Towards optimization of pulsed sodium laser guide stars

Pulsed sodium laser guide stars (LGS) are useful because they allow for Rayleigh blanking and fratricide avoidance in multiple-LGS systems. Bloch-equation simulations of sodium-light interactions show that these may be able to achieve photon returns nearly equal to, and in some cases greater than, what is seen from continuous-wave (CW) excitation. In this work, we study the time-dependent characteristics of sodium fluorescence, and investigate the optimal format for the new fiber laser LGS that will be part of the upgraded adaptive optics (AO) system on the Shane telescope at Mt. Hamilton. Results of this analysis are examined in the context of their general applicability to other LGS systems and the potential benefits of uplink correction are considered. Comparisons of simulation predictions with measurements from existing LGS are also presented and discussed.Comment: 9 pages, 7 figures, accepted by JOSA

Studies in slipped capital femoral epiphysis

[From the Introduction] This study serves to define the population at risk for developing slipped capital femoral epiphysis (SCFE). Although epidemiological studies of this disease have been completed, this large sample helps to confirm the earlier work. Moreover, it characterizes the relationship of this sample with previous samples and hence evaluates the contention that the results of other studies on this sample are based on a typical group of SCFE victims