Medicare is considering an expansion of the bundle of dialysis-related services to be paid on a prospective basis. Exploratory models were developed to assess the potential limitations of case-mix adjustment for such an expansion. A broad set of patient characteristics explained 11.8% of the variation in Medicare allowable charges per dialysis session. Although adding recent hematocrit values o...

We calculate numerically the spectrum of disordered electrons in the lowest Landau level at filling factor 1/5 using the self-consistent Hartree-Fock approximation for systems containing up to 400 flux quanta. Special attention is paid to the correct treatment of the q = 0 component of the Coulomb interaction. For sufficiently strong disorder, the system is an insulator at this filling factor. ...

Gas-phase acidities of 15 aliphatic carboxylic acids, X CH -,COOH, have been calculated using the MNDO method. Among the substituted groups exist the electron donor alkyl groups and electron acceptor halogens. The average error in acidity is within the experimental uncertainty of the data. Systematic errors have been found for the substituents which form internal hydrogen bondings. A reaso...

This short note provides a systematic construction of market models without unbounded profits but with arbitrage opportunities.

We report our analysis, using account data from a large discount brokerage firm, of the common stock investment performance of 166 investment clubs from February 1991 through January 1997. The average club tilted its common stock investment toward high-beta, small-cap growth stocks and turned over 65 percent of its portfolio annually. The average club lagged the performance of a broad-based mar...

In many cases, buyers must incur search costs to find the price of a product. This search cost affects the behavior of consumers, and through that, it affects the profit maximizing behavior of the firms. As search costs change, so do the competitive marketing mix strategies of the firms. In predicting the effect of changing search costs on the equilibrium prices and allocations, it is important...

A microscopic formalism based on computing many-particle densities is applied to the analysis of the diffusion-controlled kinetics of pattern formation in oppositely charged molecules on surfaces or adsorbed at interfaces with competing long-range Coulomb and short-range Lennard-Jones interactions. Particular attention is paid to the proper molecular treatment of energetic interactions driving ...

Upcoming modifications are designed to capture current service delivery patterns, reimbursement methods, and payment sources for hospital visits, rather than what the hospital charges for individual treatment inputs; the result will be an index that better reflects price changes in the dynamic health care field.