Master of Science

thesisHealth care costs in the United States are rising at an alarming rate. Although much of the cost of care is dependent on the decisions of care providers, providers remain largely unaware of those costs. Legislators have passed initiatives aimed at increasing cost transparency, but the impact of cost transparency on the cost of care is uncertain. The purpose of this study was to systematically review trials investigating the impact of cost transparency on the cost of care delivery, identify the factors likely to increase the effectiveness of such interventions, and suggest directions for future research. We searched the Scopus database for relevant studies published up to November 2014. After identifying potentially relevant studies, we performed additional searches for publications citing or cited by the selected studies. This process was repeated until no additional studies were identified. Key characteristics of relevant studies were extracted for analysis. We screened a total of 4,906 articles, 23 of which were included in the final analysis. We identified timing (education prior to the decision vs. feedback following the decision) and medium (electronic vs. nonelectronic) of communication as key factors impacting the effectiveness of the cost transparency intervention. One hundred percent (9 of 9) of "postorder feedback" studies resulted in decreased costs, whereas only 54% (7 of 13) of studies in which cost was communicated prior to the clinical decision ("pre-order education" studies) lowered the cost of care delivery. Eighty-eight percent (14 of iv 16) of nonelectronic studies reduced costs; 29% (2 of 7) of electronic studies reduced costs. Cost transparency can be an effective strategy to reduce utilization of expensive tests or therapies. Intervention strategies that employ nonelectronic media for communication of financial information to providers and that communicate postdecision feedback may be most likely to succeed. The trend in current publications suggests that health care providers may be moving toward the less effective methods of cost transparency, which could hamper cost containment efforts. The strength of these observations is limited by the absence of prospective studies that directly compare the effectiveness of various cost transparency intervention methods. Future studies are needed to verify these findings and to determine the impact of cost transparency in new cost-centric organizations and incentive structures

Chandra/HETGS Observations of the Capella System: the Primary as a Dominating X-ray Source

Using the Chandra/High Energy Transmission Grating Spectrometer (hereafter HETGS) we have detected Doppler motion of Capella's X-ray emission lines in the 6 -- 25AA wave-band. The observed motion follows the expected orbital motion of Capella's primary. This finding implies that the primary G8 III star, not the secondary G1 III star in the Hertzsprung gap, has been the dominant source of hot 10^{6.8} -- 10^{7}K plasma at least in the last six years. In addition, the results demonstrate the long-term stability of the HETGS and demonstrate small uncertainties of 25 and 33 km/s in the velocity determination with the HEG and MEG, respectively.Comment: 4 pages, 4 figures, accepted by Astrophysical Journal Letter

Image Analysis of Air Voids in Air-Entrained Concrete

The application of image analysis techniques to characterize the air-void system in hardened concrete is demonstrated. Both lineal and areal feature analyses are investigated. Feature size distributions and total air contents are obtained using s both types of analysis. The areal analyses also include the measurement of individual feature perimeters for use in comparing void shapes. A two phase standard specimen ip developed to insure the consistency of measurements and repeatability of results. Correction methods, based on geometric probability, are developed to remove the distortions in the image analysis data resulting from frame edge effects. Separate r:nethods are presented for lineal and areal analyses. Using discrete class sizes, both correction procedures are expressed in a matrix format. The corrected areal feature distributions are used to obtain volume distributions of spherical air voids using standard stereological procedures. The procedures are applied to ten concrete specimens, at magnifications of 12x and 30x. The specimens represent concretes made using three different airentraining admixtures, as well as non-air entrained concrete. Air-void parameters calculated from corrected image analysis results for the ten specimens are compared to results obtained using the modified point count method and to freeze-thaw results obtained from surface scaling tests of companion specimens. The differences in the air-void systems created by the various air entraining agents are studied by comparing different characteristics including: the Powers spacing factor, the Philleo factor, profile shape, average feature size, numerical density of features, and the cumulative percent of total air versus feature size. The study demonstrates that image analysis provides a viable alternative to traditional lineal traverse and modified point count methods for characterization of air-void systems in hardened concrete and, in the process, provides significant detail not available with the traditional methods. The study indicates that airentraining agents produce characteristic air void distributions. Comparisons made in the study show that lineal and areal image analysis techniques provide similar determinations of total air content that are, on average, 1. i 5 volume percent lower than those obtained from a modified point count analysis. Application of the frame edge effect correction procedures to the lineal data results in an average decrease in the total chord density of 2.3% and 5.0% for magnifications of i 2x and 30x, respectively. Application of the frame edge effect correction proced.ures tq the areal data results in an average decrease in the total profile density of 3.3% and 5.9% for magnifications of i 2x and 30x, respectively. The accuracy of the analysis decreases if size classes are much greater than 30 Jlm. Accurate lineal analyses require the class size to be an exact increment of pixel length. A similar requirement does not apply to areal analyses

Mitigating Citation Errors in the Interlibrary Loan System

Journal articles from most academic disciplines have long shown high rates of citation errors. American law reviews, with their careful cite-checking, are a rare exception to the overall rule. Incorrect citations are especially costly and problematic for interlibrary loan librarians. This article offers practical suggestions to address the problem

Rotorcraft aeroelastic stability

Theoretical and experimental developments in the aeroelastic and aeromechanical stability of helicopters and tilt-rotor aircraft are addressed. Included are the underlying nonlinear structural mechanics of slender rotating beams, necessary for accurate modeling of elastic cantilever rotor blades, and the development of dynamic inflow, an unsteady aerodynamic theory for low-frequency aeroelastic stability applications. Analytical treatment of isolated rotor stability in hover and forward flight, coupled rotor-fuselage stability in hover and forward flight, and analysis of tilt-rotor dynamic stability are considered. Results of parametric investigations of system behavior are presented, and correlation between theoretical results and experimental data from small and large scale wind tunnel and flight testing are discussed

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

Survey of Army/NASA rotorcraft aeroelastic stability research

Theoretical and experimental developments in the aeroelastic and aeromechanical stability of helicopters and tilt-rotor aircraft are addressed. Included are the underlying nonlinear structural mechanics of slender rotating beams, necessary for accurate modeling of elastic cantilever rotor blades, and the development of dynamic inflow, an unsteady aerodynamic theory for low frequency aeroelastic stability applications. Analytical treatment of isolated rotor stability in hover and forward flight, coupled rotor-fuselage stability are considered. Results of parametric investigations of system behavior are presented, and correlations between theoretical results and experimental data from small- and large-scale wind tunnel and flight testing are discussed

High-Resolution X-ray Spectroscopy of SNR 1987A: Chandra LETG and HETG Observations in 2007

We present an extended analysis of the deep Chandra LETG and HETG observations of the supernova remnant 1987A (SNR 1987A) carried out in 2007. The global fits to the grating spectra show that the temperature of the X-ray emitting plasma in the slower shocks in this system has remained stable for the last three years, while that in the faster shocks has decreased. This temperature evolution is confirmed by the first light curves of strong X-ray emission lines and their ratios. On the other hand, bulk gas velocities inferred from the X-ray line profiles are too low to account for the post-shock plasma temperatures inferred from spectral fits. This suggests that the X-ray emission comes from gas that has been shocked twice, first by the blast wave and again by shocks reflected from the inner ring of SNR 1987A. A new model that takes these considerations into account gives support to this physical picture.Comment: 36 pages, 10 figures, Accepted for publication in Ap

Intraspecific variation among clones of a naıve rare grass

Intraspecific variation can have a major impact on plant community composition yet there is little information available on the extent that such variation by an already established species affects interspecific interactions of an invading species. The current research examined the competitiveness of clones of a globally rare but locally common native grass, Calamagrostis porteri ssp. insperata to invasion by Alliaria petiolata, a non-native invasive species. A greenhouse experiment was conducted twice over consecutive years in which 15 clones from three populations of Calamagrostis were paired with rosettes of Alliaria in pots containing native forest soil previously uninvaded by Alliaria. Both species showed a negative response to the presence of the other species, although Alliaria more so than Calamagrostis. Moreover, the effect of Calamagrostis depended upon population, and, to a lesser extent, the individual clone paired with Alliaria. Competitive effects were stronger in the first experiment compared with when the experiment was repeated in the second year. The influence of Calamagrostis clones on the outcome of the experiment varied among populations and among clones, but also between years. Clones from one of the three populations were more influential than clones from the other two populations. Only one of 15 clones, both from the same population, was influential in both experiments. This research supports a growing literature indicating that intraspecific variability among clones of a dominant species can affect interspecific interactions and that such variability in a native species can affect performance of an invading species