Persistent and Transitory Sexualized Behavior Problems in Children.

The aim of this longitudinal study was to examine the course of sexualized behavior problems (SBP) over 2 years in a sample comprised of 104 children aged 2-12, including 62 children with histories of child sexual abuse (CSA). Parents completed questionnaires assessing SBP, internalizing and externalizing difficulties at baseline, as well as 2 years later. In more than half (56.7%) of children with clinically significant SBP at baseline, sexualized behaviors persisted and remained at a clinically significant level over time. In children with CSA, 48.4% presented persistent SBP, 27.4% presented transitory SBP, while 19.4% did not present clinically significant SBP at either time. CSA increased the relative risk of persistent SBP 3.29 times, and for each one-unit increase in scores of externalizing difficulties, the odds of persistent SBP increased by 21%. The findings suggest that SBP consequent to CSA, especially when it co-occurs with externalizing difficulties, is likely to remain at levels warranting clinical intervention.

Fast and simple characterization of a photon pair source.

We present an exact model of the detection statistics of a probabilistic source of photon pairs from which a fast, simple and precise method to measure the source's brightness and photon channel transmissions is demonstrated. We measure such properties for a source based on spontaneous parametric downconversion in a periodically poled LiNbO(3) crystal producing pairs at 810 and 1550 nm wavelengths. We further validate the model by comparing the predicted and measured values for the g((2))(0) of a heralded single photon source over a wide range of the brightness. Our model is of particular use for monitoring and tuning the brightness on demand as required for various quantum communication applications. We comment on its applicability to sources involving spectral and/or spatial filtering.

Dynamics of parabolic pulses in an ultrafast fiber laser.

We report experimental and numerical results on the dynamics and propagation of parabolic pulses in a passively mode-locked ytterbium-doped fiber laser. Experimental data and numerical simulations are shown to match. Particular importance is attached to the pulse-shaping process in the different sections of the resonator. The paramount role of the gain fiber and saturable absorber in the laser is explicated.

Transient regime in a nth-order cascaded CW Raman fiber laser.

The transient regime of a nth-order CW Raman fiber laser is simulated from switch-on to the steady-state and from the steady-state to switch-off. The Stokes waves exhibit high-power spikes during the switch-on transition. We find that the high order Stokes fields reach steady-state faster than the low order ones and the pump.

Nonlinear self-phase-modulation effects: a vectorial first-order perturbation approach.

A full-vectorial integral expression is derived to compute the effective mode area of any Kerr-type nonlinearoptical waveguide working in a self-phase-modulation regime. In order to highlight the correction brought by the vectorial approach in a strong guidance situation, we compare the effective area of a tapered fiber computed by the usual scalar expression with the one obtained with the full-vectorial approach.