BALANCE OF PAYMENTS CRISES UNDER FIXED EXCHANGE RATE IN COLOMBIA: 1938-1967

Between 1938 and 1967, including the Bretton Woods period after 1947, Colombia pegged its currency to the dollar. Although the exchange rate was fixed, the peso was devaluated more than 12% on six occasions. The devaluation episodes were complex, traumatic, highly politicized and had costly macroeconomic effects. The Bretton Woods agreement stated that countries could only devalue their exchange rate in the presence of fundamental imbalances driven, for example, by structural terms of trade deterioration. However, this paper states that in Colombia, the imbalance in the money market was a key factor in explaining the exchange rate crises during the period. The paper is organized as follows: first, a simple theoretical model of a small open economy with imperfect capital mobility is described in order to examine the possible causes of nominal devaluations; second, a narrative approach is used to describe the economic circumstances that surrounded each of the devaluation episodes; finally, a set of econometric tests are used in order to identify the key variables behind the macroeconomic imbalances that preceded each exchange rate crisis. The results show that the external imbalances were mainly associated with the imbalances in the money market. Terms of trade deterioration account for just a small part of current account crisesBretton Woods, Devaluation, Fixed Exchange Rate Regime, Monetary Policy

A beyond mean field study of Bose gases in a double-well potential with a Feshbach resonance

The Bose-Hubbard model coupled to a Feshbach resonance is studied. Quantum phase transitions are analyzed within a beyond mean field framework in order to get finite size corrections to the simple mean field approach. Analytical results for the ground state energy and the first few energy gaps are presented

El sabor agridulce de los grupos de trabajo.

This article analyses a type of organisation in the workplace known as "teamwork" or "working groups". The interest in analysing these groups lies in that, in the opinion of the author, they are a turning point, an open situation that can be implemented either with competitive instrumentalisation or democratically, based on the fundaments of solidarity. The complexity of working groups leads the author to take up issues such as the ample leeway for self-organisation and co-operation at work, allowing for participation and creativity, thereby increasing democracy within companies. By analysing working groups that actually exist, one can deduce that in their majority, these groups operative in a competitive, instrumental framework and often suffer due to a lack of resources and time, to inadequate qualifications and to limited participation. Finally, the article considers working group management in the current context of both national and international competition.La presente contribución analiza un tipo de forma organizativa como es el "trabajo en equipo" o los "grupos de trabajo". El interés de su análisis radica en que se trata para el autor de un cruce de caminos, de una situación abierta que puede resolverse o bien de una forma (la instrumental-competitiva) o bien de otra (la democráticasolidaria). Tal complejidad de los grupos de trabajo lleva a considerar sus amplios márgenes de autoorganización y de cooperación en el trabajo, que posibilitan espacios de participación y de creatividad, ampliando así el espacio de democracia en la empresa. Del análisis de la realidad de los grupos de trabajo realmente existentes se deduce que mayoritariamente se decantan hacia una gestión competitiva-instrumental, destacando algunas limitaciones como la falta de medios, la falta de tiempo, la carencia de cualificaciones, y las limitaciones a la participación. Finalmente en el artículo se considera la gestión realizada a través de grupos de trabajo en el contexto actual de la competitividad nacional e internacional

Thermochemical conversion of biomass in a Swirling Fluidized Bed: a design procedure and numerical simulation

Process intensification of biomass conversion as a route to a low-carbon manufacturing industry pursues novel solutions able to achieve safe, cost-efficient, energy-efficient, and environment-friendly processes. Implementation of process intensification in gas-solid operations enhances mass, heat, and momentum transfer rates, while develops multifunctional equipment to increase production capacity per size of installation. The Swirling Fluidized Bed reactor is a gas-solid contacting device that replaces the Earth's gravitational field with a centrifugal field generating a centrifugal bed that achieves more uniform beds, higher transfer rates, and shorter processing times than conventional fluidized beds. However, there is a gap of research in two points: a binary-phase numerical simulation to study both gas and solid hydrodynamics, and the constructive design of the swirling fluidized bed reactor related to expected operating conditions. In the present work, a design procedure of swirling fluidized beds for thermochemical conversion of biomass is proposed. The study of the swirling fluidized bed reactor comprises three stages: a systematic literature review, a numerical simulation of the reactor, and the development of the design procedure. The simulation gives insight of the SFB reactor operation useful for the decision making during early stages of design. Thermochemical and mechanical models together with technical procedures are used for the reactor design. The proposed design shows good agreement with an operational reactor used for rice husk combustion.MaestríaMagister en Ingeniería Mecánic

Image processing techniques for plant phenotyping using RGB and thermal imagery = Técnicas de procesamiento de imágenes RGB y térmicas como herramienta para fenotipado de cultivos

[eng] World cereal stocks need to increase in order to meet growing demands. Currently, maize, rice, wheat, are the main crops worldwide, while other cereals such as barley, sorghum, oat or different millets are also well placed in the top list. Crop productivity is affected directly by climate change factors such as heat, drought, floods or storms. Researchers agree that global climate change is having a major impact on crop productivity. In that way, several studies have been focused on climate change scenarios and more specifically abiotic stresses in cereals. For instance, in the case of heat stress, high temperatures between anthesis to grain filling can decrease grain yield. In order to deal with the climate change and future environmental scenarios, plant breeding is one of the main alternatives breeding is even considered to contribute to the larger component of yield growth compared to management. Plant breeding programs are focused on identifying genotypes with high yields and quality to act as a parentals and further the best individuals among the segregating population thus develop new varieties of plants. Breeders use the phenotypic data, plant and crop performance, and genetic information to improve the yield by selection (GxE, with G and E indicating genetic and environmental factors). More factors must be taken into account to increase the yield, such as, for instance, the education of farmers, economic incentives and the use of new technologies (GxExM, with M indicating management). Plant phenotyping is related with the observable (or measurable) characteristics of the plant while the crop growing as well as the association between the plant genetic background and its response to the environment (GxE). In traditional phenotyping the measurements are collated manually, which is tedious, time consuming and prone to subjective errors. Nowadays the technology is involved in many applications. From the point of view of plan phenotyping, technology has been incorporated as a tool. The use of image processing techniques integrating sensors and algorithm processes, is therefore, an alternative to asses automatically (or semi-automatically) these traits. Images have become a useful tool for plant phenotyping because most frequently data from the sensors are processed and analyzed as an image in two (2D) or three (3D) dimensions. An image is the arrangement of pixels in a regular Cartesian coordinates as a matrix, each pixel has a numerical value into the matrix which represents the number of photons captured by the sensor within the exposition time. Therefore, an image is the optical representation of the object illuminated by a radiating source. The main characteristics of images can be defined by the sensor spectral and spatial properties, with the spatial properties of the resulting image also heavily dependent on the sensor platform (which determines the distance from the target object).[spa] Las existencias mundiales de cereales deben aumentar para satisfacer la creciente demanda. Actualmente, el maíz, el arroz y el trigo son los principales cultivos a nivel mundial, otros cereales como la cebada, el sorgo y la avena están también bien ubicados en la lista. La productividad de los cultivos se ve afectada directamente por factores del cambio climático como el calor, la sequía, las inundaciones o las tormentas. Los investigadores coinciden en que el cambio climático global está teniendo un gran impacto en la productividad de los cultivos. Es por esto que muchos estudios se han centrado en escenarios de cambio climático y más específicamente en estrés abiótico. Por ejemplo, en el caso de estrés por calor, las altas temperaturas entre antesis y llenado de grano pueden disminuir el rendimiento del grano. Para hacer frente al cambio climático y escenarios ambientales futuros, el mejoramiento de plantas es una de las principales alternativas; incluso se considera que las técnicas de mejoramiento contribuyen en mayor medida al aumento del rendimiento que el manejo del cultivo. Los programas de mejora se centran en identificar genotipos con altos rendimientos y calidad para actuar como progenitores y promover los mejores individuos para desarrollar nuevas variedades de plantas. Los mejoradores utilizan los datos fenotípicos, el desempeño de las plantas y los cultivos, y la información genética para mejorar el rendimiento mediante selección (GxE, donde G y E indican factores genéticos y ambientales). El fenotipado plantas está relacionado con las características observables (o medibles) de la planta mientras crece el cultivo, así como con la asociación entre el fondo genético de la planta y su respuesta al medio ambiente (GxE). En el fenotipado tradicional, las mediciones se clasifican manualmente, lo cual es tedioso, consume mucho tiempo y es propenso a errores subjetivos. Sin embargo, hoy en día la tecnología está involucrada en muchas aplicaciones. Desde el punto de vista del fenotipado de plantas, la tecnología se ha incorporado como una herramienta. El uso de técnicas de procesamiento de imágenes que integran sensores y algoritmos son por lo tanto una alternativa para evaluar automáticamente (o semiautomáticamente) estas características

Fabric defect detection using the wavelet transform in an ARM processor

Small devices used in our day life are constructed with powerful architectures that can be used for industrial applications when requiring portability and communication facilities. We present in this paper an example of the use of an embedded system, the Zeus epic 520 single board computer, for defect detection in textiles using image processing. We implement the Haar wavelet transform using the embedded visual C++ 4.0 compiler for Windows CE 5. The algorithm was tested for defect detection using images of fabrics with five types of defects. An average of 95% in terms of correct defect detection was obtained, achieving a similar performance than using processors with float point arithmetic calculations

Formación superior y formación para la investigación en ciencias básicas : enfoque de competencias y bases de una "concepción teórica situada"

Se presentan los avances en un proyecto de tesis doctoral cuyo objetivo final es elaborar una concepción teórica situada ("teoría local") que permita diseñar e implementar propuestas de intervención que favorezcan el desarrollo de la capacidad para Investigar en estudios de grado en la FCEN-UNCUYO. La ponencia aborda las premisas clave sobre las que se basa la construcción del marco de referencia y el relevamiento empírico realizado. La metodología incluye estrategias de investigación que incluyen la búsqueda y análisis crítico de la bibliografía, entrevistas, encuestas, interpretación de datos cuantitativos y cualitativos, y elaboración de esquemas y/o modelos. Los avances logrados en el desarrollo de la teoría local (situada) indican que el logro de la capacidad para investigar involucra el desarrollo articulado de 16 componentes.Fil: Rubau, Carina.Fil: Fernández Guillermet, Armando

COMPARATIVE STUDY OF LIBERALIZATION PROCESS OF PASSENGERS RAILWAY MARKET IN SPAIN AND ENGLAND

[EN] This article provides an overview of the privatization of railway passengers market in Spain through a background to the most relevant cases studies in Europe, particularly the liberalization process in England. The English case study is a paradigmatic example to assess how the liberalization process was developed and its effect in the present. This assessment has been undertaken to analyse the railway franchise structure, ticketing measures, role of national and regional authorities, etc. and possible analogies to be adapted to the case of Spain. Firstly, this article reviews the origin of the privatization of the railway market in both Spain and England, describing every phase of the liberalization and the success of every stage. Secondly, a critical approach assessment exposes those market failures of the liberalization process in England that caused negative impacts on society. In addition, the role of the Government is analysed to measure their implication in order to solve that situation. Furthermore, the paper expounds a wide analysis of the rail ticketing in England, its effects on increased passenger number. Finally, this article proposes some measures to be followed on the privatization of passenger rail market in Spain, as well as some key concepts to guarantee its success as taken from the case studies that have been reviewed.Fernández Morote, G.; Ortuño Padilla, A.; Fernández Aracil, P. (2016). COMPARATIVE STUDY OF LIBERALIZATION PROCESS OF PASSENGERS RAILWAY MARKET IN SPAIN AND ENGLAND. En XII Congreso de ingeniería del transporte. 7, 8 y 9 de Junio, Valencia (España). Editorial Universitat Politècnica de València. 553-560. https://doi.org/10.4995/CIT2016.2016.3522OCS55356

Width of the charge-transfer peak in the SU(N) impurity Anderson model and its relevance to nonequilibrium transport

We calculate the width 2ΔCT and intensity of the charge-transfer peak (the one lying at the on-site energy Ed) in the impurity spectral density of states as a function of Ed in the SU(N) impurity Anderson model (IAM). We use the dynamical density-matrix renormalization group (DDMRG) and the noncrossing approximation (NCA) for N=4 and a 1/N variational approximation in the general case. In particular, while for Ed Δ, where Δ is the resonant level half-width, ΔCT=Δ as expected in the noninteracting case, for Ed NΔ one has ΔCT=NΔ. In the N=2 case, some effects of the variation of ΔCT with Ed were observed in the conductance through a quantum dot connected asymmetrically to conducting leads at finite bias [J. Könemann, Phys. Rev. B 73, 033313 (2006)PRBMDO1098-012110.1103/PhysRevB.73.033313]. More dramatic effects are expected in similar experiments that can be carried out in systems of two quantum dots, carbon nanotubes or other, realizing the SU(4) IAM.Fil: Fernández, Joaquín. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; Argentina. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; ArgentinaFil: Lisandrini, Franco Thomas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Física de Rosario. Universidad Nacional de Rosario. Instituto de Física de Rosario; ArgentinaFil: Roura Bas, Pablo Gines. Comisión Nacional de Energía Atómica. Centro Atómico Constituyentes; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Gazza, Claudio Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Física de Rosario. Universidad Nacional de Rosario. Instituto de Física de Rosario; ArgentinaFil: Aligia, Armando Ángel. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; Argentin