Is the fee-for-service model for remuneration of medical practitioners in private practice morally justifiable?

Submitted in partial fulfillment of the degree of MSc (Med) in Bioethics and Health Law Steve Biko Centre for Bioethics, University of the Witwatersrand Johannesburg, 10 April 2015In this research report I defend the thesis that the fee-for-service remuneration model for private medical practitioners is not morally justifiable as it does not promote a paying patient’s best interests. A review of the salary, capitation, pay-for-performance and fee-for-service payment models is followed by a review of the philosophical fundamentals of caring for patients and promoting their best interests. The suitability of the fee-for-service model as it is applied to private practice is analysed with respect to its compliance / non-compliance with these fundamentals. Particular reference is given to principlism, consequentialism and virtue ethics as well as the South African health care environment. In the absence of specific and viable alternatives I propose how a moral checklist could be applied to payment models generally in order to safeguard promotion of a patient’s best interests

Linear determinantal equations for all projective schemes

We prove that every projective embedding of a connected scheme determined by the complete linear series of a sufficiently ample line bundle is defined by the 2-minors of a 1-generic matrix of linear forms. Extending the work of Eisenbud-Koh-Stillman for integral curves, we also provide effective descriptions for such determinantally presented ample line bundles on products of projective spaces, Gorenstein toric varieties, and smooth n-folds.Comment: 17 pages; several improvements in the exposition following the referee's suggestion

Strategic Trade: Weighted Payoff Functions And Diverse Trade Patterns

This paper extends the basic intra-industry trade model, Brander and Spencer (1985), in two directions. A weight is included in the foreign government’s payoff function, similar to Collie (1997), which alters the traditional policy choice when this weight is different than one. We also require each firm’s output choice be nonnegative. These constraints and the weighted payoff function lead to several Nash equilibria that have not been analyzed in the intra-industry trade literature. Our analysis helps explain why industries satisfying the necessary conditions for intra-industry trade patterns may not actually display such trade patterns. [F12, F13, C72

Development of trip production models incorporating accessibility measures for a rapidly developing region

Traffic forecasters traditionally rely on stability of populations and land uses to predict future trip data. In a number of rapidly growing cities of the western United States, where the population has been expanding at a pace far greater than the average community in the country, traditional travel demand models using the Four Step Process have been found to be not sufficiently accurate. The focus of this dissertation was to examine whether the predictive ability of traditional trip production models could be improved by the incorporation of accessibility and network variables, when applied to a rapidly growing region. The variables examined were developed on a disaggregate, per household basis using geographic information systems. The purpose of this research was to identify the factors which significantly affect trip production for a rapidly growing area, and to develop a regression model that improves upon the accuracy of trip production models that incorporate traditionally used socioeconomic variables; The travel survey data used in the research was taken from two household travel surveys, from the years 1996 and 2005. The dependent variables in the trip production equations---total number of non-work trips and total number of home-based shopping trips per household---were recorded from the household travel surveys. The three traditionally-used independent variables input into trip production regression equations---the number of persons in each household, the number of vehicles available for use by each household, and the household income---were also taken from the household travel surveys. Data were obtained from Clark County and used to develop additional independent variables. Once the development of variables was completed, regression equations were calibrated. The trip production models were then evaluated statistically, and observations were made; It was concluded that accessibility and transportation network variables can be developed on a disaggregate, per household basis for inclusion into trip production models. Whether or not such models created with the additional variables predict future trip production more effectively than models containing traditional variables proved inconclusive. However, by including the accessibility and transportation network variables in trip production equations, growth can be included in trip generation models

Strategic Trade: Weighted Payoff Functions And Diverse Trade Patterns

This paper extends the basic intra-industry trade model, Brander and Spencer (1985), in two directions. A weight is included in the foreign government’s payoff function, similar to Collie (1997), which alters the traditional policy choice when this weight is different than one. We also require each firm’s output choice be nonnegative. These constraints and the weighted payoff function lead to several Nash equilibria that have not been analyzed in the intra-industry trade literature. Our analysis helps explain why industries satisfying the necessary conditions for intra-industry trade patterns may not actually display such trade patterns. [F12, F13, C72

Remarks on the instability of black Dp-branes

We show that for black D$p$-branes having charge $Q$ and Hawking temperature $T$, the product $QT^{7-p}$ is bounded from above for $p\leq 5$ and is unbounded for $p=6$. While the maximum occurs at some finite value of a parameter for $p \leq 4$, it occurs at infinity of the parameter for $p=5$. As a consequence, for fixed charge, there are two black D$p$-branes (for $p\leq 4$) at any given temperature less than its maximum value, and when the temperature is maximum there is one black D$p$-brane. For $p=5$, there is only one black D5-brane at a given temperature less than its maximum value, whereas, for $p=6$, since there is no bound for the temperature, there is always a black D6-brane solution at a given temperature. Of the two black D$p$-branes (for $p\leq 4$), one is large which is shown to be thermodynamically unstable and the other is small which is stable. But for $p=5,6$, the black D$p$-branes are always thermodynamically unstable. The stable, small black D$p$-brane, however, under certain conditions, can become unstable quantum mechanically and decay either to a BPS D$p$-brane or to a Kaluza-Klein "bubble of nothing" through closed string tachyon condensation. The small D5, D6 branes, although classically unstable, have the same fate under similar conditions.Comment: 12 pages, LaTeX, 1 figure, v2: minor clarifications added, v3: added free energy calculation, version to appear in Phys. Lett.

Constructing A Flexible Likelihood Function For Spectroscopic Inference

We present a modular, extensible likelihood framework for spectroscopic inference based on synthetic model spectra. The subtraction of an imperfect model from a continuously sampled spectrum introduces covariance between adjacent datapoints (pixels) into the residual spectrum. For the high signal-to-noise data with large spectral range that is commonly employed in stellar astrophysics, that covariant structure can lead to dramatically underestimated parameter uncertainties (and, in some cases, biases). We construct a likelihood function that accounts for the structure of the covariance matrix, utilizing the machinery of Gaussian process kernels. This framework specifically address the common problem of mismatches in model spectral line strengths (with respect to data) due to intrinsic model imperfections (e.g., in the atomic/molecular databases or opacity prescriptions) by developing a novel local covariance kernel formalism that identifies and self-consistently downweights pathological spectral line "outliers." By fitting many spectra in a hierarchical manner, these local kernels provide a mechanism to learn about and build data-driven corrections to synthetic spectral libraries. An open-source software implementation of this approach is available at http://iancze.github.io/Starfish, including a sophisticated probabilistic scheme for spectral interpolation when using model libraries that are sparsely sampled in the stellar parameters. We demonstrate some salient features of the framework by fitting the high resolution $V$-band spectrum of WASP-14, an F5 dwarf with a transiting exoplanet, and the moderate resolution $K$-band spectrum of Gliese 51, an M5 field dwarf.Comment: Accepted to ApJ. Incorporated referees' comments. New figures 1, 8, 10, 12, and 14. Supplemental website: http://iancze.github.io/Starfish