20,079 research outputs found

    A monopole solution from noncommutative multi-instantons

    Get PDF
    We extend the relation between instanton and monopole solutions of the selfduality equations in SU(2) gauge theory to noncommutative space-times. Using this approach and starting from a noncommutative multi-instanton solution we construct a U(2) monopole configuration which lives in 3 dimensional ordinary space. This configuration resembles the Wu-Yang monopole and satisfies the selfduality (Bogomol'nyi) equations for a U(2) Yang-Mills-Higgs system.Comment: 19 pages; title and abstract changed, brane interpretation corrected. Version to appear in JHE

    Difficulties to identify and pronounce the sounds /s/ and /z/ as EFL students in the second semester 2013, belonging to the Saturday program of the English Major at UNAN MANAGUA

    Get PDF
    One major concern about the EFL Saturday courses at UNAN-Managua is if the students are acquiring a good level of proficiency on pronunciation. It is a strong belief that EFL learners have great difficulties on pronunciation due to negative transfer; especially with difficult twin sounds which do not have an equivalent in the mother tongue of non-native speakers. This research was applied to a group of 15 students of the Saturday program of the English Major at UNAN. To this purpose were applied one survey to the students, two interviews, and several class observations. There were interesting findings about the subject and the most important is the concern to create phonological awareness in the students to improve their pronunciation

    Technical, financial and environmental evaluation of 4G long term evolution: advanced with femtocell base stations

    Get PDF
    Recent advances in mobile communication technology have allowed for considerable growth both in traffic and user numbers. However, in order to maintain acceptable quality of experience and service levels with increasing network capacity requirements, a mobile communications operator is challenged with high investment costs and high operating costs. Cost effectiveness and environmental sustainability are two major factors a mobile telecommunications operator must take into account in order to maintain its network planning techniques ready for the accelerated growth of traffic in future mobile networks. With the incoming LTE-Advanced system and with the increasing popularity of femtocells, it becomes necessary to evaluate and quantify the economic viability and sustainability of this new type of base station when used as a standalone deployment option, as well as when used in a two-tier network. Therefore, different cases were used with a deployment method based on capacity used with a varying non-uniform traffic distribution in order to assess the future resistance and flexibility of this proposed solution. A comparison was made between macro cell coverage only, full femtocell coverage and a two-tier joint solution. Our study has concluded that for low capacity demands, the best approach is a two-tier network with femtocells used for indoor backhaul. A joint solution also allows for the cost-effective resolution of indoor coverage issues. According to our future capacity requirements projected, it has been concluded that a full femtocell deployment, by far, the most economically viable option. A method for the quantification and suppression of carbon emissions due to energy consumption is also proposed, through which we studied and estimated the price for the achievement of a zero carbon emissions network.Os recentes avanços na tecnologia de comunicações móveis têm permitido um crescimento considerável da indústria, tanto em termos de tráfego como em número de clientes. No entanto, para conseguir manter uma qualidade de experiência aceitável e com elevada qualidade de serviço, um operador de comunicações móveis depara-se com elevados custos de investimento e operação. A eficácia em termos de custos e a pegada ambiental são dois factores que, entre outros, um operador de telecomunicações móveis deve ter em conta de modo a manter as suas técnicas de planeamento de rede preparadas para o acelerado crescimento do tráfego nas redes móveis do futuro. Com a chegada próxima do LTE-Advanced e com a crescente popularidade de femtocells, torna-se necessário avaliar e quantificar a viabilidade económica e o potencial de poupança de energia deste novo tipo de estação de base quando utilizado como uma opção de implantação autónoma, ou quando utilizado para suporte de uma rede de macro células. Dessa forma, foram dimensionados diferentes casos de implementação baseados nos requisitos de capacidade. Foi também aplicada uma distribuição de tráfego não-uniforme, a fim de avaliar a resistência ao futuro e a flexibilidade de aplicação desta solução proposta. Fez-se uma comparação entre uma implementação apenas com recurso a macro células, uma implementação feita completamente com recurso a femtocells e uma solução conjunta destes dois tipos de estação-base. O estudo concluiu que, para requisitos de baixa capacidade, a melhor implementação é uma rede de duas camadas, com femtocells utilizadas para o backhaul das ligações indoor. A solução conjunta permite ainda a resolução eficaz de problemas de cobertura no interior de edifícios. De acordo com a nossa projecção das necessidades futuras de capacidade concluiu-se que a implementação de uma rede apenas com recurso a femtocells é a melhor opção, do ponto de vista da capacidade, financeiro e ambiental. Também foi apresentada uma metodologia para quantificar a pegada ambiental devida ao consumo de energia, através da qual se estudou e estimou os custos associados à implementação de uma rede com pegada ambiental nula

    High-pressure Raman study of L-alanine crystal

    Full text link
    Pressure-dependent Raman scattering studies in the range 0.0 -- 32 kbar were carried out in L-alanine in order to investigate its external mode phonon spectra in relation to the phase transitions in the crystal. A careful analysis of the spectra shows that the low-energy Raman modes exhibit variation both in frequency and in intensity and between 26 and 28 kbar it is observed a splitting of a external mode, indicating that the D_2 normal phase undergoes a transition. Pressure coefficients for external modes are also given.Comment: 11 pages, Latex, 2 figure

    Aplicación de las leyes rectoras de la educación Nicaragüense en las funcione administrativas del colegio Cristiano Nueva vida, en la modalidad de secundaria, en el II Semestre de 2017

    Get PDF
    Esta investigación está dirigida a indagar sobre la adecuada aplicación de las leyes rectoras de la Educación Nicaragüense en el Colegio Cristiano Nueva Vida, en la modalidad de secundaria. El problema de investigación surge ante la necesidad de que la Directora del centro se apropie de las leyes educativas, las cuales por la naturaleza de la institución están vinculadas al desempeño del proceso administrativo y se justifica porque aportará los elementos necesarios en cuanto a normas jurídicas que son fundamentales en el proceso administrativo que se desarrolla en un centro educativo. El estudio es de tipo descriptivo, se aplicó el método analítico-sintético, el método inductivo deductivo y método empírico a través de la observación, entrevistas, encuestas, guía de observación. Las principales fuentes de información que nutrieron el estudio fueron la directora, docentes y estudiantes. Las principales conclusiones a que se llegó con este estudio es que existe desconocimiento de las Leyes Rectoras de la Educación y por consiguiente falta de aplicación de ellas, lo cual afecta tanto el desempeño de las funciones administrativas y disminuye la calidad educativa de la institución. Las principales recomendaciones son el estudio y apropiación de las leyes educativas por parte de la directora, posteriormente hacer partícipes de éstas a los docentes y trabajar articuladamente en función de ellas, para lograr el objetivo primordial de la educación: la formación plena e integral del estudiante. Palabras claves del estudio: Leyes, aplicación, función administrativa

    Variables predictors of the set in the defence complex in volleyball

    Get PDF
    El objetivo de la investigación fue conocer las variables predictoras de la eficacia de colocación en el complejo de defensa (KII), en ambos géneros, en categorías de formación. La muestra del estudio estuvo compuesta por 2.404 acciones de juego, 1.104 en género masculino y 1.300 en género femenino, desarrolladas por los 34 equipos participantes en el Campeonato de España Under 16. La variable dependiente fue la eficacia de colocación. Las variables independientes se agruparon en: variables de defensa, de colocación en KII y de bloqueo. Los resultados determinaron que, en ambos géneros, la eficacia de defensa, la técnica de colocación y la participación en bloqueo predecían la eficacia de la colocación; en género masculino, zona de defensa y tiempo de colocación; ninguna variable fue predictora únicamente en género femenino. Esta información puede ser relevante para el desarrollo del proceso de entrenamiento en voleibolThe objective of the research was to analyse the variables predictors of the setting efficacy in the defence complex (KII), in youth athlete, in both genders. The study sample was comprised of 2404 game actions, 1104 in the male gender and 1300 in the female gender. The actions were carried out by the 34 teams that participated in the Spanish Under-16 Championship. The dependant variable was the setting efficacy. The results determined that, in both genders, the dig efficacy, setting technique and the participation in block predicted the setting efficacy; in male gender, the defence zone and tempo of set; no predictor variables were exclusive to the female gender. This information may be relevant when developing training processes in volleyballEste estudio se ha realizado gracias a la aportación de la Consejería de Economía e Infraestructuras de la Junta de Extremadura a través del Fondo Europeo de Desarrollo Regiona

    Mercado de capitales en México Vs mercado de capitales en Colombia

    Get PDF
    Trabajo de Síntesis AplicadaSe pretende establecer un comparativo del mercado de capitales entre México y Colombia, donde se define que el mercado de capitales es un tipo de mercado financiero donde se comercializa, es decir, compra y venta de títulos valor, activos financieros de empresas y otras unidades económicas como lo son las acciones, obligaciones y títulos de deuda a largo plazo.Introducción 1. Problema de Investigación 2. Pregunta de Investigación 3. Objetivos 4. Desarrollo al problema de investigación 5. Mercado de Capitales en México 6. Mercado de Capitales en Colombia 7. Resultados Conclusiones BibliografíaEspecializaciónEspecialista en Formulación y Evaluación Social y Económica de Proyecto
    corecore