The (k, s)-SAT problem is the satisfiability problem restricted to instances where each clause has exactly k literals and every variable occurs at most s times. It is known that there exists a function f such that for s ≤ f(k) all (k, s)-SAT instances are satisfiable, but (k, f(k)+1)-SAT is already NP-complete (k ≥ 3). We prove that f(k) = O(2 · log k/k), improving upon the best know upper boun...

Reconnection within planetary magnetotails is responsible for locally energizing particles and changing the magnetic topology. Its role in terms of global magnetospheric dynamics can involve changing the mass and flux content of the magnetosphere. We have identified reconnection related events in spacecraft magnetometer data recorded during Cassini's exploration of Saturn's magnetotail. The eve...

Information and communication technology (ICT) alters the temporal conditions in which groups operate and transforms the way time is perceived, used, managed and disciplined in groups. A review of empirical research on groups interacting with ICT reveals that little research examines time per se as a variable of interest. This proposed research endeavors to examine (1) how the use of ICT is rel...

In this paper I investigate the evolution of cooperation in the prisoner's dilemma when individuals change their strategies subject to performance evaluation of their neighbours over variable time horizons. In the monochrome setting, in which all agents per default share the same performance evaluation rule, weighing past events strongly dramatically enhances the prevalence of cooperators. For ...

A plausible explanation for the contradictory results published by several groups on the dimensionality of the concept of aromaticity is found. We demonstrate that the good linear relationships between the molar diamagnetic exaltation (Λ) and the resonance energy (RE) of heteroaromatic compounds is not fundamental, but only a consequence of the strong correlation of both properties with the mol...