Empirical calibration of the near-IR Ca II triplet - I. The stellar library and index definition

A new stellar library at the near-IR spectral region developed for the empirical calibration of the Ca II triplet and stellar population synthesis modeling is presented. The library covers the range 8348-9020 Angstrom at 1.5 Angstrom (FWHM) spectral resolution, and consists of 706 stars spanning a wide range in atmospheric parameters. We have defined a new set of near-IR indices, CaT*, CaT and PaT, which mostly overcome the limitations of previous definitions, the former being specially suited for the measurement of the Ca II triplet strength corrected for the contamination from Paschen lines. We also present a comparative study of the new and the previous calcium indices, as well as the corresponding transformations between the different systems. A thorough analysis of the sources of index errors and the procedure to calculate them is given. Finally, index and error measurements for the whole stellar library are provided together with the final spectra.Comment: 24 pages, 10 figures, LaTeX. For associated spectra, tables and software, see http://www.ucm.es/info/Astrof/ellipt/CATRIPLET.html or http://www.nottingham.ac.uk/~ppzrfp/CATRIPLET.htm

The dynamics of vortices on S^2 near the Bradlow limit

The explicit solutions of the Bogomolny equations for N vortices on a sphere of radius R^2 > N are not known. In particular, this has prevented the use of the geodesic approximation to describe the low energy vortex dynamics. In this paper we introduce an approximate general solution of the equations, valid for R^2 close to N, which has many properties of the true solutions, including the same moduli space CP^N. Within the framework of the geodesic approximation, the metric on the moduli space is then computed to be proportional to the Fubini- Study metric, which leads to a complete description of the particle dynamics.Comment: 17 pages, 9 figure

Efectos de la aplicación de secuencias didácticas en el aprendizaje del concepto de función bajo la teoría de las representaciones semióticas con docentes en formación

El concepto matemático más importante en la transición de la educación media a la educación superior, es el de función. Al ingresar a la universidad los estudiantes inician con el curso de cálculo diferencial donde este concepto se hace imprescindible para el desarrollo de los contenidos. Investigaciones precedidas a esta permitieron identificar debilidades en los estudiantes recurrentes en los últimos cuatro semestres, por ello, se propone una serie de secuencias didácticas con el fin de mejorar el aprendizaje de la temática a abordar. Partiendo desde las investigaciones que afirman que el estudiante tiene total apropiación del concepto cuando hace transformaciones coherentes entre los diferentes registros de representación, se definen las secuencias didácticas bajo la teoría de las representaciones semióticas. Para esta investigación se tomó como población a los docentes en formación del programa de Licenciatura en Matemáticas de la Universidad Francisco de Paula Santander matriculados en el I semestre de 2018

Superconductivity and charge carrier localization in ultrathin La1.85Sr0.15CuO4/La2CuO4\mathbf{{La_{1.85}Sr_{0.15}CuO_4}/{La_2CuO_4}} bilayers

$\mathrm{La_{1.85}Sr_{0.15}CuO_4}$/$\mathrm{La_2CuO_4}$ (LSCO15/LCO) bilayers with a precisely controlled thickness of N unit cells (UCs) of the former and M UCs of the latter ([LSCO15\_N/LCO\_M]) were grown on (001)-oriented {\slao} (SLAO) substrates with pulsed laser deposition (PLD). X-ray diffraction and reciprocal space map (RSM) studies confirmed the epitaxial growth of the bilayers and showed that a [LSCO15\_2/LCO\_2] bilayer is fully strained, whereas a [LSCO15\_2/LCO\_7] bilayer is already partially relaxed. The \textit{in situ} monitoring of the growth with reflection high energy electron diffraction (RHEED) revealed that the gas environment during deposition has a surprisingly strong effect on the growth mode and thus on the amount of disorder in the first UC of LSCO15 (or the first two monolayers of LSCO15 containing one $\mathrm{CuO_2}$ plane each). For samples grown in pure $\mathrm{N_2O}$ gas (growth type-B), the first LSCO15 UC next to the SLAO substrate is strongly disordered. This disorder is strongly reduced if the growth is performed in a mixture of $\mathrm{N_2O}$ and $\mathrm{O_2}$ gas (growth type-A). Electric transport measurements confirmed that the first UC of LSCO15 next to the SLAO substrate is highly resistive and shows no sign of superconductivity for growth type-B, whereas it is superconducting for growth type-A. Furthermore, we found, rather surprisingly, that the conductivity of the LSCO15 UC next to the LCO capping layer strongly depends on the thickness of the latter. A LCO capping layer with 7~UCs leads to a strong localization of the charge carriers in the adjacent LSCO15 UC and suppresses superconductivity. The magneto-transport data suggest a similarity with the case of weakly hole doped LSCO single crystals that are in a so-called {"{cluster-spin-glass state}"

Modelo de gesti?n para la convivencia escolar basado en la conducta social

166 p. Recurso Electr?nicoLa gesti?n escolar en los establecimientos es un proceso sistem?tico que est? orientado al fortalecimiento de las instituciones y sus proyectos, con el fin de enriquecer los procesos pedag?gicos, directivos, comunitarios y administrativos. Existen infinidad de mecanismos para el mejoramiento de la convivencia, en la mayor?a de los casos descontextualizados. Por tal motivo, una estrategia de intervenci?n que surge de los problemas de conducta y personalidad de los estudiantes, permite garantizar un mayor grado de efectividad para la implementaci?n y el compromiso de los actores. La Instituci?n Educativa La Tigrera ubicada en la zona rural del municipio de Alvarado Tolima, no es ajena a los problemas de convivencia escolar; en ella, se presenta agresi?n f?sica, verbal, sexual, discriminaci?n de diversos tipos, sustentado en los anecdotarios de los estudiantes e indicadores de las pruebas externas que se aplican por el ICFES. Dicha situaci?n, es la motivaci?n para desarrollar la propuesta de investigaci?n titulada Modelo de Gesti?n para la Convivencia Escolar Basado en la Conducta Social, en la cual se plantea la identificaci?n de aspectos facilitadores y perturbadores del comportamiento social que determinan el perfil de socializaci?n de los estudiantes de la instituci?n. Los resultados de la aplicaci?n de las bater?as de socializaci?n permitieron identificar los elementos cr?ticos que requer?an una acci?n para mitigar los efectos sobre la convivencia escolar; constituy?ndose en la base previa para la estructuraci?n de una rueda l?gica, que permita generar acciones de mejora contempladas en la construcci?n e implementaci?n de la propuesta. Una vez implementado el modelo de gesti?n por parte de los directivos, docentes, padres de familia y estudiantes se aplic? una prueba post test para obtener los resultados y poder analizar los datos que permiten dar comprobaci?n de las hip?tesis planteadas. Es de resaltar, que la metodolog?a pretende un alcance descriptivo, un enfoque cuantitativo y un dise?o de tipo pre experimental; con una muestra no param?trica de la poblaci?n. Palabras Clave: Convivencia, Conducta, Gesti?n, Escolar.Management in educational institutions is a systematic process focused on the school strengthening and its projects, in order to improve pedagogical, managerial, community and administrative processes. There are many mechanisms for the school life improvement in most decontextualized cases. For this reason, an intervention strategy is arisen on the behavior and personality students problems, making it possible to guarantee greater effectiveness in the implementation and actors commitment. La Tigrera School located in Alvarado - Tolima rural area is no stranger to the living together problems; it presents physical, verbal and sexual assaults, various types of discrimination, reflected in the students' academic records and external tests indicators applied by ICFES. Previous context is motivation to develop this research called MANAGEMENT MODEL FOR SCHOOL LIFE BASED ON SOCIAL BEHAVIOR, in which, to identify facilitating and disturbing aspects of social behavior that determine socialization profile of the students is raised. Results from Socialization Batteries Test allowed identifying critical elements that required an action to mitigate effects on school life, constituting itself in the previous base for ?the logical wheel? structuring; it favored generating improvement actions contemplated in the proposal (construction and implementation). Once model was implemented by management team, teachers, parents and students, a post-test was applied to obtain results and analyze data that allow verifying hypotheses. In this way, methodology aims at a descriptive scope, a quantitative approach and a pre-experimental type design; with a population non-parametric sample. Keywords: School life, social behavior, School Management

Controlling the charge state of single Mo dopants in a CaO film

Recent experiments have demonstrated that tiny amounts of Mo impurities give rise to drastic changes in the adsorption characteristic of a wide-gap CaO(001) film. In this scanning tunneling microscopy (STM) and density functional theory paper, we elucidate the underlying mechanism by analyzing the energy levels of the Mo dopants as a function of their oxidation state and depth below the surface. We show that Mo2+ ions in CaO subsurface layers can be reversibly charged and discharged by inducing local band-bending effects with the STM tip. A similar charge switching is not possible for Mo species in a higher oxidation state, as their highest-occupied molecular orbitals are located well below the onset of the CaO conduction band. The easiness of charge switching in Mo2+ ions explains the remarkable chemical properties of doped CaO films, as it renders the material a strong electron donor to adsorbates bound to the oxide surface

An?lisis de la evoluci?n de las concepciones de la ndc a trav?s de secuencias did?cticas centradas en aspectos sociol?gicos de la nomenclatura de compuestos qu?micos inorg?nicos

146 P?ginasRecurso Electr?nicoLa presente investigaci?n tiene como objeto de estudio determinar la evoluci?n de las concepciones sobre Naturaleza de la Ciencia ?NdC? que tienen los estudiantes de educaci?n media colombiana a trav?s de secuencias did?cticas centrada en aspectos sociol?gicos de la Nomenclatura de Compuestos Qu?micos Inorg?nicos ?NCQI?. El problema de investigaci?n se sustenta desde la perspectiva te?rica de la naturaleza de ciencia y las concepciones metadisciplinares que los estudiantes tienen sobre ?sta. Se plantea un estudio de car?cter educativo, bajo un enfoque cualitativo-hermen?utico. En el an?lisis de contenido se identific? el sentido expl?cito de las ideas de los estudiantes acerca de la Nomenclatura de Compuestos Qu?micos Inorg?nicos ?NCQI? y la incidencia de estos compuestos en el medio ambiente. El proceso de investigaci?n estuvo regido por un sistema categorial que orient? el proceso, el cual se encuentra en el marco de los consensos de naturaleza de ciencia (Aduriz, 2001). En los resultados y las conclusiones se presentan las concepciones que tienen los estudiantes sobre NdC desde el componente sociol?gico de la NCQI a partir de la incidencia de la aplicaci?n de las secuencias did?cticas en la evoluci?n conceptual.ABSTRACT. This research study aims to determine the evolution of the conceptions of Nature of Science "NdC" with the Colombian high school students through didactic sequences focused on sociological aspects of the Nomenclature of Inorganic Chemistry "NCQI". The research problem is based from the theoretical perspective of the nature of science and metadisciplinares conceptions that students have on it. A study of educational, low-hermeneutic qualitative approach arises. In content analysis explicit meanings of the ideas of students about the Nomenclature of Inorganic Chemistry "NCQI" and the incidence of these compounds in the environment are identified. The research process was governed by a categorical system that guided the process, which is part of the consensus nature of science (Aduriz, 2001). The results and conclusions conceptions that students have about NdC from the sociological component NCQI from the impact of the application of didactic sequences in the conceptual evolution are presented.INTRODUCCI?N 16 1. PLANTEAMIENTO DEL PROBLEMA 18 2. JUSTIFICACI?N 18 3. OBJETIVOS 24 3.1. OBJETIVO GENERAL 24 3.2. OBJETIVOS ESPEC?FICOS 24 4. MARCO TE?RICO 25 4.1. ANTECEDENTES 25 4.1.1. Generalidades Did?ctica de las Ciencias 25 4.1.2. Ense?anza de las ciencias 26 4.2. CONCEPTUALIZACI?N DE NdC 31 4.2.1. Naturaleza de la ciencia 31 4.3. COMPONENTE SOCIOL?GICO DE LA CIENCIA 32 4.3.1. Concepciones de NdC 34 4.4. EDUCACI?N DE LA QU?MICA 29 4.5. EL MEDIO AMBIENTE UN EXPERIMENTO QU?MICO. 38 4.6. LA NdC EN LA QU?MICA 39 5. DISE?O METODOL?GICO 44 5.1. ETAPAS METODOL?GICAS 44 5.2. DISE?O DE LA INVESTIGACI?N 46 5.3. DISE?O DID?CTICO 49 5.4. UNIVERSO DOCUMENTAL 50 5.5. AN?LISIS DE CONTENIDO 54 5.5.1. Proceso de an?lisis 54 5.5.2. Documentos usados 54 5.5.3. Categorizaci?n 54 5.5. CARACTERIZACI?N DEL CONTEXTO 54 5.5.1. Poblaci?n objeto. 55 6. RESULTADOS 57 6.1. An?lisis de datos del pre-test del COCTS de Clasificaci?n en La Ciencia 57 6.1.1. An?lisis por categor?as 59 6.2. AN?LISIS DE DATOS DEL PRE-TEST DEL COCTS 60 6.3. RESULTADOS DESCRIPTIVOS CUALITATIVOS. 61 6.3.1. Resultados de la aplicaci?n de la Secuencia did?ctica No.1 61 6.3.2. Resultados de la aplicaci?n de la Secuencia did?ctica No.2 75 6.4. AN?LISIS DE DATOS DEL POST-TEST DEL COCTS DE CLASIFICACI?N EN LA CIENCIA 102 6.5. AN?LISIS DE DATOS DEL POST-TEST DEL COCTS DE MODELOS CIENT?FICOS 103 7. CONCLUSIONES 104 REFERENCIAS 107 ANEXOS 11