The Value of Multi-slice CT Imaging in Cardiac Myxomas in Comparison with Follow-Up Screening in Thoracoscopic Surgery.

In this study, we evaluated the ability of multi-slice CT (MSCT) imaging for the diagnosis of cardiac myxomas (CMs) in comparison with follow-up screening in thoracoscopic surgery. 40 consecutive patients who had CMs confirmed by thoracoscopic surgery underwent MSCT scanning. The radiological findings were analyzed to reveal the tumor location, appearance, size, pedicle diameter and originating, and compared with surgical outcomes in the follow-up studies. We found that the tumor location and appearance were all definitely diagnosed in the radiological findings and were consistent with the surgical outcomes with the coincidence rate of 100 %. All the tumors showed heterogeneous enhancement, with a pedicle originating from the atrial septum. Compared with the results of surgical outcomes, the accuracy of MSCT for measuring tumor size and pedicle diameter has no statistical difference. The results indicate that MSCT imaging provides a great incremental value for the diagnosis of CMs in comparison with follow-up screening in thoracoscopic surgery.

Evolutionary minority game wtih multiple options.

We propose and study an evolutionary minority game (EMG) in which the agents are allowed to choose among three possible options. Unlike the original EMG where the agents either win or lose one unit of wealth, the present model assigns one unit of wealth to the winners in the least popular option, deducts one unit from the losers in the most popular option, and awards R (-1 R(c), where R(c) (N) is a critical value for optimal performance of the system that drops to zero as the number of agents N increases.

Finite-size effect in the Eguíluz and Zimmermann model of herd formation and information transmission.

The Eguíluz and Zimmermann model of information transmission and herd formation in a financial market is studied analytically. Starting from a formal description on the rate of change of the system from one partition of agents in the system to another, a mean-field theory is systematically developed. The validity of the mean-field theory is carefully studied against fluctuations. When the number of agents N is sufficiently large and the probability of making a transaction a<<1/N ln N, finite-size effect is found to be significant. In this case, the system has a large probability of becoming a single cluster containing all the agents. For small clusters of agents, the cluster size distribution still obeys a power law but with a much reduced magnitude. The exponent is found to be modified to the value of -3 by the fluctuation effects from the value of -5/2 in the mean-field theory.