5257 research outputs found
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Application of real options in decision-making in power markets [Aplicación de las opciones reales en la toma de decisiones en los mercados de electricidad]
No full textStrategic investment decisions in power markets are subject to high risk and uncertainty, therefore Real Options appear to be an appropriate tool to assess the decision-making processes in such markets. This paper presents a literature review, analyzing and classifying Real Options applications in power markets on investments and operation decisions; energy policy and programs. A synthetic application model is presented using binomial models to introduce wind power instead of coal fired plants according coal prices volatility. Finally it is concluded that Real Options improves the decision-making processes better than traditional methods, as it better captures the uncertainties of this kind of market. © 2013 Universidad ICESI. Published by Elsevier Espanã, S.L.U. All rights reserved
Implementation of a GIS-based pilot application for roads management applied to the conservation and maintenance of unpaved low traffic roads
No full text"The lack of updating and unreliability of information has become one of the main problems that occur in the area of management of unpaved roads in developing countries as Colombia. Therefore, a GIS-based application was developed which allows keeping updated all the information at the structural and functional level of the road, and to control the premature pavement deterioration favouring the support for making decisions in management activities of the unpaved road network. In the municipality of Urrao (Antioquia), a research proposal on ""La Encarnación"" road was proposed. The Road Trial Section (RTS) is part of a bidirectional 3rd level road, which has 240 m-length and a 4 m-width. The RTS was divided into eight segments or cells (30 m-length), where each of them was stabilized with different conventional and unconventional materials (cement, hydrated lime, coal ash, brick dust, sulfonated oil, polymer and sugarcane sludge). Based on the results gathered in six pavement performance follow-up and evaluation campaigns, a geospatial database (GDB) was designed. This GDB is the core of the application ""SGVVT Urrao v1.0"" which is able to represent graphically the behaviour of the tests of functionality and the bearing capacity carried out (International Roughness Index, slip resistance, surface macro texture, lightweight deflectometer and visual inspection). The application is able to forecast the deterioration values allowing the prioritization of rehabilitation activities for the most affected sections in a given time period which is possible to extend the useful life of the roads, reduce the operation cost of the vehicles, and guarantee the road safety and the comfort of the unpaved road network users. © Published under licence by IOP Publishing Ltd.
Laboratories of social innovation, as a strategy for the strengthening of citizen participation [Laboratorios de innovación social, como estrategia para el fortalecimiento de la participación ciudadana]
No full textThe present article approaches elements of the design of a laboratory of social innovation from the Faculty of Social Sciences of the Greater School of Antioquia in the city of Medellin-Colombia, with the purpose of generating a space that promotes the cocreacion to solve social problems, by means of the application of innovation and technology processes for social appropriation, which allows connecting, more and more, the university with the community, where the strategies of university practices, extension and social projection, and civil society converge. The focus of the research is qualitative and contemplates a phenomenological design with interview techniques with alternative didactic approaches such as Participation Action Research. As a result, the most representative elements of the bibliographic review carried out on the social innovation laboratory are presented, as well as the interviews and panels with experts carried out, which show the importance that these spaces take in the development of the communities, starting from Public efforts calling them citizen laboratories or public innovation, promoting the strengthening of collaboration networks between different agents of society. It concludes with the importance of initiating the pilot test in a Higher Education Institution. © 2019 Universidad del Zulia
Identifying molecularly defined antigens for a Histoplasma capsulatum-specific interferon gamma release assay [Identificación de antígenos definidos molecularmente para un ensayo de liberación de interferón-gamma específico para Histoplasma capsulatum]
No full textBackground: In a previous work we showed the feasibility of an interferon gamma release assay (IGRA) for detecting latent infection by Histoplasma capsulatum. While in that proof-of-concept study we used crude fungal extracts as antigens, the newest IGRAs developed for other infections are based on molecularly defined antigens, mostly on mixtures of immunogenic peptides. Aims: To identify proteins in H. capsulatum that might serve as molecularly defined antigens for an IGRA test. Methods: We surveyed the literature looking for known H. capsulatum-immunogenic proteins and assayed two of them as antigens in an IGRA test, in a study that involved 80 volunteers. Furthermore, we used several bioinformatics tools to identify specific H. capsulatum proteins and to analyze possible strategies for the design of H. capsulatum-specific immunogenic peptides. Results: Seven H. capsulatum-immunogenic proteins were retrieved from the literature. IGRA tests using either the heat shock protein 60 or the M antigen showed high sensitivities but low specificities, most likely due to the high sequence similarity with the corresponding orthologs in other pathogenic microorganisms. We identified around 2000 H. capsulatum-specific proteins, most of which remain unannotated. Class II T-cell epitope predictions for a small number of these proteins showed a great variability among different alleles, prompting for a brute force approach for peptide design. Conclusions: The H. capsulatum genome encodes a large number of distinctive proteins, which represent a valuable source of potential specific antigens for an IGRA test. Among them, the Cfp4 protein stands out as a very attractive candidate. © 2019 Asociación Española de Micologí
Experimental and computational data set on adsorption of Cr (VI) from water using an activated carbon
No full textChromium (Cr) is a widely used metal in metallurgical and chemical industries, whose waste contaminates the surface and groundwater. Cr (VI) is toxic and produces carcinogenic effects owing to its high mobility in water and soil. In this work, computational and experimental studies from the adsorption of Cr(VI) from aqueous solutions on teak wood residues activated with ZnCl2 (AT) are presented. Full interpretation of data can be found in DOI:10.1016/j.jece.2020.103702 [1]. Experimental data were adjusted to Langmuir, Freundlich and Temkin isothermal models and the nonlinear and linear forms of the Pseudo-first and Pseudo-second order kinetic models. Computational data allow to understand the adsorption process of Cr(VI) on carbonaceous materials. © 2020 The Author(s
Probing the origin of ultra-high-energy cosmic rays with neutrinos in the EeV energy range using the Pierre Auger Observatory
No full textInfluence of Lifestyle and Cultural Traits on the Willingness to Telework: A Case Study in the Aburrá Valley, Medellín, Colombia
No full textTelework is a decentralized work arrangement. Although it is a widely studied topic, there still is no single definition of telework . The empirical verification of research in this area remains a pending subject. In this context, our work determines the influence of lifestyle and cultural traits on the preparedness or willingness to telework in Medellín, Colombia. Accordingly, we start by reviewing the available literature. We propose a conceptual model, which subsequently is verified at an empirical level, applying a sequential mixed methodology. In a first phase of this empirical verification, several in-depth interviews with teleworkers and their supervisors or superiors are analysed, using a qualitative approach. Then, in a second phase and based on the previous stage, we verify the incidence of two of the emerging categories with respect to the preparedness for telework. These two categories are lifestyle and cultural traits. The verification process is carried out based on structural equations. The obtained results show that cultural traits have a more significant impact than lifestyle when it comes to determining the willingness to telework. Based on these results, we recommend future telework research in the following areas: background analysis, software and hardware requirements and the effects of telework. © 2020 International Management Institute, New Delhi
Effect of Acute Physical Exercise on Executive Functions and Emotional Recognition: Analysis of Moderate to High Intensity in Young Adults
No full textPhysical exercise (PE) is associated with cognitive changes and brain function. However, it is required to clarify the effect of PE in different intensities, population groups conditions and the EF duration over different cognitive domains. Besides, no studies are known to have evaluated the contextual emotional recognition. Therefore, we studied the effect of acute PE of moderate intensities up to higher ones to the executive functions and the contextual emotional recognition. The participants were evaluated and classified in two experiments according to the IPAQ short form self-report and control measures. In both experiments, the groups were randomized, controlled, and exposed to one session of indoor cycling through intervals of high measure intensity (75 85% HRmax). Experiment 1 comprised young adults who were physically active (PA) and healthy, apparently (n = 54, Mage = 20.7, SD = 2.5). Experiment 2 involved young adults who were physically inactive (IP) and healthy, apparently (n = 36, Mage = 21.6, SD = 1.8). The duration was the only factor that varied: 45 min for PA and 30 min for PI. The executive functions were evaluated by the Stroop, TMT A/B, and verbal fluency, and the emotional recognition through a task that includes body and facial emotions in context, simultaneously. The analysis of factorial mixed ANOVA showed effects on the right choices of the indoor cycling groups in the PA, and the time response in PI. Also, other effects were observed in the controlled groups. TMT-A/B measures showed changes in the pre-test post-test measures for both experiments. Verbal fluency performance favored the control group in both experiments. Meanwhile, the emotional recognition showed an effect of the PE in error-reduction and enhanced the scores in the right choices of body emotions. These results suggest that the EF with intensities favored cognitive processes such as inhibitory control and emotional recognition in context. We took into account the importance of high-complexity tasks design that avoid a ceiling effect. This study is the first on reporting a positive effect of PE over the emotional contextual recognition. Important clinical and educational implications are presented implications which highlight the modulatory role of EF with moderate to high intensities. © Copyright © 2019 Aguirre-Loaiza, Arenas, Arias, Franco-Jímenez, Barbosa-Granados, Ramos-Bermúdez, Ayala-Zuluaga, Núñez and García-Mas
Effect of lattice deformation on electronic and optical properties of CuGaSe2: Ab-initio calculations
No full textIn this study, we have investigated the effect of bi-axial, ?ab, and uni-axial, ?c, strains on the optoelectronic properties of chalcopyrite semiconductor CuGaSe2 through first-principles full potential linearized augmented plane wave method. These materials have recently attracted much interest within the materials science community. The results are obtained in the framework of Density Functional Theory (DFT), using the Generalized Gradient Approximation based on the minimization of total energy, together with the modified Becke-Johnson exchange-correlation potential, as implemented in the WIEN2k code. Our results show that unstrained CuGaSe2 is a direct band gap semiconductor with a energy of 1.16 eV, thus improving the results of some previous DFT calculations, but still below the accepted experimental data. The incorporation of biaxial and uniaxial strain results in a monotonous decreasing behavior of the energy band gap when both ?ab and ?c change between -8% and +8%, with unstrained value being, approximately, at the middle of the variation range. It is also found that strain causes modifications in the index of refraction of the material, with modifications of its static value that rank above 10% over the entire range of deformations considered. © 2019 Elsevier B.V
Grain Size Reduction Effect on Structural and Magnetic Properties in La1-xSrxMnO3 (x = 0.3 y 0.4) by Mechanical Ball Milling
No full textWe have investigated the magnetic, structural and morphological properties of ferromagnetic phases of manganite La1-xSrxMnO3 with x = 0.3 (LSMO-30) and x = 0.4 (LSMO-40) prepared by solid state reaction method, and then subjected to mechanical ball milling at different times of 3, 6 and 12 h. All of the samples were characterized by X-ray diffraction (XRD) and magnetic measurements. From Rietveld analysis of XRD patterns it was found a reduction in crystallite average size (Dv) with increasing milling time, for both concentrations. For LSMO-30 sample a mix of two different crystallographic structures, an orthorhombic phase (Pnma), and another rhombohedral (R3C) were identified at 3 and 6 h, but for 12 h of milling the R3C structure was the only phase identified. In contrast, for LSMO-40 the R3C structure was discerned as the unique phase independent of milling time. For both samples, a low value of the saturation magnetization was obtained for the longer milling time (smaller Dv). This behaviour was attributed to surface effects that induce magnetically disordered states with decreasing of particle size. This magnetic anisotropy surface was also evidenced on Zeta potential values and the changes of coercive fields, which increased most drastically with the first hours of mechanical ball milling time. © Published under licence by IOP Publishing Ltd