155 research outputs found

    Children’s reading with digital books: past moving quickly to the future

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    Digital books, such as e-books, story apps, picture book apps, and interactive stories, are narratives presented on touchscreens with multimedia and interactive features. Evidence suggests that early reading of print versus digital books is associated with different patterns of parent–child engagement and children’s outcomes. Parents’ verbal scaffolding, children’s age, and the congruence between a book’s narrative and its interactive and multimedia features are three documented process variables that explain the difference between reading print and digital books. To maximize the added value of digital books for children, we need to study the interaction among the characteristics of parents, children, and books; we also need to target these interactions through interventions and through collaborations between designers and researchers

    Nutrient resorption in dominant species of forests in the 'Espinal Mesopotámico' (Argentina)

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    Se estudió durante dos años (2009 y 2010) la retranslocación de nutrientes en especies dominantes de bosques correspondientes a una secuencia sucesional del Espinal Mesopotámico. El objetivo fue comparar la retranslocación de nutrientes (nitrógeno, fósforo, potasio, calcio, magnesio y azufre) entre especies de familias fabáceas (Acacia caven, Prosopis affinis y Prosopis nigra; con capacidad de fijar biológicamente el nitrógeno atmosférico) y celtidáceas (Celtis tala, sin capacidad de fijar biológicamente el nitrógeno atmosférico). Se analizaron químicamente las muestras de hojas maduras (recolectadas en primavera) y senescentes (recolectadas en otoño) para determinar la concentración de nutrientes y luego se calcularon los índices de retranslocación (Rc1 y Rc2). Se determinó que la mayor retranslocación del nitrógeno estuvo asociada la imposibilidad de fijar biológicamente el nitrógeno atmosférico, observándose que ambos índices denotaron una máxima retranslocación de nitrógeno en C. tala y mínima en A. caven. Contrariamente, los demás elementos (P, K, Ca, Mg y S) mostraron diferencias en la retranslocación en uno de los índices utilizados, indicando mayor resorción en fabáceas respecto a celtidácea, asociado a una mayor demanda foliar de estos elementos.The resorption of nutrients of dominant species in a successional sequence of forests of the Argentinean Mesopotamian Espinal was studied for two years (2009-2010). The aim was to compare nutrient resorption (nitrogen, phosphorus, potassium, calcium, magnesium and sulphur) among species of the Fabaceae (Acacia caven, Prosopis affinis and Prosopis nigra with the capacity of biologically fixing the atmospheric nitrogen) and Celtidacea families (Celtis tala, without the capacity of biologically fixing the atmospheric nitrogen). Samples of mature leaves (collected in spring) and senescent leaves (collected in autumn) were chemically analyzed to determine nutrient concentration; afterwards, resorption rates were calculated (Rc7 and Rc2). It was found that the higher nitrogen resorption was associated with the inability of biologically fixing the atmospheric nitrogen, having both indexes a maximum nitrogen resorption in C. tala and a minimum in A. caven. On the contrary, the other elements (P, K, Ca, Mg and S) showed resorption differences in one of the indexes used, indicating a higher resorption in Fabaceae in contrast with Celtidaceae, associated with a higher foliar demand of these elements.Fil: Mendoza, Carlos A.. Universidad Autónoma de Entre Ríos. Facultad de Ciencia y Tecnología; ArgentinaFil: Turrión, M. Belén. Universidad de Valladolid; EspañaFil: Aceñolaza, Pablo Gilberto. Provincia de Entre Ríos. Centro de Investigaciones Científicas y Transferencia de Tecnología a la Producción. Universidad Autónoma de Entre Ríos. Centro de Investigaciones Científicas y Transferencia de Tecnología a la Producción. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Centro de Investigaciones Científicas y Transferencia de Tecnología a la Producción; Argentina. Universidad Autónoma de Entre Ríos. Facultad de Ciencia y Tecnología; ArgentinaFil: Gallardo, Juan F.. Consejo Superior de Investigaciones Cientificas; EspañaFil: Pando, Valentín. Universidad de Valladolid; Españ

    Color characterization of coatings with diffraction pigments

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    Coatings with diffraction pigments present high iridescence, which needs to be characterized in order to describe their appearance. The spectral bidirectional reflectance distribution functions (BRDFs) of six coatings with SpectraFlair diffraction pigments were measured using the robot-arm-based goniospectrophotometer GEFE, designed and developed at CSIC. Principal component analysis has been applied to study the coatings of BRDF data. From data evaluation and based on theoretical considerations, we propose a relevant geometric factor to study the spectral reflectance and color gamut variation of coatings with diffraction pigments. At fixed values of this geometric factor, the spectral BRDF component due to diffraction is almost constant. Commercially available portable goniospectrophotometers, extensively used in several industries (automotive and others), should be provided with more aspecular measurement angles to characterize the complex reflectance of goniochromatic coatings based on diffraction pigments, but they would not require either more than one irradiation angle or additional out-of-plane geometries.European Metrology Research Programme (EMRP) (EMRP IND52); Comunidad de Madrid (SINFOTON-CM: S2013/MIT-2790); Ministerio de Economía y Competitividad (MINECO) (DIP2015-65814)

    Visibility of sparkle in metallic paints

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    For suitable illumination and observation conditions, sparkles may be observed in metallic coatings. The visibility of these sparkles depends critically on their intensity, and on the paint medium surrounding the metallic flakes. Based on previous perception studies from other disciplines, we derive equations for the threshold for sparkles to be visible. The resulting equations show how the visibility of sparkles varies with the luminosity and distance of the light source, the diameter of the metallic flakes, and the reflection properties of the paint medium. The predictions are confirmed by common observations on metallic sparkle. For example, under appropriate conditions even metallic flakes as small as 1 μm diameter may be visible as sparkle, whereas under intense spot light the finer grades of metallic coatings do not show sparkle. We show that in direct sunlight, dark coarse metallic coatings show sparkles that are brighter than the brightest stars and planets in the night sky. Finally, we give equations to predict the number of visually distinguishable flake intensities, depending on local conditions. These equations are confirmed by previous results. Several practical examples for applying the equations derived in this article are provided.European Metrology Research Programme (EMRP) Spanish Ministry of Economy and Competitiveness(DPI2011-30090-C02) Comunidad de Madrid (CM: S2013/MIT-2790). The EMRP is jointly funded by the EMRP participating countries within the European Association of National Meteorlogy (EURAMET) and the European Union

    Global color estimation of special-effect coatings from measurements by commercially available portable multiangle spectrophotometers

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    Colors of special-effect coatings have strong dependence on illumination/viewing geometry and an appealing appearance. An open question is to ask about the minimum number of measurement geometries required to completely characterize their observed color shift. A recently published principal components analysis (PCA)-based procedure to estimate the color of special-effect coatings at any geometry from measurements at a reduced set of geometries was tested in this work by using the measurement geometries of commercial portable multiangle spectrophotometers X-Rite MA98, Datacolor FX10, and BYK-mac as reduced sets. The performance of the proposed PCA procedure for the color-shift estimation for these commercial geometries has been examined for 15 special-effect coatings. Our results suggest that for rendering the color appearance of 3D objects covered with special-effect coatings, the color accuracy obtained with this procedure may be sufficient. This is the case especially if geometries of X-Rite MA98 or Datacolor FX10 are used.The authors are grateful to EMRP for funding the project “Multidimensional Reflectometry for Industry.” The EMRP is jointly funded by the EMRP participating countries within EURAMET and the European Union. This study was also supported by the Spanish Ministry of Economy and Competitiveness under grant no. DPI2011-30090-C02-02 and the European Union

    La introducción de la práctica química en la Real Botica Española

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    The introduction of Chemist in the elaboration of medicines in the Spanish Royal Pharmacy will finally be done effective at the same time that the proclamation of King Philipe V.Los intentos de introducir la aplicación de la química en la elaboración de medicamentos en la Real Botica española se harán realidad definitivamente, coincidiendo con la llegada a la corte de Felipe V y de su equipo de sanitarios: médicos, cirujanos y boticarios

    Vertical misfit of laser-sintered and vacuum-cast implant-supported crown copings luted with definitive and temporary luting agents

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    Objectives. This study aimed to evaluate the vertical discrepancy of implant-supported crown structures constructed with vacuum-casting and Direct Metal Laser Sintering (DMLS) technologies, and luted with different cement types. Study D esign. Crown copings were fabricated using: (1) direct metal laser sintered Co-Cr (LS); (2) vacuum-cast Co-Cr (CC); and (3) vacuum-cast Ti (CT). Frameworks were luted onto machined implant abutments under constant seating pressure. Each alloy group was randomly divided into 5 subgroups (n = 10 each) according to the cement system utilized: Subgroup 1 (KC) used resin-modified glass-ionomer Ketac Cem Plus; Subgroup 2 (PF) used Panavia F 2.0 dual-cure resin cement; Subgroup 3 (RXU) used RelyX Unicem 2 Automix self-adhesive dual-cure resin cement; Subgroup 4 (PIC) used acrylic/urethane-based temporary Premier Implant Cement; and Subgroup 5 (DT) used acrylic/urethane-based temporary DentoTemp cement. Vertical misfit was measured by scanning electron microscopy (SEM). Two-way ANOVA and Student-Newman-Keuls tests were run to investigate the effect of alloy/fabrication technique, and cement type on vertical misfit. The statistical significance was set at ? = 0.05. Results. The alloy/manufacturing technique and the luting cement affected the vertical discrepancy (p < 0.001). For each cement type, LS samples exhibited the best fit (p < 0.01) whereas CC and CT frames were statistically similar. Within each alloy group, PF and RXU provided comparably greater discrepancies than KC, PIC, and DT, which showed no differences. Conclusions. Laser sintering may be an alternative to vacuum-casting of base metals to obtain passive-fitting implant-supported crown copings. The best marginal adaptation corresponded to laser sintered structures luted with glass-ionomer KC, or temporary PIC or DT cements. The highest discrepancies were recorded for Co-Cr and Ti cast frameworks bonded with PF or RXU resinous agents. All groups were within the clinically acceptable misfit range

    Spectral BRDF-based determination of proper measurement geometries to characterize color shift of special effect coatings

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    A reduced set of measurement geometries allows the spectral reflectance of special effect coatings to be predicted for any other geometry. A physical model based on flake-related parameters has been used to determine nonredundant measurement geometries for the complete description of the spectral bidirectional reflectance distribution function (BRDF). The analysis of experimental spectral BRDF was carried out by means of principal component analysis. From this analysis, a set of nine measurement geometries was proposed to characterize special effect coatings. It was shown that, for two different special effect coatings, these geometries provide a good prediction of their complete color shift.The authors are grateful to “Plan Nacional de Física” for funding this work (FIS2010-19756-E), to CSIC’s JAE Program, and the “European Social Fund” for awarding us a research trainee. This study was also supported by the Spanish Ministry of Economy and Competitiveness under the grant DPI2011-30090-C02-02 and the European Union

    An insight into the present capabilities of national metrology institutes for measuring sparkle

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    Large effect pigments, due to their strongly specular reflectance, produce a special visual texture known as sparkle. The use of these pigments in many industries (automotive, cosmetic, paper, architecture...) makes the control of this visual texture necessary. A measurement scale has to be developed, so that traceability can be provided by national metrology institutes (NMI) or designated institutes. Some of them (PTB, METAS, CMI and CSIC) have tested their existing capabilities to measure sparkle, and their results are presented. Two possible sources of systematic errors have been identified: inadequate illumination and collection full-angles, and inadequate size of the virtual aperture used to assess the luminous flux reflected on the effect pigments. The measurement scale of sparkle used in this comparison is thoroughly presented. This comparison will allow the methodology to measure sparkle to be improved.This article was written within the EMPIR 16NRM08 Project “Bidirectional reflectance definition” (BiRD). The EMPIR is jointly funded by the EMPIR participating countries within EURAMET and the European Union. The EMPIR is jointly funded by the EMPIR participating countries within EURAMET and the European Union. Part of the authors (Instituto de Óptica “Daza de Valdés”) are also grateful to Comunidad de Madrid for funding the project S2018/NMT-4326-SINFOTON2-C

    Improved Limit on Direct α Decay of the Hoyle State

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    The current evaluation of the triple-α reaction rate assumes that the α decay of the 7.65 MeV, 0+ state in 12C, commonly known as the Hoyle state, proceeds sequentially via the ground state of 8Be. This assumption is challenged by the recent identification of two direct α-decay branches with a combined branching ratio of 17(5)%. If correct, this would imply a corresponding reduction in the triple-α reaction rate with important astrophysical consequences. We have used the 11B(3He,d) reaction to populate the Hoyle state and measured the decay to three α particles in complete kinematics. We find no evidence for direct α-decay branches, and hence our data do not support a revision of the triple-α reaction rate. We obtain an upper limit of 5×10-3 on the direct α decay of the Hoyle state at 95% C.L., which is 1 order of magnitude better than a previous upper limit
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