Credibilidad en la política monetaria: Papel de políticas en la estabilidad del Presidente del Banco Central

Este documento estudia la relación entre el índice de riesgo de salida de un presidente de banco central y una medida de credibilidad en la política monetaria. El índice de riesgo de salida previsto se considera como una función de variables legales y políticas. La medida de credibilidad es la probabilidad prevista de un principio de deflación cuando la inflación está en aumento. En una muestra de 22 países latinoamericanos y del G7, se encuentra una relación negativa entre el índice de riesgo de salida y la medida de credibilidad. Los resultados demuestran que la independencia legal después de controlar el índice de riesgo de la salida del presidente no está asociada a aumentos de credibilidad.

Do Campaign Contribution Limits Curb the Influence of Money in Politics?

Over 40% of countries around the world have adopted limits on campaign contributions to curb the influence of money in politics. Yet, we have limited knowledge on whether and how these limits achieve this goal. With a regression discontinuity design that uses institutional rules on contribution limits in Colombian municipalities, we show that looser limits increase the number and value of public contracts assigned to the winning candidate’s donors. The evidence suggests that this is explained by looser limits concentrating influence over the elected candidate among top donors and not by a reduction in electoral competition or changes in who runs for office. We further show that looser limits worsen the performance of donor-managed contracts: they are more likely to run over costs and require time extensions. Overall, this paper demonstrates a direct link between campaign contribution limits, donor kickbacks, and worse government contract performance

Numerical simulations of the internal shock model in magnetized relativistic jets of blazars

The internal shocks scenario in relativistic jets is used to explain the variability of the blazar emission. Recent studies have shown that the magnetic field significantly alters the shell collision dynamics, producing a variety of spectral energy distributions and light-curves patterns. However, the role played by magnetization in such emission processes is still not entirely understood. In this work we numerically solve the magnetohydodynamic evolution of the magnetized shells collision, and determine the influence of the magnetization on the observed radiation. Our procedure consists in systematically varying the shell Lorentz factor, relative velocity, and viewing angle. The calculations needed to produce the whole broadband spectral energy distributions and light-curves are computationally expensive, and are achieved using a high-performance parallel code.Comment: 7 pages, 5 figures, proceeding of the "Swift: 10 Years of Discovery" conference (December 2014, Rome, Italy

EFECTO DE EXIGENCIA EN CALIFICACIÓN SOBRE EL DESEMPEÑO ACADÉMICO. ESTUDIO DE LOS CURSOS DE MATEMÁTICAS BÁSICOS EN LA UNIVERSIDAD DE LOS ANDES

Este trabajo investiga cómo la exigencia de calificación de los profesores de los cursos de Cálculo, Algebra Lineal y Ecuaciones Diferenciales afecta el desempeño académico de sus estudiantes en estas materias. Utilizando una base de datos que incluye características de los profesores y alumnos se estiman los determinantes de desempeño académico encontrando evidencia de un efecto positivo de aumentar la exigencia en la calificación. Por medio de modelos de regresión cuantílica se encuentra que el efecto de mayor exigencia es uniforme entre estudiantes ubicados en distintos puntos de la distribución del desempeño académico. De manera adicional, se encontró que el efecto de aumentar el nivel de exigencia sobre la probabilidad de retirar un curso por parte de un estudiante es positivo y de magnitud cercana a cuatro puntos porcentuales.Enseñanza, incentivos a la educación, exigencia en calificación

Numerical study of broadband spectra caused by internal shocks in magnetized relativistic jets of blazars

The internal-shocks scenario in relativistic jets has been used to explain the variability of blazars' outflow emission. Recent simulations have shown that the magnetic field alters the dynamics of these shocks producing a whole zoo of spectral energy density patterns. However, the role played by magnetization in such high-energy emission is still not entirely understood. With the aid of \emph{Fermi}'s second LAT AGN catalog, a comparison with observations in the $\gamma$-ray band was performed, in order to identify the effects of the magnetic field.Comment: Proceedings of the meeting The Innermost Regions of Relativistic Jets and Their Magnetic Fields, June 10-14, 2013, Granada (Spain), 4 pages, 3 figure

Biotechnological approaches to increase biomass production in trees

Nutrient use efficiency is one of the factors influencing growth and therefore of high importance for biomass production in trees. Poplar is a model tree widely used for molecular and functional studies and the characterization of transgenic poplars overexpressing structural and regulatory genes involved in glutamine biosynthesis has provided insights on how glutamine metabolism is involved in N economy and biomass production in woody plant models. Numerous studies have shown the relevance of GS isoenzymes in plant development, biomass production, and yield (Cánovas et al. 2006; Castro-Rodríguez et al. 2015). In this communication two examples of functional analysis of plant genes in poplar, and their potential interest for biotechnological approaches are presented (Pascual et al. 2018; Rueda-López et al. 2017). Overexpression of cytosolic NADP+-isocitrate dehydrogenase (ICDH), one of the major enzymes involved in the production of 2-oxoglutarate for amino acid biosynthesis in plants, yields poplar trees with increased growth and enhanced vascular development in young leaves and apical stems. These plants also show an increased expression of genes associated with vascular differentiation and altered amino acids and organic acids content (Pascual et al. 2018). In other study, we observed that overexpression of Dof5, a transcriptional regulator of lignin production and the carbon-nitrogen balance, produced poplar trees with increased growth and biomass production when N availability in the soil is sufficient (Rueda-López et al. 2017). Taken together, these results suggest a close relationship between carbon and nitrogen metabolism and highlights the relevance of glutamine and glutamate biosynthesis in the control of growth and development. Research supported by Spanish Ministry of Economy and Competitiveness and Junta de Andalucía (Grants BIO2015-69285-R, BIO2012-0474 and research group BIO-114).Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec

Bioimpedance real-time charazterization of neointimal tissue inside stents

It is hereby presented a new approach to monitor restenosis in arteries fitted with a stent during an angioplasty. The growth of neointimal tissue is followed up by measuring its bioimpedance with Electrical Impedance Spectroscopy (EIS). Besides, a mathematical model is derived to analytically describe the neointima’s histological composition from its bioimpedance. The model is validated by finite-element analysis (FEA) with COMSOL Multiphysics®. Satisfactory correlation between the analytical model and the FEA simulation is achieved for most of the characterization range, detecting some deviations introduced by the thin "double layer" that separates the neointima and the blood. It is shown how to apply conformal transformations to obtain bioimpedance models for stack-layered tissues over coplanar electrodes. Particularly, this is applied to characterize the neointima in real-time. This technique is either suitable as a main mechanism of restenosis follow-up or it can be combined with proposed blood-pressure-measuring intelligent stents to auto-calibrate the sensibility loss caused by the adherence of the tissue on the micro-electro-mechanical sensors (MEMS).Ministerio de Economía, Industria y Competitividad (Spain): projects TEC2013-46242-C3-1-PMinisterio de Economía, Industria y Competitividad (Spain): projects TEC2013-46242-C3-2-