Theoretical study on the molecular mechanism of the [5 + 2] vs. [4 + 2] cyclization mediated by Lewis acid in the quinone system

[EN] The thermal and Lewis acid (LA) catalyzed cyclizations of quinone 1 involved in the synthesis of Colombiasin A and Elipsaterosin B have been theoretically studied using DFT methods at the B3LYP/6-311G(d,p) computational level. B3LYP calculations suggest that the formal endo [4 + 2] cycloadduct allowing the synthesis of Colombiasin A is preferentially formed under thermal conditions, while in the presence of the BF3 LA catalyst the formal [5 + 2] cycloadduct is seen, allowing the synthesis of Elipsaterosin B. The BF3 LA catalyst not only accelerates the nucleophilic attack on the C2 carbon of the quinone framework through a more polar C-C bond formation, but also provokes a different electron density rearrangement along the nucleophilic attack favoring the subsequent C-C bond formation at the C4 carbon with the formation of the formal [5 + 2] cycloadduct. ELF bonding analysis along these cyclizations indicates that the C-C single bond formation takes place in the range of 1.91-2.1 angstrom by C-to-C coupling of two pseudoradical centers. Along the formation of the first C2-C9 single bond, these pseudoradical centers appear at one of the most electrophilic and at one of the most nucleophilic centers of quinone 1, C2 and C9 carbons, respectively. Analysis of the Parr functions suggests that although the most favorable electrophilic/nucleophilic interaction is that involving the C2 carbon of quinone and the C12 carbon of the butadiene framework, the intramolecular nature of the cyclization prevents the corresponding reactive channel.This work was supported by the Post-Doctoral fellow FONDECYT Grant 3130359 and Project ICM-P10-003-F CILIS granted by Fondo de Innovacion para la Competitividad del Ministerio de Economia, Fomento y Turismo, Chile.Soto-Delgado, J.; Sáez-Cases, JA.; Tapia, RA.; Domingo, LR. (2013). Theoretical study on the molecular mechanism of the [5 + 2] vs. [4 + 2] cyclization mediated by Lewis acid in the quinone system. Organic and Biomolecular Chemistry. 11(48):8357-8365. https://doi.org/10.1039/c3ob41860jS83578365114

Planeamiento estratégico agregado de la macro región VII

El Plan Estratégico Agregado para la macro región siete, que está conformada por los departamentos de Ayacucho, Huancavelica e Ica, se ha realizado tomando en cuenta el modelo secuencial del Proceso Estratégico hecho por el Dr. Fernando D´Alessio, donde se plantean las estrategias que permitirán el crecimiento sostenible de los sectores económicos de la macro región, utilizando de manera eficiente los recursos naturales y planteando nuevas actividades económicas que permitirá el desarrollo socio-económico de su población, para ello se realizó un análisis de su situación actual, en la cual se determinó las fortalezas y debilidades así como sus oportunidades y amenazas. La macro región siete cuenta con las tres regiones naturales del país, lo que le otorga una ventaja comparativa con respecto a otras macro regiones y será explotada respetando la sostenibilidad de los recursos. Así, en el análisis elaborado, se está planteando el desarrollo del primer circuito turístico que integre a toda la macro región, para ello se incentivará el turismo vivencial y eco turismo, que permitirá a los pobladores de las zonas de influencia obtener ingresos por los servicios prestados a los visitantes. El Plan Estratégico de la macro región siete se basa en cuatro pilares fundamentales que permitirán su desarrollo y crecimiento, estos son: (a) la educación, su posición competitiva está ligeramente debajo del promedio nacional pero es muy factible de revertir a mediano plazo, (b) el turismo, para potenciarlo se mejoraran las redes viales de conexión, con la ayuda del sector privado, obras por impuestos, etc., (c) la agro exportación, que se potenciará con la reducción de costos logísticos, y (d) la utilización de energías renovables, para ello los objetivos de largo plazo planteados permitirán elevar la competitividad de la macro región siete convirtiéndola en el referente del paísThe Added Strategic Plan for the seven macro region, which is made up of the departments of Ayacucho, Huancavelica and Ica, has been made taking into account the sequential model of the Strategic Process by Dr. Fernando D'Alessio, where strategies arise that will enable sustainable growth of economic sectors of the macro region, efficiently using natural resources and raising new economic activities that will enable the socio-economic development of its people, to do an analysis of their current situation was conducted in which the strengths and weaknesses as well as its opportunities and threats was determined. The seven macro region has three natural regions of the country, which gives it a comparative advantage over other macro regions and will be exploited respecting the sustainability of resources. Thus, in the analysis prepared, it is considering the development of the first tourist circuit that integrates the entire macro region, for which the experiential tourism and ecotourism, which will allow the inhabitants of the areas of influence monetizing services will be encouraged provided to visitors. The Strategic Plan of the seven macro region is based on four pillars that allow development and growth, these are: (a) education, its competitive position is slightly below the national average but is very likely to reverse in the medium term, ( b) tourism, to enhance it road networks connecting improve, with the help of the private sector, tax works, etc., (c) agro export, which will be enhanced by reducing logistics costs, and (d) the use of renewable energies, for this long-term goals raised, will enable increase the competitiveness of the seven macro region making it the benchmark in the countryTesi

Examining the compatibility of collagen and a polythiophene derivative for the preparation of bioactive platforms

Fundamental characteristics of bioactive platforms based on biocomposites of poly(3,4-ethylenedioxythiophene) (PEDOT) and collagen, named P(EDOT:CLG), have been examined using an experimental–computational approach. The protein affects both the morphology and electrochemical activity of PEDOT. Specifically, P(EDOT:CLG) shows spherical-like nodules that have been attributed to the collagen rod aggregates organized in phases separated from that of PEDOT. This phase separation results in a reduction of the ability to exchange charge reversibly, even though collagen stabilizes the PEDOT matrix from electrochemical degradation. On the other hand, viability assays indicate that the bioactivity of P(EDOT:CLG) is significantly higher than that of PEDOT in terms of cellular adhesion and proliferation. Thus, the biocomposite promotes the formation of 3D biostructures formed by the superposition of cellular monolayers, mimicking the growth of biological tissues. In order to gain microscopic information about the formation of specific interactions between PEDOT and collagen molecules in the biocomposite, quantum mechanical calculations on complexes formed by their building blocks have been performed in different environments (i.e. vacuum, chloroform and aqueous solution). Results evidence the important role played by non-conventional C–HO hydrogen bonds, which is consistent with previous findings on complexes involving DNA and dopamine. The environment affects considerably the binding energy, which decreases with increasing polarity of the environment. However, in all environments the repeating units of PEDOT form stronger interactions with L-hydroxyproline than with L-proline. On the other hand, intermolecular interaction patterns predicted using implicit and explicit solvation models present a remarkable agreement and have been identified by visualizing the reduced electron density gradient.Peer ReviewedPostprint (published version

As demandas de aprendizado como chaves para o desenho de sequências de ensino e aprendizado que promovam a modelagem

In natural science classes, it is observed that teachers apply diagnostic evaluations, but the information obtained is not usually taken into account to adjust the planning of teaching. In this Bio-chronicle the learning demands were identified (Leach et al., 2000) in three groups of students regarding the modeling of: the effects of urbanism on an Andean forest ecosystem, the origin of life on Earth and air pollution. By comparing the social language of the students (in their Student Model-SM) and that of science (in theDisciplinary Model-DM) the nature (ontological, epistemological or of reasoning) of each demand emerged. The results suggest that once the learning demands and their nature have been identified, it is easier for the teacher to decide in which of the phases of the teaching and learning sequence they should be addressed to help students to model the phenomenon.En las clases de ciencias naturales se observa que los profesores aplican evaluaciones diagnósticas, pero la información obtenida no suele tenerse en cuenta para ajustar la planeación de la enseñanza. En esta Bio-crónica se identificaron las demandas de aprendizaje (Leach, et ál., 2000) en tres grupos de estudiantes respecto a la modelización de: los efectos del urbanismo sobre un ecosistema de bosque andino, el origen de la vida en la Tierra y la contaminación atmosférica. Al comparar el lenguaje social de los estudiantes (en su Modelo Estudiantil-ME) y el de la ciencia (en el Modelo Disciplinar-MD) emergió la naturaleza (ontológica, epistemológica o de razonamiento) de cada demanda. Los resultados sugieren que una vez identificadas las demandas de aprendizaje y su naturaleza, se facilita al profesor decidir en cuál de las fases de la secuencia de enseñanza y aprendizaje deberían atenderse para ayudar a los estudiantes a la modelización del fenómeno.Nas aulas de ciências naturais, observa-se que os professores aplicam avaliações diagnósticas, mas as informações obtidas geralmente não são levadas em consideração para ajustar o planejamento do ensino. Nesta Biocrônica, as demandas de aprendizado foram identificadas (Leach et al., 2000) em três grupos de estudantes quanto à modelagem de: os efeitos do urbanismo em um ecossistema florestal andino, a origem da vida na Terra e a poluição do ar. Ao comparar a linguagem social dos alunos (em seu Modelo de Estudante-ME) e esse da ciência (no Modelo Disciplinar-MD), surgiu a natureza (ontológica, epistemológica ou racional) de cada demanda. Os resultados sugerem que, uma vez identificadas as demandas de aprendizagem e sua natureza é mais fácil para o professor decidir em qual das fases da sequência de ensino e aprendizagem deve ser abordada para ajudar os alunos a modelar o fenômeno

LICENCIATURA DE INGENIERO AGRÓNOMO EN FLORICULTURA. PROYECTO CURRICULAR

La Facultad de Ciencias Agrícolas dependiente de la Universidad Autónoma del Estado de México en su calidad de fuente permanente de conocimientos e inmersa en un mundo cambiante y globalizador, tiene como compromiso formar profesionales en la Ciencias Agropecuarias, que impacten en el sector florícola del país y coadyuven a su transformación. Con fundamento en el Plan Rector, el Plan de Desarrollo de la Facultad y el Comité Mexicano de Acreditación de Educación Agronómica A.C el Curricular, integrado por profesores de la Facultad de Ciencias Agrícolas y el Centro Universitario UAEM Tenancingo, llevo a cabo la evaluación del programa educativo de Ingeniero Agrónomo en Floricultura a fin de valorar su diseño, instrumentación y operación, que derivó en una reestructuración del proyector curricular, con base en el Reglamento de Estudios Profesionales de esta Universidad. Así el programa educativo de Ingeniero Agrónomo en Floricultura forma profesionales con competencias para generar, innovar, aplicar y transmitir el conocimiento de la actividad florícola e impactar en el desarrollo del sector agrícola del país, mediante un proceso formativo integrador, actualizado y flexible, con pertinencia social, formación humanística y desarrollo sustentable

Diurnal and seasonal active layer and permafrost dynamics from boreholes of the Latin American permafrost network

Permafrost is present in the high-altitude mountains of the Trans-Mexican Volcanic Belt as well as the Andes, even in the extreme dry Atacama highland. The permafrost and active layer termal state are characterized at Latin American Permafrost Network study sites. Ice rich or extremely dry permafrost was observed during drilling operations from Mexico (Pico de Orizaba, 5636m a.s.l. Iztaccíhuatl, 5230m a.s.l.), Colombia, Ecuador (Chimborazo, 6263m a.s.l.), Peru (Coropuna 5250 m a.s.l., Ampato 5850 m a.s.l., Chachani 5600 m a.s.l.) including the highest human habitation in the world: La Rinconada 5100 m a.s.l., Bolivia (Chacaltaya 5300 m a.s.l. where glacier disappeared in 2005), and the Chilean/Argentinian border (up to 6750 m a.s.l. including Parinacota, Aucanquilcha, Ojos del Salado, Llullaillaco, Tupungato and Tupungatito). The Lower Limit of Alpine Permafrost (LLAP) is redrawn from this study between latitude 19˚N and 40˚S where it is mainly in the tropical and arid Andes. This is not a rock glacier monitoring program that not mapping sporadic permafrost, but continuous permafrost terrains for long term temperature monitoring and understanding for local hydrological problems such as glacier/snow melt runoff or sublimation rate of higher elevations. The maximum active layer is typically influenced by the diurnal fluctuations which is between 12-30 cm deep however, maximum 2m depth of the seasonal active layer was observed at Ojos del Salado near the LLAP (5200 m a.s.l.). Daily severe frost shattering occurs near the ground surface, producing a dusty, fine-material horizon at an active layer near the LLAP, however a few freeze-thaw actions are higher than 6400 m. The snow-covered periods are important for providing protection from strong tropic solar radiation

Postharvest storage of three chayote (Sechium edule (Jacq.) Sw.) varieties

The consumer demand for chayote (Sechium edule (Jacq.) Sw.) fruits has increased in recent years, virens levis being the most important variety, although other chayote varieties are gaining importance such as nigrum xalapensis and n. spinosum. However, the postharvest behavior of these varieties is different, so it is important to evaluate the factors that limit the shelf life of each variety. Therefore, in this study, fruits of each variety from the Mexican National Germplasm Bank of Sechium edule were used. The following fruit quality variables were evaluated: weight loss, humidity (%), color, chlorophyll, titratable acidity, total soluble solids (TSS), total sugars, and stomatal characteristics. In addition, the storage potential of each variety was evaluated for two weeks at different temperatures, 7°, 13° (85% RH) and 24 °C (60% RH), with the application of 1-methylcyclopropene (1-MCP). The variables evaluated were viviparism, disease severity, weight loss, dehydration and chilling injury (CI). The fruits of n. xalapensis and n. spinosum have a higher content of chlorophylls and carotenoids, but similar contents of TSS, acidity and total sugars than v. levis fruits. The use of 1-MCP reduced viviparism in all varieties, and the severity of blisters was higher in v. levis. The fruits of the three varieties presented severe CI when stored at 7 °C but the most susceptible to dehydration and diseases severity is n. spinosum

Satisfacción y rotación laboral en personal de empresas mineras de Arequipa y Cusco

En la actualidad, la satisfacción laboral y la intención de rotación son considerados fenómenos organizacionales de gran importancia en la gestión empresarial debido al impacto que tienen sobre el desempeño de las empresas. A nivel internacional, existen varios estudios que buscan explicar estos fenómenos analizándolos de manera individual. Sin embargo, son pocos aquellos tratados que intentan explicar la relación existente entre ambos. Por este motivo, la presente investigación intenta demostrar la existencia de una relación causa-efecto entre ambos fenómenos organizacionales y con ello, mejorar la efectividad de los esfuerzos realizados por diversas compañías, las mismas que invierten recursos para mejorar la satisfacción de su personal sin necesariamente impactar positivamente la tasa de rotación del mismo. El presente estudio es de naturaleza descriptiva y emplea un enfoque cuantitativo de diseño correlacional en el que se obtuvo una muestra de 111 funcionarios de mando medio de las dos principales empresas de gran minería en los departamentos de Arequipa y Cusco para identificar los rangos de satisfacción laboral y su influencia en la intención de rotación. Para ello, se utilizó el cuestionario “Escala de Opiniones SL-SPC” (Palma, 2005) y el cuestionario de “Intención de Rotación Laboral” (Jacobo & Roodt, 2008). Consecuencia de este estudio, se identificó una relación causa-efecto entre ambos fenómenos. No obstante, no todos los componentes de la satisfacción laboral realmente influyeron sobre la intención de rotación. En este sentido y raíz de este estudio, ambas empresas pueden identificar qué aspectos de satisfacción laboral en su personal deben ser priorizados en aras de reducir verdaderamente la tasa de rotaciónNowadays, job satisfaction and turnover intention are considered organizational phenomena with great importance in business management due to the impact they have on companies’ performance. Internationally, there are several studies that seek to explain these phenomena, analyzing them individually. However, only few treaties attempt to explain the relationship between both concepts. In consequence, this research tries to demonstrate the existence of a cause-effect relationship between these two organizational phenomena and improve the effectiveness of different companies’ efforts, which invest resources to improve employee satisfaction without necessarily impact positively the turnover rate. This study has a descriptive nature and uses quantitative approach of correlational design which was obtained from a 111 senior executive sample of two leading companies in large-scale mining sector of Arequipa and Cusco, to identify the relationship between job satisfaction and its influence on turnover intention. This thesis used the "Scale of Views SL-SPC Questionnaire" (Palma, 2005) and the "Employment Turnover Intent Questionnaire" (Jacobo & Roodt, 2008). As a result, the relationship between both phenomena was identified, but not all job satisfaction components actually influenced the employee turnover intention. Therefore, using these study results, both companies (which provided the sample) can identify which aspects of job satisfaction in their employees must be prioritized in order to truly reduce the employee turnover rateTesi

Identificación de fallas en instalaciones solares fotovoltaicas

Proyecto de Investigación y extensión (Código: 1360051) Instituto Tecnológico de Costa Rica. Vicerrectoría de Investigación y Extensión (VIE). Dirección de Proyectos. Escuela de Ingeniería Electrónica, Escuela de Ingeniería en Computación, Escuela de Ingeniería Electromecánica, Escuela de Física, 2023La creciente adopción de sistemas fotovoltaicos alrededor del mundo a obligado buscar alternativas que permitan detectar fallas en los módulos fotovoltaicos; para un máximo aprovechamiento energético. En este proyecto se desarrolló un método de identificación de fallas que integró la termografía infrarroja, la inspección visual y el análisis de variables eléctricas, por medio de un sistema basado en Internet de las cosas e inteligencia artificial. El sistema desarrollado mostró un mejor desempeño con relación a las soluciones tradicionales que utilizan un solo método. Los resultados demuestran las capacidades tecnológicas actuales para mejorar la gestión de las instalaciones fotovoltaicas y orientan a los administrados de estas instalaciones para hacer una mejor elección de soluciones de mantenimiento. Este informe se presenta como un compendio de artículos publicados y sometidos a publicación, los cuales se concretaron gracias al desarrollo y a los resultados del proyecto.The growing adoption of photovoltaic systems around the world has forced the search for alternatives to detect faults in photovoltaic modules; for maximum energy utilization. In this project, a fault identification method was developed that integrated infrared thermography, visual inspection and analysis of electrical variables, through a system based on the Internet of Things and artificial intelligence. The developed system showed an improved performance over traditional solutions using a single method. The results demonstrate the current technological capabilities to enhance the management of photovoltaic installations and guide the managers of these installations to make a better choice of maintenance solutions. This report is presented as a compendium of articles published and submitted for publication, which were made possible thanks to the development and results of the project