4,773 research outputs found

    Approach of Processes for the Distribution of Economic Resources in Public University of Ecuador

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    The objective of the study was to analyze the process approach in the context of university management, applied to the economic and financial process, as a contribution to the fulfillment of the criteria of the formula of distribution of resources for the Ecuadorian Higher Education Institutions, describing the criteria and parameters based on current regulations. The research that was developed is empirical, descriptive in scope, using as methods, historical logic, analysis, and synthesis of the documentary sources linked to the study object, induction - deduction and mapping for the graphical representation of the information collected. The results allow identifying that the Ecuadorian public universities as of 2013 have an instrument that weighs the quality of the distribution of resources

    Ethane internal rotation-Vibrational Hamiltonian

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    One of the main purposes of a theoretical spectroscopist is to propose a model to reproduce the xperimental spectra available in the literature as accurate and with as much physical information as possible. In this case it has been studied the Far infrared an Infrared spectra of non-rigid molecules, introducing in the Vibrational Potential their dependence on the large amplitude variables. The molecule that has been selected to test our proposed Hamiltonian is ethane which is a very well studied molecule. The molecule is a non-rigid molecule and their experimental spectra have been reported in the literature. © 2008, Sociedad Química de MéxicoPeer Reviewe

    Polylectrolyte- versus membrane-coated electrodes for energy production by Capmix salinity exchange methods

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    La versión final publicada se puede encontrar en: Journal of Power Sources, 302(20): 387-393 (2016). http://dx.doi.org/10.1016/j.jpowsour.2015.10.076In this paper we analyze the energy and power achievable by means of a re- cently proposed salinity gradient technique for energy production. The method, denominated soft electrode or SE, is based on the potential di erence that can be generated between two porous electrodes coated with cationic and anionic polyelectrolytes. It is related to the Capacitive Donnan Potential (CDP) tech- nique, where the electrical potential variations are mostly related to the Donnan potential, of ion-selective membranes in the case of CDP, and of the polyelec- trolyte coating in SE. It is found that although SE is comparable to CDP in terms of energy production, it presents slower rates of voltage change, and lower achieved power. The separate analysis of the response of positively and neg- atively coated electrodes shows that the latter produces most of the voltage rise and also of the response delay. These results, together with electrokinetic techniques, give an idea on how the two types of polyelectrolytes adsorb on the carbon surface and a ect di erently the di usion layer. It is possible to suggest that the SE technique is a promising one, and it may overcome the drawbacks associated to the use of membranes in CDP.MINECO FIS2013-47666-C3-1-RJunta de Andalucía, PE2012-FQM0694European Union 7th Framework Programme (FP7/2007–2013) under agreement No. 25686

    Influencia de la atmósfera de sinterización en la estabilidad térmica de cerámicas de hidroxiapatita reforzadas con zircona

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    En este trabajo se estudia la influencia de la atmósfera de sinterización sobre la estabilidad térmica de cerámicas de hidroxiapatita (HA) reforzadas con partículas de circona parcialmente estabilizada con magnesia (Mg-PSZ). Los cuerpos verdes fueron obtenidos por prensado uniaxial y las sinterizaciones se realizaron en aire y en oxígeno húmedo. El estudio por difracción de rayos-X y espectroscopía infrarroja permitió comprobar que la atmósfera húmeda evita la descomposición de la hidroxiapatita, todo lo contrario a lo que sucede en aire donde es evidente la presencia del zirconato cálcico (CZ) en la interfaz entre la partícula de circona y la matriz de HA. La caracterización microestructural de los materiales por Microscopía Electrónica de Barrido permitió apreciar el desarrollo de tamaño de grano de los materiales sinterizados. El estudio del comportamiento mecánico mediante ensayos de indentación reveló un aumento de la tenacidad a la fractura en el caso de los materiales que presentaban Mg-PSZ con respecto a la HA pura

    Anti-tumor activity of functionalized biomimetic magnetite nanoparticles produced in the presence of MamC protein of Magnetococcus marinus MC-1

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    Magnetite Nanoparticles (MNPs) find many applications, including biotechnology, as they can be manipulated by an external magnetic field and functionalized with different molecules. Magnetotactic bacteria bio-mineralize magnetosomes (membrane-enveloped magnetites), which are the ideal magnetic particle. However, scaling-up magnetosome production is still challenging, so bio-mimetics, i.e. in vitro magnetite synthesis mediated by magnetosome-associated proteins is being explored. Our group is working with MamC from Magnetococcus marinus MC-1 that controls the morphology and size of the crystals, producing well faceted Biomimetic Magnetic Nanoparticles (BMNPs) of ~40 nm, which are paramagnetic at room and body temperature while having a large magnetic moment per particle under an external magnetic field. These BMNPs were cytocompatible and biocompatible in vivo. BMNPs were functionalized (isothermal adsorption) with a monoclonal antibody (mAb) recognizing the ectodomain of the human Met/HGF receptor (overexpressed in many cancers) and the chemotherapeutic Doxorubicin (DOXO). The functionalized BMNPs present hyperthermia and were stable at physiological pH, while releasing the adsorbed DOXO at acidic pH. mAb functionalization of BMNPs favored their interaction with cells expressing the Met/HGFR and cellular DOXO uptake and toxicity, which was enhanced upon cell exposition to a continuous magnetic field. Real-time cytotoxicity of the BMNPs showed that DOXO-mAb-BMNPs were significantly more toxic than DOXO-BMNPs on Met/HGFR expressing cells, while no differential toxicity was observed on cells not expressing this receptor. When DOXO-BMNPs were injected intravenously in tumor bearing mice and an external magnetic field was applied there, a higher amount of BMNPs accumulated in the tumor and tumor growth was decreased in comparison to mice in which no magnetic field was applied. These BMNPs could thus represent effective nano-carriers for targeted drug delivery and might be combined with hyperthermia to increase efficiency, resulting in a targeted local treatment of tumors with a decrease in the deleterious systemic side effects

    ¿Cómo monitorear el movimiento del ganado en un mosaico de áreas boscosas con GPS en combinación con SIG?

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    El manejo de bosques de Piñon-Juniper (PJ) ocupa más de 30 millones de hectáreas en el oeste de Estados Unidos. Este ecosistema constituye un importante recurso para la producción y conservación de vida silvestre. Sin embargo, estos han cambiado considerablemente los últimos 30 años, principalmente para manejar ganado en pastoreo. El objetivo fue determinar la cobertura de dosel (TCC) y monitorear, durante la primavera, el uso del ganado del paisaje arbolado. El estudio se realizó en una pastura de 146 ha de la zona central de Nuevo México. La TCC de PJ se determinó a partir de ortofotos digitales recientes usando Feature Analyst® para ArcGIS® 9.1. El sitio de estudio fue segmentado en celdas de 1 ha para mapear cobertura arbórea. Ocho vacas, equipadas con GPS, fueron rastreadas durante 31 días a intervalos de 5 min. Una sección de la pastura con cobertura arbórea mayor que 30 % se utilizó para describir la relación distribución de pastoreo y cobertura de dosel. Se encontró una relación exponencial negativa significativa entre TCC y el uso relativo del ganado (y = 450,41e-12,329x). La cubierta arbórea explicó 50,1 % de la variación en la utilización relativa por el ganado de las celdas. La mayoría de las posiciones animales registradas en áreas dominadas por PJ ocurrieron en celdas con 30-50 % de TCC. Una cobertura del dosel de 50 % podría proporcionar un equilibrio adecuado entre la permanencia y el consumo de  forraje para el ganado durante la primavera

    Stacking of capacitive cells for electrical energy production by salinity exchange

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    Publisher's link: http://www.sciencedirect.com/science/article/pii/S0378775316303676?np=yHa estado embargado durante 1 año, hasta julio 2017In this paper we explore methods for stacking individual cells in order to increase the amount of energy that can be extracted from salinity gradient cycles (capmix methods). Each of the cells consists of a pair of parallel electrodes made of activated carbon particles, either bare or coated by a layer of polyelectrolyte. In these methods, energy is produced based on the modifications in the electrical double layer (EDL) structure in the pores of the carbon particles upon exchange of the salinity of the surrounding medium. In the case of the bare carbon particles, the electrodes are externally charged in presence of high-salt concentration, and discharged after exchanging the solution for a dilute one (sea- vs. river-water cycles). In a first stacking approach, we simply connect the electrodes side-by-side and only the outermost ones can be connected to the external source. Using a stack where potential and current between cells can be measured, it is shown that only the external electrodes seem to work, and it is suggested that this is a consequence of internal short-circuit currents between oppositely charged electrodes of different cells through the electrolyte. In contrast, the side-by-side configuration is operational if coated electrodes are used.MICINN, Spain (Project FIS2013-47666-C3-1R)RYC-2014-16901 (MINECO)FEDER Funds E
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