A Two-Dimensional Mesh Refinement Method for Problems with One-Dimensional Singularities

This paper introduces a method for resolving internal layers that can occur in the solutions of time-dependent differential equations in two space dimensions. Singular features in these solutions that are essentially one-dimensional in nature but are not oriented with the computational mesh are resolved using one-dimensional mesh refinement techniques with a procedure that is similar to an ADI method. A careful interpolation procedure assures that the resolution obtained in each ADI step is not lost in the succeeding ADI step

Gist and Verbatim in Narrative Memory

A major concern regarding the study of narratives regards how they are indexed and retrieved. This is a question which touches on the structure of human memory in general. Indeed, if narratives capture the substance of human thought, then data that we have already collected regarding human memory is of central importance to the computational study of narrative. Fuzzy Trace Theory assumes that memory for narrative is simultaneously stored at multiple levels of abstraction and, whenever possible, decision-makers interpret a stimulus qualitatively and therefore operate on a simple - typically categorical - "gist" representation. Here, we present a computational model of Fuzzy Trace Theory applied to explain the impact of changes in a narrative upon risky-choice framing effects. Overall, our theory predicts the outcome of 20 experimental effects using only three basic assumptions: 1) preference for lowest level of gist, that is, categorical processing; 2) decision options that fall within the same categorical description are then interpreted using finer-grained (ordinal or verbatim) distinctions; and 3) once the options are mentally represented, decision preferences are generated on the basis of simple positive vs. negative valences stored in long-term memory (e.g., positive value for human lives). A fourth assumption - that negatively-valenced decision options are preferentially converted to positive decision options - is used when categories are not otherwise comparable

Implications on Households of Bank's Asset Substitution

In this paper we develop a DSGE model to analyze the welfare implications over households that bank's asset recomposition might have. We model a representative bank that potentially faces liquidity dificulties due to a mismatch between credits issued to firms and deposits supplied by households. This bank has a portfolio consisting of loans and bonds. The results show that positive liquidity shocks, driven by changes in the household preferences, affect the bank's asset allocation decisions and are beneficial to households. Similarly, when the bond's return rate increases, there is a substitution effect that lowers the loan to bond ratio, but despite this, the bank's intermediation activity increases inducing a positive effect over the household's welfare.bank asset recomposition, DSGE model with banking sector, loans deposit mismatch, liquidity shock Classification JEL: D58,E32, E44.

Cambios en los incentivos de los bancos como consecuencia de modificaciones en los esquemas de encaje.

El uso del encaje como medida de política monetaria cobró relevancia desde 2007 en Colombia. Las modificaciones a los regímenes de encaje que se presentaron desde entonces cambiaron los incentivos de los establecimientos de crédito sobre sus preferencias de captación y sus respuestas de colocación. En este trabajo se plantea un modelo de organización industrial para analizar dichos cambios en los incentivos. Los resultados sugieren que incrementos en el requerimiento de encaje y disminuciones en la remuneración sobre el mismo para un tipo de depósitos generan recomposición hacia los demás, al igual que contracción en la cartera e incrementos en el margen de intermediación. Los resultados cualitativos son robustos ante diferentes parametrizaciones razonables. Este modelo puede ser utilizado como herramienta para medir los efectos de recomposición causados por cambios en los requerimientos de encaje y su estructura de remuneración.Organización industrial; Política monetaria; Encaje bancario; Sistema financiero colombiano Classification JEL: E58; G21; L12.

El mercado de crédito comercial y las restricciones de endeudamiento en Colombia.

En este trabajo se estudian los determinantes de la oferta y demanda de la cartera comercial en Colombia, tanto a nivel macroeconómico como usando información por empresas, por medio de un modelo de desequilibrio que permite analizar posibles restricciones de crédito. Para esto se usa información a nivel de firma de desembolsos de crédito, al igual que otras variables del balance y del estado de resultados, disponibles desde 1998 hasta 2008. Las estimaciones indican que el nivel de actividad de las empresas tiene una relación positiva con la demanda de crédito, y que el valor del colateral y la percepción de riesgo que se tenga de la firma influyen sobre la oferta.Modelo de desequilibrio; restricciones de crédito; Mercado de crédito comercial; Sistema financiero colombiano. Classification JEL: C31; E32; G32.

Propuesta de articulación intermunicipal que permita la implementación de políticas públicas y proyectos de inversión en la zona metropolitana de Puebla-Tlaxcala a partir de las experiencias en las áreas metropolitanas en el Valle de Aburrá y Centro Occidente

El presente trabajo de investigación titulado “Propuesta de articulación intermunicipal que permita la implementación de políticas públicas y proyectos de inversión en la zona metropolitana de Puebla-Tlaxcala a partir de las experiencias en las Áreas Metropolitanas en el Valle de Aburrá y Centro Occidente”, se ha desarrollado en respuesta a la imperante necesidad de establecer eficientes mecanismos de cooperación intergubernamental para las zonas metropolitanas en los Estados Unidos Mexicanos. El Objetivo General planteado como eje de esta investigación se ha formulado en razón de “formular una propuesta de articulación intermunicipal para la zona metropolitana de Puebla-Tlaxcala, que permitan generar una estructura de gestión adecuada y de participación de la sociedad civil, a partir de experiencias registradas en la República de Colombia”. En el transcurso del proceso investigativo hemos sido capaces de identificar una profunda carencia en los mecanismos de atención de las necesidades surgidas a raíz de los procesos de conurbación en México, así como de cuestionar las fortalezas y debilidades de la delimitación de las zonas conurbadas en virtud de los procesos de conurbación intermunicipal así como de las relaciones funcionales existentes entre un municipio núcleo y las entidades territoriales en su entorno. La propuesta generada como resultado de esta investigación retoma elementos exitosos observados en las instituciones metropolitanas del Valle de Aburrá y Centro Occidente y fundamenta su estructura en el análisis de las dificultades identificadas en ambas entidades metropolitanas.The present research work entitled "Proposal of inter-municipal articulation that allows the implementation of public policies and investment projects in the metropolitan area of Puebla-Tlaxcala from the experiences in the Metropolitan Areas in the Aburrá Valley and Central West", is It has developed in response to the imperative need to establish efficient intergovernmental cooperation mechanisms for metropolitan areas in the United Mexican States. The General Objective proposed as the axis of this research has been formulated in order to “formulate a proposal for inter-municipal articulation for the metropolitan area of Puebla-Tlaxcala, which allows generating an adequate management structure and participation of civil society, based on experiences registered in the Republic of Colombia ”. In the course of the investigative process, we have been able to identify a profound lack in the mechanisms for attending to the needs arising from the conurbation processes in Mexico, as well as questioning the strengths and weaknesses of the delimitation of conurbation areas by virtue of of the inter-municipal conurbation processes as well as of the existing functional relationships between a core municipality and the territorial entities in its environment. The proposal generated as a result of this research takes up successful elements observed in the metropolitan institutions of Valle de Aburrá and Centro Occidente and bases its structure on the analysis of the difficulties identified in both metropolitan entities

Essays on International Economics

University of Minnesota Ph.D. dissertation. August 2014. Major: Economics. Advisor: Timothy J. Kehoe. 1 computer file (PDF);viii, 102 pages, appendices A-C.This dissertation consists of three essays. In the first essay, Enoch Hill and I present a general equilibrium model where heterogeneous consumers endogenously choose whether to become workers, consumers or entrepreneurs in order to analyze how limits on the leverage of banks affect real output. In our model tighter limits on the leverage of banks cause an increase in the spread between the interest rate that banks charge for loans and the interest rate that banks pay for deposits. A higher spread results in two types of distortions: First, firms with the same productivity will have different size. Second, productive firms will cease to exist, while nonproductive ones will enter. These distortions result in lower production.In the second essay, Enoch Hill and I develop a general equilibrium model of theft, private security and public law enforcement (PLE) which matches both macro and micro empirical evidence. We find a non-monotonic relation between PLE and aggregate production. In particular, for countries with relatively small amounts of PLE, increasing the level can result in a reduction of aggregate production and welfare primarily due to an increase in the incarceration rate. However, for countries with higher levels of PLE, an increase in the level improves production and welfare. We also find the private security causes a negative externality in economies with low levels of PLE.In the third essay, Enoch Hill, Michael Maio and I propose an original model of firm hierarchy which suggests that firm structure is important for understanding the wage structure. In our model, more productive firms choose to employ more levels of management, which requires a higher average level of skill in workers and consequently a higher average skill premium. This is consistent with what we document in the Chilean data and also agrees with the firm size to skill premium relationship commonly documented in the literature. Additionally, our model predicts that skill premium is increasing in the ratio of workers to managers, a fact we also observe in the Chilean data