Trade Liberalization and Industry Dynamics: A Difference in Difference Approach

Recent models of trade with firm heterogeneity predict that opening to trade reduces the number of firms, increases the average size of firms, and decreases firms’ markups. This paper uses a large dataset for 28 manufacturing industries and 46 countries to test these predictions. The econometric analysis based on the treatment effects literature shows that on average, trade liberalizations do not decrease the number of firms nor increase the average size of firms. Markups appear to decrease during the three years after the liberalization. We also find that the number of firms and the average size of firms increase in comparative advantage industries.

Skill Upgrading and the Real Exchange Rate

This paper examines the effect of changes in the real exchange rate on skill upgrading in the case of Chile. Using plant-level data from the manufacturing sector we find that a real depreciation increases the share of skilled workers in the total wage bill in exporters but not in non-exporters. This result suggests that depreciations or, more generally, increases in export profitability, may induce exporters to adopt more skilled-intensive technologies. This finding gives support to recent models of trade that highlight the possible effect of the real exchange rate on skill upgrading and wage inequality. This paper also finds that real depreciations increase plants’ export intensity, suggesting that skill upgrading for already exporters is the channel through which real exchange depreciations affect wage inequality.

Is Previous Exporting Experience Relevant for New Exports?

Recent models of international trade show that trade costs are important determinants of exporting decisions and productivity dynamics. By assuming that these costs are exogenous and constant across firms, these theories do not take into account that experienced firms may have lower trading costs or that new exporters may reduce these costs by observing the decisions of other exporters. This study argues that firms with previous experience exporting a product to a particular market are more likely to start exporting the same product to another market, or a different product to the same market. The paper also contends that the previous experience of other exporters can significantly influence a firm’s decision to introduce a new product to a new market. Using a firm-level dataset from Chile with information on exports by product and destination market, the paper finds that an increase in the cumulative value exported by a firm increases the probability that the firm will export a previously exported product to a different market or a different product to a market to which the firm already exported a product. The results also show that an increase in the cumulative value exported of a product, or to a foreign market, by other exporters raises the probability that firms will export new products and/or to new markets. Our findings are consistent with the idea that previous exporting experience may help reduce the firm’s entry costs to international markets. The rich dataset used in this study allows the identification of these effects controlling for various time-varying observed and unobserved characteristics which may create a spurious correlation between firms’ export decisions, their previous exporting experience, and the export activity of other exporters

Exchange Rate Volatility and Export Margins.

This paper examines the effect of real exchange rate volatility on the intensive margin and the extensive margin of exports. Using highly disaggregated U.S. import data by product and country of origin, and a methodology that takes into account the possible endogeneity of volatility to trade, this paper finds that exchange rate volatility hinders trade by reducing the number of goods exported by countries. This result suggests that exchange rate volatility can make countries more dependent on a narrower set of export goods, particularly in developing economies with export concentration. Policy makers should take this effect into account when deciding their exchange rate regimes.

Protocols for Microcontrollers Networks

The microcontrollers are embedded in our way of life and are found in many devices. The ability of Very High Scale Integration (VLSI) - with almost exponential growth in recent years makes these devices every day contain functions previously unthinkable. Therefore, a grouping of these networked devices creates a very powerful system, which equipped with a standard protocol that allows interconnection to the Internet gives you a virtually unlimited range of scalability. For these reasons, this thesis studied the implementation of a network of microcontrollers, defining functions equivalent to those with Supervisory Control and Data Acquisition (SCADA) of great scale. Based on the definition we have, we studied among others, the protocols of communications layers to reach two of the most popular implementations used in industrial environments: Rs485 and Ethernet. While the former is much older, it remains still active and has been promoted from creating compatible interfaces, due to Rs485’s high immunity to electrical noise that provides a transparent interface over fiber. The second, more modern, already have set a trend because of its ubiquity and extent of benefits.Resumen de la tesis del autor para acceder al título de Magister en Redes de Datos (UNLP, 2010)Es revisión de: http://sedici.unlp.edu.ar/handle/10915/4177Facultad de Informátic

Protocols for Microcontrollers Networks

The microcontrollers are embedded in our way of life and are found in many devices. The ability of Very High Scale Integration (VLSI) - with almost exponential growth in recent years makes these devices every day contain functions previously unthinkable. Therefore, a grouping of these networked devices creates a very powerful system, which equipped with a standard protocol that allows interconnection to the Internet gives you a virtually unlimited range of scalability. For these reasons, this thesis studied the implementation of a network of microcontrollers, defining functions equivalent to those with Supervisory Control and Data Acquisition (SCADA) of great scale. Based on the definition we have, we studied among others, the protocols of communications layers to reach two of the most popular implementations used in industrial environments: Rs485 and Ethernet. While the former is much older, it remains still active and has been promoted from creating compatible interfaces, due to Rs485’s high immunity to electrical noise that provides a transparent interface over fiber. The second, more modern, already have set a trend because of its ubiquity and extent of benefits.Resumen de la tesis del autor para acceder al título de Magister en Redes de Datos (UNLP, 2010)Es revisión de: http://sedici.unlp.edu.ar/handle/10915/4177Facultad de Informátic

Redes de microcontroladores: definición, evaluación y perspectivas de un sistema distribuido

Este proyecto se enfoca directamente en la definición, implementación y utilización de una red de microcontroladores con fines docentes y de investigación. Los temas más básicos relacionados con las redes, sean de microcontroladores o de sistemas de cómputo en general, se orientarán hacia el contexto de docencia. En este sentido, los microcontroladores pueden considerarse una de las mejores alternativas en cuanto a costo y sencillez en el contexto del proceso de enseñanza tanto de conceptos de hardware de procesamiento como de interconexión de sistemas distribuidos. Los temas más avanzados de redes se pueden orientar a la docencia en cursos avanzados o de postgrado y también se pueden utilizar para investigar algunos detalles importantes de la implementación y utilización en las redes de microcontroladores. Un ejemplo de estos temas es el estudio al menos en términos de experimentación de la relación costo/beneficio de diferentes algoritmos de control de errores de comunicación con unidades de procesamiento tan sencillas y de bajo rendimiento y capacidad de almacenamiento como los microcontroladores. Desde una perspectiva más general, contando con una red de microcontroladores siempre es posible definir y avanzar en líneas de investigación más relacionadas con los sistemas distribuidos en general, en temas tales como la respuesta a eventos complejos con múltiples puntos de adquisición de datos, por ejemplo en un sistema de tipo SCADA (Supervisory Control and Data Acquisition).Eje: Arquitectura, Redes y Sistemas Operativo

Ambiente de desarrollo y puesta en marcha de sistemas basados en microcontroladores

Este proyecto tiene como objetivo llevar a cabo una definición y una implementación de referencia (también llamada “proof of concept”) de un entorno de desarrollo que involucra múltiples microcontroladores interconectados en red. El sistema debería ser capaz de adquirir y enviar datos/señales desde el exterior (con marcas de tiempo como para establecer un orden), ser controlado desde una PC como en un sistema de tipo SCADA (Supervisory Control and Data Acquisition) y mantener una base de datos accesible al menos para consulta vía un servidor web. En términos generales, este proyecto se orienta a establecer los lineamientos generales para contar con un sistema de desarrollo sobre una red de microcontroladores de bajo costo, documentando y normalizando técnicas y módulos de hardware y software. Además, la implementación de referencia del entorno de desarrollo no solamente se utilizará para verificar la propuesta, sino que también quedará a disposición de cátedras y/o de investigación de la Facultad de Ingeniería de la UNPSJB, como para el desarrollo de sistemas de control a ser aplicados en producción. Posteriormente, se podrá evaluar la posibilidad de distribuir esta implementación de referencia con licencia de software libre, por ejemplo.Eje: Agentes, Redes y Sistemas Operativo

Artroplastia total de cadera no cementada : resultados a corto plazo con los componentes femorales de los modelos poro-palcar y PCA

Se presentan los resultados clínicos y radiológicos, a corto plazo, referentes al componente femoral de una serie de 62 artroplastias totales de cadera no cementadas. Treinta y tres correspondían al modelo PORO-PALCAR y 29 al modelo PCA. La edad media de los pacientes fue de 62 años (ds = 9,6). El tiempo medio de seguimiento postoperatorio ha sido 2 años (1,5-3). En la valoración clínica se ha utilizado el Test de Harris. La puntuación final total alcanzó 88,7 puntos (ds = 6,9) para el modelo PCA y 83,5 puntos (ds = 13,2) para el POROPALCAR. Los resultados clínicos fueron excelentes (80 a 100 puntos) en el 93 % de los implantes PCA y en el 67% PORO-PALCAR (p<0,01), con una remisión completa del dolor en más del 90% de los casos para ambos modelos. La mejoría funcional fue significativamente mayor para el modelo PCA. En cuanto a los resultados radiológicos, el modelo PORO-PALCAR presentó un hundimiento medio de 1,73 mm (p < 0,05). El 80% de los vástagos PCA y el 48% de los PORO-PALCAR no presentaban líneas radiolucientes en las zonas porosas (p<0,01). En las zonas inferiores, en más del 75% de los modelos PORO-PALCAR aparecieron líneas de hasta 2 mm de espesor y en el 21,2% líneas mayores de 2 mm en el vértice del vástago. Dos vástagos del modelo PORO-PALCAR presentaron signos de aflojamiento aséptico. Por lo tanto, el componente femoral del modelo PCA presentó una mejor fijación y osteointegración que el modelo PORO-PALCAR.The clinical and roentgenographic short-term results regarding femoral component of 62 non cemented total hip arthroplasties were evaluated. In 33 cases PORO-PALCAR model were implanted and in 29 cases PCA model were implanted. The average age of patients was 62 years (sd = 9,6). The average follow-up was 2 years, ranging from 1,5 to 3 years. Clinical assesment was performed using the Harris' score. The total end score reached 88,7 points (sd = 6,9) for the PCA model and 83,5 points (sd = 13,2) for the PORO-PALCAR model. Excellent clinical results (80 to 100 points) were found in 93 % of the patients with PCA model and in 67% of those with the PORO-PALCAR model (p<0,01). Pain was removed in more than 90% of the cases independently of the femoral model implanted. As for radiologic results, PORO-PALCAR model presented an average vertical subsidence of 1,73 mm (p<0,05). Radiolucent lines were not detected in 80% of PCA models and in 48% of PORO-PALCAR models around porous-surfaced (p < 0,01). In more of 75% of PORO-PALCAR models were observed radiolucent lines untill 2 mm of density in lower zones, and in 21% of cases radiolucent lines was greater than 2 mm around of stem apex. Two cases of PORO-PALCAR stem presented sings of aseptic loosening. Fixation and osteointegration seems to be better for the femoral component of PCA model than for the PORO-PALCAR stem

Componentes acetabulares no cementados: resultados preliminares con los modelos PCA y Poro-palcar

Se comparan los resultados clínicos y radiológicos a corto plazo referente s al component e acetabula r de 62 artroplastia s totale s de cader a no cementadas. Treinta y tres implante s correspondían al modelo Poro-palcar y 29 al modelo PCA. La edad media en el momento de la intervención fue de 62 años (ds=9.6). El tiempo medio de seguimient o postoperatorio fue de un año y siet e mese s (máximo 3 años y mínimo un año). Para la valoración clínica se utiliza el test de Harris. La puntuación final total alcanza 88.7 puntos (ds=6.9) para el modelo PCA y 83.5 puntos (ds=13.2) para el poropalear. Los resultados clínicos fueron excelente s (80-100 puntos) en el 93% de los implante s PCA y en el 67% poro-palear (p<0.01), con una remisión completa del dolor en más del 90% de los casos para ambos modelos. La mejoría de la capacidad funcional fue significativament e mayo r en los enfermo s intervenido s con e l model o PCA. En cuanto a los resultados radiológicos, no hubo signos significativos de migración acetabular en ninguno de los modelos. Respecto a la aparición de radiolucencias, no se detectaron en el 72% de las copas PCA y en 60% de las copas poro-palear, presentando el resto radiolucencias de hasta 2 mm, lo cual indica una mejor osteointegración de las copas PCA respecto de las poro-palear.The clinical and roentgenographi c short-term results regarding the acetabular component wer e aveluated in a series of 62 noncemented total hip arthroplastie s in whic h eithe r the PCA cup (29 cases) or the poro-palcar mode l (33 cases) wer e implanted. At the time of surgery, the mean age of patients wa s 62 year s (ds=9.6). The average follow-up wa s 1 year and 7 months, ranging from 1 to 3 years. Clinical assesment wa s performed usin g the Harris'score . At review, the total scor e reache d 88.7 points (ds=6.9) for the PCA model and 83.5 (ds+13.2) for the poro-palcar cup. Excellent clinical results (80-100points) wer e found in 93% of the patients operated on wich the PCA cup and in 67% of those with the poro-palcar model (p<0.01). Pain was removed in more than 90% of the case s independently of the cup model used. The improvement of function was significantly better in patients receiving the PCA cup. There was not acetabular migration in any of the groups. Periacetabular radiolucent images wer e not detected in 72% of PCA case s an in 60% of the poro-palcar group. In case s with radiolucent images, these don't exceded more than 2 mm. Osteointegration seens to be better for the PCA cups than for the poro-palcar models