Detrended Fluctuation Analysis of Systolic Blood Pressure Control Loop (2009)
Galhardo, C. E. C., Penna, T. J. P., De Menezes, M. Argollo, Soares, P. P. S.
We use detrended fluctuation analysis (DFA) to study the dynamics of blood pressure oscillations and its feedback control in rats by analyzing systolic pressure time series before and after a...
Analysis of a large-scale weighted network of one-to-one human communication (2007)
Onnela, Jukka-Pekka, Saramaki, Jari, Hyvonen, Jorkki, Szabo, Gabor, De Menezes, M. Argollo, Kaski, Kimmo, ...
We construct a connected network of 3.9 million nodes from mobile phone call records, which can be regarded as a proxy for the underlying human communication network at the societal level. We assign...
Separating internal and external dynamics of complex systems (2004)
The observable behavior of a complex system reflects the mechanisms governing the internal interactions between the system's components and the effect of external perturbations. Here we show that by...
Fluctuations in network dynamics (2003)
De Menezes, M. Argollo, Barabasi, A-L.
Most complex networks serve as conduits for various dynamical processes, ranging from mass transfer by chemical reactions in the cell to packet transfer on the Internet. We collected data on the time...
Using Entropy-Based Methods to Study General Constrained Parameter Optimization Problems (2001)
Lima, A. R., De Menezes, M. Argollo
In this letter we propose the use of physics techniques for entropy determination on constrained parameter optimization problems. The main feature of such techniques, the construction of an unbiased...
Entropy-based analysis of the number partitioning problem (2000)
Lima, A. R., De Menezes, M. Argollo
In this paper we apply the multicanonical method of statistical physics on the number-partitioning problem (NPP). This problem is a basic NP-hard problem from computer science, and can be formulated...
First-order transition in small-world networks (1999)
De Menezes, M. Argollo, Moukarzel, C., Penna, T. J. P.
The small-world transition is a first-order transition at zero density $p$ of shortcuts, whereby the normalized shortest-path distance undergoes a discontinuity in the thermodynamic limit. On finite...
Search for an unitary mortality law through a theoretical model for biological ageing (1997)
Racco, A., De Menezes, M. Argollo, Penna, T. J. P.
In this work we check the occurrence of the Azbel assumption of mortality within the framework of a bit string model for biological ageing. We reproduced the observed feature of linear correspondence...
Improving the Hopfield-Tank approach for the traveling salesman problem (1997)
De Menezes, M. Argollo, Penna, T. J. P.
In this work we revisit the Hopfield-Tank algorithm for the traveling salesman problem (TSP) and report encouraging results, with a different dynamics, that makes the algorithm more efficient finding...
Beyond the Hubbard-I Solution with a One-Pole and a Two-Pole Self-Energy: Moment Approach (1997)
Rodriguez-Nunez, J. J., De Menezes, M. Argollo
We have postulated a single pole for the self-energy looking for the consequences on the one-particle Green function, G(k,w), in the Hubbard model. We find that G(k,w) satisfies the first two sum...