A new ESSC research article entitled “Analysis of ray stability and caustic formation in a layered moving fluid medium” have been posted at xxx.lanl.gov.  The article may be found at arXiv:1504.07270.  The article presents an analysis of ray stability and caustic formation based on the conjugate point theorems of differential geometry.  Also presented is a novel method for determining caustics in environments modeled with piece-wise continuous sound speed profiles and wind profiles.