657 research outputs found

    Adaptive refinement and selection process through defect localization for reconstructing an inhomogeneous refraction index

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    We consider the iterative reconstruction of both the internal geometry and the values of an inhomogeneous acoustic refraction index through a piecewise constant approximation. In this context, we propose two enhancements intended to reduce the number of parameters to reconstruct, while preserving accuracy. This is achieved through the use of geometrical informations obtained from a previously developed defect localization method. The first enhancement consists in a preliminary selection of relevant parameters, while the second one is an adaptive refinement to enhance precision with a low number of parameters. Each of them is numerically illustrated

    Modular assembly of transposable element arrays by microsatellite targeting in the guayule and rice genomes

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    Abstract Background: Guayule (Parthenium argentatum A. Gray) is a rubber-producing desert shrub native to Mexico and the United States. Guayule represents an alternative to Hevea brasiliensis as a source for commercial natural rubber. The efficient application of modern molecular/genetic tools to guayule improvement requires characterization of its genome. Results: The 1.6 Gb guayule genome was sequenced, assembled and annotated. The final 1.5 Gb assembly, while fragmented (N50 =22 kb), maps >95% of the shotgun reads and is essentially complete. Approximately 40,000 transcribed, protein encoding genes were annotated on the assembly. Further characterization of this genome revealed 15 families of small, microsatellite-associated, transposable elements (TEs) with unexpected chromosomal distribution profiles. These SaTar (Satellite Targeted) elements, which are non-autonomous Mu-like elements (MULEs), were frequently observed in multimeric linear arrays of unrelated individual elements within which no individual element is interrupted by another. This uniformly non-nested TE multimer architecture has not been previously described in either eukaryotic or prokaryotic genomes. Five families of similarly distributed non-autonomous MULEs (microsatellite associated, modularly assembled) were characterized in the rice genome. Families of TEs with similar structures and distribution profiles were identified in sorghum and citrus. Conclusion: The sequencing and assembly of the guayule genome provides a foundation for application of current crop improvement technologies to this plant. In addition, characterization of this genome revealed SaTar elements with distribution profiles unique among TEs. Satar targeting appears based on an alternative MULE recombination mechanism with the potential to impact gene evolution. Keywords: Natural rubber, Genome, Assembly, Annotation, Class II transposable element, Non-autonomous, Transposo

    A Molecular Imprinted Polymer as a Flow-Through Optical Sensor for Oxazepam

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    A flow-through optosensing system for oxazepam recognition with fluorescence detection was performed by means of a molecular imprinted polymer based on its acid hydrolysis product, 2-amino-5-chlorobenzophenone. )e synthesis was conducted via a noncovalent imprinting methodology, using methacrylic acid as a functional monomer and ethylene glycol dimethacrylate as a cross-linking agent. Hydrolysis (types and concentration of acids), polymer retention capacity, binding properties, and elution (selectivity and reversibility) conditions were optimized. )eselected molecular imprinted polymer had a molar ratio composition of 1 : 6 : 45 (template : functional monomer : cross-linker). )e proposed method was applied to the determination of oxazepam in a pharmaceutical formulation. External standard calibration, standard additions calibration, and Youden’s calibration were carried out in order to evaluate constant and proportional errors due to the matrix. )e developed metabolite-based recognition system for benzodiazepines is an innovative procedure that could be followed in routine and quality control assays.Facultad de Ciencias ExactasLaboratorio de Investigación y Desarrollo de Métodos Analíticos (LIDMA

    Una Revisión Sistemática en los Marcos de Trabajo de Desarrollo Software en las MiPyMEs Productoras de Software

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    Resumen: Una revisión sistemática es considerada como un método o protocolo que permite sintetizar investigaciones científicas de diversas áreas, la Ingeniería de Software no es la excepción. En este artículo se presenta este protocolo aplicado en la búsqueda de publicaciones relacionadas con las adaptaciones a los marcos de trabajo de desarrollo de software llevadas a cabo en MiPyMEs desarrolladoras de software, en el período comprendido de 1995 al 2013, centrándose en tendencias, países y sectores que publican; así como en los modelos, metodologías, estándares, procesos técnicos, procesos de implementación y procesos de reúso del software. Los resultados obtenidos muestran que los países con mayor número de publicaciones sobre el tópico seleccionado son Estados Unidos y Reino Unido, que en su conjunto suman 21%; y que otros países suman el 79% restante. Se observa que el sector con mayor número de publicaciones es el sector educativo con 76%, seguido por los centros de investigación con 18% y el sector privado con el 6%. El modelo de procesos y la metodología más utilizados son CMMi con 33% e IDEAL con 22%, respectivamente. Los estándares más utilizados, con el 18% cada uno, son el ISO/IEC 15504 y CORBA; y los procesos del ciclo de vida del software mayormente abordados son: análisis de requisitos del sistema con un 33% y construcción con un 29%. Palabras Clave: MiPyME, revisión sistemática, modelos, metodologías, estándares de desarrollo de software, procesos técnicos, procesos de implementación, procesos de reúso del software

    Downregulation of a CYP74 Rubber Particle Protein Increases Natural Rubber Production in \u3ci\u3eParthenium argentatum\u3c/i\u3e

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    We report functional genomics studies of a CYP74 rubber particle protein from Parthenium argentatum, commonly called guayule. Previously identified as an allene oxide synthase (AOS), this CYP74 constitutes the most abundant protein found in guayule rubber particles. Transgenic guayule lines with AOS gene expression down-regulated by RNAi (AOSi) exhibited strong phenotypes that included agricultural traits conducive to enhancing rubber yield. AOSi lines had higher leaf and stem biomass, thicker stembark tissues, increased stem branching and improved net photosynthetic rate. Importantly, the rubber content was significantly increased in AOSi lines compared to the wild-type (WT), vector control and AOS overexpressing (AOSoe) lines, when grown in controlled environments both in tissue-culture media and in greenhouse/growth chambers. Rubber particles from AOSi plants consistently had less AOS particle-associated protein, and lower activity (for conversion of 13-HPOT to allene oxide). Yet plants with downregulated AOS showed higher rubber transferase enzyme activity. The increase in biomass in AOSi lines was associated with not only increases in the rate of photosynthesis and non-photochemical quenching (NPQ), in the cold, but also in the content of the phytohormone SA, along with a decrease in JA, GAs, and ABA. The increase in biosynthetic activity and rubber content could further result from the negative regulation of AOS expression by high levels of salicylic acid in AOSi lines and when introduced exogenously. It is apparent that AOS in guayule plays a pivotal role in rubber production and plant growth

    Valoración económico-ambiental de recursos naturales seleccionados en la cuenca del río Guanabo, La Habana, Cuba

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    En el estudio se identifican las principales funciones ambientales asociadas a recursos naturales degradados en sectores seleccionados de la cuenca del río Guanabo, ubicada en La Habana, Cuba. Parte de estas funciones se valoran económicamente y se ofrecen criterios para un mejor aprovechamiento de dichos recursos, teniendo en cuenta su valor económico total.In this research, the main environmental functions associated to degraded natural resources in selected sites of the Guanabo river basin, located in Havana, were identified. Some of these functions were valued in economic terms and guidance criteria were offered to improve management and use of the studied resources based on their estimated total economic value
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