Changing perceptions of seeking help: A test of the effectiveness of an intervention video

The purpose of this study was to assess the effectiveness of an intervention video designed to promote positive associations with help seeking for mental health concerns. Participants were 290 undergraduates who were randomly assigned to a repeated exposure video intervention, a single exposure video intervention, or a control video condition. Participants completed measures pre-intervention, post-interventions, and at a six-week follow-up. The intervention repeated exposure group improved significantly more than the control group on help-seeking peer norms but not on the other outcome variables. The effect for peer norms was found at each time point, indicating both immediate and longer-term effects. The repeated exposure group also improved significantly more than the single exposure group on peer norms from pretest to Time 3. Effective, empirically supported interventions capable of reaching large numbers of people are necessary to help improve the under-utilization of mental health services. The present study offers some initial support for such theory-based video interventions for changing perceptions of normative behavior of seeking help

Propagation and interaction of ultrashort electromagnetic pulses in nonlinear media with a quadratic-cubic nonlinearity

Propagation of extremely short unipolar pulses of electromagnetic field ("videopulses") is considered in the framework of a model in which the material medium is represented by anharmonic oscillators (approximating bound electrons) with quadratic and cubic nonlinearities. Two families of exact analytical solutions (with positive or negative polarity) are found for the moving solitary pulses. Direct simulations demonstrate that the pulses are very robust against perturbations. Two unipolar pulses collide nearly elastically, while collisions between pulses with opposite polarities and a small relative velocity are inelastic, leading to emission of radiation and generation of a small-amplitude additional pulse.Comment: 12 pages, 10 figure

Eigenstate Structure in Graphs and Disordered Lattices

We study wave function structure for quantum graphs in the chaotic and disordered regime, using measures such as the wave function intensity distribution and the inverse participation ratio. The result is much less ergodicity than expected from random matrix theory, even though the spectral statistics are in agreement with random matrix predictions. Instead, analytical calculations based on short-time semiclassical behavior correctly describe the eigenstate structure.Comment: 4 pages, including 2 figure

The Hypertriton in Effective Field Theory

Doublet Lambda d scattering and the hypertriton are studied in the framework of an effective field theory for large scattering lengths. As in the triton case, consistent renormalization requires a one-parameter three-body force at leading order whose renormalization group evolution is governed by a limit cycle. Constraining unknown parameters from symmetry considerations and the measured binding energy of the hypertriton, we calculate the low-energy phase shifts for doublet Lambda d scattering. For the low-energy parameters, we find a_{Lambda d}=(16.8^{+4.4}_{-2.4}) fm and r_{Lambda d}=(2.3 +/- 0.3) fm, where the errors are due to the uncertainty in the hypertriton binding energy. Since the hypertriton is extremely shallow, low-energy three-body observables in this channel are very insensitive to the exact values of the Lambda N low-energy parameters.Comment: 16 pages, revtex4, 5 ps figures, reference added, typos in appendix A correcte