Recent macroeconomic performance in colombia: what went wrong?

Al finalizar la d�cada anterior la actividad real en Colombia experiment� la m�s aguda recesi�n de los �ltimos 50 a�os. Para explicar este fen�meno, postulamos un modelo VAR estructural no-triangular que describe la din�mica de la producci�n, los precios, el desempleo y los salarios durante las �ltimas dos d�cadas. La evidencia sugiere que, en el largo plazo, la pol�tica monetaria ha sido neutral con respecto al producto y la desempleo, mientras que la principal raz�n para el incremento de �ste �ltimo se explica por la forma en que se han determinado los salarios (formaci�n de expectativas hacia atr�s) y el incremento de los costos no salariales.structural VAR, unemployment, monetary policy, wages, nonwage labour costs, expectations

De cómo la Administración podrá desarrollar una teoría que favorezca el bienestar

La administración como campo del conocimiento ha dedicado sus esfuerzos a producir teorías, métodos y técnicas que permiten desarrollar la racionalidad prevista por el sistema económico imperante, con lo cual ha contribuido al establecimiento de desigualdades inicuas y a la destrucción de la naturaleza.Resolver el problema de cómo administrar, ha llevado a encontrar soluciones y modelos que buscan la eficiencia en la relación costo-beneficio para satisfacción de los inversionistas privados, desconociendo sus impactos sociales y ecológicos.Las escuelas y los tratadistas que producen las teorías de la administración debería ocuparse de diseñar modelos organizacionales que incorporen al sistema económico nuevos conceptos y nuevas estructuras de costos que incluyan la cooperación y la ecología al lado del concepto de competencia.Administration, as a field of knowledge, has dedicated its efforts into producing theories. aproaches and techniques that open way to the development of rationality, foreseen by the ruling economical systems, with which it has contributed to the establishment of iniquitous inequalities and to the destruction of nature.Resolving the problem of how to administrate has led into finding solutions that seek effi-ciency in the cost-benefit relatinship for the satisfaction of private investors, failing to rec-ognize its social and ecological impacts.Schools and experts who produce theories of administration should occupy themselves in designing organizational models that would incorpórate new concepts and new structures of costs to the economical system, which in-clude cooperation and ecology along with the concept of competition

Impacto de la regulación en la eficiencia asignativa del mercado spot eléctrico colombiano

Este paper utilizando un modelo de regresión con estructura ARCH, analiza el efecto de la implementación de algunas medidas regulatorias y de variables fundamentales (relación entre la demanda comercial y la disponibilidad real, El Niño y los aportes hidrológicos) en el Mercado de Energía Mayorista en Colombia sobre el precio spot. Los resultados obtenidos evidencian que las regulaciones establecidas por la Comisión de Regulación de Energía y Gas, han impactado estadística y significativamente el precio spot. Además, El Niño y los aportes hidrológicos presentan un impacto positivo y negativo, respectivamente sobre el precio spot, debido a la gran participación hidráulica de este mercado.This paper uses an ARCH regression model to analyze the effect of several regulatory measures and fundamental factors (the relationship between commercial demand and real availability, El Niño, and water supplies) on the spot price in the Colombian wholesale power market. The results indicate that the regulations established by the Electricity and Gas Regulatory Commission have had a substantial and statistically-significant effect on spot prices. In addition, El Niño and hydro supplies have a positive and negative respectively effect on the spot price, due to the large share of hydropower in this market

Seismic Stability Analysis of a High Earth and Rockfill Dam

Accumulation of knowledge on earthquake activity in California has lead to stronger ground motions being postulated for the evaluation of the seismic stability of dams. A recent regional seismicity study for a 555 ft high earth and rockfill dam in central California lead to a ground motion with peak ground acceleration (PGA) of 0.50g originating in a local fault system 3 miles from the dam site. This PGA is more than 6 times higher than the PGA=0.08g value originally adopted when the Dam was analyzed for seismic stability 20 years ago. Thus, as part of FERC Part 12 evaluation requirements, the seismic stability of the Dam was re-evaluated using the updated ground motion and state-of-the-practice technology. This paper presents the analysis procedures and the results

Abundance and size of birds determine the position of the species in plant-frugivore interaction networks in fragmented forests

Abstract The relationships between frugivorous animals and plants are of vital importance particularly in tropical forests. The way species interact and how they are organized within interaction networks could be determined by their ecological and morphological characteristics. This study evaluates the hypothesis that the topological position of species within an interaction network is determined by their degree of frugivory, body size, and abundance. Thus, we constructed the frugivory network between birds and plants in a rainforest fragment in northwestern Colombia. The position of the species within the network was calculated based on three centrality measures (degree, betweenness, and closeness), and its association with relative abundance, degree of frugivory, and body size of each bird species was evaluated by means of a generalized linear model. We found that the species that were most abundant and had the smallest body size had central positions in the interaction network. This pattern is contrary to what has been observed in pristine forests, where species with large body size are more important for network stability. Our results suggest that forest fragmentation modifies the roles of species within the network structure, in part, due to changes in the makeup of the original frugivore community. The information presented may be useful to evaluate the effects of the loss of species as a result of anthropic actions, with the aim of generating ecosystem restoration strategies

Improvement and application of a methodology to perform the Global Energy Balance in internal combustion engines. Part 1: Global Energy Balance tool development and calibration

[EN] The increasingly stringent internal combustion engines emissions regulations, has led to the extended use of after-treatment systems, giving progressively more importance to the engine efficiency optimization. In this framework, the combined modelling and experimental methodologies to perform and analyse the energy balance are key to evaluate the potential of different engine strategies aimed at the consumption optimization and the identification of the improvement paths. This work has been divided into two parts, dealing separately with the development and application of a Global Energy Balance tool. This article corresponds to the first part, which comprises the description of the models required to perform a detailed energy balance and the calibration methodologies followed to achieve accurate energy terms estimation. The models are calibrated based on experimental information, thus, a thermodynamic analysis aimed at defining comparable quantities between experimental and modelled terms is performed. The uncertainty analysis of the tool shows a deviation in the determination of the heat transfer to the coolant and the oil of about ±2%, and in terms of fuel energy about ±1%.This work was partially funded by the Government of Spain through Project TRA2013-41348-R. In addition, the authors acknowledge that some equipment used in this work has been partially supported by FEDER project funds (FEDER-ICTS-2012-06), framed in the operational program of unique scientific and technical infrastructure of the Ministry of Science and Innovation of Spain.López, JJ.; Payri, F.; Martín, J.; Carreño-Arango, R. (2018). Improvement and application of a methodology to perform the Global Energy Balance in internal combustion engines. Part 1: Global Energy Balance tool development and calibration. Energy. 152:666-681. https://doi.org/10.1016/j.energy.2018.03.118S66668115

Caracterización sistemas de producción CRECED Guanentá Comunero

El departamento de Santander esta ubicado en el sector Noreste del país, formando parte de la región andina; su territorio (3'o53.70o hectáreas) se extiende por la vertiente occidental de la Cordillera Oriental

Establecimiento de leguminosas en praderas nativas en suelos de páramo.

Maestría en CienciasMaestrí

The function of the secondary lining in the New Austrian Tunnelling Method

The decision to build the Secondary Lining in Route Tunnels which are perforated using the New Austrian Tunnelling Method does not generally depend on reasons of structural strength. The paper discusses the implications of the issue as well as the pros and cons of the current alternative courses of action