4,840 research outputs found
Filtro predictor basado en redes neuronales para pronóstico de series temporales de lluvia acumulada empleando submuestreo
En éste trabajo se presenta un filtro predictor basado en redes neuronales (RNs) directas para pronóstico de series temporales de alta rugosidad empleando submuestreo, contribuyendo a la nueva generación de herramientas que permiten conocer la previsibilidad de agua de lluvia. Se generan series temporales a partir de submuestrear a una serie dato original, partiendo del valor disponible más reciente hacia el más antiguo. Se usaron series provenientes de la Ecuación Mackey-Glass (MG) de 120 datos, donde se usaron para validar al algoritmo los últimos 18 valores. También se usó una serie de lluvia mensual acumulada proveniente del establecimiento Santa Francisca, Alta Gracia, Córdoba, que tiene 125 valores. Para cada una de las series generadas por el submuestreo, se ajustó a un filtro diferente basado en RNs, y cada uno de ellos genera un pronóstico que luego es promediado en su conjunto. La regla de ajuste utilizada en el proceso de aprendizaje se basa en el método Levenberg-Marquard y el desempeño del filtro propuesto se evalúa a través del índice SMAPE. En muchos casos se obtienen mejoras muy notorias respecto del resultado obtenido mediante el filtro basado en RNs sin submuestreo.In this work, a neural networks (NN) -based predictor filter for forecasting cumulative rainfall sub-sampled time series of high roughness is presented. It is intended to contribute to the generation of tools to ascertain the predictability of rainfall. Time series are generated from a series down sample the original data, based on the latest available value to the oldest. Using series from the Mackey-Glass Equation (MG) 120 data, which were used the last 18 values to validate the algorithm . Series of monthly rainfall accumulated from Santa Francisca, Alta Gracia, Cordoba, were used which consist of 125 values. For each series generated by sub- sampling, was adjusted to a different filter based on NN, and each one generates a forecast that is then averaged together. The adjustment rule used in the learning process is based on the Levenberg-Marquard method and the proposed filter performance is evaluated by SMAPE index. In many cases very noticeable improvements are obtained with respect to the result obtained by filter based on NN without down sampling.Sociedad Argentina de Informática e Investigación Operativ
Rapid monitoring of anti-tuberculosis therapy using fluorescein diacetate microscopy: a simple method to determine infectiousness and screen for drug resistance
Background: Tuberculosis treatment and infection control are hampered by difficulty assessing mycobacterial viability to determine infectiousness and early treatment response. TB culture takes weeks; molecular tests are technically demanding; and acid-fast staining cannot differentiate live from dead tuberculosis. / Objectives: To develop and evaluate a simple slide-microscopy test to rapidly determine tuberculosis viability. / Methods: A protocol was optimized to stain viable but not dead tuberculosis in decontaminated sputum dried onto microscope slides and stained with the vital stain fluorescein diacetate (FDA). The reliability of this FDA slide microscopy for determining the concentration of viable tuberculosis in sputum was then compared with quantitative culture. / Results-laboratory evaluation: In untreated patients, tuberculosis auramine staining was unaffected whether sputum was fresh or had been sterilized by boiling, whereas FDA stained only un-boiled, viable tuberculosis. Quantification of viable tuberculosis by culture was reliably predicted by FDA, but not by auramine microscopy. / Results-clinical evaluation : Sequential sputums were collected from 35 patients before and after 3, 6 and 9 days of first-line tuberculosis treatment. Culture quantification of viable mycobacteria in sputum was predicted by slide microscopy with FDA (r2=0.77) but not auramine (r2=0.33). Quantification of viable tuberculosis in sputum by both quantitative culture and FDA microscopy fell 10-100 fold during the first nine days of treatment in all patients with drug-susceptible tuberculosis, whereas there was little change for patients with MDRTB. Specifically, 70% of samples from patients with drug-susceptible tuberculosis had a decline in the FDA count of viable tuberculosis of at least 0.2 logs/treatment-day, compared with none of the samples from MDRTB patients (P1 month required for culture. This simple and inexpensive technique rapidly assessed patient infectiousness on treatment, potentially guiding infection control measures. FDA staining also revealed differences in early treatment response between non-MDR and MDRTB and may allow early field screening for MDRTB and impending treatment failure
Heterologous constitutive production of short-chain-length polyhydroxyalkanoates in Pseudomonas putida KT2440: the involvement of IbpA inclusion body protein
Designing cell factories for the production of novel polyhydroxyalkanoates (PHAs) via smart metabolic engineering is key to obtain à la carte materials with tailored physicochemical properties. To this end, we used the model medium-chain-length-PHA producing bacterium, P. putida KT2440 as a chassis, which is characterized by its metabolic versatility and stress tolerance. Different PHA biosynthetic modules were assembled in expression plasmids using the Golden gate/MoClo modular assembly technique to implement an orthogonal short-chain-lengh-PHA (scl-PHA) switch in a “deaf” PHA mutant. This was specifically constructed to override endogenous multilevel regulation of PHA synthesis in the native strain. We generated a panel of engineered approaches carrying the genes from Rhodospirillum rubrum, Cupriavidus necator and Pseudomonas pseudoalcaligenes, demonstrating that diverse scl-PHAs can be constitutively produced in the chassis strain to varying yields from 23% to 84% PHA/CDW. Co-feeding assays of the most promising engineered strain harboring the PHA machinery from C. necator resulted to a panel of PHBV from 0.6% to 19% C5 monomeric incorporation. Chromosomally integrated PHA machineries with high PhaCCn synthase dosage successfully resulted in 68% PHA/CDW production. Interestingly, an inverse relationship between PhaC synthase dosage and granule size distribution was demonstrated in the heterologous host. In this vein, it is proposed the key involvement of inclusion body protein IbpA to the heterologous production of tailored PHA in P. putida KT2440
Técnicas para datos multinivel: Aplicación a los determinantes del rendimiento educativo
This paper consists of the application of the Hierarchical lineal model (multilevel methodology) which takes in consideration the interaction between individual and aggregated variables. It is intented to measure eterminants of student performance in their last year of school in three departments of Tucuman’s province (educational census year 2000). Data has multilevel structure indeed students belong to different schools. The GEE method “Generalized Estimated Equation”, suitable for conglomerate data, allows to model correlation between students within the same school. So multilevel modeling strategies are more likely to produce unbiased estimators than Least Squares, which suppose independence between observations
Técnicas para datos multinivel: Aplicación a los determinantes del rendimiento educativo
This paper consists of the application of the Hierarchical lineal model (multilevel methodology) which takes in consideration the interaction between individual and aggregated variables. It is intented to measure eterminants of student performance in their last year of school in three departments of Tucuman’s province (educational census year 2000). Data has multilevel structure indeed students belong to different schools. The GEE method “Generalized Estimated Equation”, suitable for conglomerate data, allows to model correlation between students within the same school. So multilevel modeling strategies are more likely to produce unbiased estimators than Least Squares, which suppose independence between observations
Pneumocystis jirovecii Transmission from Immunocompetent Carriers to Infant
We report a case of Pneumocystis jirovecii transmission from colonized grandparents to their infant granddaughter. Genotyping of P. jirovecii showed the same genotypes in samples from the infant and her grandparents. These findings support P. jirovecii transmission from immunocompetent carrier adults to a susceptible child
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