Quasimodes of a chaotic elastic cavity with increasing local losses

We report non-invasive measurements of the complex field of elastic quasimodes of a silicon wafer with chaotic shape. The amplitude and phase spatial distribution of the flexural modes are directly obtained by Fourier transform of time measurements. We investigate the crossover from real mode to complex-valued quasimode, when absorption is progressively increased on one edge of the wafer. The complexness parameter, which characterizes the degree to which a resonance state is complex-valued, is measured for non-overlapping resonances and is found to be proportional to the non-homogeneous contribution to the line broadening of the resonance. A simple two-level model based on the effective Hamiltonian formalism supports our experimental results

The wave energy flux of high frequency diffracting beams in complex geometrical optics

We consider the construction of asymptotic solutions of Maxwell's equations for a diffracting wave beam in the high frequency limit and address the description of the wave energy flux transported by the beam. With this aim, the complex eikonal method is applied. That is a generalization of the standard geometrical optics method in which the phase function is assumed to be complex valued, with the non-negative imaginary part accounting for the finite width of the beam cross section. In this framework, we propose an argument which simplifies significantly the analysis of the transport equation for the wave field amplitude and allows us to derive the wave energy flux. The theoretical analysis is illustrated numerically for the case of electron cyclotron beams in tokamak plasmas by using the GRAY code [D. Farina, Fusion Sci. Technol. 52, 154 (2007)], which is based upon the complex eikonal theory. The results are compared to those of the paraxial beam tracing code TORBEAM [E. Poli et al., Comput. Phys. Commun. 136, 90 (2001)], which provides an independent calculation of the energy flow

Is Heightened Disgust Propensity Truly a Risk Factor for Contamination-Related Obsessive-Compulsive Disorder?

Disgust propensity (DP) has been conceptualized as a stable personality trait that confers risk for contamination-related OCD (C-OCD). However, the extent to which DP leads to the subsequent development of C-OCD is unclear. In fact, the presence of C-OCD might lead to an increase in DP rather than the inverse. The present study was aimed to test this hypothesis in a large clinical sample of OCD patients ( 65 21 years of age) with (C-OCD; n = 56) and without (NC-OCD; n = 103) contamination-related symptoms that completed measures of OCD symptoms, depression, anxiety, and DP. DP was assessed twice, in reference to the present situation (T1) and to when the participant was 18 years old (T0). The two groups did not significantly differ in DP at T0. However, C-OCD participants reported higher DP scores than NC-OCD at T1. Furthermore, the T1 vs T0 difference in DP was significant only in the C-OCD group. Subsequent analyses also showed that T1 DP levels, but not T0 levels, significantly predicted contamination-related symptoms. Despite study limitations, these findings question the role of DP as a risk factor for C-OCD