4,861 research outputs found

    Differential efficacy of lithium and carbamazepine in the prophylaxis of bipolar disorder: Results of the MAP study

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    In a randomized clinical trial with an observation period of 2.5 years, the differential efficacy of lithium versus carbamazepine was compared in 171 bipolar patients (DSM-IV). In order to investigate the efficacy of the two drugs in clearly defined subsamples, a series of subgroup analyses was carried out. First, patients with a bipolar I disorder (n = 114) were analyzed separately. In these patients, lithium was superior to carbamazepine. In contrast, carbamazepine was at least equally as efficacious as lithium in the subsample of patients with bipolar II disorder or bipolar disorder not otherwise specified (n = 57). In a second analysis on differential efficacy, the whole sample was subdivided into a classical subgroup (bipolar I patients without mood-incongruent delusions and without comorbidity; n = 67) and a nonclassical subgroup including all other patients (n = 104). Classical bipolar patients had a significantly lower hospitalization rate under lithium than under carbamazepine prophylaxis (26 vs. 62%, p = 0.012). For the nonclassical group, a tendency in favor of carbamazepine was found. In a third step, we analyzed the impact of episode sequence on differential efficacy. In a global view, the episode sequence prior to the index episode was not correlated to differential efficacy. Our results might, however, indicate that patients with an episode sequence of mania-depression-free interval responded better to lithium. Besides differential efficacy, suicidal behavior and patients' satisfaction with treatment were investigated. Regarding suicidal behavior, a trend in favor of lithium was found. The data on patients' satisfaction were significantly in favor of carbamazepine. In conclusion, lithium appears to be superior to carbamazepine in classical bipolar cases and might have additional impact on proneness to suicide. The distinctly larger group of patients with nonclassical features might profit more from carbamazepine which seems to be well accepted by the patients. Hence, treatment alternatives to lithium a re desirable for the majority of bipolar patients. Copyright (C) 2000 S. Karger AG, Basel

    Chiral extrapolation of baryon mass ratios

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    We analyze lattice data for octet baryon masses from the QCDSF collaboration employing manifestly covariant Baryon Chiral Perturbation Theory. It is shown that certain combinations of low-energy constants can be fixed more accurately than before from this data. We also examine the impact of this analysis on the pion-nucleon sigma term, and on the convergence properties of baryon mass expansions in the SU(3) symmetry limit.Comment: Updated version, to be published in Phys. Rev.

    Critical Boolean networks with scale-free in-degree distribution

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    We investigate analytically and numerically the dynamical properties of critical Boolean networks with power-law in-degree distributions. When the exponent of the in-degree distribution is larger than 3, we obtain results equivalent to those obtained for networks with fixed in-degree, e.g., the number of the non-frozen nodes scales as N2/3N^{2/3} with the system size NN. When the exponent of the distribution is between 2 and 3, the number of the non-frozen nodes increases as NxN^x, with xx being between 0 and 2/3 and depending on the exponent and on the cutoff of the in-degree distribution. These and ensuing results explain various findings obtained earlier by computer simulations.Comment: 5 pages, 1 graph, 1 sketch, submitte

    Number and length of attractors in a critical Kauffman model with connectivity one

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    The Kauffman model describes a system of randomly connected nodes with dynamics based on Boolean update functions. Though it is a simple model, it exhibits very complex behavior for "critical" parameter values at the boundary between a frozen and a disordered phase, and is therefore used for studies of real network problems. We prove here that the mean number and mean length of attractors in critical random Boolean networks with connectivity one both increase faster than any power law with network size. We derive these results by generating the networks through a growth process and by calculating lower bounds.Comment: 4 pages, no figure, no table; published in PR

    Attractor and Basin Entropies of Random Boolean Networks Under Asynchronous Stochastic Update

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    We introduce a numerical method to study random Boolean networks with asynchronous stochas- tic update. Each node in the network of states starts with equal occupation probability and this probability distribution then evolves to a steady state. Nodes left with finite occupation probability determine the attractors and the sizes of their basins. As for synchronous update, the basin entropy grows with system size only for critical networks, where the distribution of attractor lengths is a power law. We determine analytically the distribution for the number of attractors and basin sizes for frozen networks with connectivity K = 1.Comment: 5 pages, 3 figures, in submissio
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