The Incentive Effects of Organizational Forms: Evidence from Florida’s Non-Emergency Medicaid Transportation Programs

We analyze the incentive effects of organizational forms using data from Florida’s Non-Emergency Medicaid Transportation (NEMT) programs. These programs differ in the extent to which their brokers are directly involved in providing transit services. Based on a simple model of moral hazard, we predict that the number of users and the number of claims per user of the program increase, but cost per claim of the program decreases, as its broker’s share of transit services increases. The empirical evidence supports our theoretical predictions on the incentive effects of different organizational forms

A computational model of the hypothalamic - pituitary - gonadal axis in female fathead minnows (Pimephales promelas) exposed to 17α-ethynylestradiol and 17β-trenbolone

© 2011 Li et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.Background - Endocrine disrupting chemicals (e.g., estrogens, androgens and their mimics) are known to affect reproduction in fish. 17α-ethynylestradiol is a synthetic estrogen used in birth control pills. 17β-trenbolone is a relatively stable metabolite of trenbolone acetate, a synthetic androgen used as a growth promoter in livestock. Both 17α-ethynylestradiol and 17β-trenbolone have been found in the aquatic environment and affect fish reproduction. In this study, we developed a physiologically-based computational model for female fathead minnows (FHM, Pimephales promelas), a small fish species used in ecotoxicology, to simulate how estrogens (i.e., 17α-ethynylestradiol) or androgens (i.e., 17β-trenbolone) affect reproductive endpoints such as plasma concentrations of steroid hormones (e.g., 17β-estradiol and testosterone) and vitellogenin (a precursor to egg yolk proteins). Results - Using Markov Chain Monte Carlo simulations, the model was calibrated with data from unexposed, 17α-ethynylestradiol-exposed, and 17β-trenbolone-exposed FHMs. Four Markov chains were simulated, and the chains for each calibrated model parameter (26 in total) converged within 20,000 iterations. With the converged parameter values, we evaluated the model's predictive ability by simulating a variety of independent experimental data. The model predictions agreed with the experimental data well. Conclusions - The physiologically-based computational model represents the hypothalamic-pituitary-gonadal axis in adult female FHM robustly. The model is useful to estimate how estrogens (e.g., 17α-ethynylestradiol) or androgens (e.g., 17β-trenbolone) affect plasma concentrations of 17β-estradiol, testosterone and vitellogenin, which are important determinants of fecundity in fish.The Medical Research Foundation of Oregon, U.S. Environmental Protection Agency, and the National Center for Computational Toxicology of the EPA Office of Research and Development

Estrogenic activity of tropical fish food can alter baseline vitellogenin concentrations in male fathead minnow (Pimephales Promelas)

The official published version can be obtained at the link below - copyright @ 2011 John Wiley and SonsVitellogenin (VTG) is a precursor of egg-yolk protein and is therefore present at high concentrations in the plasma of female fish. In male fish, VTG concentrations are usually undetectable or low but can be induced upon exposure to estrogenic substances either via the water or the diet. This work was performed to determine the reason for the apparently elevated VTG concentrations in unexposed stock male fathead minnow maintained in our laboratory. The results showed clearly that some Of the food given to the fish was estrogenic and that replacement of this with nonestrogenic food led to a significant reduction in the basal VTG levels measured in male fish after a six-month period. This reduction in male VTG concentrations drastically increased the sensitivity of the VTG test in further studies carried out with these fish. Moreover, a review of published concentrations of VTG in unexposed male fathead minnow suggests that this problem may exist in other laboratories. The fathead minnow is a standard ecotoxicological fish test species, so these findings will be of interest to any laboratory carrying out fish tests on endocrine-disrupting chemicals

Strategic Recruitment

This paper suggests that the process of recruitment should be more closely examined. Examples of current methods of recruitment will be reviewed, a framework for a systematic recruitment campaign will be suggested, and practical techniques displayed