Parallel preconditioners for high order discretizations arising from full system modeling for brain microwave imaging

This paper combines the use of high order finite element methods with parallel preconditioners of domain decomposition type for solving electromagnetic problems arising from brain microwave imaging. The numerical algorithms involved in such complex imaging systems are computationally expensive since they require solving the direct problem of Maxwell's equations several times. Moreover, wave propagation problems in the high frequency regime are challenging because a sufficiently high number of unknowns is required to accurately represent the solution. In order to use these algorithms in practice for brain stroke diagnosis, running time should be reasonable. The method presented in this paper, coupling high order finite elements and parallel preconditioners, makes it possible to reduce the overall computational cost and simulation time while maintaining accuracy

Argentina's Monetary and Exchange Rate Policies after the Convertibility Regime Collapse

This paper offers a comprehensive look at how Argentina managed a remarkable economic recovery from its collapse in 2001. The authors show how the Argentine government's policy of targeting a stable and competitive real exchange rate was crucial to the country's economic recovery. They also analyze the various sources of aggregate demand and government revenue in different phases of the expansion. In addition to the crucial role of the exchange rate, the authors look at other policies -- such as an export tax, capital controls, and the default on much of the country's sovereign debt -- which were met with disapproval by many economists and other commentators but played an important role in the recovery

A Selective Bibliography, 1949 - 1965

Kennedy Space Center development from 1949 through 1965 - selected bibliography of article

A Concise History of Exchange Rate Regimes in Latin America

The paper analyzes exchange rate regimes implemented by the major Latin American countries since the Second World War, with special attention on the period of the second globalization process beginning in the 1970s. The analysis follows a historical narrative aiming to provide an understanding of the domestic and external circumstances in which various regimes were adopted. A simple conceptual framework is developed in order to emphasize how the exchange rate regime may affect key nominal and real variables in a small open economy. After an overview of the main trends followed by the major countries in the region over the last 60 years, the paper focuses on regimes that were implemented 1) with stabilization purposes (nominal anchors) and 2) with the aim of targeting the level of the real exchange rate. These two sections analyze in greater detail some experiences illustrating the pros and cons of both strategies. The paper closes with an assessment about exchange rate experiences in Latin America. JEL Categories: F41, N16, F31Latin America, exchange rate regimes, real exchange rate, inflation targeting.

A Concise History of Exchange Rate Regimes in Latin America

This paper analyzes the experience of the major Latin American countries including Argentina, Brazil, Mexico, Colombia, Chile, Peru and others in the post-World-War period, up to the crisis caused by the collapse of the U.S. housing bubble. The authors provide a detailed historical analysis that takes into account the most important economic events that helped determine exchange rate policy, and evaluates the strengths and weaknesses of the various exchange rate regimes, and their impact on outcomes including economic growth and inflation.capital controls, capital flows

Argentina's Monetary and Exchange Rate Policies after the Convertibility Regime Collapse

This paper offers a comprehensive look at how Argentina managed a remarkable economic recovery from its collapse in 2001. The authors show how the Argentine government's policy of targeting a stable and competitive real exchange rate was crucial to the country's economic recovery. They also analyze the various sources of aggregate demand and government revenue in different phases of the expansion. In addition to the crucial role of the exchange rate, the authors look at other policies - such as an export tax, capital controls, and the default on much of the country's sovereign debt - which were met with disapproval by many economists and other commentators but played an important role in the recovery.

Constraining Dark Energy with X-ray Galaxy Clusters, Supernovae and the Cosmic Microwave Background

We present new constraints on the evolution of dark energy from an analysis of Cosmic Microwave Background, supernova and X-ray galaxy cluster data. Our analysis employs a minimum of priors and exploits the complementary nature of these data sets. We examine a series of dark energy models with up to three free parameters: the current dark energy equation of state w_0, the early time equation of state w_et and the scale factor at transition, a_t. From a combined analysis of all three data sets, assuming a constant equation of state and that the Universe is flat, we measure w_0=-1.05+0.10-0.12. Including w_et as a free parameter and allowing a_t to vary over the range 0.5<a_t<0.95 where the data sets have discriminating power, we measure w_0=-1.27+0.33-0.39 and w_et=-0.66+0.44-0.62. We find no significant evidence for evolution in the dark energy equation of state parameter with redshift. Marginal hints of evolution in the supernovae data become less significant when the cluster constraints are also included in the analysis. The complementary nature of the data sets leads to a tight constraint on the mean matter density, Omega_m and alleviates a number of other parameter degeneracies, including that between the scalar spectral index n_s, the physical baryon density Omega_bh^2 and the optical depth tau. This complementary nature also allows us to examine models in which we drop the prior on the curvature. For non-flat models with a constant equation of state, we measure w_0=-1.09+0.12-0.15 and Omega_de=0.70+-0.03. Our analysis includes spatial perturbations in the dark energy fluid, assuming a sound speed c_s^2 =1. For our most general dark energy model, not including such perturbations would lead to spurious constraints on w_et which would be tighter by approximately a factor two with the current data. (abridged)Comment: 11 pages, 13 figures, 2 tables. Accepted for publication in MNRAS. Two new figures added: Fig.9 shows the effects of including dark energy perturbations and Fig.10 compares X-ray cluster data with 2dF dat