The Demand Elasticity of Health Care Spending for Low-Income Individuals

Low-income individuals are typically the most price sensitive segment of the mar-ket, but this is not true in the market for health care services. I show that low-income individuals have a smaller demand elasticity of medical spending with re-spect to coinsurance, relative to their higher income counterparts, using data from the RAND Health Insurance experiment. The null effect is driven by disproportion-ate share of low-income individuals who consume zero health care. The key insight is that low-income individuals may optimally consume zero health care because, when marginal utility of consumption is high, forgoing non-medical consumption becomes very costly

Agile Spacecraft Attitude Control: An Incremental Nonlinear Dynamic Inversion Approach

This paper presents an agile and robust spacecraft attitude tracking controller using the recently reformulated incremental nonlinear dynamic inversion (INDI). INDI is a combined model- and sensor-based control approach that only requires a control effectiveness model and measurements of the state and some of its derivatives, making a reduced dependency on exact system dynamics knowledge. The reformulated INDI allows a non-cascaded dynamic inversion control in terms of Modified Rodrigues Parameters (MRPs) where scheduling of the time-varying control effectiveness is done analytically. This way, the controller is only sensitive to parametric uncertainty of the augmented spacecraft inertia and its wheelset alignment. Moreover, we draw some parallels to time-delay control (TDC) -more familiar in the robotics community- which have been shown to be equivalent to the incremental formulation of proportional-integralderivative (PID) control for second order nonlinear systems in controller canonical form. Simulation experiments for this particular problem demonstrate that INDI has similar nominal performance as TDC/PID control, but superior robust performance and stability

Rentas de recursos naturales no renovables en América Latina y el Caribe: evolución y participación estatal, 1990-2010

Incluye BibliografíaEl presente documento se enfoca en examinar la siguiente pregunta de investigación: Cómo ha evolucionado la captación de rentas de los sectores de recursos naturales norenovables por los países de la región durante el último período de auge de precios , en comparación con el período anterior? Específicamente el documento revisa cómo ha evolucionado la participación de los Estados en las rentas económicas del sector minero y del sector hidrocarburos durante el último período de auge 2003-2010, en contraste con el desempeño del período precedente 1990-2003 en estos sectores. El porcentaje de participación logrado por los Estados de la renta económica total de estos sectores, y su comparación internacional, es un indicador de la efectividad de los marcos institucionales actuales para lograr la apropiación pública de riqueza derivada de las actividades extractivas. Esta información puede informar la discusión sobre la primera tarea entre las tres señaladas arriba.Introducción .-- Resumen de principales resultados .-- Sector de minería metálica: tendencias y evolución durante la última década .-- Panorama del sector hidrocarburos en América Latina y el Caribe y su evolución durante la última décad

Lessons from the analysis of nonhuman primates for understanding human aging and neurodegenerative diseases

Animal models are necessary tools for solving the most serious challenges facing medical research. In aging and neurodegenerative disease studies, rodents occupy a place of choice. However, the most challenging questions about longevity, the complexity and functioning of brain networks or social intelligence can almost only be investigated in nonhuman primates. Beside the fact that their brain structure is much closer to that of humans, they develop highly complex cognitive strategies and they are visually-oriented like humans. For these reasons, they deserve consideration, although their management and care are more complicated and the related costs much higher. Despite these caveats, considerable scientific advances have been possible using nonhuman primates. This review concisely summarizes their role in the study of aging and of the mechanisms involved in neurodegenerative disorders associated mainly with cognitive dysfunctions (Alzheimer’s and prion diseases) or motor deficits (Parkinson’s and related diseases)

Financing for sustainable development in Latin America and the Caribbean

Includes bibliographyDocument to serve as a basis for the deliberations of the Panel of Financing for Sustainable Development organized jointly by ECLAC, UNDP and UNEP. Produced within the framework of the Regional Preparatory Conference of Latin America and the Caribbean for the World Conference on Sustainable Development (Johannesburg, South Africa, 2002), Rio de Janeiro, Brazil, 23 and 24 October 2001 The document and case studies are products of a joint ECLAC/UNDP project , financially supported by the United Nations Development Programme

Design of a Control Allocation Solution for the Winged Reusable Launch Vehicle ReFEx

This paper presents a control allocation solution for the technology demonstrator mission ReFEx, which focuses on a vertical takeoff and horizontal landing strategy with autonomous navigation, online guidance, and controlled flight throughout the mission. The trajectory for the demonstration flight is aimed as one for a winged launch vehicle first stage: maintaining stability and control of the vehicle while reaching a predefined target. During the atmospheric phase the vehicle is stabilized by using an active aerodynamic control system which transforms inputs from the guidance and navigation systems into control commands for the individual actuators. In that sense, the control allocation subsystem translates commanded moments into commanded aerodynamic surface deflections. Due to the effect of modeling uncertainties, navigation errors, and underactuated regions, this subsystem needs to be robustified. The algorithm proposed in this paper addresses this challenge via a combination of the deflections required to trim the vehicle together with delta-deflections that aim at converging iteratively to the commanded moments. The combination of these two contributions is able to respond fast to state changes, compensate for modeling uncertainties and navigation errors, and provide a safe mode for the underactuated regions. The performance of the system is studied using a high-fidelity simulator

A Sampled-Data Form of Incremental Nonlinear Dynamic Inversion for Spacecraft Attitude Control

This paper presents a sampled–data form of the recently reformulated incremental nonlinear dynamic inversion (INDI) applied for robust spacecraft attitude control. INDI is a combined model– and sensor–based approach mostly applied for attitude control that only requires an accurate control effectiveness model and measurements of the state and some of its derivatives. This results in a reduced dependency on exact knowledge of system dynamics which is known as a major disadvantage of model–based nonlinear dynamic inversion controllers. However, most of the INDI derivations proposed in the literature assume a very high sampling rate of the system and its controller while also not explicitly considering the available sampling time of the digital control computer. Neglecting the sampling time and its effect in the controller derivations can lead to stability and performance issues of the resulting closed–loop nonlinear system. Therefore, our objective is to bridge this gap between continuous–time, highly sampled INDI formulations and their discrete, lowly sampled counterparts in the context of spacecraft attitude control where low sampling rates are common. Our sampled–data reformulation allows explicit consideration of the sampling time via an approximate sampled–data model in normal form widely known in the literature. The resulting sampled–data INDI control is still robust up to a certain sampling time since it remains only sensitive to parametric uncertainties. Simulation experiments for this particular problem demonstrate the bridge considered between INDI formulations which allows for low sampling control rates

Unusual sequelae after percutaneous mitral valvuloplasty: A Doppler echocardiographic study

AbstractPercutaneous mitral valvuloplasty is a promising new technique for the treatment of mitral stenosis, with a relatively low complication rate reported to date. To assess the sequelae of this procedure, Doppler echocardiographic studies were prospectively performed before and after percutaneous mitral valvuloplasty in a series of 172 patients (mean age 53 ± 17 years). After balloon dilation, mitral valve area increased from 0.9 ± 0.3 to 2 ± 0.8 cm2(p < 0.0001), mean gradient decreased from 16 ± 6 to 6 ± 3 mm Hg (p < 0.0001) and mean left atrial pressure decreased from 24 ± 7 to 14 ± 6 mm Hg (p < 0.0001).Although most patients were symptomatically improved, six (4%) were identified who had unusual sequelae evident on Doppler echocardiographic examination immediately after percutaneous mitral valvuloplasty. These included rupture of a posterior mitral valve leaflet, producing a flail distal leaflet portion with severe mitral regurgitation detected on Doppler color flow mapping (n = 1); asymptomatic rupture of the chordae tendineae attached to the anterior mitral valve leaflet with systolic anterior motion of the ruptured chordae into the left ventricular outflow tract (n = 1); a double-orifice mitral valve (n = 1); and evidence of a tear in the anterior mitral valve leaflet (n = 3), producing on both pulsed Doppler ultrasound and color flow mapping a second discrete jet of mitral regurgitation in addition to regurgitation through the main mitral valve orifice. All six patients made a satisfactory recovery and none has required mitral valve replacement.In a small percent of cases, percutaneous mitral valvuloplasty may produce unusual disruption of the mitral valve and supporting apparatus that may be readily detected by Doppler echocardiographic studies