The simple calving laws currently used in ice-sheet models do not adequately reflect the complexity and diversity of calving processes. To be effective, calving laws must be grounded in a sound understanding of how calving actually works. Here, we develop a new strategy for formulating calving laws, using (a) the Helsinki Discrete Element Model (HiDEM) to explicitly model fracture and calving processes, and (b) the continuum model Elmer/Ice to identify critical stress states associated with HiDEM calving events. A range of observed calving processes emerges spontaneously from HiDEM in response to variations in ice-front buoyancy and the size of subaqueous undercuts. Calving driven by buoyancy and melt under-cutting is under-predicted by existing calving laws, but we show that the location and magnitude of HiDEM calving events can be predicted in Elmer/Ice from characteristic stress patterns. Our results open the way to developing calving laws that properly reflect the diversity of calving processes, and provide a framework for a unified theory of the calving process continuum.

We develop a model of third party guaranteed debt and show that interest rate premiums are multiplicatively related to firm and guarantor risk. We apply the model to thrifts issuing CDs guaranteed by the FSLIC and then estimate firm probabilities of insolvency and guarantor risk across 20 observed months. This time period spans the insolvency of the guarantor followed by two recapitalizations. The relative stability in firm risk across time offers no evidence of generalized risk contagion among firms. We attribute elevated CD premiums and rate spreads to increases in guarantor risk rather than changes in firm risk.

In this paper we first give a brief overview of the MOCVD of high temperature superconductors and consider the general requirements of a precursor. We then present results for deposition from Y containing precursors and compare apparent enthalpies of sublimation and deposition activation energies with values in the literature. The problem of Ba containing precursors are briefly reviewed and results given for the sublimation of and deposition from a new stable and volatile precursor. Finally, some comments are made about possible deposition mechanisms.