Does Hospital Competition Improve Efficiency? An Analysis of the Recent Market-Based Reforms to the English NHS

This paper uses a difference-in-difference estimator to test whether the introduction of patient choice and hospital competition in the English NHS in January 2006 has prompted hospitals to become more efficient. Efficiency was measured using hospitals' average length of stay (LOS) for patients undergoing elective hip replacement. LOS was broken down into its two key components: the time from a patient's admission until their surgery and the time from their surgery until their discharge. Our results illustrate that hospitals exposed to competition after a wave of market-based reforms took steps to shorten the time patients were in the hospital prior to their surgery, which resulted in a decrease in overall LOS. We find that hospitals shortened patients' LOS without compromising patient outcomes or by operating on healthier, wealthier or younger patients. Our results suggest that hospital competition within markets with fixed prices can increase hospital efficiency.Hospital Competition, Market Structure, Prospective Payment, Incentive Structure

Extrinisic Calibration of a Camera-Arm System Through Rotation Identification

Determining extrinsic calibration parameters is a necessity in any robotic system composed of actuators and cameras. Once a system is outside the lab environment, parameters must be determined without relying on outside artifacts such as calibration targets. We propose a method that relies on structured motion of an observed arm to recover extrinsic calibration parameters. Our method combines known arm kinematics with observations of conics in the image plane to calculate maximum-likelihood estimates for calibration extrinsics. This method is validated in simulation and tested against a real-world model, yielding results consistent with ruler-based estimates. Our method shows promise for estimating the pose of a camera relative to an articulated arm's end effector without requiring tedious measurements or external artifacts. Index Terms: robotics, hand-eye problem, self-calibration, structure from motio

Is There a Democracy–Civil Society Paradox in Global Environmental Governance?

Civil society is commonly assumed to have a positive effect on international cooperation. This paper sheds light on one important facet of this assumption: we examine the impact of environmental non-governmental organizations (ENGOs) on ratification behavior of countries vis-à-vis international environmental agreements (IEAs). The main argument of the paper focuses on a “democracy-civil society paradox”: although ENGOs have a positive effect on ratification of IEAs on average, this effect decreases with increasing levels of democracy. This argument is counter-intuitive and appears paradoxical because democracy is generally associated both with a more active civil society and more international cooperation. The reasons for this hypothesized effect pertain to public demand for environmental public goods provision, government incentives, and problems of collective action among ENGOs. To test the net effect of ENGOs on countries' ratification behavior, the paper uses a new dataset on ENGOs in the time-period 1973–2006. The results offer strong support for the presumed democracy–civil society paradox. </jats:p

Initial Incidence of White Matter Hyperintensities on MRI in Astronauts

Introduction: Previous literature has described the increase in white matter hyperintensity (WMH) burden associated with hypobaric exposure in the U-2 and altitude chamber operating personnel. Although astronauts have similar hypobaric exposure pressures to the U2 pilot population, astronauts have far fewer exposures and each exposure would be associated with a much lower level of decompression stress due to rigorous countermeasures to prevent decompression sickness. Therefore, we postulated that the WMH burden in the astronaut population would be less than in U2 pilots. Methods: Twenty-one post-flight de-identified astronaut MRIs (5 mm slice thickness FLAIR sequences) were evaluated for WMH count and volume. The only additional data provided was an age range of the astronauts (43-57) and if they had ever performed an EVA (13 yes, 8 no). Results: WMH count in these 21 astronaut MRI was 21.0 +/- 24.8 (mean+/- SD) and volume was 0.382 +/- 0.602 ml, which was significantly higher than previously published results for the U2 pilots. No significant differences between EVA and no EVA groups existed. Age range of astronaut population is not directly comparable to the U2 population. Discussion: With significantly less frequent (sometimes none) and less stressful hypobaric exposures, yet a much higher incidence of increased WMH, this indicates the possibility of additional mechanisms beyond hypobaric exposure. This increase unlikely to be attributable just to the differences in age between astronauts and U2 pilots. Forward work includes continuing review of post-flight MRI and evaluation of pre to post flight MRI changes if available. Data mining for potential WMH risk factors includes collection of age, sex, spaceflight experience, EVA hours, other hypobaric exposures, hyperoxic exposures, radiation, high performance aircraft experience and past medical history. Finally, neurocognitive and vision/eye results will be evaluated for any evidence of impairment linked to increased WMH