383 research outputs found

    Análisis de la composición mineral en alimentos congelados precocinados de consumo habitual

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    La realización del presente estudio analítico ha tenido como principal objetivo ampliar y mejorar los datos queactualmente vienen reflejados en las tablas de composición de alimentos españoles, aportando datos que, además depropios, corresponden a alimentos ampliamente distribuidos en el mercado español y son consumidos de formahabitual en nuestro país. El análisis de los diferentes minerales se ha realizado en 28 alimentos precocinados congelados,previamente seleccionados, entre los que se incluyen pastas, pizzas, arroces y fritos de mayor consumo. Estetipo de alimentos son susceptibles de sufrir pérdidas en minerales debido a los procesos de elaboración, congelacióny pretratamiento culinario a que son sometidos antes de su consumo, por lo que es de gran interés el conocimientode su composición mineral, dando respuesta a las exigencias de un amplio grupo de profesionales y consumidoresque requieren de esta información nutricional

    Péptidos y proteínas de la leche con propiedades funcionales

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    La fracción proteica de la leche contiene un gran número de compuestos biológicamente activos. Además de lasproteínas de la leche, caseínas y proteínas del suero lácteo, existen también pequeñas cantidades de otras proteínasy péptidos. Estos péptidos, que son inactivos dentro de la secuencia de la proteína nativa, pueden ser liberados porhidrólisis enzimática, por ejemplo, durante la digestión gastrointestinal o durante el procesado del alimento. Estospéptidos bioactivos procedentes de proteínas lácteas presentan una actividad moduladora de numerosos procesosmetabólicos del organismo. Asimismo, las proteínas del suero lácteo representan una mezcla variada de proteínassecretadas, tales como á-lactoalbúmina, â-lactoglobulina, lactoferrina, lactoperoxidasa, inmunoglobulinas,glicomacropéptido y una gran cantidad de factores de crecimiento. Estas proteínas tienen una serie de efectosbiológicos, que van desde un efecto anticancerígenos hasta efectos en la función digestiva

    Regional effects of atmospheric aerosols on temperature: An evaluation of an ensemble of online coupled models

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    The climate effect of atmospheric aerosols is associated with their influence on the radiative budget of the Earth due to the direct aerosol–radiation interactions (ARIs) and indirect effects, resulting from aerosol–cloud–radiation interactions (ACIs). Online coupled meteorology–chemistry models permit the description of these effects on the basis of simulated atmospheric aerosol concentrations, although there is still some uncertainty associated with the use of these models. Thus, the objective of this work is to assess whether the inclusion of atmospheric aerosol radiative feedbacks of an ensemble of online coupled models improves the simulation results for maximum, mean and minimum temperature at 2 m over Europe. The evaluated models outputs originate from EuMetChem COST Action ES1004 simulations for Europe, differing in the inclusion (or omission) of ARI and ACI in the various models. The cases studies cover two important atmospheric aerosol episodes over Europe in the year 2010: (i) a heat wave event and a forest fire episode (July–August 2010) and (ii) a more humid episode including a Saharan desert dust outbreak in October 2010. The simulation results are evaluated against observational data from the E-OBS gridded database. The results indicate that, although there is only a slight improvement in the bias of the simulation results when including the radiative feedbacks, the spatiotemporal variability and correlation coefficients are improved for the cases under study when atmospheric aerosol radiative effects are included

    Anelastic deformation of a Pd40Cu30Ni10P20 bulk metallic glass during nanoindentation

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    This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics.Time-dependent deformation processes during nanoindentation have been investigated on a Pd40Cu30Ni10P20 bulk metallic glass. Deformation under constant load has been studied as a function of prior loading rate and temperature. The constant-load displacement of the indenter into the sample shows classic relaxation kinetics and reveals the importance of anelasticity for the mechanical behavior of metallic glasses at the nanoscale

    Fractal surfaces of gold and platinum electrodeposits. Dimensionality determination by scanning tunneling microscopy

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    The structure of gold and platinum deposits grown on gold and platinum wire cathodes, respectively, by electroreduction of the corresponding oxide layers has been analyzed in terms of surface fractals by measuring the perimeter L and area A of intergranular voids. Perimeter and area were determined from scanning tunneling microscopy (STM) topographic images of the deposit surfaces. Fractal behavior, L ∞ AD'/2 with D'= 1.5 ± 0.1, is found for both platinum and gold deposits. From these measurements, the fractal dimension of the surfaces was 2.5. The D' value of the gold deposits decreases by aging in the electrolyte at 325 K as a consequence of surface diffusion processes.Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA)Facultad de Ciencias Exacta

    An assessment of aerosol optical properties from remote-sensing observations and regional chemistry–climate coupled models over Europe

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    Atmospheric aerosols modify the radiative budget of the Earth due to their optical, microphysical and chemical properties, and are considered one of the most uncertain climate forcing agents. In order to characterise the uncertainties associated with satellite and modelling approaches to represent aerosol optical properties, mainly aerosol optical depth (AOD) and Ångström exponent (AE), their representation by different remote-sensing sensors and regional online coupled chemistry–climate models over Europe are evaluated. This work also characterises whether the inclusion of aerosol–radiation (ARI) or/and aerosol–cloud interactions (ACI) help improve the skills of modelling outputs.Two case studies were selected within the EuMetChem COST Action ES1004 framework when important aerosol episodes in 2010 all over Europe took place: a Russian wildfire episode and a Saharan desert dust outbreak that covered most of the Mediterranean Sea. The model data came from different regional air-quality–climate simulations performed by working group 2 of EuMetChem, which differed according to whether ARI or ACI was included or not. The remote-sensing data came from three different sensors: MODIS, OMI and SeaWIFS. The evaluation used classical statistical metrics to first compare satellite data versus the ground-based instrument network (AERONET) and then to evaluate model versus the observational data (both satellite and ground-based data).Regarding the uncertainty in the satellite representation of AOD, MODIS presented the best agreement with the AERONET observations compared to other satellite AOD observations. The differences found between remote-sensing sensors highlighted the uncertainty in the observations, which have to be taken into account when evaluating models. When modelling results were considered, a common trend for underestimating high AOD levels was observed. For the AE, models tended to underestimate its variability, except when considering a sectional approach in the aerosol representation. The modelling results showed better skills when ARI+ACI interactions were included; hence this improvement in the representation of AOD (above 30 % in the model error) and AE (between 20 and 75 %) is important to provide a better description of aerosol–radiation–cloud interactions in regional climate models

    Fractal surfaces of gold and platinum electrodeposits. Dimensionality determination by scanning tunneling microscopy

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    The structure of gold and platinum deposits grown on gold and platinum wire cathodes, respectively, by electroreduction of the corresponding oxide layers has been analyzed in terms of surface fractals by measuring the perimeter L and area A of intergranular voids. Perimeter and area were determined from scanning tunneling microscopy (STM) topographic images of the deposit surfaces. Fractal behavior, L ∞ AD'/2 with D'= 1.5 ± 0.1, is found for both platinum and gold deposits. From these measurements, the fractal dimension of the surfaces was 2.5. The D' value of the gold deposits decreases by aging in the electrolyte at 325 K as a consequence of surface diffusion processes.Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA)Facultad de Ciencias Exacta

    Aerosol optical properties over Europe: an evaluation of the AQMEII Phase 3 simulations against satellite observations

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    Abstract. The main uncertainties regarding the estimation of changes in the Earth's energy budget are related to the role of atmospheric aerosols. These changes are caused by aerosol–radiation (ARIs) and aerosol–cloud interactions (ACIs), which heavily depend on aerosol properties. Since the 1980s, many international modeling initiatives have studied atmospheric aerosols and their climate effects. Phase 3 of the Air Quality Modelling Evaluation International Initiative (AQMEII) focuses on evaluating and intercomparing regional and linked global/regional modeling systems by collaborating with the Task Force on the Hemispheric Transport of Air Pollution Phase 2 (HTAP2) initiative. Within this framework, the main aim of this work is the assessment of the representation of aerosol optical depth (AOD) and the Ångström exponent (AE) in AQMEII Phase 3 simulations over Europe. The evaluation was made using remote-sensing data from the Moderate Resolution Imaging Spectroradiometer (MODIS) sensors aboard the Terra and Aqua platforms, and the instruments belonging to the ground-based Aerosol Robotic Network (AERONET) and the Maritime Aerosol Network (MAN). Overall, the skills of AQMEII simulations when representing AOD (mean absolute errors from 0.05 to 0.30) produced lower errors than for the AE (mean absolute errors from 0.30 to 1). Regardless of the models or the emissions used, models were skillful at representing the low and mean AOD values observed (below 0.5). However, high values (around 1.0) were overpredicted for biomass burning episodes, due to an underestimation in the common fires' emissions, and were overestimated for coarse particles – principally desert dust – related to the boundary conditions. Despite this behavior, the spatial and temporal variability of AOD was better represented by all the models than AE variability, which was strongly underestimated in all the simulations. Noticeably, the impact of the model selection when representing aerosol optical properties is higher than the use of different emission inventories. On the other hand, the influence of ARIs and ACIs has a little visible impact compared to the impact of the model used

    Componentes biológicamente activos de la leche materna

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    La leche materna es un complejo fluido biológico que aporta la energía y los nutrientes esenciales para el desarrolloy crecimiento del recién nacido. Pero además, la leche materna contiene toda una serie de compuestos bioactivoscomo enzimas, hormonas, factores de crecimiento, proteínas específicas, poliaminas, nucleótidos, oligosacáridos, etc.,que ejercen efectos biológicos y que en conjunto reciben el nombre de “factores tróficos de la leche”. Estos compuestosbiactivos son considerados nutrientes potencialmente esenciales en periodos de desarrollo y en determinadasenfermedades, cuando la capacidad de síntesis no supera las necesidades de los mismos. Aunque las fórmulasinfantiles aportan todos los nutrientes para un adecuado desarrollo del recién nacido, carecen de muchos de estoscompuestos. Este artículo pretende realizar una revisión acerca de los conocimientos actuales sobre los efectosbiológicos de la lactoferrina, nucleótidos, poliaminas y oligosacáridos

    Importancia del lugar de elaboración de un producto de bollería de alto consumo sobre su composición grasa

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    Many epidemiologic studies show the relationship between the amount and the quality of the fat in the diet and the incidence of some patologies such as cardiovasculardiseases, cancer, etc. These data, adicionally to the fat that in later years the industrialized bakery food high in fat, are becoming a very important part of the children and adolescents diet, have motivated us to study the fat cuality of a industrialized bakery named "bollo relleno al cacao", Knowing the diferences product widely knowledge of elaboration of the same product but in differentnational factories.Numerosos estudios epidemiológicos ponen de manifiesto la relación entre la cantidad y calidad de la grasa ingerida en la dieta y la incidencia de determinadas patologías como enfermedades cardiovasculares, cáncer, etc. Estos datos sumados al hecho de que en la dieta del niño y del adolescente, en los últimos años, han adquirido una gran importancia los productos de bollería industriales, productos con alto contenido en grasas, nos ha motivado a realizar el análisis de la calidad de la grasa de un tipo de producto de bollería ampliamente consumido, denominado bollo relleno al cacao, teniendo en cuenta las diferencias de elaboración de este mismo producto en distintas fabricas a nivel nacional
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