Cielo dividido. Recuerda cómo pasó, antes de que llegue el olvido

[Resumen] En el cine de Julián Hernández el manejo del tiempo enunciativo es muy importante debido a que no sólo se crea significación con lo que ocurre en el presente, sino con el tiempo pasado, aquel que se relaciona con los recuerdos es igualmente importante. La estructura de los filmes de Hernández recurre al recuerdo y a un tiempo psicológico en el cual se han vivido situaciones límite que marcan a los personajes y que los hacen encontrar su identidad personal, emotiva y genérica. El tiempo que se maneja como una forma privilegiada de enunciación y que se expresa en todos los elementos técnicos como la cámara, la música y el montaje. En su filme Cielo Dividido un mismo hecho se repite varias veces, desde diferentes puntos de vista como una forma de expresar como vive una separación cada uno de los personajes. El tiempo se se vuelve subjetivo debido a que cada sujeto experimenta diferente los acontecimientos. Pero, es un tiempo que se superpone al tiempo presente en una coexistencia del pasado con el tiempo actual y que determina el actuar de los personaje

MT1a mRNA Expression in Human Lung Cells (BEAS 2B) After Airborne PM10 and Copper Exposure: A Possible Biomarker for Asthma

Puerto Ricans have the highest prevalence, morbidity and mortality of asthma than any other ethnic group in the U.S. and can be triggered by different stimuli such as airborne Particle pollution (PM). PM transfers transition metals, including cooper, to the human airways generating reactive oxygen species (ROS). Metallothionein protein (MT1A) is a free radical scavenger expected to be induced in lung cells by PM exposure; however, this has never been proven nor demonstrated. The hypothesis involves the amounts of PM10 in 2004, which would be significantly higher in the urban sites during months of March and June, thereby increasing PM metal exposure and inducing MT1A gene at the urban site. PM10 filters for Urban (Guaynabo) and rural (Fajardo) site were provided by the PREQB. Organic extracts were prepared from filters by means of Soxhlet Extraction and heavy metals were determined using Atomic Absorption Spectrometry. BEAS-2B cells were cultured and exposed to PM10 during 4 hrs. RNA was isolated and relative mRNA levels of MT1A were determined by RT-PCR. Urban PM10 concentrations were 35 ug/m3 and 60ug/m3 for the months of March and June, respectively. Concentrations of copper for this urban PM10 were 29.6 ppm and 50.3 ppm, for March and June, respectively. Exposure to Cu leads to an MT1A expression in lung cells demonstrating its response to metal exposure. Cellular response for the mRNA expression of MT1A was greater in relative high inflammation markers than in PM10 samples

Nonlinear self-collimated sound beams in sonic crystals

We report the propagation of high-intensity sound beams in a sonic crystal, under self-collimation or reduced-divergence conditions. The medium is a fluid with elastic quadratic nonlinearity, where the dominating nonlinear effect is harmonic generation. The conditions for the efficient generation of narrow, non-diverging beam of second harmonic are discussed. Numerical simulations are in agreement with the analytical predictions made, based on the linear dispersion characteristics in modulated media and the nonlinear interaction in a quadratic medium under phase matching conditions.Comment: Sent to PR

Ultradiscrete kinks with supersonic speed in a layered crystal with realistic potentials

We develop a dynamical model of the propagating nonlinear localized excitations, supersonic kinks, in the cation layer in a silicate mica crystal. We start from purely electrostatic Coulomb interaction and add the Ziegler-Biersack-Littmark short-range repulsive potential and the periodic potential produced by other atoms of the lattice. This approach allows the construction of supersonic kinks which can propagate in the lattice within a large range of energies and velocities. The interparticle distances in the lattice kinks with high energy are physically reasonable values. The introduction of the periodic lattice potential results in the important feature that the kinks propagate with a single velocity and a single energy which are independent on the excitation conditions. The found kinks are ultra-discrete and can be described with the "magic wave number" $q\simeq 2\pi/3a$, which was previously revealed in the nonlinear sinusoidal waves and supersonic kinks in the Fermi-Pasta-Ulam lattice. The extreme discreteness of the supersonic kinks, with basically two particles moving at the same time, allows the interpretation of their double-kink structure. The energy of the supersonic kinks is between the possible source of $^{40}$K recoil in beta decay and the energy necessary for the ejection of an atom at the border as has been found experimentally.Comment: 14 pages, 15 figure

Modelling ceramics and piezoelectric transducers vibrating in thickness mode using transfer matrices

[EN] In this work we present the modeling of a piezoelectric ceramic vibrating in thickness mode using transfer matrices. The complete modeling of the vibratory behavior of a piezoelectric ceramic is a complex problem.This is mainly due to the tensorial denition of the involved stresses and the anisotropy of the piezoelectric solids, both arising due to their intrinsic elastic and piezoelectric properties. This problem is recurrent when teaching of Acoustics and Ultrasound, Telecommunications and electronic sensors. The modeling using transfer matrices provides a simple but accurate method, since it captures the main physical phenomena of the electromechanical problem. In particular, the presented modeling allows a high degree of freedom to modify the design by adding layers of different materials and / or electronic components, with, in addition, it also allows the student to obtain an analytical model of the piezoelectric effect and the study of the electrical-elastic system.[ES] En este trabajo presentamos la modelización de una cerámica piezoeléctrica vibrando en modo espesor empleando matrices de transferencia. La modelización completa del comportamiento vibratorio de un material piezoeléctrico es un problema complejo. Ello es debido principalmente al carácter tensorial de los esfuerzos junto a la anisotropía de los sólidos piezoeléctricos, tanto en sus propiedades elásticas como piezoeléctricas. Este es un problema recurrente en la docencia de Acústica y Ultrasonidos, Telecomunicaciones y sensores electrónicos. La modelización mediante matrices de transferencia proporciona un método simple pero preciso, pues captura los principales fenómenos físicos del problema electromecánico. En particular, la modelización presentada permite al estudiante por un lado obtener un modelo analítico del efecto piezoeléctrico y el estudio del sistema eléctrico-elástico, y por otro lado permite un elevado grado de libertad para modificar el diseño añadiendo capas de diferentes materiales y/o componentes electrónicos.Este trabajo ha sido financiado por la Generalitat Valenciana a través del contrato APOSTD/2017/042 y las subvenciones para la realización de proyectos de I+D+i desarrollados por grupos de investigación emergentes GV/2018/011. Actuación cofi nanciada por la Unión Europea a través del Programa Operativo del Fondo Europeo de Desarrollo Regional (FEDER) de la Comunitat Valenciana 2014-2020 (IDIFEDER/2018/022). Este trabajo ha sido co financiado por la Agència Valenciana de la Innovació a través de la Unitat Científica d'Innovació Empresarial (INNCON00/18/9).Jiménez, N.; Camarena, F. (2019). Modelización de cerámicas y transductores piezoeléctricos vibrando en espesor mediante matrices de transferencia. Modelling in Science Education and Learning. 12(1):87-110. https://doi.org/10.4995/msel.2019.10803SWORD87110121Gordon S Kino. Acoustic waves: devices, imaging, and analog signal processingPrentice-Hall Signal Processing Series. Englewood Clis, Prentice-Hall, 1987.Antonio Arnau. Piezoelectric transducers and applications. Springer Science & Business Media, 2008.JL San Emeterio, PT Sanz, E Riera, and A Ramos. Una implementación del modelo klm para transductores piezoeléctricos en modo espesor. In Anales Fisica B, volume 84, pages 48-55, 1988.JA Gallego-Juarez. Piezoelectric ceramics and ultrasonic transducers. Journal of Physics E: Scientic Instruments, 22(10):804, 1989.Nuria González-Salido, Marcelino Ferri, Noé Jiménez, Francisco Camarena, Rubén Picó, Javier Redondo, and Bernardino Roig. Simulación numérica de una cerámica piezoeléctrica. Modelling in Science Education and Learning, 6:131 144, 2013.JLS Emeterio, PT Sanz, A Ramos, and E Riera. Modelado de transductores piezoeléctricos multicapa para ecograa. representaciones circuitales equivalentes.Mundo Electron., (187):159 165, 1988.M Redwood. Experiments with the electrical analog of a piezoelectric transducer. The Journal of the Acoustical Society of America, 36(10):1872 1880, 1964.W.P. Mason. Electromechanical transducers and wave lters. Bell Telephone Laboratories series. D. Van Nostrand Co., 1948.Richard Krimholtz, David A Leedom, and George L Matthaei. New equivalent circuits for elementary piezoelectric transducers. Electronics Letters, 6(13):398-399, 1970.José Luis San Emeterio and Antonio Ramos. Models for piezoelectric transducers used in broadband ultrasonic applications. In Piezoelectric transducers and applications, pages 97-116. Springer, 2009.Lester Schmerr and Jung-Sin Song. Ultrasonic nondestructive evaluation systems. Springer, 2007.Francisco Camarena, Silvia Adrián-Martínez, Noé Jiménez, and Víctor Sánchez-Morcillo. Nonlinear focal shift beyond the geometrical focus in moderately focused acoustic beams. The Journal of the Acoustical Society of America, 134(2):1463-1472,Noé Jiménez, Francisco Camarena, and Nuria González-Salido. Dynamic nonlinear focal shift in amplitude modulated moderately focused acoustic beams. Ultrasonics, 75:106-114, 2017

Lactic Acid Bacteria and Yeast Inocula Modulate the Volatile Profile of Spanish-Style Green Table Olive Fermentations

In this work, Manzanilla Spanish-style green table olive fermentations were inoculated with Lactobacillus pentosus LPG1, Lactobacillus pentosus Lp13, Lactobacillus plantarum Lpl15, the yeast Wickerhanomyces anomalus Y12 and a mixed culture of all them. After fermentation (65 days), their volatile profiles in brines were determined by gas chromatography-mass spectrometry analysis. A total of 131 volatile compounds were found, but only 71 showed statistical differences between at least, two fermentation processes. The major chemical groups were alcohols (32), ketones (14), aldehydes (nine), and volatile phenols (nine). Results showed that inoculation with Lactobacillus strains, especially L. pentosus Lp13, reduced the formation of volatile compounds. On the contrary, inoculation with W. anomalus Y12 increased their concentrations with respect to the spontaneous process, mainly of 1-butanol, 2-phenylethyl acetate, ethanol, and 2-methyl-1-butanol. Furthermore, biplot and biclustering analyses segregated fermentations inoculated with Lp13 and Y12 from the rest of the processes. The use of sequential lactic acid bacteria and yeasts inocula, or their mixture, in Spanish-style green table olive fermentation could be advisable practice for producing differentiated and high-quality products with improved aromatic profile.Gobierno de España-OliFilm-AGL-2013-48300-

El parqués como estrategia para la enseñanza-aprendizaje de números enteros en grado séptimo

El parqués es uno de los juegos de mesa más populares en Colombia, de muy poca complejidad y, un juego para casi todas las edades, mientras que por el contrario las matemáticas son una ciencia abstracta en la cual hay grandes dificultades a la hora de su aprendizaje. Por esta razón se decide unir el juego y la ciencia visto desde hace mucho como la forma más práctica para la enseñanza-aprendizaje, con el fin de que los estudiantes quieran las matemáticas y la vean de forma divertida y sencilla. Además para que logren entender que las matemáticas y el juego van de la mano, ver un poco de ciencia en el juego y un poco de juego en la ciencia

Nonlinear waves in a chain of magnetically coupled pendula

A motivation for the study of reduced models like one-dimensional systems in Solid State Physics is the complexity of the full problem. In recent years our group has studied theoretically, numerically and experimentally wave propagation in lattices of nonlinearly coupled oscillators. Here, we present the dynamics of magnetically coupled pendula lattices. These macroscopic systems can model the dynamical processes of matter or layered systems. We report the results obtained for harmonic wave propagation in these media, and the different regimes of mode conversion into higher harmonics strongly influenced by dispersion and discreteness, including the phenomenon of acoustic dilatation of the chain, as well as some results on the propagation of localized waves i.e., solitons and kinks.Generalitat Valenciana APOSTD/2017/042Umiversitat Politècnica de València PAID-01-14Ministerio de Economía y Competitividad (MINECO), Spain FIS2015-65998-C2-2-PJunta de Andalucía 2017/FQM-28