5,105 research outputs found

    Micro-Jet Test Facility for Aerospace Propulsion Engineering Education

    Get PDF
    This paper describes the methodology that has been developed and implemented at the School ofAeronautics (ETSIA) of the Universidad Politecnica de Madrid (UPM) to familiarize aerospaceengineering students with the operation of real complex jet engine systems. This methodology has atwo-pronged approach: students carry out preparatory work by using, first, a gas turbineperformance prediction numerical code; then they validate their assumptions and results on anexperimental test rig. When looking at the educational aspects, we have taken care that, apart frombeing sufficiently robust and flexible, the experimental set-up is similar to real jet engine rigs, so thestudents are not constrained to exploring a much too limited parametric space. Also, because afacility like this is usually subject to extensive and somewhat rugged use, we have focused on a lowcost design

    Demand Shocks and Trade Balance Dynamics

    Get PDF
    This paper studies the current account dynamics in the G-7 countries plus Spain. We estimate a SVAR model which allows us to identify three different shocks: supply shocks, real demand shocks and nominal shocks. We use a different identification procedure from previous work based on a microfounded stochastic open-economy model in which the real exchange rate is a determinant of the Phillips curve. Estimates from a structural VAR show that real demand shocks explain most of the variability of current account imbalances, whereas, contrary to previous findings, nominal shocks play no role. The results we obtain are consistent with the predictions of a widely set of open-economy models and illustrate that demand policies are the main responsible of trade imbalances.Current account, SVAR.

    Relapse of incisor crowding: a visit to the prince of salina

    Get PDF
    The management of the retention period after comprehensive orthodontic treatment is of great importance, as a primary goal of clinician. Considerable controversy still surrounds the problem of stability after the retention period. Many studies analyze factors associated to the presence of crowding or incisor irregularity and find predictive features on its relapse. Most studies have reported little o no correlation between the treatment changes in the biological parameters - clinical, biometric (irregularity index, intermolar width, intercanine width, arch length, overjet, overbite), or cephalometric variables- that ocurred and the posttretament and postretention changes that may predict their future development. This article provides a bibliographical overview on the relapse of dental alignment in treated cases. In a brief historical introduction, the first studies on the long-term stability of orthodontic results are analysed. The article then goes on to assess studies that focus attention on anteroinferior alignment before finally studying relapse of upper crowding. It concludes by making some final comments in the light of the bibliography provided and the differents schools regarding retention needs and methods

    Strategies for development of media literacy in Primary: Action proposal

    Get PDF
    La competencia digital desempeña un papel fundamental en la formación de los estudiantes actualmente. Sólo tenemos que considerar que la tecnología es ubicua en la vida de los estudiantes y también en sus rutinas diarias. Las escuelas deben plantearse cómo implementar e integrar en el currículo la tecnología educativa. La alfabetización mediática se refiere al conocimiento y destrezas que el alumnado debe adquirir para poder analizar, evaluar y crear mensajes mediáticos. Este artículo trata sobre alumnado entre 8 y 11 años que no tiene formación multimedia previa, y aprende lo básico sobre la competencia digital, así como el impacto que esa formación tiene en su progreso académico. Dada la edad de la muestra, las destrezas mediáticas trabajadas no han ido más allá de las tecnológicas, aunque algunas habilidades evaluadoras y críticas se han practicado oralmente. Los resultados muestran que los estudiantes han mejorado significativamente sus destrezas básicas y también su conocimiento sobre los media. Sin embargo, no podemos concluir que una formación tan corta y básica impacte su progreso académico.Digital competency plays an essential role in students' training nowadays. We just need to consider that technology is ubiquitous in students' lives and also part of their daily routines. Schools need to address how ICT is going to be implemented and integrated into the curriculum. Media literacy refers to the knowledge and skills individuals are to be achieved in order to analyze, evaluate, or produce media messages. This article is about how 8 to 11 years old students with no previous background, learn the basics on ICT and its impact on their grades. Because of students' age, literacy skills do not go beyond creating media messages, although some critical and evaluative skills were also orally practiced. Results show that students have significantly improved their basic skills and also their knowledge on media. However, we cannot conclude that this type of short in time and basic training impacts their academic grades

    Asymptotic behaviour of a singularly perturbed convection-diffusion problem in a rectangle with discontinuous Dirichlet data

    Get PDF
    We consider a singularly perturbed convection-diffusion equation, −ε△u+ −→v · −→∇u = 0, defined on a rectangular domain Ω ≡ {(x, y)| 0 ≤ x ≤ πa, 0 ≤ y ≤ π}, a > 0, with Dirichlet-type boundary conditions discontinuous at the points (0, 0) and (πa, 0): u(x, 0) = 1, u(x, π) = u(0, y) = u(πa, y) = 0. An asymptotic expansion of the solution is obtained from a a series representation in two limits: a) when the singular parameter ε → 0 + (with fixed distance to the points (0, 0) and (πa, 0)) and b) when (x, y) → (0, 0) or (x, y) → (πa, 0) (with fixed ε). It is shown that the first term of the expansion at ε = 0 contains a linear combination of error functions. This term characterizes the effect of the discontinuities on the ε−behaviour of the solution u(x, y) in the boundary or the internal layers. On the other hand, near the points of discontinuity (0, 0) and (πa, 0), the solution u(x, y) is approximated by a linear function of the polar angle

    [4+2] and [4+3] catalytic cycloadditions of allenes

    Get PDF
    This feature review describes the development of catalytic [4+2] and [4+3] cycloadditions of allenes, as efficient and practical methodologies for assembling six and seven-membered cyclic systems. The different methodologies have been classified depending on the type of key reactive intermediate that was proposed in the catalytic cycleS

    Análisis de las Estrategias Metodológicas que emplea el docente durante el proceso de enseñanza - aprendizaje y su incidencia en la adquisición de las habilidades y destrezas para la lectoescritura, en los estudiantes del tercer grado “B” en el Centro Escolar Público Ricardo Morales Avilés, del Municipio San Rafael del Sur, durante el segundo semestre del año 2014

    Get PDF
    El presente trabajo tiene como propósito analizar las estrategias metodológicas que emplea el docente en el procesode lectoescritura y como inciden en las habilidades que desarrollan los estudiantes de tercer grado B en la disciplina Lengua y Literatura del Centro Escolar Publico Ricardo Morales Avilés, Municipio San Rafael del sur, Departamento Managua en el segundo semestre del año 2013. Esta investigación es de enfoque cualitativo, porque los instrumentos son abiertos, la información es densa, abundante, se intenta recopilar todos los elementos del fenómeno, el fenómeno se estudia de forma natural, se anota exactamente lo que sucede, como una conversación vía entrevista, observaciones, grupo focales, otra de la razones que el porqué es cualitativo es la palabra propia de la persona que se utiliza pueden ser aquellas palabras sucias que expresen si es necesaria se anota, esto nos permita en la interpretación de análisis para enriquecer el trabajo investigativo. Esta investigación permitió conocer las estrategias metodológicas que emplea el docente en el aula de clase, y su incidencia en la adquisición de las habilidades y destrezas para la lectoescritura de los estudiantes. Para obtener los datos y la información necesaria para el análisis se utilizaron instrumentos tales como: observación al aula de clase, entrevista al docente, asesora pedagógica del MINED y estudiantes, padres de familia y la dirección del centro. Como resultado se obtuvo que el docente no utiliza diversas estrategias que permitan el adecuado desarrollo de habilidades en la lectoescritura y carece de material didáctico, medios de enseñanza, conociéndose además factores externos a la escuela los cuales también inciden en el aprendizaje a la lectoescritura. En este contexto se considera que es recomendable que el docente integre en su plan de clase diario estrategias metodológicas que permitan el desarrollo de las habilidades en la lectoescritura, adecuando los contenidos a los diferentes niveles de aprendizaje en la diversidad de estudiante

    Nucleotido-cíclico ciclasas del díptero ceratitis capitata

    Get PDF
    Tesis - Universidad Complutense de Madrid, 1980.Depto. de Bioquímica y Biología MolecularFac. de Ciencias QuímicasTRUEProQuestpu
    corecore