679 research outputs found

    Classification of hydrometeors based on polarimetric radar measurements: development of fuzzy logic and neuro-fuzzy systems, and in situ verification

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    Includes bibliographical references (page 164).A fuzzy logic and neuro-fuzzy system for classification of hydrometeor type based on polarimetric radar measurements is described in this paper. The hydrometeor classification system is implemented by using fuzzy logic and a neural network, where the fuzzy logic is used to infer hydrometeor type, and the neural network learning algorithm is used for automatic adjustment of the parameters of the fuzzy sets in the fuzzy logic system according to prior knowledge. Five radar measurements, namely, horizontal reflectivity (ZH), differential reflectivity (ZDR), differential propagation phase shift (KDP), correlation coefficient [ρHV(0)], and linear depolarizationratio (LDR), and corresponding altitude, have been used as input variables to the neuro-fuzzy network. The output of the neuro-fuzzy system is one of the many possible hydrometeor types: 1) drizzle, 2) rain, 3) dry and low density snow, 4) dry and high-density crystals, 5) wet and melting snow, 6) dry graupel, 7) wet graupel, 8)small hail, 9) large hail, and 10) a mixture of rain and hail. The neuro-fuzzy classifier is more advantageous than a simple neural network or a fuzzy logic classifier because it is more transparent (instead of a "black box") and can learn the parameter of the system from the past data (unlike a fuzzy logic system). The hydrometeor classifier has been applied to several case studies and the results are compared against in situ observations

    An Adaptive Neural Network Scheme for Radar Rainfall Estimation from WSR-88D Observations

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    Recent research has shown that neural network techniques can be used successfully for ground rainfall estimation from radar measurements. The neural network is a nonparametric method for representing the rela-tionship between radar measurements and rainfall rate. The relationship is derived directly from a dataset consisting of radar measurements and rain gauge measurements. The effectiveness of the rainfall estimation by using neural networks can be influenced by many factors such as the representativeness and sufficiency of the training dataset, the generalization capability of the network to new data, season change, location change, and so on. In this paper, a novel scheme of adaptively updating the structure and parameters of the neural network for rainfall estimation is presented. This adaptive neural network scheme enables the network to account for any variability in the relationship between radar measurements and precipitation estimation and also to incorporate new information to the network without retraining the complete network from the beginning. This precipitation estimation scheme is a good compromise between the competing demands of accuracy and generalization. Data collected by a Weather Surveillance Radar—1988 Doppler (WSR-88D) and a rain gauge network were used to evaluate the performance of the adaptive network for rainfall estimation. It is shown that the adaptive network can estimate rainfall fairly accurately. The implementation of the adaptive network is very efficient and convenient for real-time rainfall estimation to be used with WSR-88D. 1

    Reflective Full Subcategories of the Category of L

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    This paper focuses on the relationship between L-posets and complete L-lattices from the categorical view. By considering a special class of fuzzy closure operators, we prove that the category of complete L-lattices is a reflective full subcategory of the category of L-posets with appropriate morphisms. Moreover, we characterize the Dedekind-MacNeille completions of L-posets and provide an equivalent description for them

    Local Buckling of Concrete Filled Rectangular Steel Tube with Longitudinal Stiffener under Axial Compression

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    Width-thickness ratio was an important parameter for designing Concrete Filled Rectangular Steel Tube (CFRST). Welding longitudinal stiffener on the internal wall of steel pipe could delay the local buckling, which increased the limit of width-thickness ratio. If there was not enough stiffener and its sectional dimension was too small, the local buckling of steel pipe would occur, inducing its bearing capacity seriously. If the stiffener sectional dimension was too large, concrete filled in steel tube would be broken up, which reduces its bearing capacity. To solve that problem, this paper studied local buckling of CFRST with longitudinal stiffener under axial compression and design of longitudinal stiffener. It established buckling analysis model, simplified local buckling analysis as calculating buckling load of thin plate clamped on loading side and unloading side under axial force. It deduced buckling load and buckling coefficient based on the principle of energy. The results showed that buckling mode depended on stiffening rigidity. Therefore, it put forward minimum stiffening rigidity ratio that controlled the stiffener design. This paper also came up with a formula to calculate minimum stiffening rigidity ratio. It provided guidance on designing number, sectional dimension and material performance

    Effects of caffeine, tea polyphenol and daidzein on the pharmacokinetics of lansoprazole and its metabolites in rats

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    O objetivo deste estudo foi avaliar os efeitos da cafeína, do polifenol do chá e da daidzeína na farmacocinética do lansoprazol e de seus metabólitos. Administraram-se, intragastricamente, aos ratos cafeína (30 mg·kg-1, uma vez ao dia), polifenol do chá(400 mg·kg-1, uma vez ao dia) ou daidzeína (13,5 mg·kg-1, uma vez ao dia), por 14 dias, seguindo-se a administração de lansoprazol (8 mg·kg-1) no 15º. dia. As concentrações plasmáticas do lansoprazol e de seus dois metabólitos primários, 5-hidroxilansoprazol e sulfona de lansoprazol, foram determinadas por cromatografia líquida de alta eficiência acoplada com espectrometria de massas (CLAE-EM/EM). O polifenol do chá elevou, significativamente, a Área Sob a Curva (ASC) do lansoprazol de 680,29 ± 285,99 para 949,76 ± 155,18 μg/L.h e reduziu a da sulfona de lansoprazol de 268,82 ± 82,37 para 177,72 ± 29,73 μg/L.h. A daidzeína aumentou a ASC do lansoprazol de 680,29 ± 285,99 para 1130,44 ± 97,6 μg/L.h e reduziu a da sulfona de lansoprazol de 268,82 ± 82,37 para 177,72 ± 29,73 μg/L.h. A farmacocinética do 5-hidroxilansoprazol permaneceu intacta na presença de polifenol do chá ou daidzeína. A cafeína não afetou a farmacocinética do lansoprazol e de seus metabólitos. Os resultados sugerem que o polifenol do chá e a daidzeína podem inibir o metabolismo in vivo do lansoprazol por supressão da CYP3A.The aim of this study was to evaluate the effects of caffeine, tea polyphenol and daidzein on the pharmacokinetics of lansoprazole and its metabolites. Rats were intragastrically administered caffeine (30 mg·kg-1, once per day), tea polyphenol (400 mg·kg-1, once per day) or daidzein (13.5 mg·kg-1, once per day) for 14 days, followed by an intragastric administration of lansoprazole (8 mg·kg-1) on the 15th day. The plasma concentrations of lansoprazole and its two primary metabolites, 5-hydroxylansoprazole and lansoprazole sulfone, were determined by high-performance liquid chromatography coupled with tandem mass spectrometry (HPLC-MS/MS). Tea polyphenol significantly elevated the Area Under the Curve (AUC) of lansoprazole from 680.29 ± 285.99 to 949.76 ± 155.18 μg/L.h and reduced that of lansoprazole sulfone from 268.82 ± 82.37 to 177.72 ± 29.73 μg/L.h. Daidzein increased the AUC of lansoprazole from 680.29 ± 285.99 to 1130.44 ± 97.6 μg/L.h and decreased that of lansoprazole sulfone from 268.82 ± 82.37 to 116.23 ± 40.14 μg/L.h. The pharmacokinetics of 5-hydroxylansoprazole remained intact in the presence of tea polyphenol or daidzein. Caffeine did not affect the pharmacokinetics of lansoprazole and its metabolites. The results imply that tea polyphenol and daidzein may inhibit the in vivo metabolism of lansoprazole by suppressing CYP3A

    Biodiversity of wild alfalfa pollinators and their temporal foraging characters in Hexi Corridor, Northwest China

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    Seed production of alfalfa (Medicago sativa L.) is important in determining the effective distribution of new cultivars to farmers. However, little is known about the biodiversity and their community function of native wild pollinators of alfalfa in agronomic systems. We investigated the biodiversity of insects which visited alfalfa flowers and their temporal foraging characters in Hexi Corridor, China. A high biodiversity of insect visitors was discovered, 20 insect taxa in all, including 13 species of Hymenoptera, 3 species of Coleoptera, 3 species of Lepidoptera and 1 species of Diptera. Three native bee species, Andrena squamata, Anthophora melanognatha and Megachile abluta,were validated as the principal pollinators. They showed significant variations in tripping mode and their diurnal distribution patterns. Our results indicated that the native wild bees are diverse and they complement each other. This means they have developed a more complex system for the pollination of alfalfa than has been previously found out

    NDM-1-producing Enterobacteriaceae in a teaching hospital in Shanghai, China: IncX3-type plasmids may contribute to the dissemination of blaNDM-1

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    SummaryObjectivesTo provide the epidemiological dissemination and the genetic characteristics of blaNDM-1 in a teaching hospital in Shanghai, China.MethodsHere, the carbapenemase genes of 114 CRE isolates were evaluated by polymerase chain reaction (PCR). Clonal relatedness was assessed by pulsed-field gel electrophoresis (PFGE). Conjugation experiments and Southern blot hybridization were performed to determine the transferability of plasmids. Then plasmids were completely sequenced by the shotgun method.ResultsTwo Klebsiella pneumoniae strains (RJA1227 and RJF866) and one Raoultella planticola strain (RJA274) were identified as NDM-1 positive. The two K. pneumoniae isolates belonged to ST11 and exhibited highly similar PFGE patterns. Shotgun sequencing showed that plasmid pRJF866 (ca. 110kb) contained genes associated with the IncFII-FIB group and was highly similar to plasmid pKOX_NDM1. RJA274 (ca. 50kb) harbored blaNDM-1 on an IncX3 plasmid, which was nearly identical to plasmid pNDM-HN380 except that part of the ISAba125 element is missing.ConclusionThis is the first report of NDM-1-positive Enterobacteriaceae from Shanghai, China. IncX3 plasmids, reported in various species in the United Arab Emirates and China, may contribute to the dissemination of blaNDM-1.. More attention should be devoted to monitoring the dissemination of the NDM-1 gene due to its potential horizontal transfer via mobile genetic elements
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