Pump-probe transmission experiments have been performed on PbSe above the fundamental absorption edge near 4 m in the temperature range 30 to 300 K, using the Dutch ps free-electron laser. For temperatures below 200 K and carrier densities above the threshold for stimulated emission, stimulated recombination represents the most efficient recombination mechanism with relatively fast kinetics in the 50-100-ps regime, in good agreement with earlier reports of photoluminescent emission. Above this temperature Auger recombination dominates, and the Auger coefficient C is determined from the pump-probe decay curves. In the lowtemperature regime the Auger coefficient is determined from the decay curves at times beyond 100 ps. The Auger coefficient is approximately constant ͑with a value of about 8ϫ10 Ϫ28 cm 6 s Ϫ1) between 300 and 70 K, and then drops a value of about 1ϫ10 Ϫ28 cm 6 s Ϫ1 at 30 K, in good agreement with the theory for nonparabolic near-mirror bands and nondegenerate statistics. It is found that C for PbSe is between one and two orders of magnitude lower than for Hg 1Ϫx Cd x Te of comparable band gap. ͓S0163-1829͑98͒07243-9͔

Objectives To determine whether the perimeatal-based ap technique or the tubularized incised-plate repair is the more appropriate treatment for distal hypospadias in terms of ®stula rate, cosmesis of the meatus and operative duration. Patients and methods Between July 1997 and August 1998, 60 children (none of whom had previously undergone a procedure for hypospadias) underwent primary distal hypospadias repair in a prospective randomized trial. Thirty patients were allocated to undergo a Mathieu repair (mean age 24.9 months, range 9±72) and 30 a Snodgrass procedure (mean age 23.1 months, range 7±19). The mean follow-up was 15.4 months. Results The mean duration of surgery was signi®cantly lower for the Snodgrass procedure than for the Mathieu repair (75 vs 115 min, P<0.05). Three children undergoing a Mathieu repair had complications (two a urethrocutaneous ®stula and one a meatal stenosis), compared with only one in the Snodgrass group (glanular dehiscence). The resultant meatus was slit-like in all patients undergoing the Snodgrass repair whereas those with a Mathieu repair had a rounded and horizontal meatus. Conclusion The overall complication rate was lower and the surgery signi®cantly quicker with the Snodgrass urethroplasty, which also had a better cosmetic outcome. The Snodgrass technique is recommended as a primary treatment for distal hypospadias.

Pretreatment with dihydrotestosterone transdermal gel was effective in decreasing the complications and improving the cosmetic results after hypospadias repair.

Comparison of all 4 groups revealed significant differences in varicocele recurrence (p = 0.038) and hydrocele formation (p = 0.023). Pairwise group comparison showed that the modified Palomo technique resulted in a significant decrease in the incidence of postoperative hydrocele formation compared with the standard Palomo method (p = 0.015). This procedure can be recommended as the optimal surgical technique for varicocele treatment in males of this young age.