@article{GozolchianiMoshelHausdorffetal.2006, author = {Gozolchiani, Avi and Moshel, Shay and Hausdorff, Jeffrey M. and Simon, Ely and Kurths, J{\"u}rgen and Havlin, Shlomo}, title = {Decaying of phase synchronization in parkinsonian tremor}, issn = {0378-4371}, doi = {10.1016/j.physa.2005.10.033}, year = {2006}, abstract = {We describe effects of the asymmetry of cycles and non-stationarity in time series on the phase synchronization method which may lead to artifacts. We develop a modified method that overcomes these effects and apply it to study parkinsonian tremor. Our results indicate that there is synchronization between two different hands and provide information about the time delay separating their dynamics. These findings suggest that this method may be useful for detecting and quantifying weak synchronization between two non-stationary signals.}, language = {en} } @article{ZhouKurths2006, author = {Zhou, Changsong and Kurths, J{\"u}rgen}, title = {Dynamical weights and enhanced synchronization in adaptive complex networks}, doi = {10.1103/Physrevlett.96.164102}, year = {2006}, abstract = {Dynamical organization of connection weights is studied in scale-free networks of chaotic oscillators, where the coupling strength of a node from its neighbors develops adaptively according to the local synchronization property between the node and its neighbors. We find that when complete synchronization is achieved, the coupling strength becomes weighted and correlated with the topology due to a hierarchical transition to synchronization in heterogeneous networks. Importantly, such an adaptive process enhances significantly the synchronizability of the networks, which could have meaningful implications in the manipulation of dynamical networks}, language = {en} } @misc{MotterMatiasKurthsetal.2006, author = {Motter, Adilson E. and Matias, Manuel A. and Kurths, J{\"u}rgen and Ott, Edward}, title = {Dynamics on complex networks and applications}, series = {Physica. D, Nonlinear phenomena}, volume = {224}, journal = {Physica. D, Nonlinear phenomena}, number = {1-2}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0167-2789}, doi = {10.1016/j.physd.2006.09.012}, pages = {VII -- VIII}, year = {2006}, language = {en} } @article{DanaBlasiusKurths2006, author = {Dana, Syamal Kumar and Blasius, Bernd and Kurths, J{\"u}rgen}, title = {Experimental evidence of anomalous phase synchronization in two diffusively coupled Chua oscillators}, issn = {1054-1500}, doi = {10.1063/1.2197168}, year = {2006}, abstract = {We study the transition to phase synchronization in two diffusively coupled, nonidentical Chua oscillators. In the experiments, depending on the used parameterization, we observe several distinct routes to phase synchronization, including states of either in-phase, out-of-phase, or antiphase synchronization, which may be intersected by an intermediate desynchronization regime with large fluctuations of the frequency difference. Furthermore, we report the first experimental evidence of an anomalous transition to phase synchronization, which is characterized by an initial enlargement of the natural frequency difference with coupling strength. This results in a maximal frequency disorder at intermediate coupling levels, whereas usual phase synchronization via monotonic decrease in frequency difference sets in only for larger coupling values. All experimental results are supported by numerical simulations of two coupled Chua models}, language = {en} } @article{PereiraBaptistaReyesetal.2006, author = {Pereira, Tiago and Baptista, Murilo da Silva and Reyes, Marcelo Bussotti and Caldas, Ibere Luiz and Sartorelli, Jos{\´e} Carlos and Kurths, J{\"u}rgen}, title = {Global bifurcation destroying the experimental torus T-2}, doi = {10.1103/Physreve.73.017201}, year = {2006}, abstract = {We show experimentally the scenario of a two-frequency torus T-2 breakdown, in which a global bifurcation occurs due to the collision of a torus with an unstable periodic orbit, creating a heteroclinic saddle connection, followed by an intermittent behavior}, language = {en} } @article{ZhouZemanovaZamoraetal.2006, author = {Zhou, Changsong and Zemanova, Lucia and Zamora, Gorka and Hilgetag, Claus C. and Kurths, J{\"u}rgen}, title = {Hierarchical organization unveiled by functional connectivity in complex brain networks}, series = {Physical review letters}, volume = {97}, journal = {Physical review letters}, publisher = {American Physical Society}, address = {College Park}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.97.238103}, pages = {4}, year = {2006}, abstract = {How do diverse dynamical patterns arise from the topology of complex networks? We study synchronization dynamics in the cortical brain network of the cat, which displays a hierarchically clustered organization, by modeling each node (cortical area) with a subnetwork of interacting excitable neurons. We find that in the biologically plausible regime the dynamics exhibits a hierarchical modular organization, in particular, revealing functional clusters coinciding with the anatomical communities at different scales. Our results provide insights into the relationship between network topology and functional organization of complex brain networks.}, language = {en} } @article{ZhouKurths2006, author = {Zhou, Changsong and Kurths, J{\"u}rgen}, title = {Hierarchical synchronization in complex networks with heterogeneous degrees}, issn = {1054-1500}, doi = {10.1063/1.2150381}, year = {2006}, abstract = {We study synchronization behavior in networks of coupled chaotic oscillators with heterogeneous connection degrees. Our focus is on regimes away from the complete synchronization state, when the coupling is not strong enough, when the oscillators are under the influence of noise or when the oscillators are nonidentical. We have found a hierarchical organization of the synchronization behavior with respect to the collective dynamics of the network. Oscillators with more connections (hubs) are synchronized more closely by the collective dynamics and constitute the dynamical core of the network. The numerical observation of this hierarchical synchronization is supported with an analysis based on a mean field approximation and the master stability function. (C) 2006 American Institute of Physics}, language = {en} } @article{BaptistaZhouKurths2006, author = {Baptista, Murilo da Silva and Zhou, Changsong and Kurths, J{\"u}rgen}, title = {Information transmission in phase synchronous chaotic arrays}, issn = {0256-307X}, doi = {10.1088/0256-307X/23/3/010}, year = {2006}, abstract = {We show many versatile phase synchronous configurations that emerge in an array of coupled chaotic elements due to the presence of a periodic stimulus. Then, we explain the relevance of these configurations to the understanding of how information about such a. stimulus is transmitted from one side to the other in this array. The stimulus actively creates the ways to be transmitted, by making the chaotic elements to phase synchronize}, language = {en} } @article{RaabWesselSchirdewanetal.2006, author = {Raab, Corinna and Wessel, Niels and Schirdewan, Alexander and Kurths, J{\"u}rgen}, title = {Large-scale dimension densities for heart rate variability analysis}, issn = {1539-3755}, doi = {10.1103/Physreve.73.041907}, year = {2006}, abstract = {In this work, we reanalyze the heart rate variability (HRV) data from the 2002 Computers in Cardiology (CiC) Challenge using the concept of large-scale dimension densities and additionally apply this technique to data of healthy persons and of patients with cardiac diseases. The large-scale dimension density (LASDID) is estimated from the time series using a normalized Grassberger-Procaccia algorithm, which leads to a suitable correction of systematic errors produced by boundary effects in the rather large scales of a system. This way, it is possible to analyze rather short, nonstationary, and unfiltered data, such as HRV. Moreover, this method allows us to analyze short parts of the data and to look for differences between day and night. The circadian changes in the dimension density enable us to distinguish almost completely between real data and computer-generated data from the CiC 2002 challenge using only one parameter. In the second part we analyzed the data of 15 patients with atrial fibrillation (AF), 15 patients with congestive heart failure (CHF), 15 elderly healthy subjects (EH), as well as 18 young and healthy persons (YH). With our method we are able to separate completely the AF (rho(mu)(ls)=0.97 +/- 0.02) group from the others and, especially during daytime, the CHF patients show significant differences from the young and elderly healthy volunteers (CHF, 0.65 +/- 0.13; EH, 0.54 +/- 0.05; YH, 0.57 +/- 0.05; p < 0.05 for both comparisons). Moreover, for the CHF patients we find no circadian changes in rho(mu)(ls) (day, 0.65 +/- 0.13; night, 0.66 +/- 0.12; n.s.) in contrast to healthy controls (day, 0.54 +/- 0.05; night, 0.61 +/- 0.05; p=0.002). Correlation analysis showed no statistical significant relation between standard HRV and circadian LASDID, demonstrating a possibly independent application of our method for clinical risk stratification}, language = {en} } @article{ZaikinKurths2006, author = {Zaikin, Alexey and Kurths, J{\"u}rgen}, title = {Optimal length transportation hypothesis to model proteasome product size distribution}, series = {Journal of biological physics : emphasizing physical principles in biological research ; an international journal for the formulation and application of mathematical models in the biological sciences}, volume = {32}, journal = {Journal of biological physics : emphasizing physical principles in biological research ; an international journal for the formulation and application of mathematical models in the biological sciences}, number = {3-4}, publisher = {Springer}, address = {Dordrecht}, issn = {0092-0606}, doi = {10.1007/s10867-006-9014-z}, pages = {231 -- 243}, year = {2006}, abstract = {This paper discusses translocation features of the 20S proteasome in order to explain typical proteasome length distributions. We assume that the protein transport depends significantly on the fragment length with some optimal length which is transported most efficiently. By means of a simple one-channel model, we show that this hypothesis can explain both the one- and the three-peak length distributions found in experiments. A possible mechanism of such translocation is provided by so-called fluctuation-driven transport.}, language = {en} }