1,617 research outputs found
Aprender cooperando en aulas universitarias de informática
En este artÃculo se describe cómo es posible
conjugar la docencia tradicional con la puesta en
práctica de otras metodologÃas alternativas en
materias tecnológicas. En concreto esta
experiencia se ha llevado a la práctica en la
asignatura Estructura y TecnologÃa de
Computadores II. Se trata de una asignatura
obligatoria de primer curso de la IngenierÃa
Técnica en Informática de Gestión de la
Universidad de Sevilla, en la que cada grupo tiene,
de media, 80 alumnos matriculados. Se conjugan
técnicas de aprendizaje cooperativo con algunas
herramientas de evaluación como las rúbricas (o
listas de comprobación) y el portafolio
electrónico. Se ha comprobado que, con la
combinación de estas metodologÃas, los alumnos
encuentran más satisfactorio el proceso de
aprendizaje, se comprometen en ese proceso y,
además, fomentan el desarrollo de muchas de las
competencias transversales que demanda el EEES.Peer Reviewe
Use of 3D Printing in Model Manufacturing for Minor Surgery Training of General Practitioners in Primary Care
In order to increase the efficiency of the Spanish health system, minor surgery programs are currently carried out in primary care centers. This organizational change has led to the need to train many general practitioners (GPs) in this discipline on a practical level. Due to the cost of the existing minor surgery training models in the market, pig’s feet or chicken thighs are used to practice the removal of figured lesions and the suture of wounds. In the present work, the use of 3D printing is proposed, to manufacture models that reproduce in a realistic way the most common lesions in minor surgery practice, and that allow doctors to be trained in an adequate way. Four models with the most common dermal lesions have been designed and manufactured, and then evaluated by a panel of experts. Face validity was demonstrated with four items on a five-point Likert scale that was completed anonymously. The models have obtained the following results: aesthetic recreation, 4.6 ± 0.5; realism during anesthesia infiltration, 4.8 ± 0.4; realism during lesion removal, 2.8 ± 0.4; realism during surgical wound closure, 1.2 ± 0.4. The score in this last section could be improved if a more elastic skin-colored filament were found on the market
Localized oscillations in nonlinear hamiltonian Klein-Gordon lattices. Breathers and Anderson modes
PósterThere are two different sources of localization in
discrete lattices:
• Anderson modes in disordered harmonic
lattices [1]
• Discrete breathers in homogeneous nonlinear
lattices [2
Análisis de los minerales de la arcilla y sus procesos genéticos en las formaciones arcillosas de la Cuenca del Tajo.
Se han estudiado seis sondeos, realizados en la cuenca neógena del Tajo, con el fin de conocer los procesos genéticos de los materiales arcillosos de la cuenca. Estos sondeos cortan facies correspondientes a distintos ambientes deposicionales. La evolución observada puede relacionarse con dos etapas distintas de sedimentación. La primera corresponde a la sedimentación de la Unidad de Yesos; la asociación de minerales de arcilla en esta unidad está constituida principalmente por illita, menores contenidos de esmectita, interestratificados I/Sm, Cl/Sm, Glauconita/Sm, palygorskita y clorita. El origen de esta asociación es en parte detrÃtica y en parte neoformada; los aportes detrÃticos corresponden a illita y esmectita, mientras que los minerales neoformados son principalmente illita e interestratificados, clorita y palygorskita. Esta etapa se caracteriza por la existencia de procesos de illitización. En la segunda etapa de sedimentación (Unidad de Arcillas Verdes), se observa un incremento de los aportes detrÃticos y una evolución hacia condiciones de menor salinidad. El ambiente de formación de esta unidad se encuentra enriquecido en magnesio y los minerales de la arcilla más caracterÃsticos de las facies que componen dicha unidad son las esmectitas magnésicas (saponita y estevensita) y, en menor proporción, los interestratificados Cl/Sm. Esta asociación mineralógica se origina por la reacción entre las partÃculas detrÃticas arcillosas y los cationes del medio
Solving random homogeneous linear second-order differential equations: a full probabilistic description
[EN] In this paper a complete probabilistic description for the solution of random homogeneous linear second-order differential equations via the computation of its two first probability density functions is given. As a consequence, all unidimensional and two-dimensional statistical moments can be straightforwardly determined, in particular, mean, variance and covariance functions, as well as the first-order conditional law.
With the aim of providing more generality, in a first step, all involved input parameters are assumed to be statistically dependent random variables having an arbitrary joint probability density function. Second, the particular case that just initial conditions are random variables is also analysed. Both problems have common and distinctive feature which are highlighted in our analysis. The study is based on random variable
transformation method. As a consequence of our study, the well-known deterministic results are nicely generalized. Several illustrative examples are included.This work has been partially supported by the Spanish M. C. Y. T. Grant MTM2013-41765-P.Casabán, M.; Cortés, J.; Romero, J.; Roselló, M. (2016). Solving random homogeneous linear second-order differential equations: a full probabilistic description. Mediterranean Journal of Mathematics. 13(6):3817-3836. https://doi.org/10.1007/s00009-016-0716-6S38173836136Øksendal B.: Stochastic Differential Equations: An Introduction with Applications, 6th edn. Springer, Berlin (2007)Soong T.T.: Random Differential Equations in Science and Engineering. Academic Press, New York (1973)Neckel, T., Rupp, F.: Random Differential Equations in Scientific Computing. Versita, London (2013)Nouri, K., Ranjbar, H.: Mean square convergence of the numerical solution of random differential equations. Mediterr. J. Math. 1–18 (2014). doi: 10.1007/s00009-014-0452-8Villafuerte, L., Chen-Charpentier, B.M.: A random differential transform method: theory and applications. Appl. Math. Lett. 25(10), 1490–1494 (2012). doi: 10.1016/j.aml.2011.12.033Licea, J.A., Villafuerte, L., Chen-Charpentier, B.M.: Analytic and numerical solutions of a Riccati differential equation with random coefficients. J. Comput. Appl. Math. 239, 208–219 (2013). doi: 10.1016/j.cam.2012.09.040Casabán, M.C., Cortés, J.C., Romero, J.V., Roselló, M.D.: Probabilistic solution of random homogeneous linear second-order difference equations. Appl. Math. Lett. 34, 27–32 (2014). doi: 10.1016/j.aml.2014.03.010Santos, L.T., Dorini, F.A., Cunha, M.C.C.: The probability density function to the random linear transport equation. Appl. Math. Comput. 216 (5), 1524–1530 (2010). doi: 10.16/j.amc.2010.03.001El-Tawil, M., El-Tahan, W., Hussein, A.: Using FEM-RVT technique for solving a randomly excited ordinary differential equation with a random operator. Appl. Math. Comput. 187(2), 856–867 (2007). doi: 10.1016/j.amc.2006.08.164Hussein, A., Selim, M.M.: Solution of the stochastic radiative transfer equation with Rayleigh scattering using RVT technique. Appl. Math. Comput. 218(13), 7193–7203 (2012). doi: 10.1016/j.amc.2011.12.088Casabán, M.C., Cortés, J.C., Romero, J.V., Roselló, M.D.: Probabilistic solution of random SI-type epidemiological models using the random variable transformation technique. Commun. Nonlinear Sci. Numer. Simul. 24(1–3), 86–97 (2015). doi: 10.1016/j.cnsns.2014.12.016Casabán, M.C., Cortés, J.C., Romero, J.V., Roselló, M.D.: Determining the first probability density function of linear random initial value problems by the random variable transformation (RVT) technique: a comprehensive study. In: Abstract and Applied Analysis 2014-ID248512, pp. 1–25 (2014). doi: 10.1155/2013/248512Casabán, M.C., Cortés, J.C., Navarro-Quiles, A., Romero, J.V., Roselló, M.D., Villanueva, R.J.: A comprehensive probabilistic solution of random SIS-type epidemiological models using the random variable transformation technique. Commun. Nonlinear Sci. Numer. Simul. 32, 199–210 (2016). doi: 10.1016/j.cnsns.2015.08.009El-Wakil, S.A., Sallah, M., El-Hanbaly, A.M.: Random variable transformation for generalized stochastic radiative transfer in finite participating slab media. Phys. A 435 66–79 (2015). doi: 10.1016/j.physa.2015.04.033Dorini, F.A., Cunha, M.C.C.: On the linear advection equation subject to random fields velocity. Math. Comput. Simul. 82, 679–690 (2011). doi: 10.16/j.matcom.2011.10.008Dhople, S.V., DomÃnguez-GarcÃa, D.: A parametric uncertainty analysis method for Markov reliability and reward models. IEEE Trans. Reliab. 61(3), 634–648 (2012). doi: 10.1109/TR.2012.2208299Williams, M.M.R.: Polynomial chaos functions and stochastic differential equations. Ann. Nucl. Energy 33(9), 774–785 (2006). doi: 10.1016/j.anucene.2006.04.005Chen-Charpentier, B.M., Stanescu, D.: Epidemic models with random coefficients. Math. Comput. Model. 52(7/8), 1004–1010 (2009). doi: 10.1016/j.mcm.2010.01.014Papoulis A.: Probability, Random Variables and Stochastic Processes. McGraw-Hill, New York (1991
Semiclassical Dynamics from Zeno-Like measurements
The usual semiclassical approximation for atom-field dynamics consists in
substituting the field operators by complex numbers related to the (supposedly
large enough) intensity of the field. We show that a semiclassical evolution
for coupled systems can always be obtained by frequent Zeno-like measurements
on the state of one subsystems, independently of the field intensity in the
example given. We study the Jaynes Cummings model from this perspective
Experimental infection of encapsulated and free larvae of Anisakis larvae type I in Wistar rats
En este trabajo se realiza un estudio sobre el papel patógeno de las larvas de Anisakis encapsuladas en las vÃsceras del pez y las que se encuentran libres en la cavidad corporal del mismo, mediante la
estimación de las lesiones causadas en el tracto digestivo de ratas Wistar. Los resultados muestran que
el porcentaje de lesiones fue mayor (92,9%) en las ratas infectadas con larvas libres que en aquellas a
las cuales se les administraron las larvas encapsuladas (35,7%), además, ninguna de ellas se encontró
en la cavidad corporal del animal.In this study we performed a research on the pathogenic role of encapsulated Anisakis larvae in the
viscera of the fish and free larvae in the body cavity of the fish, through the evaluation of the lesions
induced in the digestive tract of Wistar rats. The results show that the percentage of lesions was higher
(92.9%) in rats infected with free larvae than in those receiving encapsulated larvae (35.7%), besides, none of the larvae was found in the body cavity of the animals.Trabajo financiado por el proyecto: P07-CVI-0324
Quasi-particle Lifetimes in a d_{x^2-y^2} Superconductor
We consider the lifetime of quasi-particles in a d-wave superconductor due to
scattering from antiferromagnetic spin-fluctuations, and explicitly separate
the contribution from Umklapp processes which determines the electrical
conductivity. Results for the temperature dependence of the total scattering
rate and the Umklapp scattering rate are compared with relaxation rates
obtained from thermal and microwave conductivity measurements, respectively.Comment: 14 pages, 4 figure
Second Screen Interactions for Automatically Web-Enriched Broadcast Video
Including hypermedia in broadcast video combines content formatted
for a lean-forward medium (the Web) with a lean-back one (TV) to form a
hybrid medium. We identify four challenges for interacting with and
experiencing this new medium. We discuss the role a second screen may play in
addressing these challenges
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