La creatividad en la resolución de un problema de modelización por futuros maestros de educación primaria.

Trabajo fin de Máster. Máster universitario en modelización matemática. Curso académico 2020-2021.[ES]La implementación de problemas de modelización matemática en la Educación Primaria constituye un elemento esencial en los planes de formación académica, contribuyendo no solo en el desarrollo de las matemáticas en un contexto real para los alumnos, sino también en su creatividad. No obstante, son escasas las investigaciones sobre el impacto de este tipo de problemas en el desarrollo de la creatividad de los estudiantes. El propósito del estudio es analizar la creatividad de estudiantes del Grado de Maestro en Educación Primaria de la Universidad de Salamanca cuando resuelven un problema de modelización matemática que consistía en la realización de un mural de dimensiones dadas que debía rellenarse con una determinada pieza. Concretamente, se pedía construir la pieza y determinar la cantidad de piezas necesaria. La experiencia se llevó a cabo con estudiantes de tercer curso, del Grado en Maestro en Educación Primaria, que resolvieron la tarea de forma grupal, durante los cursos 2019-20 (de manera virtual, 10 grupos) y 2020-21 (de manera virtual 5 grupos y presencial 7 grupos). Se analizaron las distintas resoluciones, de cada grupo para la construcción de la pieza, el cálculo del área de cada una de ellas (como paso intermedio), la cantidad de piezas necesaria y la validación de la solución (como paso final). Para estudiar el grado de creatividad se valoraron sus tres componentes: fluidez, flexibilidad y originalidad (Leikin y Lev, 2013). El valor de la creatividad de cada grupo en cada actividad se obtuvo como suma de las puntuaciones obtenidas en la flexibilidad multiplicada por las de la originalidad de todas las resoluciones dadas por ese grupo y todo ello multiplicado por la puntuación obtenida en la fluidez total. Los resultados muestran gran variedad de estrategias de resolución y permiten apreciar pequeñas diferencias en la fluidez, flexibilidad, originalidad y creatividad en función del curso y de la forma de enseñanza. Las diferencias fueron significativas únicamente en la flexibilidad entre los grupos virtuales del curso 2019-20 como los del curso 2020-21 respecto a la actividad de la construcción de la pieza. Otro resultado que cabe destacar es que prácticamente todos los grupos calcularon el área de la pieza construida, en cambio, solo el 36’36% realizó la validación del resultado. Aunque no se cuenta con una muestra amplia, estos resultados permiten abrir líneas de investigación. Esto podría tener implicaciones en la formación de los futuros docentes respecto a la capacidad de abordar situaciones de modelización matemática.[EN]The implementation of mathematical modelling problems in Primary Education constitutes an essential element in academic training plans, contributing not only to the development of mathematics in a real context for students, but also to their creativity. However, research on the impact of this kind of problem on the development of students’ creativity is scarce. The purpose of the study is to analyse the creativity of students of Master’s Degree in Primary Education at the University of Salamanca when they solve a mathematical modelling problem which consisted of making a mural of specificated dimensions that must be filled in with a certain piece. Specifically, it was asked to construct of the piece and determine the necessary number of pieces. The experience was carried out with third-year students of the Degree in Primary Education, who solved the task in small groups, in sessions during 2019-20 (virtually, 10 groups) and 2020-21 (virtually 5 groups and 7 groups respectively). The different resolutions of each group were analysed for the construction of the piece, the calculation of the area of each one of them (as an intermediate step), the necessary amount of pieces and the validation of the solution (as a final step). To study the degree of creativity, three components were valued: fluency, flexibility and originality (Leikin y Lev, 2013). The creativity value for each group in each activity was obtained as the sum of the scores obtained in flexibility multiplied by those of the originality of all the resolutions given by that group and then multiplied by the score obtained in total fluency. Results show a large variety of resolution strategies and allow us to appreciate little differences in fluency, flexibility, originality and creativity depending on the academic course and the way of teaching. The presence of significant differences was found in the flexibility between 2019-20 virtual groups and those of the 2020-21 to the construction of the piece. Another result that should be standed out is that practically all the groups calculated the area of the constructed piece, on the other hand, only 36’36% carried out the validation of the result. Although there is not a large sample, these results allow us to open lines of research. This could have implications for the training of future teachers regarding the ability to deal with mathematical modelling situations

Mejora de la resolución espectral de un monocromador usando un controlador de micropasos

En este trabajo se presenta la implementación de un controlador de micropasos para un motor paso a paso (MPP) de 1.8° por paso para aumentar la resolución espectral de un monocromador en la rendija de salida de un nanómetro a un décimo de nanómetro. El MPP está acoplado mecánicamente a una barra sinusoidal que controla la posición angular de la rejilla de difracción del monocromador. La técnica de micropasos, consiste en que un MPP alcance posiciones intermedias entre un paso y un medio paso. De esta manera, en un motor de 1.8° por paso realizando 16 micropasos por paso se puede obtener movimientos de 0.1125° por micropaso. Configurando el modo de operación de un controlador de micropasos A4988 en avances de 16 micropasos por paso es posible aumentar la resolución del MPP de 1.8° por paso a 0.1125° por micropaso, lo que significa un aumento de la resolución espectral del monocromador de un nanómetro a un décimo de nanómetro. El control del monocromador se realiza mediante una interfaz de usuario en una PC que se comunica mediante el puerto RS232 con un Arduino UNO, que controla a su vez al A4988.Palabra(s) Clave(s): Arduino, A4988, micropasos, monocromador

Mid-infrared optical properties of non-magnetic-metal/CoFeB/MgO heterostructures

We report on the optical characterization of non-magnetic metal/ferromagnetic (Co$_{20}$Fe$_{60}$B$_{20}$)/MgO heterostructures and interfaces by using mid infrared spectroscopic ellipsometry at room temperature. We extracted for the mid-infrared range the dielectric function of Co$_{20}$Fe$_{60}$B$_{20}$, that is lacking in literature, from a multisample analysis. From the optical modelling of the heterostructures we detected and determined the dielectric tensor properties of a two-dimensional gas (2DEG) forming at the non-magnetic metal and the CoFeB interface. These properties comprise independent Drude parameters for the in-plane and out-of plane tensor components, with the latter having an epsilon-near-zero frequency within our working spectral range. A feature assigned to spin-orbit coupling (SOC) is identified. Furthermore, it is found that both, the interfacial properties, 2DEG Drude parameters and SOC strength, and the apparent dielectric function of the MgO layer depend on the type of the underlying nonmagnetic metal, namely, Pt, W, or Cu. The results reported here should be useful in tailoring novel phenomena in such types of heterostructures by assessing their optical response noninvasively, complementing existing characterization tools such as angle-resolved photoemission spectroscopy, and those related to electron/spin transport.Comment: 11 pages, 7 figures. See supplemental material in 10.1088/1361-6463/acd00f/met

Estudio de reintegrantes pictóricos aplicados en la restauración de azulejería expuesta al exterior

Los productos utilizados en la reintegración cromática de azulejería expuesta al exterior ha sido un campo hasta hoy poco estudiado. Por lo general, los restauradores especializados en este tipo de material cerámico han ido experimentando, a lo largo de las últimas décadas, distintos productos comerciales, decantándose por los materiales que mejores resultados ofrecen en un inicio y son fáciles de trabajar, sin tener datos objetivos de durabilidad y estabilidad cromática que éstos ofrecen con el paso del tiempo. En este trabajo se muestran los resultados obtenidos mediante colorimetría tras realizar ensayos de envejecimiento acelerado a dos tipos de materiales utilizados en la reintegración cromática de azulejería, la resina epoxi aglutinada con pigmentos y un producto comercial, listo para su uso, denominado Cerámica en frío. De este modo se pretende comparar ambos productos en cuanto a la variación cromática que sufren ante condiciones extremas.Lastras Pérez, M.; Martínez Bazán, ML.; Martínez Cabezuelo, E.; Simón Cortés, JM. (2011). Estudio de reintegrantes pictóricos aplicados en la restauración de azulejería expuesta al exterior. Arché. (6):221-228. http://hdl.handle.net/10251/33515221228

Electron-phonon renormalization of the absorption edge of the cuprous halides

Compared to most tetrahedral semiconductors, the temperature dependence of the absorption edges of the cuprous halides (CuCl, CuBr, CuI) is very small. CuCl and CuBr show a small increase of the gap $E_0$ with increasing temperature, with a change in the slope of $E_0$ vs. $T$ at around 150 K: above this temperature, the variation of $E_0$ with $T$ becomes even smaller. This unusual behavior has been clarified for CuCl by measurements of the low temperature gap vs. the isotopic masses of both constituents, yielding an anomalous negative shift with increasing copper mass. Here we report the isotope effects of Cu and Br on the gap of CuBr, and that of Cu on the gap of CuI. The measured isotope effects allow us to understand the corresponding temperature dependences, which we also report, to our knowledge for the first time, in the case of CuI. These results enable us to develop a more quantitative understanding of the phenomena mentioned for the three halides, and to interpret other anomalies reported for the temperature dependence of the absorption gap in copper and silver chalcogenides; similarities to the behavior observed for the copper chalcopyrites are also pointed out.Comment: 14 pages, 5 figures, submitted to Phys. Rev.

Morphometry of Conception Bank: Evidence of geological and biological processes on a large volcanic seamount of the Canary Islands Seamount Province.

Concepcion Bank is the largest seamount in the Canary Islands Seamount Province (CISP), an oceanic area off NW Africa including 16 main seamounts, the Canaries archipelago and the Selvagens subarchipelago. The Bank is located 90 km northeast of Lanzarote Island and has been identified as a candidate Marine Protected Area (MPA) to be included in the Natura 2000 network. A compilation of complementary datasets consisting of multibeam bathymetry, TOPAS seismic reflection profiles, side scan sonar sonographs, Remotely Operated Vehicle video records and seafloor samples allowed describing in detail and ground truthing the submarine landforms and bioconstructions exhibited by the bank. The Concepcion Bank presently rises up to 2,433 m above the adjacent seafloor and exhibits two main domains: an extensive summit plateau and steep flanks. The sub-round summit plateau is 50km by 45 km and ranges from 158 to 1,485 m depth. The steep flanks that bound it descend to depths ranging between 1,700 and 2,500 m and define a seamount base that is 66km by 53 km. This morphology is the result of constructive and erosive processes involving different time scales, volumes of material and rates of change. The volcanic emplacement phase probably lasted 25-30 million years and was likely responsible for most of the 2,730 km3 of material that presently form the seamount. Subsequently, marine abrasion and, possibly, subaerial erosion modulated by global sea level oscillations, levelled the formerly emerging seamount summit plateau, in particular its shallower (<400 m), flatter (<0.5°) eastern half. Subsidence associated to the crustal cooling that followed the emplacement phase further contributed the current depth range of the seamount. The deeper and steeper (2.3°) western half of Concepcion Bank may result from tectonic tilting normal to a NNE-SSW fracture line. This fracture may still be expressed on the seafloor surface at some scarps detected on the seamount's summit. Sediment waves and cold-water coral (CWC) mounds on the bank summit plateau are the youngest features contributing to its final shaping, and may be indicative of internal wave effects. Numerous submarine canyons generally less than 10 km in length are incised on the bank's flanks. The most developed, hierarchized canyon system runs southwest of the bank, where it merges with other canyons coming from the southern bulges attached to some sections of the seamount flanks. These bulges are postulated as having an intrusive origin, as no major headwall landslide scars have been detected and their role as deposition areas for the submarine canyons seems to be minor. The results presented document how geological processes in the past and recent to subrecent oceanographic conditions and associated active processes determined the current physiography, morphology and sedimentary patterns of Concepcion Bank, including the development and decline of CWC mounds The setting of the seamount in the regional crustal structure is also discussed

Infrared Ellipsometry Analysis of Heritage Photographic Prints

[EN] Focusing on the photographic archive of Julian Carrillo (Mexico), we study and characterize the photographic processes of a set of 13 photographs dated between 1884 and 1925. By using infrared spectroscopic ellipsometry, we classified a selected set of photographs according to its kind of binder. Thus, we recognized for each photograph, the presence of proteins, and therefore, the particular photographic process. Furthermore, we have identified the presence of baryta layer, the use of plasticizer, and the eventual coating utilized to protect the photograph, whose composition was based in natural organic components, mainly shellac, beeswax, or camphorNieto-Villena, A.; Martinez, JR.; Flores-Camacho, JM.; Lastras-Martinez, A.; De La Cruz-Mendoza, JA.; Ortega-Zarzosa, G.; Valcarcel Andrés, JC.... (2018). Infrared Ellipsometry Analysis of Heritage Photographic Prints. Studies in Conservation. 63(8):466-476. https://doi.org/10.1080/00393630.2018.1476962S466476638Brambilla, L., Riedo, C., Baraldi, C., Nevin, A., Gamberini, M. C., D’Andrea, C., … Toniolo, L. (2011). Characterization of fresh and aged natural ingredients used in historical ointments by molecular spectroscopic techniques: IR, Raman and fluorescence. Analytical and Bioanalytical Chemistry, 401(6), 1827-1837. doi:10.1007/s00216-011-5168-zCasoli, A., & Fornaciari, S. (2014). An analytical study on an early twentieth-century Italian photographs collection by means of microscopic and spectroscopic techniques. Microchemical Journal, 116, 24-30. doi:10.1016/j.microc.2014.04.003Cattaneo, B., Chelazzi, D., Giorgi, R., Serena, T., Merlo, C., & Baglioni, P. (2008). Physico-chemical characterization and conservation issues of photographs dated between 1890 and 1910. Journal of Cultural Heritage, 9(3), 277-284. doi:10.1016/j.culher.2008.01.004Daher, C., Paris, C., Le Hô, A.-S., Bellot-Gurlet, L., & Échard, J.-P. (2010). A joint use of Raman and infrared spectroscopies for the identification of natural organic media used in ancient varnishes. Journal of Raman Spectroscopy, 41(11), 1494-1499. doi:10.1002/jrs.2693Edwards, H. G. M., Farwell, D. W., & Daffner, L. (1996). Fourier-transform Raman spectroscopic study of natural waxes and resins. I. Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 52(12), 1639-1648. doi:10.1016/0584-8539(96)01730-8Fujiwara, H. (2007). Spectroscopic Ellipsometry. doi:10.1002/9780470060193Hendriks, K., & Ross, L. (1988). Chemical Treatments of Discoloured Photographic Prints: Image Manipulation or Legitimate Restoration? The Journal of Photographic Science, 36(3), 132-132. doi:10.1080/00223638.1988.11736990Mallégol, J., Gardette, J.-L., & Lemaire, J. (2000). Long-term behavior of oil-based varnishes and paints. Photo- and thermooxidation of cured linseed oil. Journal of the American Oil Chemists’ Society, 77(3), 257-263. doi:10.1007/s11746-000-0042-4Nieto-Villena, A., Martínez, J. R., de la Cruz-Mendoza, J. A., Valcárcel-Andrés, J. C., Ortega-Zarzosa, G., Solbes-García, Á., & Vázquez-Martínez, E. (2018). Atomic force microscopy as a tool for binder identification in ancient photographic processes. Surface and Interface Analysis, 50(4), 496-505. doi:10.1002/sia.6408Ostroff, Eugene. 1966. “Restoration of Photographs by Neutron Activation.” Science 154 (3745): 119–123. http://science.sciencemag.org/content/154/3745/119.Othmer, Kirk, ed. 2005. Encyclopedia of Chemical Technology. Vol. 17, 5th ed. New York: Wiley.Ricci, C., Bloxham, S., & Kazarian, S. G. (2007). ATR-FTIR imaging of albumen photographic prints. Journal of Cultural Heritage, 8(4), 387-395. doi:10.1016/j.culher.2007.07.002Sifontes, Á. B., Cañizales, E., Toro-Mendoza, J., Ávila, E., Hernández, P., Delgado, B. A., … Cruz-Barrios, E. (2015). Obtaining Highly Crystalline Barium Sulphate Nanoparticles via Chemical Precipitation and Quenching in Absence of Polymer Stabilizers. Journal of Nanomaterials, 2015, 1-8. doi:10.1155/2015/510376Stulik, Dusan, Herant Khanjian, Alberto de Tagle, and Alexandra M. Botelho. 2002. “Investigation of Jean-Louis-Marie-Eugene Durieu’s Toning and Varnishing Experiments: A Non-Destructive Approach.” ICOM Committee for Conservation 13th Triennial Meeting, Río de Janeiro, 658–663.Price, Beth A., and Boris Pretzel, eds. 2009. Infrared and Raman Users Group Spectral Database. 2007 ed. Vol. 1 & 2. Philadelphia: IRUG. Accessed June 20, 2014. http://www.irug.org/.Vila, A., & Centeno, S. A. (2013). FTIR, Raman and XRF identification of the image materials in turn of the 20th century pigment-based photographs. Microchemical Journal, 106, 255-262. doi:10.1016/j.microc.2012.07.01