Análisis de datos para la evaluación externa de la Reforma de las Enseñanzas Medias. Comparación de los resultados obtenidos por los alumnos de octavo de EGB y su promoción correspondiente en primero de Enseñanzas Medias.

Comparar los resultados obtenidos sobre dos muestras de la misma generación de alumnos de octavo de EGB y, 5 meses después, en primero de Enseñanzas Medias, con el fin de aislar las características y/o determinantes que inciden sobre los sujetos que optan por cada uno de los tipos de Enseñanza Secundaria. 4101 sujetos de octavo de EGB, de los cuales 2723 pensaban seguir estudios de BUP y 1378 de FP. 4130 sujetos de Enseñanzas Medias, de los cuales 1534 seguían estudios de BUP, 1396 de FP y 1200 Enseñanza Experimental. Variables: rendimiento académico, a través de indicadores como las calificaciones del profesorado y pruebas de rendimiento; aptitudes a través de indicadores como razonamiento mecánico, aptitud espacial, palabra diferente, vocabulario, factor verbal, razonamiento asbstracto, factor numérico y puntuación global en aptitudes escolares; actitudes hacia el estudio a través de indicadores como la ansiedad, la obsesión, depresión, desorganización, baja motivación, reacciones fisiológicas, satisfacción en el trabajo y convergencia divergencia; actitudes de carácter cívico social a través de indicadores como autoritarismo, tolerancia libertades, eficacia, derechos de la mujer y criticismo. También se evaluó la homogeneidad de las muestras atendiendo a las siguientes variables de clasificación: autonomía, población, tipo de centro, sexo y categoría socioprofesional del padre. Calificaciones escolares. Pruebas de rendimiento. Tests de Aptitudes. Tests de Actitudes. Pruebas de significación estadística. La composición de las muestras de EGB y de Enseñanzas Medias no resultan homogéneas en todas las variables de clasificación consideradas. Las diferencias son evidentes en las variables tipo de centro, sexo y clase social. Si se comparan las muestras por colectivos, según el tipo de estudios a elegir (EGB) o que están realizando (Enseñanza Media), las diferencias entre los que optan por FP y BUP son claras y muy marcadas, especialmente en pruebas de rendimiento. Los alumnos de BUP son siempre superiores a los de FP y los que siguen Enseñanzas Experimentales mantienen una posición intermedia. Las diferencias son igualmente importantes cuando se comparan estas muestras en función del sexo y el nivel de éxito-fracaso de los sujetos. Las variables discriminantes en este caso no sólo pertenecen a los conocimientos sino que apuntan hacia diferencias en aptitudes y actitudes. El peso o contribución a la explicación del criterio de las variables utilizadas en los sucesivos análisis realizados sigue el orden habitual: primero las variables de rendimiento, en segundo lugar las pruebas aptitudinales y, finalmente, las relativas a las actitudes. Si se relacionan las diversas opciones de estudio con las variables de origen (clase social, sexo y estudios de los padres) se observa que existe una evidente influencia de estas variables en la opción de estudios elegida por el sujeto.

Programa Escuela 2.0 : itinerario formativo, implantación en Castilla-La Mancha.

Resumen basado en el de la publicación

Creatividad en la escuela y libre expresión: iniciación al lenguaje plástico y visual mediante la exploración

Los dibujos de los niños son como sus relatos, sus movimientos, sus gestos, sus canciones inventadas (Coll, Elkonin, Freire, Gardner, Heathcote, Lowenfeld, Moll, Monereo, Read, Vygotsky). Expresan lo que viven, y cómo lo viven, su entorno, sus gustos, intereses, miedos… Aprenden a comunicarlo en los lenguajes que aprenden de los adultos, tanto verbales como corporales, visuales, musicales. Para entender el mundo adulto, ellos nos imitan, copian nuestros elementos y nos cuentan sus cosas. Pero poco a poco van eligiendo unos elementos y desechando otros que no les gustan o no les convencen, y se quedan con un lenguaje particular y propio, personalizado, de todos aquellos que han aprendido

Aprender a incluir em contexto de sala de aula do 1º ano de escolaridade

O presente trabalho teve por objectivo investigar e construir um Plano de Intervenção baseado numa sala de 1º ano de escolaridade na cidade de Portalegre com vista à inclusão, na turma, de um aluno em situação de Necessidade Educativa Especial. Este plano integra uma componente teórica – prática uma vez que foi feita uma análise teórica prévia que tinha como objectivo conhecer e caracterizar cientificamente toda a situação – problema e, consequentemente foram aplicadas técnicas de análise e recolha de dados: pesquisa documental, entrevista, sociometria e observação naturalista com base na literatura de referência para a aplicação dessas técnicas. Posteriormente foi feita a análise de toda a situação e foram identificadas quais as áreas de intervenção que seriam pertinentes para a problemática em estudo com o intuito de ser elaborado um Plano de Intervenção, realizado durante quatro meses em contexto de sala de aula e com o objectivo de proporcionar alguma mudança face à situação – problema encontrada. Este projecto de investigação – acção teve como objectivo responder à questão de partida: Como promover as aprendizagens numa ambiência inclusiva numa turma de 1º ano de escolaridade? O Plano de Intervenção foi estruturado em quinze sessões de aproximadamente 90 minutos cada, onde foram desenvolvidas actividades com a turma que promovessem, o mais possível, a progressão académica e a participação do aluno em situação de NEE. Para a avaliação do Plano de Intervenção recorreu-se às técnicas de recolha e análise de dados: entrevista e sociometria, assim como às reflexões semanais elaboradas após cada intervenção. O Plano de Intervenção interferiu positivamente na inclusão do aluno em situação de NEE na sua turma. Palavras

Immediate recall by aphasic, deaf and normally hearing children for visual forms presented simultaneously or sequentially in tim

This paper discusses a study to investigate immediate recall of visual stimuli presented simultaneously or sequentially in time.

Cue combination for 3D location judgements

Cue combination rules have often been applied to the perception of surface shape but not to judgements of object location. Here, we used immersive virtual reality to explore the relationship between different cues to distance. Participants viewed a virtual scene and judged the change in distance of an object presented in two intervals, where the scene changed in size between intervals (by a factor of between 0.25 and 4). We measured thresholds for detecting a change in object distance when there were only 'physical' (stereo and motion parallax) or 'texture-based' cues (independent of the scale of the scene) and used these to predict biases in a distance matching task. Under a range of conditions, in which the viewing distance and position of the tarte relative to other objects was varied, the ration of 'physical' to 'texture-based' thresholds was a good predictor of biases in the distance matching task. The cue combination approach, which successfully accounts for our data, relies on quite different principles from those underlying geometric reconstruction.

Latitude and longitude vertical disparities

The literature on vertical disparity is complicated by the fact that several different definitions of the term “vertical disparity” are in common use, often without a clear statement about which is intended or a widespread appreciation of the properties of the different definitions. Here, we examine two definitions of retinal vertical disparity: elevation-latitude and elevation-longitude disparities. Near the fixation point, these definitions become equivalent, but in general, they have quite different dependences on object distance and binocular eye posture, which have not previously been spelt out. We present analytical approximations for each type of vertical disparity, valid for more general conditions than previous derivations in the literature: we do not restrict ourselves to objects near the fixation point or near the plane of regard, and we allow for non-zero torsion, cyclovergence, and vertical misalignments of the eyes. We use these expressions to derive estimates of the latitude and longitude vertical disparities expected at each point in the visual field, averaged over all natural viewing. Finally, we present analytical expressions showing how binocular eye position—gaze direction, convergence, torsion, cyclovergence, and vertical misalignment—can be derived from the vertical disparity field and its derivatives at the fovea.

Stereo and motion parallax cues in human 3D vision: can they vanish without a trace?

In an immersive virtual reality environment, subjects fail to notice when a scene expands or contracts around them, despite correct and consistent information from binocular stereopsis and motion parallax, resulting in gross failures of size constancy (A. Glennerster, L. Tcheang, S. J. Gilson, A. W. Fitzgibbon, & A. J. Parker, 2006). We determined whether the integration of stereopsis/motion parallax cues with texture-based cues could be modified through feedback. Subjects compared the size of two objects, each visible when the room was of a different size. As the subject walked, the room expanded or contracted, although subjects failed to notice any change. Subjects were given feedback about the accuracy of their size judgments, where the “correct” size setting was defined either by texture-based cues or (in a separate experiment) by stereo/motion parallax cues. Because of feedback, observers were able to adjust responses such that fewer errors were made. For texture-based feedback, the pattern of responses was consistent with observers weighting texture cues more heavily. However, for stereo/motion parallax feedback, performance in many conditions became worse such that, paradoxically, biases moved away from the point reinforced by the feedback. This can be explained by assuming that subjects remap the relationship between stereo/motion parallax cues and perceived size or that they develop strategies to change their criterion for a size match on different trials. In either case, subjects appear not to have direct access to stereo/motion parallax cues.

In vitro degradability of mature and immature leaves of tropical forage legumes differing in condensed tannin and non-starch polysaccharide content and composition

A study was designed to examine the relationships between protein, condensed tannin and cell wall carbohydrate content and composition and the nutritional quality of seven tropical legumes (Desmodium ovalifolium, Flemingia macrophylla, Leucaena leucocephala, L pallida, L macrophylla, Calliandra calothyrsus and Clitotia fairchildiana). Among the legume species studied, D ovalifolium showed the lowest concentration of nitrogen, while L leucocephala showed the highest. Fibre (NDF) content was lowest in C calothyrsus, L Leucocephala and L pallida and highest in L macrophylla, which had no measurable condensed tannins. The highest tannin concentration was found in C calothyrsus. Total non-structural polysaccharides (NSP) varied among legumes species (lowest in C calothyrsus and highest in D ovalifolium), and glucose and uronic acids were the most abundant carbohydrate constituents in all legumes. Total NSP losses were lowest in F macrophylla and highest in L leucocephala and L pallida. Gas accumulation and acetate and propionate levels were 50% less with F macrophylla and D ovalifolium as compared with L leucocephala. The highest levels of branched-chain fatty acids were observed with non-tanniniferous legumes, and negative concentrations were observed with some of the legumes with high tannin content (D ovalifolium and F macrophylla). Linear regression analysis showed that the presence of condensed tannins was more related to a reduction of the initial rate of gas production (0-48 h) than to the final amount of gas produced or the extent (144h) of dry matter degradation, which could be due to differences in tannin chemistry. Consequently, more attention should be given in the future to elucidating the impact of tannin structure on the nutritional quality of tropical forage legumes. (C) 2003 Society of Chemical Industry.

An approximate Bayesian computation approach to overcome biases that arise when using amplified fragment length polymorphism markers to study population structure

There is great interest in using amplified fragment length polymorphism (AFLP) markers because they are inexpensive and easy to produce. It is, therefore, possible to generate a large number of markers that have a wide coverage of species genotnes. Several statistical methods have been proposed to study the genetic structure using AFLP's but they assume Hardy-Weinberg equilibrium and do not estimate the inbreeding coefficient, F-IS. A Bayesian method has been proposed by Holsinger and colleagues that relaxes these simplifying assumptions but we have identified two sources of bias that can influence estimates based on these markers: (i) the use of a uniform prior on ancestral allele frequencies and (ii) the ascertainment bias of AFLP markers. We present a new Bayesian method that avoids these biases by using an implementation based on the approximate Bayesian computation (ABC) algorithm. This new method estimates population-specific F-IS and F-ST values and offers users the possibility of taking into account the criteria for selecting the markers that are used in the analyses. The software is available at our web site (http://www-leca.uif-grenoble.fi-/logiciels.htm). Finally, we provide advice on how to avoid the effects of ascertainment bias.

Determination of mitochondrial genetic diversity in mammals

Mitochondrial DNA (mtDNA) is one of the most Popular population genetic markers. Its relevance as an indicator Of Population size and history has recently been questioned by several large-scale studies in animals reporting evidence for recurrent adaptive evolution, at least in invertebrates. Here we focus on mammals, a more restricted taxonomic group for which the issue of mtDNA near neutrality is crucial. By analyzing the distribution of mtDNA diversity across species and relating 4 to allozyme diversity, life-history traits, and taxonomy, we show that (i) mtDNA in mammals (toes not reject the nearly neutral model; (ii) mtDNA diversity, however, is unrelated to any of the 14 life-history and ecological variables that we analyzed, including body mass, geographic range, and The World Conservation Union (IUCN) categorization; (iii) mtDNA diversity is highly variable between mammalian orders and families; (iv) this taxonomic effect is most likely explained by variations of mutation rate between lineages. These results are indicative of a strong stochasticity of effective population size in mammalian species. They Suggest that, even in the absence of selection, mtDNA genetic diversity is essentially unpredictable, knowing species biology, and probably uncorrelated to species abundance.

The population genetic structure of clonal organisms generated by exponentially bounded and fat-tailed dispersal

Long distance dispersal (LDD) plays an important role in many population processes like colonization, range expansion, and epidemics. LDD of small particles like fungal spores is often a result of turbulent wind dispersal and is best described by functions with power-law behavior in the tails ("fat tailed"). The influence of fat-tailed LDD on population genetic structure is reported in this article. In computer simulations, the population structure generated by power-law dispersal with exponents in the range of -2 to -1, in distinct contrast to that generated by exponential dispersal, has a fractal structure. As the power-law exponent becomes smaller, the distribution of individual genotypes becomes more self-similar at different scales. Common statistics like G(ST) are not well suited to summarizing differences between the population genetic structures. Instead, fractal and self-similarity statistics demonstrated differences in structure arising from fat-tailed and exponential dispersal. When dispersal is fat tailed, a log-log plot of the Simpson index against distance between subpopulations has an approximately constant gradient over a large range of spatial scales. The fractal dimension D-2 is linearly inversely related to the power-law exponent, with a slope of similar to -2. In a large simulation arena, fat-tailed LDD allows colonization of the entire space by all genotypes whereas exponentially bounded dispersal eventually confines all descendants of a single clonal lineage to a relatively small area.

The evolution of mobile DNAs: when will transposons create phylogenies that look as if there is a master gene?

Some families of mammalian interspersed repetitive DNA, such as the Alu SINE sequence, appear to have evolved by the serial replacement of one active sequence with another, consistent with there being a single source of transposition: the "master gene." Alternative models, in which multiple source sequences are simultaneously active, have been called "transposon models." Transposon models differ in the proportion of elements that are active and in whether inactivation occurs at the moment of transposition or later. Here we examine the predictions of various types of transposon model regarding the patterns of sequence variation expected at an equilibrium between transposition, inactivation, and deletion. Under the master gene model, all bifurcations in the true tree of elements occur in a single lineage. We show that this property will also hold approximately for transposon models in which most elements are inactive and where at least some of the inactivation events occur after transposition. Such tree shapes are therefore not conclusive evidence for a single source of transposition.

Bayesian estimation of recent migration rates after a spatial expansion

Approximate Bayesian computation (ABC) is a highly flexible technique that allows the estimation of parameters under demographic models that are too complex to be handled by full-likelihood methods. We assess the utility of this method to estimate the parameters of range expansion in a two-dimensional stepping-stone model, using samples from either a single deme or multiple demes. A minor modification to the ABC procedure is introduced, which leads to an improvement in the accuracy of estimation. The method is then used to estimate the expansion time and migration rates for five natural common vole populations in Switzerland typed for a sex-linked marker and a nuclear marker. Estimates based on both markers suggest that expansion occurred < 10,000 years ago, after the most recent glaciation, and that migration rates are strongly male biased.