El análisis de los efectos de la escuela sobre el rendimiento académico en matemáticas: un análisis multinivel con datos de PISA 2003

Esta investigación, enmarcada dentro del movimiento sobre Eficacia de la Escuela, realiza una explotación parcial de los datos PISA 2003, para el territorio español, obtenidos en la investigación llevada a cabo por la OCDE. El alumnado español que ha participado en el estudio PISA, supone un total de 10.791 estudiantes de 383 centros de Educación Secundaría pertenecientes a varias Comunidades Autónomas. Las variables predictoras que forman parte de la investigación se obtienen de alumno y del centro. La variable de respuesta, desde un enfoque criterial, establece información sobre el nivel de competencias alcanzado por el alumno en matemáticas. Los resultados del análisis multinivel proporcionan diferentes modelos que tratan de explicar la variabilidad observada entre los centros a través de la incorporación de sus variables. El modelo resultante reconoce que las variables de centro: titularidad, porcentaje de alumnas, fomento de actividades matemáticas y compromiso y moral del alumnado se relacionan con el rendimiento en matemáticas.

Repeatability, reproducibility, and accuracy of a novel pushbroom hyperspectral system

This study analyzes the repeatability, reproducibility and accuracy of a new hyperspectral system based on a pushbroom sensor as a means of measuring spectral features and color of materials and objects. The hyperspectral system consisted of a CCD camera, a spectrograph and an objective lens. An additional linear moving system allowed the mechanical scanning of the complete scene. A uniform overhead luminaire with daylight configuration was used to irradiate the scene using d:45 geometry. We followed the guidelines of the ASTM E2214-08 Standard Practice for Specifying and Verifying the Performance of Color-Measuring Instruments that define the standards and latest multidimensional procedures. The results obtained are analyzed in-depth and compared to those recently reported by other authors for spectrophotometers and multispectral systems. It can be concluded that hyperspectral systems are reliable and can be used in the industry to perform spectral and color readings with a high spatial resolution.

Reproducibility comparison among multiangle spectrophotometers

New color-measuring instruments known as multiangle spectrophotometers have been recently created to measure and characterize the goniochromism of special-effect pigments in many materials with a particular visual appearance (metallic, interference, pearlescent, sparkle, or glitter). These devices measure the gonioapparent color from the spectral relative reflectance factor and the L*a*b* values of the sample with different illumination and observation angles. These angles usually coincide with requirements marked in American Society for Testing and Materials (ASTM) and Deutsches Institut Für Normung standards relating to the gonioapparent color, but the results of comparisons between these instruments are still inconclusive. Therefore, the main purpose of this study is to compare several multiangle spectrophotometers at a reproducibility level according to ASTM E2214-08 guidelines. In particular, we compared two X-Rite multi-gonio spectrophotometers (MA98 and MA68II), a Datacolor multi-gonio spectrophotometer (FX10), and a BYK multi-gonio spectrophotometer (BYK-mac). These instruments share only five common measurement geometries: 45° × −30° (as 15°), 45° × −20° (as 25°), 45° × 0° (as 45°), 45° × 30° (as 75°), 45° × 65° (as 110°). Specific statistical studies were used for the reproducibility comparison, including a Hotelling test and a statistical intercomparison test to determine the confidence interval of the partial color differences ΔL*, Δa*, Δb*, and the total color difference ΔE*ab. This was conducted using a database collection of 88 metallic and pearlescent samples that were measured 20 times without the replacement of all the instruments. The final findings show that in most measurement geometries, the reproducibility differences between pairs of instruments are statistically significant, although in general, there is a better reproducibility level at certain common geometries for newer instruments (MA98 and BYK-mac). This means that these differences are due to systematic or bias errors (angle tolerances for each geometry, photometric scales, white standards, etc.), but not exclusively to random errors. However, neither of the statistical tests used is valid to discriminate and quantify the detected bias errors in this comparison between instruments.

Creatividad, atención y rendimiento académico en alumnado de conservatorio profesional

El objetivo de este trabajo fue analizar la relación entre creatividad, atención y su repercusión en los resultados académicos en las enseñanzas profesionales de música. Para ello, se ha seleccionado una muestra de 84 alumnos de entre 12 y 18 años (M = 14.79; DT = 2.29) que cursan Enseñanzas Profesionales en un Conservatorio de Música público y reglado. Se utilizaron como instrumentos de medida el Test de Inteligencia Creativa (CREA; Corbalán et al. 2003) y el Test de Atención (d2; Brickenkamp, 2004). Se hallaron correlaciones positivas y estadísticamente significativas entre (a) atención y creatividad y (b) atención y resultados académicos musicales. En cambio, se hallaron correlaciones negativas y estadísticamente significativas entre creatividad y rendimiento académico musical. Tras los resultados se pueden establecer programas preventivos o potenciadores de la creatividad y la atención, con el fin de fomentar que la totalidad del alumnado de conservatorio alcance su máximo potencial y un alto rendimiento, ya que éstos son el reflejo de un aprendizaje más eficaz.

Measuring the effective focal length and shape factor of a thick lens using a microscope

The optical power of a thick spherical lens and its Coddington shape factor are essential magnitudes that characterize its image quality. Here, we propose an experimental procedure and apparatus that allow accurate determination of those magnitudes for any spherical lens from geometrical measurements. The performance of the technique and the used instruments are simple since it only requires a microscope and an optical mouse. The propose overcomes the drawbacks of other devices that need of the refractive index or may damage the lens surfaces, like spherometers, and provides similar results to those from commercial lensmeters.