A goal programming approach to strategic resource allocation in acute care hospitals

This paper describes a methodology for allocating resources in hospitals. The methodology uses two linear goal-programming models. One model sets case mix and volume for physicians, while holding service costs fixed; the other translates case mix decisions into a commensurate set of practice changes for physicians. The models allow decision makers to set case mix and case costs in such a way that the institution is able to break even, while preserving physician income and minimizing disturbance to practice. The models also permit investigation of trade-offs between case mix and physician practice parameters. Results are presented from a decision-making scenario facing the surgical division of Toronto's Mount Sinai Hospital after the announcement of a 3-year, 18% reduction in funding.     

Equivalence of Toda-Hopf invariants

In this paper it is shown that various existing constructions of ‘Hopf invariant’ are equivalent to each other. In consequence one gets that the oneToda-Hopf invariant enjoys various properties. Both authors supported in part by the NSF.     

Torsors and Stacks

It is shown that the groupoid of G-torsors, suitably defined, can be used to construct a model for the stack associated to G, for arbitrary sheaves of groupoids G. This research was supported by the Natural Sciences and Engineering Research Council of Canada.     

Uniqueness and continuous dependence on the initial data for a class of non-linear shallow shell problems

This note is concerned with the non-linear shallow shell model introduced in 1966 by W.T. Koiter, and later studied by M. Bernadou and J.T. Oden. We show the uniqueness of the solution to the dynamical model and that this solution is continuous with respect to the initial data. To cite this article: J. Cagnol et al., C. R. Acad. Sci. Paris, Ser. I 342 (2006).     

ZnS and ZnSe Nanoparticles via Solid-State and Solution Thermolysis of Zinc Silylchalcogenolate Complexes

The thermolysis of the zinc trimethylsilylchalcogenolate complexes (N,N′-tmeda)Zn(ESiMe₃)₂ (E = S, 1; E = Se, 2) and (3,5-Me₂-C₅H₃N)₂Zn(ESiMe₃)₂ (E = S, 3; E = Se, 4) has been investigated. Solid-state thermal decomposition of complexes 1–4 above 250°C results in the formation of hexagonal ZnS and cubic ZnSe, respectively, via the liberation of TMEDA (1–2) or 3,5-lutidine (3–4) and E(SiMe₃)₂. Solid-state or solution thermolysis of these complexes up to 200°C produces nanocrystalline ZnS and ZnSe materials whose surface is protected by either coordinated TMEDA or 3,5-lutidine ligands. The progress of the step-wise solid-state decomposition of these complexes was monitored by thermogravimetric and single differential thermal analysis and volatile decomposition products in both solution and solid-state experiments were identified by GC/MS.Dedicated to Professor Brian F. G. Johnson on the occasion of his retirement.     

Synthesis and optical properties of a poly(p‐phenylenevinylene) derivative and polyfluorenes with bipolar groups along the main chain

A poly(p‐phenylenevinylene) derivative (PPV–TPA)] and a series of statistical copolyfluorenes (PF–TPA)] containing oxadiazole and triphenylamine segments along the main chain were synthesized by the Heck reaction and nickel‐mediated coupling, respectively. The PF–TPA copolyfluorenes with relatively low contents of oxadiazole and triphenylamine units were readily soluble in common organic solvents, whereas the other copolyfluorenes displayed lower solubility. PPV–TPA showed excellent solubility in solvents such as tetrahydrofuran (THF), dichloromethane, chloroform, and toluene. Thin films of the polymers absorbed light in the range of 375–396 nm and had optical band gaps of 2.76–2.98 eV. They emitted blue‐green light with a maximum at 414–522 nm. The fluorescence quantum yields in THF solutions were 0.08–0.53. The copolyfluorene PF–TPA thin films with high contents of oxadiazole and triphenylamine moieties emitted pure blue light that remained stable even after annealing at 150 °C for 4 h in air. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 3556–3566, 2006