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Search Results: 1 - 10 of 342029 matches for " C. H. H.;Franco "
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Sintomas de deficiências minerais no cafeeiro
Franco, C. M.;Mendes, H. C.;
Bragantia , 1949, DOI: 10.1590/S0006-87051949000300002
Abstract: coffee plants (coffea arabica l.) were grown in nutrient solutions for the purpose of studying deficiency symptoms of the following elements : nitrogen, phosphorus, potassium, magnesium, calcium, sulphur and iron. the methods employed in the growing of coffee plants in the nutrient solutions are described. after preliminary tests with several nutrient solutions hoagland's formula was selected as most suitable for the present tests. however, the quantity of phosphate employed in the basic nutrient solution was reduced to one third of that given in hoagland's formula. this reduction in phosphate was made because of the previous results obtained by jacob which seemed to indicate that the coffee plant requires only very small amounts of phosphorus. in the present tests phosphorus deficiency symptoms were obtained and these results suggest that jacob's failure to obtain phosphorus deficiency symptoms may be ascribed to use of shive's solution, which has a very high phosphate content. while growing in this complete nutrient solution his plants may have stored enough phosphorus to supply their needs later when they were transferred to the solution lacking this element. in the course of the present investigation it was found that in the nutrient solutions containing kh2po4 and having a ph higher than 5.5, the coffee plant absorbs insufficient iron. this difficulty of iron absorption by the coffee plants grown in nutrient solution was overcome by a technique previously described that is, when iron deficiency symptoms appeared on plants being tested for other deficiencies the nutrient solution was changed and the new solution used contained no phosphate. the plants were allowed to grow in this solution for two to four days and then the phosphate was added. in this way the plants absorbed sufficient iron for their requirements. the present paper describes and the color plates illustrate the symptoms on coffee plants that were associated, in the present studies, with nutrient s
Attacking quantum key distribution with single-photon two-qubit quantum logic
Jeffrey H. Shapiro,Franco N. C. Wong
Physics , 2005, DOI: 10.1103/PhysRevA.73.012315
Abstract: The Fuchs-Peres-Brandt (FPB) probe realizes the most powerful individual attack on Bennett-Brassard 1984 quantum key distribution (BB84 QKD) by means of a single controlled-NOT (CNOT) gate. This paper describes a complete physical simulation of the FPB-probe attack on polarization-based BB84 QKD using a deterministic CNOT constructed from single-photon two-qubit quantum logic. Adding polarization-preserving quantum nondemolition measurements of photon number to this configuration converts the physical simulation into a true deterministic realization of the FPB attack.
Nota sobre la predicción del índice de precios al consumidor usando redes neuronales artificiales
Velásquez H.,Juan David; Franco C.,Carlos Jaime;
Cuadernos de Administración , 2010,
Abstract: this article forecasts the percentage variation in the colombian consumer price index, using an artificial neuronal network. the model obtained, a multiple-layer perceptron neuronal network, is capable of capturing the seasonal cycle present in the data, by solely using past data as entries into the neuronal network; it is not necessary to include fictitious variables to represent said structural component. this approach is more precise than other models presented in the literature on the topic, including those with exponential smoothing, sarima model approximations, and other neuronal network configurations.
Effectiveness of added natural antioxidants in sunflower oil
Carelli, Amalia A.,Franco, Indira C.,Crapiste, Guillermo H.
Grasas y Aceites , 2005,
Abstract: The antioxidant activity of ±- and ′-tocopherol, citric acid, ascorbic acid and ascorbyl palmitate was investigated in sunflower oil containing naturally occurring tocopherol. The effectiveness of natural antioxidants in sunflower oil was monitored by the accelerated oxidative stability test Rancimat and oxidation development during storage under different conditions. Samples in storage experiments were periodically removed and analyzed for peroxide value, p-anisidine value, total content and distribution of polar compounds, and residual naturally occurring tocopherol. The effectiveness of each antioxidant was strongly dependent on temperature and the testing method. While ascorbic acid appears to be the most effective antioxidant according to the Rancimat oxidative stability index, ′-tocopherol shows improved performance when considering storage experiments. Se investigó la actividad antioxidante de ±-tocoferol, ′-tocoferol, ácido cítrico y palmitato de ascorbilo en aceite de girasol con su conteniendo natural de tocoferol. La efectividad de los mismos fue analizada a través de la medida de la estabilidad oxidativa en Rancimat y el seguimiento de la oxidación con el almacenamiento a diferentes temperaturas. Las muestras extraídas periódicamente de la estufa fueron sometidas a los siguientes análisis: índice de peróxidos, valor de p-anisidina, contenido y distribución de compuestos polares y contenido residual de tocoferol natural. La efectividad de cada antioxidante resultó fuertemente dependiente de la temperatura y método de ensayo. Mientras el ácido ascórbico resultó ser el antioxidante más efectivo según el índice de estabilidad oxidativa medido en el equipo Rancimat, el ′-tocoferol fue el antioxidante más efectivo en las experiencias de almacenamiento.
Nota sobre la predicción del índice de precios al consumidor usando redes neuronales artificiales Nota sobre a previs o do índice de Pre os ao Consumidor usando redes neuronais artificiais Note on predicting consumer price indexes using artificial neuronal networks
Juan David Velásquez H.,Carlos Jaime Franco C.
Cuadernos de Administración , 2010,
Abstract: En este artículo se pronostica la variación porcentual del índice de Precios al Consumidor en Colombia usando una red neuronal artificial. El modelo obtenido, una red neuronal tipo perceptrón multicapa, es capaz de capturar el ciclo estacional presente en los datos usando sólo los datos pasados, como entradas a la red neuronal, y no es necesario incluir variables ficticias que representen dicha componente estructural. La precisión de esta aproximación es mejor que la obtenida por otros modelos presentados en la literatura, incluidos aquellos con suavizaciones exponenciales, aproximaciones a modelos SARIMA y otras configuraciones de redes neuronales. Neste artigo se prognostica a varia o porcentual do índice de Pre os ao Consumidor na Col mbia usando uma rede neuronal artificial. O modelo obtido, uma rede neuronal tipo perceptron multicamada, é capaz de capturar o ciclo sazonal presente nos dados usando somente os dados passados, como entradas a rede neuronal, e n o é necessário incluir variáveis fictícias que representem tal componente estrutural. A precis o desta aproxima o é melhor que a obtida por outros modelos apresentados na literatura, incluídos aqueles com suaviza es exponenciais, aproximadas a modelos SARIMA e outras configura es de redes neuronais. This article forecasts the percentage variation in the Colombian Consumer Price Index, using an artificial neuronal network. The model obtained, a multiple-layer perceptron neuronal network, is capable of capturing the seasonal cycle present in the data, by solely using past data as entries into the neuronal network; it is not necessary to include fictitious variables to represent said structural component. This approach is more precise than other models presented in the literature on the topic, including those with exponential smoothing, SARIMA model approximations, and other neuronal network configurations.
Time-bin modulated polarization-entangled biphotons from cavity-enhanced down-conversion
Christopher E. Kuklewicz,Franco N. C. Wong,Jeffrey H. Shapiro
Physics , 2006, DOI: 10.1103/PhysRevLett.97.223601
Abstract: We have generated a new type of biphoton state by cavity-enhanced down-conversion in a type-II phase-matched, periodically-poled KTiOPO_4 (PPKTP) crystal. By introducing a weak intracavity birefringence, the polarization-entangled output was modulated between the singlet and triplet states according to the arrival-time difference of the signal and idler photons. This cavity-enhanced biphoton source is spectrally bright, yielding a single-mode fiber-coupled coincidence rate of 0.7 pairs/s per mW of pump power per MHz of down-conversion bandwidth. Its novel biphoton behavior may be utilized in sensitive measurements of weak intracavity birefringence.
Sub-Rayleigh Imaging via N-Photon Detection
Fabrizio Guerrieri,Lorenzo Maccone,Franco N. C. Wong,Jeffrey H. Shapiro,Simone Tisa,Franco Zappa
Physics , 2010, DOI: 10.1103/PhysRevLett.105.163602
Abstract: The Rayleigh diffraction bound sets the minimum separation for two point objects to be distinguishable in a conventional imaging system. We demonstrate resolution enhancement beyond the Rayleigh bound using random scanning of a highly-focused beam and N-photon photodetection implemented with a single-photon avalanche detector array. Experimental results show resolution improvement by a factor ~sqrt(N) beyond the Rayleigh bound, in good agreement with theory.
Acta zoológica mexicana , 2012,
Abstract: Four new records of the banded gecko Coleonyx elegans nemoralis in Morelos, Mexico, are reported.
Bite force and masticatory efficiency in individuals with different oral rehabilitations  [PDF]
Laner B. Rosa, Cesar Bataglion, Selma Siéssere, Marcelo Palinkas, Wilson Mestriner Jr., Osvaldo de Freitas, Moara de Rossi, Lígia Franco de Oliveira, Simone C. H. Regalo
Open Journal of Stomatology (OJST) , 2012, DOI: 10.4236/ojst.2012.21004
Abstract: Objective: This study was analyzed adult individuals rehabilitated with different types of dentures, with the purpose of verifying the effect that different types of denture rehabilitation have on maximal bite force and masticatory efficiency. The aim of this study is to facilitate diagnosis and prognosis, bringing contributions to the quality and stability of treatments Materials and Methods: Fifty individuals were divided into five groups: one control group with ten dentate individuals and another four groups formed according to the type of rehabilitation treatment. Maximal bite force was recorded on the first molar regions, and masticatory efficiency rates were recorded on the right, left and habitual sides. Results: Data related to the maximal bite force recordings were statistically significant across the analyzed groups [ANOVA for p ≤ 0.01]. The data related to masticatory efficiency rates also showed statistical significance across all groups [ANOVA for p ≤ 0.05] in the three tested conditions [mastication on the right, left and habitual sides]. Conclusion: The group of individuals rehabilitated with implants and single crowns showed greater bite force values and masticatory efficiency rates compared to the other groups, and the treatment with implantsupported mandibular overdenture improved the function compared to conventional complete dentures, thus evincing that the stomatognathic system has different functional behaviors depending on the type of oral rehabilitation.
Predicción de los precios promedios mensuales de contratos despachados en el mercado mayorista de electricidad en Colombia usando máquinas de vectores de soporte
Velásquez H,Juan David; Franco C,Carlos Jaime; Olaya M,Yris;
Cuadernos de Administración , 2010,
Abstract: forecasting electricity prices in liberalized, deregulated markets has always been considered a difficult task, due to the number of factors that govern prices and to their complexity. this article predicts the average monthly prices for colombian electricity market contracts by using a novel neural network known as the support vector machine. forecasts obtained using a multilayer perceptron are compared to forecasts obtained using an arima model. the results show that the support vector machine better captures the intrinsic dynamics of the time series and is able to make more precise forecasts considering a 12-month horizon.
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