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Search Results: 1 - 10 of 54603 matches for " JUAN FERNANDO REINOSO LASTRA "
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Aplicación de un ambiente virtual de aprendizaje orientado a la formación empresarial
Estudios Gerenciales , 2012,
Abstract: this proposal stems from two projects of the eco research team at the university of tolima titled "business training educational project geared to social groups outside universities and technical training centers" and "design and implementation of a virtual learning environment (vle) aimed at entrepreneurial training of university students". the learning objective is to orient an entrepreneur attitude (entrepreneurship) towards an enterprising attitude in a pedagogical way based on the use of information and communication technologies. the vle is called "from entrepreneurs to business people." in june of 2008, it was tested with 22 business administration students for the purpose of demonstrating that the vle facilitates the development of entrepreneurial and business competencies.
Aplicación de un ambiente virtual de aprendizaje orientado a la formación empresarial
Estudios Gerenciales , 2012,
Abstract: La propuesta nace de los proyectos del grupo de investigación E.C.O. de la Universidad del Tolima: "Proyecto educativo de formación empresarial dirigido a grupos sociales externos a las universidades y centros de formación técnica y tecnológica" y "Dise o y aplicación de un Ambiente Virtual de Aprendizaje (AVA) dirigido a la formación empresarial de estudiantes universitarios". El objetivo de aprendizaje es orientar pedagógicamente la actitud emprendedora (emprendimiento) a la actitud empresarial (empresarismo), apoyado en la aplicación de Tecnologías de Información y Comunicación. El AVA se titula "Del emprendimiento al empresarismo". En junio del 2008, es aplicado a 22 estudiantes universitarios en administración de empresas con el fin de probar el AVA para facilitar el desarrollo de competencias emprendedoras y empresariales.
Ambientes virtuales y formación empresarial
Reinoso Lastra,Juan Fernando; Martínez Cárdenas,Edgar Enrique;
Pensamiento & Gestión , 2010,
Abstract: the proposal for the design of a virtual learning environment (vle) was born as a result of: the educational experiences with university students in the "entrepreneurial spirit" and "entrepreneurial creativity" classes; the participation in the specialization on "education with information and communication technologies (icts) in the universidad autónoma de bucaramanga, unab, and finally, the intervention in the curricula reform at the universidad del tolima. the learning objective is to pedagogically lead the entrepreneurial attitude (entrepreneurship) to the business attitude (empresarismo). it is supported by the application of icts. in june 2008, it was applied to 22 university students in business administration with the aim of proving the vle, make adjustments to its processes and improve its presentation.
Ambientes virtuales y formación empresarial Virtual environments and entrepreneurial training
Juan Fernando Reinoso Lastra,Edgar Enrique Martínez Cárdenas
Pensamiento & Gestión , 2010,
Abstract: La propuesta pedagógica del dise o de un ambiente virtual de aprendizaje (AVA) nace como resultado de experiencias educativas en formación empresarial con estudiantes universitarios en cátedras de espíritu empresarial, creatividad empresarial, la participación en la especialización en educación con tecnologías de información y comunicación (TIC) de la Universidad Autónoma de Bucaramanga (UNAB) y, la intervención en los procesos de reforma curricular en la Universidad del Tolima. El objetivo de aprendizaje es orientar pedagógicamente la actitud emprendedora (emprendimiento) hacia la actitud empresarial (empresarismo), a través del apoyo que brinda la aplicación de las TIC. En junio del 2008 es aplicado a 22 estudiantes universitarios en Administración de Empresas, con el fin de probar el AVA, hacer ajustes en sus procesos y mejorar su presentación. The proposal for the design of a Virtual Learning Environment (VLE) was born as a result of: the educational experiences with university students in the "entrepreneurial spirit" and "entrepreneurial creativity" classes; the participation in the specialization on "education with Information and Communication Technologies (ICTs) in the Universidad Autónoma de Bucaramanga, UNAB, and finally, the intervention in the curricula reform at the Universidad del Tolima. The learning objective is to pedagogically lead the entrepreneurial attitude (entrepreneurship) to the business attitude (empresarismo). It is supported by the application of ICTs. In June 2008, it was applied to 22 university students in Business Administration with the aim of proving the VLE, make adjustments to its processes and improve its presentation.
Adsorption of Hydrogen in Graphene without Band Gap Opening at the Dirac Point
Juan Maria Garcia-Lastra
Physics , 2010, DOI: 10.1103/PhysRevB.82.235418
Abstract: The band gap of periodically-doped graphene with hydrogen is investigated. It is found through a tight-binding model (TB) that for certain periodicities, called here NGPs (non-gap periodicities), no gap is opened at the Dirac point. This result is confirmed by Density Functional Theory (DFT) calculations. DFT results show that a tiny gap is opened for NGPs due to exchange effects, not taken into account in the TB model. However, this tiny gap is one or two orders of magnitude smaller than the gap opened for other periodicities different from NGPs. This finding opens up a new path for band gap engineering experiments in graphene.
A Research of the Environmental and Social Effects of the Adoption of Biotechnological Practices for Soybean Cultivation in Argentina  [PDF]
Guido Fernando Botta, Alfredo Tolón-Becerra, Xavier Lastra-Bravo, Mario Cesar Tourn
American Journal of Plant Sciences (AJPS) , 2011, DOI: 10.4236/ajps.2011.23041
Abstract: In recent years, the excessive and unregulated implementation of biotechnological practices has placed a large number of farmers in a precarious position throughout our country. Here we review and we analyzed results produced in field experiments installed along the Argentinean Pampas to determine environmental and social effects of the adoption of biotechnology practices associated with direct sowing (DS) of soybean. The use of machinery for farm work, the perfection of handling techniques, the incorporation of improved seeds, and the use of fertilizers and pesticides together influenced a significant increase in the productivity of the land, manual labors and capital. Despite positive economic results of this agricultural renewal also brought about consequences that proved to be detrimental to producers. By the end of the 1980s numerous sectors were in states of crisis. The major findings of our research are: 1) exhaustion of resources; 2) erosion problems brought on by inappropriate land use and soil compaction by increased area under DS system; 3) loss of biodiversity in the ecosystem; 4) crisis among family-owned farms who cannot access to new improved technologies due to profitability, obsolete machinery and the impossibility of access to credit; 5) reduction in smaller farms; 6) increase in specialized production, which implies the subordination of farming production to the dynamic of capital and finally more direct relationships between the entities generating technology and primary productions. The results of our study on adoption of biotechnology practice associated to DS of soybean give the following results: 1) the deterioration of family income from farms reached 41% per hectare comparing the average values of the 1990s to the 1980s. Farms smaller than 190 hectares, therefore, ceased to be “competitive” in Buenos Aires State, it can be observed a reduction of 24.2% in the number of farms. This occurred due to a reduction of small and medium-scale farmers associated with the concentration of land into farming units of more than 500 hectares; 2) annual losses in rural work rise 17.043.000 $/year or US$ 4.260.750 or, from another point of view, 4.128 tractor drivers, 3.926 mechanics and 4.600 farm workers, with an overall 12.000 rural workers; 3) increase of subsoil compaction and soil erosion was found due to high axle load of machinery equipment which also caused a decrease in crop yields ranging between 9% and 38% of the total yield per hectare of soybean crop, affecting the producers.
A Comparison Of Liberation Determinations By Particle Area Percentage And Exposed Particle Perimeter Percentage In A Flotation Concentrator  [PDF]
R. Lastra
Journal of Minerals and Materials Characterization and Engineering (JMMCE) , 2002, DOI: 10.4236/jmmce.2002.11003
Abstract: To simplify programming, image analyzers commonly measure either linear intercepts or the areas of particles and grains to determine liberation based on polished section mounts. However, the concentration of minerals by flotation is based on reagents that interact with the exposed surfaces of the minerals. Thus, it is often perceived that image analyzers should measure the perimeter of the mineral of interest in the ore particles. A comparative liberation study of thirteen samples collected from a flotation plant processing a complex base metal sulfide ore showed that the liberation of the ore minerals determined by area measurements is very similar to the liberation determined by the exposed perimeters. The liberation determined by exposed perimeters is more appropriate only for those cases where the mineral texture is so complex that it is retained in the small particles generated in conventional grinding operations.
Radio Pet Therapy of Healthy Wistar Rats with 64CuCl2 Labeled to 64Cu(AcAc)2 Supported in Functionalized TiO2 Nanoparticles  [PDF]
Tessy López, Juan C. Manrique-Arias, Paola Ramírez, Pamela Larraza, Francisco Rodríguez Reinoso
Journal of Encapsulation and Adsorption Sciences (JEAS) , 2017, DOI: 10.4236/jeas.2017.73009
Abstract: In recent years Copper-64 in the chemical form of copper chloride ([64Cu]CuCl2) has been identified as a potential agent for PET imaging and radionuclide therapy. The aim of this research was to determine the biodistribution and the labeling of radio nanoparticle with 64CuCl2, the nanoparticles Cu(acac)2/F-TiO2 were mixed with 64CuCl2 (20-37 MBq), then the final solution was used to injected healthy Wistar rats to probe the absorption of nanoparticle inside tissue trough of the groups OH that are formed during the functionalization of the Cu(acac)2/F-TiO2. The “in vivo” evaluation after realize the images study in micro PET equipment, uptake of the radio-nanoparticle was observed in the digestive system in the healthy Wistar rats.
Orbital-free effective embedding potential at nuclear cusp
Juan Maria Garcia Lastra,Jakub W. Kaminski,Tomasz A. Wesolowski
Physics , 2008,
Abstract: A new approach to approximate the kinetic-energy-functional dependent component ($v_t[\rho_A,\rho_B](\vec{r})$) of the effective potential in one-electron equations for orbitals embedded in a frozen density environment (Eqs. 20-21 in [Wesolowski and Warshel, {\it J. Phys. Chem.} {\bf 97}, (1993) 8050]) is proposed. The exact limit for $v_t$ at $\rho_A\longrightarrow 0$ and $\int \rho_B d\vec{r}=2$ is enforced. The significance of this limit is analysed formally and numerically for model systems including a numerically solvable model and real cases where $\int \rho_B d\vec{r}=2$. A simple approximation to $v_t[\rho_A,\rho_B](\vec{r})$ is constructed which enforces the considered limit near nuclei in the environment. Numerical examples are provided to illustrate the numerical significance of the considered limit for real systems - intermolecular complexes comprising, non-polar, polar, charged constituents. Imposing the limit improves significantly the quality of the approximation to $v_t[\rho_A,\rho_B](\vec{r})$ for systems comprising charged components. For complexes comprising neutral molecules or atoms the improvement occurs as well but it is numerically insignificant.
Mineralogical Characterization of Sieved and Un-Sieved Samples  [PDF]
Rolando Lastra, William Petruk
Journal of Minerals and Materials Characterization and Engineering (JMMCE) , 2014, DOI: 10.4236/jmmce.2014.21007
Abstract: Mineralogical characterization applied to mineral processing is now widespread. The first step for a mineralogi- cal characterization study is usually size fractionation. Preparation of polished sections is done on size fractions to reduce complications in making representative cross sections of particles with large size differences. A sample is commonly fractionated into five or six size intervals. The drawback of this procedure is that it makes liberation studies more expensive, because one sample actually produces five or six sub-samples that need to be studied, i.e. one from each size interval. Thus to reduce cost of liberation studies, it would be desirable to study the un-sized sample. This paper provides a comparative liberation study of a set of samples both using size fractions and using the un-sized samples. The samples studied are the feed, the concentrate and the tails of a lead rougher flotation circuit. The results consistently show significant differences between the sized and the un-sized samples. Nevertheless, the results indicate that un-corrected liberation data from un-sized samples can be used for comparative studies that involve several related samples. Thus, it is possible to improve (or further understand) a concentrator circuit by using mineralogical data from un-sized samples around such circuit.
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