Los applets para la enseñanza de la estadística y probabilidad.

Resumen tomado de la publicación

Múltiplos y divisores : una aplicación del material Plot.

Proyecto realizado por 6 profesores integrados en el grupo GAUSS y que ejercen su labor docente en diferentes centros públicos y privados-concertados, en los niveles de Primaria y Secundaria de la provincia de Salamanca. Tienen como objetivo: Elaborar una Unidad Didáctica de Matemáticas para la Educación Secundaria Obligatoria con las siguientes características: utilizar como base el material Plot; parte de la experiencia práctica (manipulación) hacia las estructuras conceptuales. La organización del aula será en pequeños grupos de 4-6 miembros. El desarrollo de la experiencia pasó por las siguientes fases: -elaboración de guiones de trabajo; -adquisición de materiales; -experimentación de la unidad en los Centros; -valoración de resultados. Los materiales entregados constan de una guía para el profesor y materiales para el alumno. El trabajo no está publicado..

Desarrollo de un programa informático de simulación de ciclos económicos.

Se trata esencialmente de resolver dos problemas básicos:Por una parte contar con apoyos fundamentales para el análisis teórico y empírico de los modelos dinámicos, con aplicaciones al caso español; y, en segundo término, disponer de una herramienta computacional para hacer frente a una de las áreas peor estudiadas del análisis económico. Se generan y resuelven cuatro modelos para revisar y evaluar computacionalmente cuatro áreas que combinan la ausencia y/o presencia de sector público, junto con las alternativas de trabajo divisible y nodivisible. Los programas informáticos permiten resolver y simular los modelos del ciclo comentados, y presentan para cada caso una vertiente específica escrita en Matemática y otra genérica escrita en lenguaje Gauss común para todos los modelos. Este programa proporciona una primera descripción estadística de los resultados, que resulta útil para determinar a grandes rasgos el ajuste de la simulación de los datos reales. Rodado el programa se pueden hacer aparecer en pantalla las series de desviaciones de las macrovariables fundamentales: el PIB, los consumos privado y público, el empleo, la acumulación de capital, etc. El objetivo esencial de esta estructura de apoyo a la práctica docente se satisface con gran facilidad de manejo. Por otra parte, estimula el manejo y la introducción de datos relativos a la estructura de la economía, la incorporación, el análisis deratios productivos y de mercado, la familiarización con coeficientes de correlación de los shocks tecnológicos, y la calibración del conjunto de elementos incorporados, como propuestas de comportamiento económico a corroborar. Es un programa nuevo, completo y asequible para mejorar la docencia en el área..

Taller de matemáticas.

Se realiza simultáneamente en dos Institutos de Bachillerato de Salamanca, con dos profesores implicados pertenecientes al Grupo GAUSS. Tiene como objetivos el romper un horario lectivo casi exclusivamente teórico con actividades fundamentalmente creadoras, manipulativas e investigadoras. Intentar una integración total del alumnado en la clase de matemáticas. Tiene como metodología práctica 'La Resolución de Problemas'. Se elaboran materiales a lo largo de todo el curso, se realizó la presentación de los mismos en Jornadas dirigidas a Profesores y en una Exposición-Taller de Materiales Didácticos. La valoración se realiza a través de una encuesta y exposición de los trabajos realizados. El trabajo no está publicado..

Ermeneutica della differenza

Resumen tomado de la publicaci??n

Características y factores incidentes en la estimación métrica longitudinal.

Se presenta una investigación con tres objetivos. El primero es detectar los procedimientos, recursos y estrategias que se aplican en la estimación métrica, su utilización y nivel de precisión. El segundo consiste en analizar cómo se organizan y se generan estas estructuras mentales estimativas. El último trata de plantear un enfoque didáctico que mejore su aprendizaje. Los resultados evidencian la educabilidad de la estimación métrica, el poco dominio que se tiene de ella y la insignificante incidencia de la educación formal en este aprendizaje, la casi nula correlación de las variables analizadas respecto a este dominio y que la capacidad en la estimación longitudinal rectilínea no incide en la mejora de la curvilínea, la cual necesita de procedimientos, recursos y estrategias diferentes. Se destaca la importancia de la visualización, manipulación y transformación de imágenes mentales como base del poder estimativo y para los procedimientos de transformación geométrica como la rectificación, la cuadratura y la curvalización.

El cálculo de la fecha del día de Pascua : un problema matemático de congruencias.

Analiza cada uno de los métodos de cálculo de la fecha del día de Pascua de Resurrección partiendo de los primeros siglos y pasando por el método de Gauss, el método de Hartmann y el método de Butcher.

Kipus: revista andina de letras. 20 (Reseñas)

Presenta las reseñas de los siguietnes libros: FERNANDO ALBÁN, CRISTINA BURNEO, SANTIAGO CEVALLOS E IVÁN CARVAJAL, LA CUADRATURA DEL CíRCULO. CUATRO ENSAYOS SOBRE LA CULTURA ECUATORIANA Quito: Corporación Cultural Orogenia, 2006, 297 pp. -- JUAN VALDANO, IDENTIDAD y FORMAS DE LO ECUATORIANO Quito: Eskeletra, 2006, 474 pp. -- CECILIA MAFLA BUSTAMANTE, ARí-sí-YES. ANÁLISIS LINGüíSTICO y EVALUACiÓN DE LAS TRADUCCIONES DE HUASIPUNGO AL INGLÉS Quito: Ediciones Abya-Yala, 2004. -- ROBERTO BOLAÑo, 2666 Barcelona: Anagrama, 2005, 1.125 pp. -- LUCRECIA MALDONADO, SALVO EL CALVARIO Quito: Planeta, 2005, 237 pp . -- RAÚL ARIAS, DUENDE ESCAPADO DEL ESPEJO Quito: Machete Rabioso Editores, 2006, 119 pp. -- JORGE ICAZA, TEATRO Quito: Comisión Nacional Permanente de Conmempraciones Cívicas I Libresa, 2006, 119 pp. -- MARíA LEONOR BAQUERIZO, LAs GRANDES COSAS SE PIERDEN EN LA NIEBLA Guayaquil: [s.i.1, 2005, 87 pp. -- RAÚL SERRANO SÁNCHEZ, CATÁLOGO DE ILUSIONES Quito: Eskeletra, 2006, 152 pp. -- CARLOS MARTíNEZ SARASOLA, NUESTROS PAISANOS LOS INDIOS Buenos Aires: Emecé Memoria Argentina, 2005. -- STALIN ALVEAR, EL REINO DE LOS VENCIDOS Quito: Libresa, Colección Crónica de sueños, 2006, 157 pp. -- MARCELO BÁEZ, DALTON OSORNO, EDITS., EL ESCOTE DE LO OCULTO: ANTOLOGÍA DEL RELATO PROHIBIDO Quito: b@ez.editor.es I Libresa, 2006, 183 pp. -- ALEYDA QUEVEDO ROJAS1 SOY MI CUERPO Quito: Libresa, 2006, 89 pp.

Radiative forcing since preindustrial times due to ozone change in the troposphere and the lower stratosphere

Changes in atmospheric ozone have occurred since the preindustrial era as a result of increasing anthropogenic emissions. Within ACCENT, a European Network of Excellence, ozone changes between 1850 and 2000 are assessed for the troposphere and the lower stratosphere ( up to 30 km) by a variety of seven chemistry-climate models and three chemical transport models. The modeled ozone changes are taken as input for detailed calculations of radiative forcing. When only changes in chemistry are considered ( constant climate) the modeled global-mean tropospheric ozone column increase since preindustrial times ranges from 7.9 DU to 13.8 DU among the ten participating models, while the stratospheric column reduction lies between 14.1 DU and 28.6 DU in the models considering stratospheric chemistry. The resulting radiative forcing is strongly dependent on the location and altitude of the modeled ozone change and varies between 0.25 Wm(-2) and 0.45 Wm(-2) due to ozone change in the troposphere and - 0.123 Wm(-2) and + 0.066 Wm(-2) due to the stratospheric ozone change. Changes in ozone and other greenhouse gases since preindustrial times have altered climate. Six out of the ten participating models have performed an additional calculation taking into account both chemical and climate change. In most models the isolated effect of climate change is an enhancement of the tropospheric ozone column increase, while the stratospheric reduction becomes slightly less severe. In the three climate-chemistry models with detailed tropospheric and stratospheric chemistry the inclusion of climate change increases the resulting radiative forcing due to tropospheric ozone change by up to 0.10 Wm(-2), while the radiative forcing due to stratospheric ozone change is reduced by up to 0.034 Wm(-2). Considering tropospheric and stratospheric change combined, the total ozone column change is negative while the resulting net radiative forcing is positive.

Direct radiative effect of aerosols emitted by transport from road, shipping and aviation

Aerosols and their precursors are emitted abundantly by transport activities. Transportation constitutes one of the fastest growing activities and its growth is predicted to increase significantly in the future. Previous studies have estimated the aerosol direct radiative forcing from one transport sub-sector, but only one study to our knowledge estimated the range of radiative forcing from the main aerosol components (sulphate, black carbon (BC) and organic carbon) for the whole transportation sector. In this study, we compare results from two different chemical transport models and three radiation codes under different hypothesis of mixing: internal and external mixing using emission inventories for the year 2000. The main results from this study consist of a positive direct radiative forcing for aerosols emitted by road traffic of +20±11 mW m−2 for an externally mixed aerosol, and of +32±13 mW m−2 when BC is internally mixed. These direct radiative forcings are much higher than the previously published estimate of +3±11 mW m−2. For transport activities from shipping, the net direct aerosol radiative forcing is negative. This forcing is dominated by the contribution of the sulphate. For both an external and an internal mixture, the radiative forcing from shipping is estimated at −26±4 mW m−2. These estimates are in very good agreement with the range of a previously published one (from −46 to −13 mW m−2) but with a much narrower range. By contrast, the direct aerosol forcing from aviation is estimated to be small, and in the range −0.9 to +0.3 mW m−2.

Variational calculations of rovibrational states: a precise high-energy potential surface for HCN [and discussion]

We report the results of variational calculations of the rovibrational energy levels of HCN for J = 0, 1 and 2, where we reproduce all the ca. 100 observed vibrational states for all observed isotopic species, with energies up to 18000 cm$^{-1}$, to about $\pm $1 cm$^{-1}$, and the corresponding rotational constants to about $\pm $0.001 cm$^{-1}$. We use a hamiltonian expressed in internal coordinates r$_{1}$, r$_{2}$ and $\theta $, using the exact expression for the kinetic energy operator T obtained by direct transformation from the cartesian representation. The potential energy V is expressed as a polynomial expansion in the Morse coordinates y$_{i}$ for the bond stretches and the interbond angle $\theta $. The basis functions are built as products of appropriately scaled Morse functions in the bond-stretches and Legendre or associated Legendre polynomials of cos $\theta $ in the angle bend, and we evaluate matrix elements by Gauss quadrature. The hamiltonian matripx is factorized using the full rovibrational symmetry, and the basis is contracted to an optimized form; the dimensions of the final hamiltonian matrix vary from 240 $\times $ 240 to 1000 $\times $ 1000.We believe that our calculation is converged to better than 1 cm$^{-1}$ at 18 000 cm$^{-1}$. Our potential surface is expressed in terms of 31 parameters, about half of which have been refined by least squares to optimize the fit to the experimental data. The advantages and disadvantages and the future potential of calculations of this type are discussed.

Radiative forcing due to changes in ozone and methane caused by the transport sector

The year 2000 radiative forcing (RF) due to changes in O3 and CH4 (and the CH4-induced stratospheric water vapour) as a result of emissions of short-lived gases (oxides of nitrogen (NOx), carbon monoxide and non-methane hydrocarbons) from three transport sectors (ROAD, maritime SHIPping and AIRcraft) are calculated using results from five global atmospheric chemistry models. Using results from these models plus other published data, we quantify the uncertainties. The RF due to short-term O3 changes (i.e. as an immediate response to the emissions without allowing for the long-term CH4 changes) is positive and highest for ROAD transport (31mWm-2) compared to SHIP (24 mWm-2) and AIR (17 mWm-2) sectors in four of the models. All five models calculate negative RF from the CH4 perturbations, with a larger impact from the SHIP sector than for ROAD and AIR. The net RF of O3 and CH4 combined (i.e. including the impact of CH4 on ozone and stratospheric water vapour) is positive for ROAD (+16(±13)(one standard deviation) mWm-2) and AIR (+6(±5) mWm-2) traffic sectors and is negative for SHIP (-18(±10) mWm-2) sector in all five models. Global Warming Potentials (GWP) and Global Temperature change Potentials (GTP) are presented for AIR NOx emissions; there is a wide spread in the results from the 5 chemistry models, and it is shown that differences in the methane response relative to the O3 response drive much of the spread.

A new cyano-bridged one-dimensional (GdFeIII)-Fe-III coordination polymer with o-phenanthroline as the blocking ligand: synthesis, structure, and magnetic properties

Synthesis, structural characterization, and magnetic properties of a new cyano-bridged one-dimensional iron (III)-gadolinium (III) compound, trans-[Gd(o-phen)(2)(H2O)(2)(mu-CN)(2)Fe(CN)(4)], - 2no-phen (o-phen = 1,10-phenanthroline), have been described. The compound crystallizes in the triclinic P (1) over bar space group with the following unit cell parameters: a = 10.538(14) angstrom, b = 12.004(14) angstrom, c = 20.61(2) angstrom, alpha = 92.41(1)degrees, beta = 92.76(1)degrees, gamma = 11 2.72(1)degrees, and Z = 2. In this complex, each gadolinium (III) is coordinated to two nitrile nitrogens of the CN groups coming from two different ferricyanides, the mutually trans cyanides of each of which links another different Gd-III to create -NC-Fe(CN)(4)-CN-Gd-NC- type 1-D chain structure. The one-dimensional chains are self-assembled in two-dimensions via weak C-H center dot center dot center dot N hydrogen bonds. Both the variable-temperature (2-300 K, 0.01 T and 0.8 T) and variable-field (0-50 000 Gauss, 2 K) magnetic measurements reveal the existence of very weak interaction in this molecule. The temperature dependence of the susceptibilities has been analyzed using a model for a chain of alternating classic (7/2) and quantum (1/2) spins. (c) 2005 Elsevier B.V. All rights reserved.

A fast identification algorithm for Box-Cox transformation based radial basis function neural network

In this letter, a Box-Cox transformation-based radial basis function (RBF) neural network is introduced using the RBF neural network to represent the transformed system output. Initially a fixed and moderate sized RBF model base is derived based on a rank revealing orthogonal matrix triangularization (QR decomposition). Then a new fast identification algorithm is introduced using Gauss-Newton algorithm to derive the required Box-Cox transformation, based on a maximum likelihood estimator. The main contribution of this letter is to explore the special structure of the proposed RBF neural network for computational efficiency by utilizing the inverse of matrix block decomposition lemma. Finally, the Box-Cox transformation-based RBF neural network, with good generalization and sparsity, is identified based on the derived optimal Box-Cox transformation and a D-optimality-based orthogonal forward regression algorithm. The proposed algorithm and its efficacy are demonstrated with an illustrative example in comparison with support vector machine regression.

Modified radial basis function neural network using output transformation

A modified radial basis function (RBF) neural network and its identification algorithm based on observational data with heterogeneous noise are introduced. The transformed system output of Box-Cox is represented by the RBF neural network. To identify the model from observational data, the singular value decomposition of the full regression matrix consisting of basis functions formed by system input data is initially carried out and a new fast identification method is then developed using Gauss-Newton algorithm to derive the required Box-Cox transformation, based on a maximum likelihood estimator (MLE) for a model base spanned by the largest eigenvectors. Finally, the Box-Cox transformation-based RBF neural network, with good generalisation and sparsity, is identified based on the derived optimal Box-Cox transformation and an orthogonal forward regression algorithm using a pseudo-PRESS statistic to select a sparse RBF model with good generalisation. The proposed algorithm and its efficacy are demonstrated with numerical examples.