Orthogonal, solenoidal, three-dimensional vector fields for no-slip boundary conditions

Viscous fluid dynamical calculations require no-slip boundary conditions. Numerical calculations of turbulence, as well as theoretical turbulence closure techniques, often depend upon a spectral decomposition of the flow fields. However, such calculations have been limited to two-dimensional situations. Here we present a method that yields orthogonal decompositions of incompressible, three-dimensional flow fields and apply it to periodic cylindrical and spherical no-slip boundaries.Comment: 16 pages, 2 three-part figure

Schwinger, Pegg and Barnett approaches and a relationship between angular and Cartesian quantum descriptions II: Phase Spaces

Following the discussion -- in state space language -- presented in a preceding paper, we work on the passage from the phase space description of a degree of freedom described by a finite number of states (without classical counterpart) to one described by an infinite (and continuously labeled) number of states. With that it is possible to relate an original Schwinger idea to the Pegg and Barnett approach to the phase problem. In phase space language, this discussion shows that one can obtain the Weyl-Wigner formalism, for both Cartesian {\em and} angular coordinates, as limiting elements of the discrete phase space formalism.Comment: Subm. to J. Phys A: Math and Gen. 7 pages, sequel of quant-ph/0108031 (which is to appear on J.Phys A: Math and Gen

Evaluation of SAMSON for use in a South Platte decision support system

December 1996.Includes bibliographical references (pages 28-29).The South Platte River basin is a tributary of the Missouri River. Three states share the basin (Colorado, Nebraska, and Wyoming), with most of the basin in Colorado (79 percent). Colorado's population has been growing rapidly, especially in Front-Range cities, increasing the demand on water resources in the basin. Highly productive plains agriculture is also a substantial user of water resources and new uses also can be expected for wildlife and recreation. A decision support system (DSS) is being planned by the State of Colorado for water management in South Platte River Basin. Anticipated needs of the system include data development and some model development specific to the South Platte. Due to the unique characteristics of the South Platte River Basin, the implementation of this framework is expected to be slightly different from other basins in Colorado. The SAMSON (Stream-Aquifer Model for Management by SimulatiON) Model, developed in the 1980s specifically for the South Platte River Basin, has been recommended by past studies for use in a South Platte DSS. This report provides and analysis of the current SAMSON model. The conclusions of this report recommend that SAMSON in its present form not be used as part of a DSS, largely due to recent developments in modeling philosophy, application, and use. SAMSON proved the entire South Platte River Basin system could be effectively modeled, and pointed to the priorities for data collection and development. Components of SAMSON could be part of future DSS systems, but they should be separated into individual modules and evaluated individually against existing models. In summary, the analysis of SAMSON clearly show the need for a modular and data-centered approach for a South Platte DSS.Grant no. 14-08-0001-G2008/5 Project no. 09; financed in part by the Department of the Interior, U.S. Geological Survey, through the Colorado Water Resources Research Institute

Product rule for gauge invariant Weyl symbols and its application to the semiclassical description of guiding center motion

We derive a product rule for gauge invariant Weyl symbols which provides a generalization of the well-known Moyal formula to the case of non-vanishing electromagnetic fields. Applying our result to the guiding center problem we expand the guiding center Hamiltonian into an asymptotic power series with respect to both Planck's constant $\hbar$ and an adiabaticity parameter already present in the classical theory. This expansion is used to determine the influence of quantum mechanical effects on guiding center motion.Comment: 24 pages, RevTeX, no figures; shortened version will be published in J.Phys.

Erythropoietin, Fibroblast Growth Factor 23, and Death After Kidney Transplantation

Elevated levels of erythropoietin (EPO) are associated with an increased risk of death in renal transplant recipients (RTRs), but the underlying mechanisms remain unclear. Emerging data suggest that EPO stimulates production of the phosphaturic hormone fibroblast growth factor 23 (FGF23), another strong risk factor for death in RTRs. We hypothesized that the hitherto unexplained association between EPO levels and adverse outcomes may be attributable to increased levels of FGF23. We included 579 RTRs (age 51 ± 12 years, 55% males) from the TransplantLines Insulin Resistance and Inflammation Cohort study (NCT03272854). During a follow-up of 7.0 years, 121 RTRs died, of which 62 were due to cardiovascular cause. In multivariable Cox regression analysis, EPO was independently associated with all-cause (HR, 1.66; 95% CI 1.16-2.36; P = 0.005) and cardiovascular death (HR, 1.87; 95% CI 1.14-3.06; P = 0.01). However, the associations were abrogated following adjustment for FGF23 (HR, 1.28; 95% CI 0.87-1.88; P = 0.20, and HR, 1.45; 95% CI 0.84-2.48; P = 0.18, respectively). In subsequent mediation analysis, FGF23 mediated 72% and 50% of the association between EPO and all-cause and cardiovascular death, respectively. Our results underline the strong relationship between EPO and FGF23 physiology, and provide a potential mechanism underlying the relationship between increased EPO levels and adverse outcomes in RTRs