Detection and resolution of normative conflicts in multi-agent systems : a literature survey

Peer reviewedPostprin

Entanglement Purification of Any Stabilizer State

We present a method for multipartite entanglement purification of any stabilizer state shared by several parties. In our protocol each party measures the stabilizer operators of a quantum error-correcting code on his or her qubits. The parties exchange their measurement results, detect or correct errors, and decode the desired purified state. We give sufficient conditions on the stabilizer codes that may be used in this procedure and find that Steane's seven-qubit code is the smallest error-correcting code sufficient to purify any stabilizer state. An error-detecting code that encodes two qubits in six can also be used to purify any stabilizer state. We further specify which classes of stabilizer codes can purify which classes of stabilizer states.Comment: 11 pages, 0 figures, comments welcome, submitting to Physical Review

Therapeutic Approach to Parapneumonic Effusions and Empyemas

Face à inexistência de uma metodologia única e consensual na abordagem terapêutica dos derrames pleurais parapneumónicos e empiemas, os autores propõem um protocolo de orientação, que resultou da reflexão baseada na sua experiência e na bibliografia mais recente

Invasion Percolation Between two Sites

We investigate the process of invasion percolation between two sites (injection and extraction sites) separated by a distance r in two-dimensional lattices of size L. Our results for the non-trapping invasion percolation model indicate that the statistics of the mass of invaded clusters is significantly dependent on the local occupation probability (pressure) Pe at the extraction site. For Pe=0, we show that the mass distribution of invaded clusters P(M) follows a power-law P(M) ~ M^{-\alpha} for intermediate values of the mass M, with an exponent \alpha=1.39. When the local pressure is set to Pe=Pc, where Pc corresponds to the site percolation threshold of the lattice topology, the distribution P(M) still displays a scaling region, but with an exponent \alpha=1.02. This last behavior is consistent with previous results for the cluster statistics in standard percolation. In spite of these discrepancies, the results of our simulations indicate that the fractal dimension of the invaded cluster does not depends significantly on the local pressure Pe and it is consistent with the fractal dimension values reported for standard invasion percolation. Finally, we perform extensive numerical simulations to determine the effect of the lattice borders on the statistics of the invaded clusters and also to characterize the self-organized critical behavior of the invasion percolation process.Comment: 7 pages, 11 figures, submited for PR

Sustentabilidade de sistemas de produção irrigados para agricultura familiar: um desafio para os colonos do Projeto Curu Paraipaba.

No início dos anos de 1970, uma consultoria externa aportou, com vários especialistas, no Vale do Rio Curu, para estruturar um dos maiores Projetos de Irrigação do estado Ceará. Retirar da pobreza mais de 800 famílias de agricultores familiar era sua meta primordial. Na mesma década de 1970, essas alternativas de desenvolvimento pensadas para países subdesenvolvidos exibiam sinais de ineficácia, o que aponta uma incoerência, desde sua concepção. Atualmente, o grande desafio das famílias e equipes técnicas do projeto é a discussão sobre a sua sustentabilidade. São esses os termos que posicionam o presente debate, apontando algumas dificuldades que se anunciam para o tal intento, quando se pretende alinhar resultados alcançados ao conceito mais popularizado de desenvolvimento sustentável, formulado no relatório da Comissão Brundtland em 1987

Imperfect Detectors in Linear Optical Quantum Computers

We discuss the effects of imperfect photon detectors suffering from loss and noise on the reliability of linear optical quantum computers. We show that for a given detector efficiency, there is a maximum achievable success probability, and that increasing the number of ancillary photons and detectors used for one controlled sign flip gate beyond a critical point will decrease the probability that the computer will function correctly. We have also performed simulations of some small logic gates and estimate the efficiency and noise levels required for the linear optical quantum computer to function properly.Comment: 13 pages, 5 figure