989 resultados para Moreau, Jean Michel, 1741-1814


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Comunicaciones presentadas en el marco del proyecto FRUTURA de CYTED. Reunión Científico Técnica FRUTURA San José-EARTH (Costa Rica) - Mayo de 2011

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La salinización en suelos de cultivos es un fenómeno muy relevante en el Sureste español que se produce por el empleo de aguas de riego salinas o de mala calidad. La lechuga (Lactuca sativa L.) es uno de los cultivos hortícolas de mayor implantación en esta área, destinándose principalmente para consumo en fresco y en productos cuarta gama. La salinidad puede afectar a la productividad y calidad del cultivo, sin embargo, en determinadas concentraciones investigaciones previas muestran que la salinidad puede favorecer la conservación de las hojas tras el corte, disminuyendo los procesos de degradación enzimática y el desarrollo de microorganismos. El objetivo del presente trabajo es evaluar la viabilidad de la imagen hiperespectral (400 a 1000 nm) para identificar la influencia del estrés salino en lechuga ?baby? recién recolectada. Para ello, se han adquirido imágenes de 40 hojas de diferentes lechugas sometidas a tres soluciones salinas diferentes y a una solución control. Dichas imágenes fueron sometidas a preprocesado de espectros (suavizado con el algoritmo Savitsky-Golay + normalización SNV), combinado con Análisis de Componentes Principales. Las imágenes virtuales de scores generadas con el modelo muestran diferencias progresivas en los valores asignados a los píxeles de las imágenes a medida que aumenta la concentración salina de la solución aplicada al cultivo. Se observa cómo la solución salina afecta a la hoja cambiando la coloración de las zonas medias, posiblemente debido a la concentración de solutos. La interpretación de los loadings de estos modelos permite conocer cómo afecta la salinidad al comportamiento espectral de las hojas. La imagen hiperespectral puede tener un gran potencial para identificar los límites de salinidad tolerados y evitar concentraciones tóxicas que afecten negativamente la vida útil de las hortalizas de hoja. Este conocimiento permitirá desarrollar índices multiespectrales capaces de identificar hojas afectadas por salinidad durante su cultivo y procesado postcosecha.

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BETs is a three-year project financed by the Space Program of the European Commission, aimed at developing an efficient deorbit system that could be carried on board any future satellite launched into Low Earth Orbit (LEO). The operational system involves a conductive tape-tether left bare to establish anodic contact with the ambient plasma as a giant Langmuir probe. As a part of this project, we are carrying out both numerical and experimental approaches to estimate the collected current by the positive part of the tether. This paper deals with experimental measurements performed in the IONospheric Atmosphere Simulator (JONAS) plasma chamber of the Onera-Space Environment Department. The JONAS facility is a 9- m3 vacuum chamber equipped with a plasma source providing drifting plasma simulating LEO conditions in terms of density and temperature. A thin metallic cylinder, simulating the tether, is set inside the chamber and polarized up to 1000 V. The Earth's magnetic field is neutralized inside the chamber. In a first time, tether collected current versus tether polarization is measured for different plasma source energies and densities. In complement, several types of Langmuir probes are used at the same location to allow the extraction of both ion densities and electron parameters by computer modeling (classical Langmuir probe characteristics are not accurate enough in the present situation). These two measurements permit estimation of the discrepancies between the theoretical collection laws, orbital motion limited law in particular, and the experimental data in LEO-like conditions without magnetic fields. In a second time, the spatial variations and the time evolutions of the plasma properties around the tether are investigated. Spherical and emissive Langmuir probes are also used for a more extensive characterization of the plasma in space and time dependent analysis. Results show the ion depletion because of the wake effect and the accumulation of- ions upstream of the tether. In some regimes (at large positive potential), oscillations are observed on the tether collected current and on Langmuir probe collected current in specific sites.

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NIR Hyperspectral imaging (1000-2500 nm) combined with IDC allowed the detection of peanut traces down to adulteration percentages 0.01% Contrary to PLSR, IDC does not require a calibration set, but uses both expert and experimental information and suitable for quantification of an interest compound in complex matrices. The obtained results shows the feasibility of using HSI systems for the detection of peanut traces in conjunction with chemical procedures, such as RT-PCR and ELISA

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- NIR Hyperspectral images (1000-2200 nm) allowed the detection of peanut traces down to adulteration percentages 0.01 % - Determination coefficient of R2= 0.946 was found for the quantification of peanut adulteration from 10% to 0.1%. - The obtained results shows the feasibility of using HSI systems for the detection of peanut traces in conjuction with chemical procedures, such as RT-PCR and ELISA to facilitate quality control surveyance on food product processing lines.

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En el mundo existen ciertos grupos de población que muestran una hipersensibilidad a determinados alimentos, y cuya ingestión accidental desencadena, una respuesta del tipo “shock” anafiláctico. Esto ha obligado a las empresas alimentarias a estudiar de forma exhaustiva la gestión del riesgo de todos sus productos. El cacahuete es uno de los principales alérgenos en la industria. La espectroscopia NIR se ha utilizado recientemente para analizar la cantidad total de aceite y ácido grasos en cacahuete intacto (Sudaram y colaboradores, 2012). El objetivo de este trabajo es estudiar métodos no destructivos basados en espectroscopia para la detección de trazas de cacahuete en alimentos en polvo, como complemento al método genético reacción en cadena de la polimerasa en tiempo real (Real Time -PCR) desarrollado por el grupo de investigación TRADETBIO de la UCM, en el marco de colaboración en el Campus de Excelencia Internacional Moncloa. Los materiales utilizados fueron cacahuetes de cinco variedades de origen geográfico distinto y sometidas a diferentes tratamientos, proporcionadas por el Instituto de Materiales de Referencia CE, así como leche en polvo, cacao, harina de trigo, y cacahuete de diferentes marcas comerciales. Para todos ellos, se adquirieron dos series de espectros: en el infrarrojo cercano NIR (896-1686 nm), y los extraídos de imágenes hiperespectrales HIS (400-1000nm). La espectroscopia VIS se mostró sensible a las diferencias en el cacahuete en cuanto a su origen y/o tratamiento, ya que inducen cambios en el color, siendo inviable la separación entre los cacahuetes blanqueados, la leche y la harina en esta región espectral. Las principales diferencias entre los cacahuetes y el resto de ingredientes alimentarios se han encontrado en el rango NIR, específicamente en las longitudes de onda de (1207-1210 nm), relacionadas con una región de absorción de los lípidos. El infrarrojo permite 100% de segregación de cualquier tipo de cacahuete respecto al resto de los ingredientes alimentarios. La espectroscopia NIR combinada con las técnicas de imagen (hiperespectral o multiespectral) podría por tanto, ser aplicado para detectar trazas de cacahuetes en alimentos en polvo, no influyendo su origen y/o tratamiento, ya que es capaz de separar cualquier cacahuete del resto de los ingredientes alimentarios. Este método podría ser una técnica de cribado previo al método PCR de elevado coste.

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En 2010, Recursos Naturales Canada (RNC) instaló 3 estaciones sísmicas con transmisión vía satélite en Jacmel, Léogane y Puerto Príncipe, la capital de la Republica de Haití. Dicha instalación tenía como objetivo la monitorización de las réplicas del terremoto del 12 de enero del mismo año. Con el objetivo de ampliar la cobertura de la monitorización sísmica a todo el país y tener un centro de control propio, el Observatorio Nacional de Medio Ambiente y de la Vulnerabilidad (ONEV) del Ministerio del Medio Ambiente de Haití (MDE) compró 4 estaciones sísmicas completas con transmisión vía satélite de Nanometrics Inc. y el software correspondiente. Desafortunadamente, no se está sacando provecho de dichas estaciones compradas. En la actualidad, dos de ellas, que están instaladas en Hinche y Cabo Haitiano, no están configuradas, y las otras siguen en el almacén del ONEV. No se ha conseguido el presupuesto para completar la instalación, ni tampoco para implantar el centro de control de la red sísmica digital por satélite que se quiere configurar en el país. El presente trabajo propone un diseño completo de la Red Sísmica Digital por Satélite Haitiana y la planificación para su implantación real, incluyendo las estaciones y el centro de control. Por ello se han estudiado las redes sísmicas modernas, las características de las redes sísmicas del Caribe, el sistema de transmisión Libra de Nanometrics y los software de adquisición y procesamiento de datos sísmicos Apollo y SeisComp3. También se ha estudiado la distribución espacial de las estaciones sísmicas con transmisión vía satélite instaladas en el país proponiendo alternativas y recomendaciones para futura ampliación, considerando los aspectos científicos, políticos y económicos, a la Isla de Vaca (Ile‐à‐Vache) en el extremo sur del país y la Isla de la Tortuga (Ile de la Tortue) al norte de la Falla Septentrional en el extremo norte del territorio haitiano.

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Models for prediction of oil content as percentage of dried weight in olive fruits were comput- ed through PLS regression on NIR spectra. Spectral preprocessing was carried out by apply- ing multiplicative signal correction (MSC), Sa vitzky–Golay algorithm, standard normal variate correction (SNV), and detrending (D) to NIR spectra. MSC was the preprocessing technique showing the best performance. Further reduction of variability was performed by applying the Wold method of orthogonal signal correction (OSC). The calibration model achieved a R 2 of 0.93, a SEPc of 1.42, and a RPD of 3.8. The R 2 obtained with the validation set remained 0.93, and the SEPc was 1.41.

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In current industrial environments there is an increasing need for practical and inexpensive quality control systems to detect the foreign food materials in powder food processing lines. This demand is especially important for the detection of product adulteration with traces of highly allergenic products, such as peanuts and tree nuts. Manufacturing industries dealing with the processing of multiple powder food products present a substantial risk for the contamination of powder foods with traces of tree nuts and other adulterants, which might result in unintentional ingestion of nuts by the sensitised population. Hence, the need for an in-line system to detect nut traces at the early stages of food manufacturing is of crucial importance. In this present work, a feasibility study of a spectral index for revealing adulteration of tree nut and peanut traces in wheat flour samples with hyperspectral images is reported. The main nuts responsible for allergenic reactions considered in this work were peanut, hazelnut and walnut. Enhanced contrast between nuts and wheat flour was obtained after the application of the index. Furthermore, the segmentation of these images by selecting different thresholds for different nut and flour mixtures allowed the identification of nut traces in the samples. Pixels identified as nuts were counted and compared with the actual percentage of peanut adulteration. As a result, the multispectral system was able to detect and provide good visualisation of tree nut and peanut trace levels down to 0.01% by weight. In this context, multispectral imaging could operate in conjuction with chemical procedures, such as Real Time Polymerase Chain Reaction and Enzyme-Linked Immunosorbent Assay to save time, money and skilled labour on product quality control. This approach could enable not only a few selected samples to be assessed but also to extensively incorporate quality control surveyance on product processing lines.

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The use of a common environment for processing different powder foods in the industry has increased the risk of finding peanut traces in powder foods. The analytical methods commonly used for detection of peanut such as enzyme-linked immunosorbent assay (ELISA) and real-time polymerase chain reaction (RT-PCR) represent high specificity and sensitivity but are destructive and time-consuming, and require highly skilled experimenters. The feasibility of NIR hyperspectral imaging (HSI) is studied for the detection of peanut traces down to 0.01% by weight. A principal-component analysis (PCA) was carried out on a dataset of peanut and flour spectra. The obtained loadings were applied to the HSI images of adulterated wheat flour samples with peanut traces. As a result, HSI images were reduced to score images with enhanced contrast between peanut and flour particles. Finally, a threshold was fixed in score images to obtain a binary classification image, and the percentage of peanut adulteration was compared with the percentage of pixels identified as peanut particles. This study allowed the detection of traces of peanut down to 0.01% and quantification of peanut adulteration from 10% to 0.1% with a coefficient of determination (r2) of 0.946. These results show the feasibility of using HSI systems for the detection of peanut traces in conjunction with chemical procedures, such as RT-PCR and ELISA to facilitate enhanced quality-control surveillance on food-product processing lines.

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In current industrial environments there is an increasing need for practical and inexpensive quality control systems to detect the foreign food materials in powder food processing lines. This demand is especially important for the detection of product adulteration with traces of highly allergenic products, such as peanuts and tree nuts. Manufacturing industries dealing with the processing of multiple powder food products present a substantial risk for the contamination of powder foods with traces of tree nuts and other adulterants, which might result in unintentional ingestion of nuts by the sensitised population. Hence, the need for an in-line system to detect nut traces at the early stages of food manufacturing is of crucial importance. In this present work, a feasibility study of a spectral index for revealing adulteration of tree nut and peanut traces in wheat flour samples with hyperspectral images is reported. The main nuts responsible for allergenic reactions considered in this work were peanut, hazelnut and walnut. Enhanced contrast between nuts and wheat flour was obtained after the application of the index. Furthermore, the segmentation of these images by selecting different thresholds for different nut and flour mixtures allowed the identification of nut traces in the samples. Pixels identified as nuts were counted and with the actual percentage of peanut adulteration. As a result, the multispectral system was able to detect and provide good visualisation of tree nut and peanut trace levels down to 0.01% by weight. In this context, multispectral imaging could operate in conjuction with chemical procedures, such as Real Time Polymerase Chain Reaction and Enzyme-Linked Immunosorbent Assay to save time, money and skilled labour on product quality control. This approach could enable not only a few selected samples to be assessed but also to extensively incorporate quality control surveyance on product processing lines.

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Visible-near infrared reflectance spectra are proposed for the characterization of IRMM 481 peanuts variety in comparison to powder food materials: wheat flour, milk and cocoa. Multidimensional analysis of reflectance spectra of powder samples shows a specific NIR band centred at 1200 nm that identifies peanut compared to the rest of food ingredients, regardless compaction level and temperature. Spectral range of 400-1000 nm is not robust for identification of blanched peanut. The visible range has shown to be reliable for the identification of pre-treatment and processing of unknown commercial peanut samples. A spectral index is proposed based on the combination of three wavelengths around 1200 nm that is 100% robust against pre-treatment (raw or blanched) and roasting (various temperatures and treatment duration).

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In recent years, Independent Components Analysis (ICA) has proven itself to be a powerful signal-processing technique for solving the Blind-Source Separation (BSS) problems in different scientific domains. In the present work, an application of ICA for processing NIR hyperspectral images to detect traces of peanut in wheat flour is presented. Processing was performed without a priori knowledge of the chemical composition of the two food materials. The aim was to extract the source signals of the different chemical components from the initial data set and to use them in order to determine the distribution of peanut traces in the hyperspectral images. To determine the optimal number of independent component to be extracted, the Random ICA by blocks method was used. This method is based on the repeated calculation of several models using an increasing number of independent components after randomly segmenting the matrix data into two blocks and then calculating the correlations between the signals extracted from the two blocks. The extracted ICA signals were interpreted and their ability to classify peanut and wheat flour was studied. Finally, all the extracted ICs were used to construct a single synthetic signal that could be used directly with the hyperspectral images to enhance the contrast between the peanut and the wheat flours in a real multi-use industrial environment. Furthermore, feature extraction methods (connected components labelling algorithm followed by flood fill method to extract object contours) were applied in order to target the spatial location of the presence of peanut traces. A good visualization of the distributions of peanut traces was thus obtained

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A expansão das redes sociais virtuais, o aperfeiçoamento das técnicas de informação, a penetrabilidade do capitalismo de concorrência e o fragmentado sujeito pós-moderno constituem, ao lado da sociedade de consumo, os pilares desta tese. Nossa hipótese central é que as redes sociais da Internet ampliam os espaços de participação, compartilhamento, colaboração e manifestação das decepções do consumidor, mas não diminuem as descontinuidades, a incompreensão e o desrespeito oriundos das relações e práticas de consumo, podendo, muitas vezes, aceleraremasconflitualidades. A abertura para o diálogo, o incitamento à tomada de poder do sujeito e a multiplicação das trocas entre empresas e consumidores representam a oportunidade e o desafio de valorizarmos a concepção normativa da comunicação, admitindo as dificuldades da intercompreensão, a urgência da coabitação e a realidade da incomunicação. Recorremos à Análise de Discurso de tradição francesa (AD) como campo teórico-metodológico para analisar o discurso do consumidor inscrito na plataforma Reclame AQUI e construir uma crítica à comunicação corporativa contemporânea; a partir dos conceitos de cenografia, ethos e esquematização enunciativa, verificamos como a ideologia opera no interior das cenas daenunciação do consumo, constituindo uma ordem própria ao discurso do reclamante decepcionado. Esta análise ratificou as discussões teóricas que levamos a cabo, servindo de suporte para a problematização e o debate das sete cenografias que se evidenciaram no/pelo discurso do sujeito/consumidor: respeito/desrespeito, ameaça, promessa e frustração, mau atendimento e problema não resolvido, negociação, clientes novos x antigos e consumidor enganado; a imbricação do nosso corpuse o arcabouço teórico coloca na ribalta a necessidade de políticas de comunicação organizacional norteadas pelo senso prático de outridade, transcendendo as relações puramente mercadológicas; ao mesmo tempo, lança luz sobre apremência de mais solidariedade, compaixão, capacidade de escuta, compreensão e coabitação para as corporações que funcionam em uma sociedade guiada pelo frenesi da ética da concorrência e da consumolatria. Esta tese evidencia que a atuação dos consumidores e das empresas no mundo on-line representa mais que um elemento circunstancial de (in) tolerância mútua; desenha um destino comum que pode ter como rumo a outridade solidária do próximo, aceitando a experiência da alteridade, o risco do fracasso e a esperança da confiança e do respeito que a comunicação pode conceber.

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Two mouse insulin genes, Ins1 and Ins2, were disrupted and lacZ was inserted at the Ins2 locus by gene targeting. Double nullizygous insulin-deficient pups were growth-retarded. They did not show any glycosuria at birth but soon after suckling developed diabetes mellitus with ketoacidosis and liver steatosis and died within 48 h. Interestingly, insulin deficiency did not preclude pancreas organogenesis and the appearance of the various cell types of the endocrine pancreas. The presence of lacZ expressing β cells and glucagon-positive α cells was demonstrated by cytochemistry and immunocytochemistry. Reverse transcription-coupled PCR analysis showed that somatostatin and pancreatic polypeptide mRNAs were present, although at reduced levels, accounting for the presence also of δ and pancreatic polypeptide cells, respectively. Morphometric analysis revealed enlarged islets of Langherans in the pancreas from insulin-deficient pups, suggesting that insulin might function as a negative regulator of islet cell growth. Whether insulin controls the growth of specific islet cell types and the molecular basis for this action remain to be elucidated.