La cerámica en España y la Escuela-Fábrica de Cerámica de Madrid (II).

Se estudia la historia de las fábricas de cerámica existentes en España desde el siglo XVIII. El repaso comienza con las lozas y porcelanas fabricadas en Alcora, fundación del Conde de Aranda de 1726, conocida por la calidad de su producción, y cuya decadencia empezó con el fallecimiento de su fundador. Otras manufacturas importantes son la Real Fábrica de Porcelana del Buen Retiro (1759-1812), fundada por Carlos III a su regreso de Italia para coronarse rey de España y que es continuación de la cerámica de Capo di Monte; y la Real Fábrica de la Florida, llamada después de la Moncloa, creada por Fernando VII y cerrada en época de Isabel II. Ya en el siglo XX, Francisco Alcántara erige la Escuela- Fábrica de Cerámica de Madrid en 1911, como continuación de la tradición del arte de la cerámica en la capital.

El agua y sus propiedades : análisis del proceso de emisión, verificación y modificación de hipótesis en niños de 10-11 años.

Averiguar cuáles son las posibilidades reales de los alumnos de quinto curso de EGB (10-11 años) en lo referente al proceso de emisión, verificación y modificación de hipótesis, dentro del contexto real de una clase, con la orgnización, métodos de trabajo y contenidos habituales de la misma. Obtener conclusiones metodológicas que puedan derivarse de la observación, método de trabajo y contenidos habituales de la misma. Obtener conclusiones metodológicas que puedan derivarse de la observación del trabajo de los alumnos y que supongan una mejora en la manera de enseñar. 30 alumnos de quinto de EGB pertenecientes a un colegio de Ávila. La experiencia ha durado 4 meses, en sesiones semanales o quincenales de 2 a 4 horas. Cada experiencia concreta se desarrolló en una o dos sesiones lo más próximas posible. Los grupos constaban de 3 alumnos, formados libremente por ellos. Se elaboró una guía sobre los pasos que se debían de dar en cada experiencia y lo que debían de anotar los alumnos en sus cuadernos de trabajo; al final se recogería y se analizaría por los profesores. Los contenidos desarrollados fueron: +cómo se mezclan los líquidos entre sí?, aproximación al concepto de densidad; el agua y los líquidos son incompresibles; los líquidos ejercen fuerzas (presiones) en todas direcciones; los líquidos ejercen un empuje hacia arriba; los líquidos transmiten las presiones en todas las direcciones; la prensa hidráulica. Los niños de estas edades solamente emiten hipótesis previas cuando están familiarizados con el fenómeno o cuestión planteada. Cuando los chicos se enfrentan a fenómenos relativamente conocidos, generalmente modifican muy poco sus hipótesis iniciales después de escuchar las de sus compañeros. Realizan el control de variables que ellos han considerado como pertinentes, no incorporando ninguna variable escuchada a los compañeros y que no ha sido hecha suya. El trabajo experimental siempre lo han realizado como lo han diseñado. No han tenido ninguna dificultad en modificar las hipótesis iniciales cuando éstas no concordaban con los resultados de la experimentación. Obtienen dos tipos de conclusiones, unas descriptivas (solamente describen los resultados de la experiencia sin intentar dar una explicación del porqué ocurren esos fenómenos), y explicativas (intentan dar una explicación del porqué ocurren los fenomenos que han estudiado).

Pasado y presente de la Real Academia Española.

Título anterior de la publicación: Boletín de la Comisión Española de la UNESCO

A Reestruturação do Modelo Nórdico de Educação

Este artigo discute o modelo Nórdico ou o modelo de Estado-Providência e a educação. Mostra como os processos de reestruturação estão acontecendo a nível político e a nível institucional e, ainda, como é que as estruturas básicas do modelo e exemplo nórdico, especialmente os princípios subjacentes às comprehensive schools e às escolas locais, estão a ser abandonados. Pela abordagem institucional, está a emergir um novo pacto geracional ou um modelo institucional, mas a sua legitimação e estabelecimento levarão muito tempo. As mudanças na política e na organização ocorrem de forma muito mais rápida do que nos contextos sócio-culturais. Exemplos de histórias de sucesso, como a reforma dinamarquesa do mercado laboral e o crescimento do cluster finlandês do conhecimento intensivo em TIC, abriram o caminho para esta transformação. Há ainda a possibilidade de uma estratégia de Estado-Providência e de uma estratégia de Estado Competitivo poderem coexistir.

Developmental changes in presynaptic muscarinic modulation of excitatory and inhibitory neurotransmission in rat piriform cortex in vitro: relevance to epileptiform bursting susceptibility

Suppression of depolarizing postsynaptic potentials and isolated GABA-A receptor-mediated fast inhibitory postsynaptic potentials by the muscarinic acetylcholine receptor agonist, oxotremorine-M (10 microM), was investigated in adult and immature (P14-P30) rat piriform cortical (PC) slices using intracellular recording. Depolarizing postsynaptic potentials evoked by layers II-III stimulation underwent concentration-dependent inhibition in oxotremorine-M that was most likely presynaptic and M2 muscarinic acetylcholine receptor-mediated in immature, but M1-mediated in adult (P40-P80) slices; percentage inhibition was smaller in immature than in adult piriform cortex. In contrast, compared with adults, layer Ia-evoked depolarizing postsynaptic potentials in immature piriform cortex slices in oxotremorine-M, showed a prolonged multiphasic depolarization with superimposed fast transients and spikes, and an increased 'all-or-nothing' character. Isolated N-methyl-d-aspartate receptor-mediated layer Ia depolarizing postsynaptic potentials (although significantly larger in immature slices) were however, unaffected by oxotremorine-M, but blocked by dl-2-amino-5-phosphonovaleric acid. Fast inhibitory postsynaptic potentials evoked by layer Ib or layers II-III-fiber stimulation in immature slices were significantly smaller than in adults, despite similar estimated mean reversal potentials ( approximately -69 and -70 mV respectively). In oxotremorine-M, only layer Ib-fast inhibitory postsynaptic potentials were suppressed; suppression was again most likely presynaptic M2-mediated in immature slices, but M1-mediated in adults. The degree of fast inhibitory postsynaptic potential suppression was however, greater in immature than in adult piriform cortex. Our results demonstrate some important physiological and pharmacological differences between excitatory and inhibitory synaptic systems in adult and immature piriform cortex that could contribute toward the increased susceptibility of this region to muscarinic agonist-induced epileptiform activity in immature brain slices.

An integrated model of soil-canopy spectral radiances, photosynthesis, fluorescence, temperature and energy balance

This paper presents the model SCOPE (Soil Canopy Observation, Photochemistry and Energy fluxes), which is a vertical (1-D) integrated radiative transfer and energy balance model. The model links visible to thermal infrared radiance spectra (0.4 to 50 μm) as observed above the canopy to the fluxes of water, heat and carbon dioxide, as a function of vegetation structure, and the vertical profiles of temperature. Output of the model is the spectrum of outgoing radiation in the viewing direction and the turbulent heat fluxes, photosynthesis and chlorophyll fluorescence. A special routine is dedicated to the calculation of photosynthesis rate and chlorophyll fluorescence at the leaf level as a function of net radiation and leaf temperature. The fluorescence contributions from individual leaves are integrated over the canopy layer to calculate top-of-canopy fluorescence. The calculation of radiative transfer and the energy balance is fully integrated, allowing for feedback between leaf temperatures, leaf chlorophyll fluorescence and radiative fluxes. Leaf temperatures are calculated on the basis of energy balance closure. Model simulations were evaluated against observations reported in the literature and against data collected during field campaigns. These evaluations showed that SCOPE is able to reproduce realistic radiance spectra, directional radiance and energy balance fluxes. The model may be applied for the design of algorithms for the retrieval of evapotranspiration from optical and thermal earth observation data, for validation of existing methods to monitor vegetation functioning, to help interpret canopy fluorescence measurements, and to study the relationships between synoptic observations with diurnally integrated quantities. The model has been implemented in Matlab and has a modular design, thus allowing for great flexibility and scalability.

Development of smart variable stiffness actuators using polymer hydrogels

In this work, compliant actuators are developed by coupling braided structures and polymer gels, able to produce work by controlled gel swelling in the presence of water. A number of aspects related to the engineering of gel actuators were studied, including gel selection, modelling and experimentation of constant force and constant displacement behaviour, and response time. The actuator was intended for use as vibration neutralizer: with this aim, generation of a force of 10 N in a time not exceeding a second was needed. Results were promising in terms of force generation, although response time was still longer than required. In addition, the easiest way to obtain the reversibility of the effect is still under discussion: possible routes for improvement are suggested and will be the object of future work.

A comparison of the variability of biological nutrients against depth and potential density.

The main biogeochemical nutrient distributions, along with ambient ocean temperature and the light field, control ocean biological productivity. Observations of nutrients are much sparser than physical observations of temperature and salinity, yet it is critical to validate biogeochemical models against these sparse observations if we are to successfully model biological variability and trends. Here we use data from the Bermuda Atlantic Time-series Study and the World Ocean Database 2005 to demonstrate quantitatively that over the entire globe a significant fraction of the temporal variability of phosphate, silicate and nitrate within the oceans is correlated with water density. The temporal variability of these nutrients as a function of depth is almost always greater than as a function of potential density, with he largest reductions in variability found within the main pycnocline. The greater nutrient variability as a function of depth occurs when dynamical processes vertically displace nutrient and density fields together on shorter timescales than biological adjustments. These results show that dynamical processes can have a significant impact on the instantaneous nutrient distributions. These processes must therefore be considered when modeling biogeochemical systems, when comparing such models with observations, or when assimilating data into such models.

Thermo-responsive poly(methyl methacrylate)-block-poly(N-isopropylacrylamide) block copolymers synthesized by RAFT polymerization: micellization and gelation

RAFT polymerization was used to prepare PMMA-b-PNIPAM copolymers. Two different chain transfer agents, tBDB and MCPDB, were used to mediate the sequential polymerizations. Micellar solutions and gels were prepared from the resulting copolymers in aqueous solution. When heated above T-c of PNIPAM (about 31 degrees C), DLS revealed that PNIPAM coronas collapsed, resulting in aggregation of the original micelles. The micellar gels underwent syneresis above T-c as water was expelled from the ordered gel structure, the lattice periodicity of which was determined by SANS. A large decrease in lattice spacing was observed above T-c. The gel became more viscoelastic at high temperature, as revealed by shear rheometry which showed a large increase in G".

A novel galactooligosaccharide mixture increases the bifidobacterial population numbers in a continuous in vitro fermentation system and in the proximal colonic contents of pigs in vivo

Prebiotics are nondigestible food ingredients that encourage proliferation of selected groups of the colonic microflora, thereby altering the composition toward a more beneficial community. In the present study, the prebiotic potential of a novel galactooligosaccharide (GOS) mixture, produced by the activity of galactosyltransferases from Bifidobacterium bifidum 41171 on lactose, was assessed in vitro and in a parallel continuous randomized pig trial. In situ fluorescent hybridization with 16S rRNA-targeted probes was used to investigate changes in total bacteria, bifidobacteria, lactobacilli, bacteroides, and Clostridium histolyticum group in response to supplementing the novel GOS mixture. In a 3-stage continuous culture system, the bifidobacterial numbers for the first 2 vessels, which represented the proximal and traverse colon, increased (P < 0.05) after the addition of the oligosaccharide mixture. In addition, the oligosaccharide mixture strongly inhibited the attachment of enterohepatic Escherichia coli (P < 0.01) and Salmonella enterica serotype Typhimurium (P < 0.01) to HT29 cells. Addition of the novel mixture at 4% (wt:wt) to a commercial diet increased the density of bificlobacteria (P < 0.001) and the acetate concentration (P < 0.001), and decreased the pH (P < 0.001) compared with the control diet and the control diet supplemented with inulin, suggesting a great prebiotic potential for the novel oligosaccharide mixture. J. Nutr. 135: 1726-1731, 2005.

Binocular coordination of the eyes during reading

Saccadic eye movements and fixations are the behavioral means by which we visually sample text during reading. Human oculomotor control is governed by a complex neurophysiological system involving the brain stem, superior colliculus, and several cortical areas [1, 2]. A very widely held belief among researchers investigating primate vision is that the oculomotor system serves to orient the visual axes of both eyes to fixate the same target point in space. It is argued that such precise positioning of the eyes is necessary to place images on corresponding retinal locations, such that on each fixation a single, nondiplopic, visual representation is perceived [3]. Vision works actively through a continual sampling process involving saccades and fixations [4]. Here we report that during normal reading, the eyes do not always fixate the same letter within a word. We also demonstrate that saccadic targeting is yoked and based on a unified cyclopean percept of a whole word since it is unaffected if different word parts are delivered exclusively to each eye via a dichoptic presentation technique. These two findings together suggest that the visual signal from each eye is fused at a very early stage in the visual pathway, even when the fixation disparity is greater than one character (0.29 deg), and that saccade metrics for each eye are computed on the basis of that fused signal.