The design of Medium Access Control (MAC) protocols for multi-hop ad hoc networks is challenging as each network entity has only a local view of the network. Consequently, efficient, decentralized, MAC protocols are needed. In this paper, we demonstrate that a protocol based on a local backoff mechanism can globally organize the transmissions in a network. Moreover, we show that such a protocol...

The functional repertoire of a network is determined by its topology. Ma et al. (2009) analyze enzyme networks with three nodes and take a reverse-engineering approach to ask how many core network topologies can establish perfect adaptation, the ability to reset after perturbation. Surprisingly, the answer is just two.

In combinatorial auctions that use VCG, a seller can sometimes increase revenue by dropping bidders (see e.g. [5]). In our previous work [26], we showed that such failures of “revenue monotonicity” occur under an extremely broad range of deterministic strategyproof combinatorial auction mechanisms, even when bidders have “known single-minded” valuations. In this work we consider the question of...

We have always been working hard to keep the Brazilian Journal of Cardiovascular Surgery (BJCVS) active and up-to-date, despite the uncertainties that pervade the political, economic, social and scientific activities in our country. Those who did not imagine the evil influence that would be exerted by the instability that has taken place in the public or private Universities, were wrong. The ne...

Long living software systems (LLSSs) must provide the flexibility to react to changes in their operating environment as well as to changes in the user’s requirements, even during operation. Self-adaptive software systems (SASSs) face adaptivity at runtime within predefined bounds. Yet, not all types of necessary variations can be anticipated and unforeseen changes to software may happen. Thus, ...

Temperature influences physiological processes and can corrupt nervous system function. A modelling study shows how regulation of ion channel expression can establish an acute temperature invariance of neuronal responses despite temperature-dependent and variable ionic conductances.

With the increasing explosion of human knowledge, it is necessary for people to undertake cross-space learning, cross-time learning, and eventually achieve education Leapfrog capabilities. The emergence of digital educational media has made these capabilities both desirable and highly likely.