Beam combining using Orientational Stimulated Scattering in Liquid Crystals

Possibility of beam combining and clean-up using Orientational Stimulated Scattering in a Nematic Liquid Crystal is considered. We numerically study the dynamics of the process and find that back-conversion process tends to limit the effective interaction strength. Instability of the steady state of cross-phase modulation is demonstrated, when both waves have the same frequency. We show that high conversion efficiency can be achieved, and that the shape and wave-front of the amplified output signal are robust with respect to amplitude and phase distortions of the input pump.Comment: 24 pages, 6 figures, will be published in JOSA

Improved pivot-slide model of the motion of a curling rock

The pivot-slide model (Shegelski and Lozowski) successfully predicts the slide and curl distances of a curling rock. However, in this model, there is no dependence of the curl distance on the initial velocity, because the ratio between the pivot to sliding times is constant. A refined model is presented, in which the ratio of the pivot to sliding times depends on the stone velocity via two parameters. Confidence limits for these parameters are deduced from experimental data, which show that the pivot-slide ratio depends on the stone velocity. However, precise values of these parameters could not be obtained with this study, as more precise experiment data are needed. The refined model allows one to qualitatively explain two characteristics of the stone trajectory observed in a curling game, namely the bigger final curl with lower initial velocity and the lower curl with the effect of sweeping the ice

Experimental investigation of high-power single-pass Raman shifters in the ultraviolet with Nd:YAG and KrF lasers

Single-pass Raman cells pumped by either a quadrupled Nd:YAG (266-nm) laser or a KrF excimer laser are studied. The Raman-active gases comprise H2, D2, or CH4, as well as a mixt. of them, with the addn. of He, Ne, or Ar. A parametric study, in which the Stokes conversion efficiency and the beam quality (M2) were measured, was made. The first Stokes efficiency increases and all the Stokes thresholds decrease with an increase in the lens focal length or the M2 parameter of the pump beam. The quality of the Stokes beams deteriorates when the active-gas pressure increases but is improved by the addn. of an inert gas. Laser-induced breakdown is shown to be a factor that limits the conversion efficiency and the quality of the Stokes beams. With a mixt. of D2, H2, and Ar, a 10-15-mJ pulse energy is obtained (depending on the pump M2 parameter) in the first Stokes beam of D2 (289 nm) and H2 (299 nm), with a full-angle divergence of 0.5 mrad (at 86% power)

Quality of life and sexual health after perineal reconstruction in Fournier gangrene using pedicled anterolateral thigh flaps.

To assess long-term sexual outcome and quality of life after perineal reconstruction by pedicled anterolateral thigh (ALT) flaps after Fournier's gangrene. Postoperative surgical outcomes were assessed; quality of life and sexual function were assessed at long term follow-up (>12 months) with 2 scientifically validated questionnaires. We conducted a retrospective analysis of a prospectively maintained database. Long-term sexual function and quality of life were assessed by standardized questionnaires. Descriptive statistics were conducted. 8 patients were included in our study, 5 patients responded to quality of life and sexual function analysis. Surgical outcomes were in line with literature: one minor complication (minor dehiscence requiring a skin graft), one major complication (flap loss, requiring a second, contralateral flap) occurred. No reconstructive failure occurred. Average time to complete wound healing was 17 days (SD ±5). Quality of life scores over 70/100 in four out of five categories; social function was rated lowest: patients reported very few residual complaints. Sexual outcome analysis emphasizes the positive impact of the reconstruction. As expected, Fournier's Gangrene heavily affected patient's sexual health. Perineal reconstruction with ALT shows excellent quality of life, and good sexual health outcomes. Currently the lack of reliable and relatable data leads to the impossibility to compare different reconstructive procedures. We emphasize that assessing sexual function and quality of life after perineal reconstruction is paramount to weigh reconstructive success

Hybrid Ground-State Quantum Algorithms based on Neural Schrödinger Forging

Entanglement forging based variational algorithms leverage the bi-partition of quantum systems for addressing ground state problems. The primary limitation of these approaches lies in the exponential summation required over the numerous potential basis states, or bitstrings, when performing the Schmidt decomposition of the whole system. To overcome this challenge, we propose a new method for entanglement forging employing generative neural networks to identify the most pertinent bitstrings, eliminating the need for the exponential sum. Through empirical demonstrations on systems of increasing complexity, we show that the proposed algorithm achieves comparable or superior performance compared to the existing standard implementation of entanglement forging. Moreover, by controlling the amount of required resources, this scheme can be applied to larger, as well as non permutation invariant systems, where the latter constraint is associated with the Heisenberg forging procedure. We substantiate our findings through numerical simulations conducted on spins models exhibiting one-dimensional ring, two-dimensional triangular lattice topologies, and nuclear shell model configurations