen engagement. Despite previous high expectations, citizens’ involvement in Gov 2.0 has been relatively low. Theoretical lens from service science and value co-creation are adapted from the literature and integrated with findings from prior e-Government research to develop a conceptual framewor...

Lone parents are a growing group in Great Britain and elsewhere, and one with high rates of poverty and receipt of social assistance. This article investigates some of the links between lone parenthood, economic activity and social background. It also provides longitudinal and event-history analysis of life-history data from mid-1990s Great Britain, to look at transitions between different fami...

1. L. K a r t t u n e n ( K a r t t u n e n 1970, 1971) demons t r a t ed t h a t i n E n g l i s h t h e r e e x i s t s i x c l a s s e s o f p r e d i c a t e s t h a t d i f f e r as f o r t h e r e l a t i o n s h i p s h o l d i n g be tween the p r e d i c a t e and i t s s e n t e n t i a l complement: f a c t i v e s , p o s i t i v e and n e g a t i v e two-way i m p l i o a t i v e s...

We consider two infinite games, played on a countable graph G given with an integer vertex labelling. One player seeks to construct a ray (a one-way infinite path) in G, so that the ray’s labels dominate or elude domination by an integer sequence being constructed by another player. For each game, we give a structural characterization of the graphs on which one player or the other can win, prov...

Energy efficient transmission has become increasingly important in future green communications. We focus on cooperative networks with multiple Amplify-and-Forward relays deployed in this paper. A joint relay selection and power allocation transmission scheme applicable to both one-way and two-way relay networks is proposed for minimizing the weighted energy consumed per bit transmitted. Close-f...