Essays in Applied Microeconomics on Mexico

This dissertation comprises three chapters on applied microeconomics that study different economic aspects around the intersection between street violence and nutrition in the context of Mexico. The first and pivot chapter, titled “Military Interventions and Obesity: Evidence from Mexico’s Drug War”, studies the relationship street violence and body weight. This chapter examines if exposure to street violence originated in the military interventions against the drug trafficking organizations (DTOs) that started in 2006 in Mexico had an impact on weight using longitudinal data from a household survey. My results indicate that military operations affect weight positively, increasing overweight although not to the extent of inducing obesity. The second chapter, titled “Will Violent Crime Incentivize the Hiding of Small Firms?”, explores the impact from street violence on a different outcome: tax compliance. This chapter examines the relationship between crime exposure and informality of businesses using a rotating panel survey matched to municipal homicide rates. My hypothesis is that losses derived from crime may take away income that could otherwise be used to afford formality. Also, firms may prefer to stay underground to avoid disclosing their existence to criminals. I find that exposure to violent crime promotes informality. These results are further corroborated by using temperature as an instrumental variable. The third chapter, “Fighting Against Hunger: A Country-Wide Intervention and its Impact on Birth Outcomes,” steps away from the crime scene to focus on nutrition again. This chapter studies the impact of Sin Hambre (SH), a food assistance program introduced in Mexico in 2013, on birth weight. I use a difference in difference approach exploiting timing and regional variations in exposure to evaluate the impact of the overall program on birthweight. Since municipalities were not randomly assigned, linear regression methodologies may lead to biased estimates. In order to address these concerns and obtain causal estimates, I employ a multiperiod difference-in-difference matching method. I find that exposure to SH leads to moderate impacts on birth weight at best

ONLINE PARAMETRIC IDENTIFICATION OF MASS-SPRING-DAMPER MECHANICAL SYSTEMS USING ACCELERATION MEASUREMENTS

AbstractImplementation of active vibration control schemes, failure detection and monitoring tasks of the suitable operation of flexible mechanical structures can require the use of on-line parametric identification techniques. Measurements of acceleration signals are preferred in several applications of parameter identification of vibrating mechanical systems. In this article, an on-line parameter estimation approach in time domain is proposed for linear mass-spring-damper mechanical systems of n degrees of freedom using acceleration measurements solely. Integration by parts is properly used in the synthesis of the proposed parameter identification method. In this fashion, a priori knowledge of the initial conditions of the system becomes unnecessary. The introduced identification method can be extended for real-time parametric estimation of nonlinear fully actuated or under-actuated nonlinear vibrating mechanical systems. Some numerical results are provided to show the effectiveness of the on-line estimation approach of the mass, stiffness and damping parameters combined with closed-loop reference trajectory tracking tasks specified for the vibrating mechanical system.Keywords: Active vibration control, mass-spring-damper systems, mechanical vibration systems, parameter identification.IDENTIFICACIÓN PARAMÉTRICA EN LÍNEA DE SISTEMAS MECÁNICOS DE MASA-RESORTE-AMORTIGUADOR UTILIZANDO MEDICIONES DE ACELERACIÓNResumenImplementación de esquemas de control activo de vibraciones, detección de fallas o tareas de monitoreo de la operación adecuada de estructuras mecánicas flexibles pueden requerir el uso de técnicas de identificación paramétrica ejecutadas en línea. Mediciones de señales de aceleración se usan en varias aplicaciones de identificación de parámetros en sistemas mecánicos vibratorios. En este artículo se propone un enfoque para estimación de parámetros en línea en el dominio del tiempo para sistemas mecánicos del tipo masa-resorte-amortiguador de n grados de libertad, usando únicamente mediciones de aceleración. Se usa integración por partes en la síntesis del método de identificación de parámetros propuesto. De esta manera, conocimiento previo de las condiciones iniciales del sistema son innecesarias. El método de estimación propuesto se puede extender para estimación paramétrica en tiempo real para sistemas mecánicos vibratorios no lineales, completamente actuados o sub-actuados. Se incluyen algunos resultados de simulación numérica para mostrar la efectividad del enfoque de estimación de parámetros de masa, rigidez y amortiguamiento, combinado con tareas de seguimiento de trayectorias de referencia en lazo-cerrado especificadas para el sistema mecánico vibratorio.Palabras Claves: control activo de vibraciones, identificación de parámetros, sistemas mecánicos vibratorios, sistemas masa-resorte-amortiguador

Enhanced production of multi-strange hadrons in high-multiplicity proton-proton collisions

At sufficiently high temperature and energy density, nuclear matter undergoes a transition to a phase in which quarks and gluons are not confined: the quark-gluon plasma (QGP)(1). Such an exotic state of strongly interacting quantum chromodynamics matter is produced in the laboratory in heavy nuclei high-energy collisions, where an enhanced production of strange hadrons is observed(2-6). Strangeness enhancement, originally proposed as a signature of QGP formation in nuclear collisions(7), is more pronounced for multi-strange baryons. Several effects typical of heavy-ion phenomenology have been observed in high-multiplicity proton-proton (pp) collisions(8,9), but the enhanced production of multi-strange particles has not been reported so far. Here we present the first observation of strangeness enhancement in high-multiplicity proton-proton collisions. We find that the integrated yields of strange and multi-strange particles, relative to pions, increases significantly with the event charged-particle multiplicity. The measurements are in remarkable agreement with the p-Pb collision results(10,11), indicating that the phenomenon is related to the final system created in the collision. In high-multiplicity events strangeness production reaches values similar to those observed in Pb-Pb collisions, where a QGP is formed.Peer reviewe

Production of He-4 and (4) in Pb-Pb collisions at root(NN)-N-S=2.76 TeV at the LHC

Results on the production of He-4 and (4) nuclei in Pb-Pb collisions at root(NN)-N-S = 2.76 TeV in the rapidity range vertical bar y vertical bar <1, using the ALICE detector, are presented in this paper. The rapidity densities corresponding to 0-10% central events are found to be dN/dy4(He) = (0.8 +/- 0.4 (stat) +/- 0.3 (syst)) x 10(-6) and dN/dy4 = (1.1 +/- 0.4 (stat) +/- 0.2 (syst)) x 10(-6), respectively. This is in agreement with the statistical thermal model expectation assuming the same chemical freeze-out temperature (T-chem = 156 MeV) as for light hadrons. The measured ratio of (4)/He-4 is 1.4 +/- 0.8 (stat) +/- 0.5 (syst). (C) 2018 Published by Elsevier B.V.Peer reviewe

Inclusive J/ψ production at forward and backward rapidity in p-Pb collisions at √sNN=8.16 TeV

Inclusive J/psi production is studied in p-Pb interactions at a centre-of-mass energy per nucleon-nucleon collision sqrt(s_NN) = 8.16TeV, using the ALICE detector at the CERN LHC. The J/psi meson is reconstructed, via its decay to a muon pair, in the centre-of-mass rapidity intervals 2.03 < ycms < 3.53 and -4.46 < ycms < -2.96, where positive and negative ycms refer to the p-going and Pb-going direction, respectively. The transverse momentum coverage is pT < 20 GeV/c. In this paper, ycms- and pT-differential cross sections for inclusive J/psi production are presented, and the corresponding nuclear modification factors RpPb are shown. Forward results show a suppression of the J/psi yield with respect to pp collisions, concentrated in the region pT < 5 GeV/c. At backward rapidity no significant suppression is observed. The results are compared to previous measurements by ALICE in p-Pb collisions at sqrt(s_NN) = 5.02TeV and to theoretical calculations. Finally, the ratios RFB between forward- and backward-ycms RpPb values are shown and discussed