Number of results to display per page
Search Results
7892. Estimating the rainfall erosivity factor from monthly precipitation data in the Madrid Region (Spain)
- Creator:
- Hernando, David and Romana, Manuel G.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- rainfall erosivity, R-factor, Universal Soil Loss Equation, modified Fournier index, and soil erosion
- Language:
- Slovak
- Description:
- The need for continuous recording rain gauges makes it difficult to determine the rainfall erosivity factor (Rfactor) of the Universal Soil Loss Equation in regions without good spatial and temporal data coverage. In particular, the R-factor is only known at 16 rain gauge stations in the Madrid Region (Spain). The objectives of this study were to identify a readily available estimate of the R-factor for the Madrid Region and to evaluate the effect of rainfall record length on estimate precision and accuracy. Five estimators based on monthly precipitation were considered: total annual rainfall (P), Fournier index (F), modified Fournier index (MFI), precipitation concentration index (PCI) and a regression equation provided by the Spanish Nature Conservation Institute (RICONA). Regression results from 8 calibration stations showed that MFI was the best estimator in terms of coefficient of determination and root mean squared error, closely followed by P. Analysis of the effect of record length indicated that little improvement was obtained for MFI and P over 5- year intervals. Finally, validation in 8 additional stations supported that the equation R = 1.05·MFI computed for a record length of 5 years provided a simple, precise and accurate estimate of the R-factor in the Madrid Region.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
7893. Estimation and bimodality testing in the cusp model
- Creator:
- Voříšek, Jan
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- multimodal distributions, cusp model, bimodality test, and reduced maximum likelihood estimation
- Language:
- English
- Description:
- The probability density function of the stochastic cusp model belongs to the class of generalized exponential distributions. It accommodates variable skewness, kurtosis, and bimodality. A statistical test for bimodality of the stochastic cusp model using the maximum likelihood estimation and delta method for Cardan's discriminant is introduced in this paper, as is a necessary condition for bimodality, which can be used for simplified testing to reject bimodality. Numerical maximum likelihood estimation of the cusp model is simplified by analytical reduction of the parameter space dimension, and connection to the method of moment estimates is shown. A simulation study is used to determine the size and power of the proposed tests and to compare pertinence among different tests for various parameter settings.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
7894. Estimation of ablation depth in concrete slab under reactor during nuclear accident
- Creator:
- Vaitová , M. and Štemberk , P.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- ablation depth, concrete, corium, floor slab, fuzzy logic, interaction, nuclear accident, staggered algorithm, and thermal analysis
- Language:
- English
- Description:
- The molten reactor core-concrete interaction, which describes the effect of molten reactor spread on the concrete oor of the reactor cavity, is a very complex process to simulate and predict, but the knowledge of this process is of major importance for planning the emergency counteractions for severe accidents with respect to the Stress Tests requirements after the Fukushima-Daiichi accident. The key issue is to predict the rate and most probable focusation of the melt-through process which is affected by the concrete composition, especially by the aggregate type. A limited number of small-scale experiments have been conducted over the past years along with accompanying numerical models which focused mainly on the siliceous type of aggregate. It is common for the concrete structures that the limestone type or the mixture of these two types of aggregate are used as well. Then, the objective of this paper is to extend the knowledge gained from the experiments with the siliceous aggregate to the concrete structures which are made of limestone aggregate or their combination, such as limestone sand and siliceous gravel. The proposed one-dimensional model of the melt-through process is based on the fuzzy-logic interpretation of the thermodynamic trends which reflect the aggregate type. This approach allows estimating the asymptotic cases in terms of the melt-through depth in the concrete oor over time with respect to the aggregate type, which may help to decide the rather expensive further experimental efforts.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
7895. Estimation of apparent L-amino acid diffusion in porcine jejunal enterocyte brush border membrane
- Creator:
- Fan, M. Z., Adeola, O., and Asem, E. K.
- Format:
- print, bez média, and svazek
- Type:
- article, články, model:article, and TEXT
- Subject:
- Fyziologie člověka a srovnávací fyziologie, aminokyseliny, difuze, prasata, amino acids, diffusion, pigs, enterocyte, brush border membrane vesicles, 14, and 612
- Language:
- English
- Description:
- There is an overlap of carrier-mediated L-amino acid transport and apparent simple diffusion when measured in intestinal brush border membrane vesicles. Using L-threonine and L-glutamine as representative amino acids, this study was undertaken to estimate apparent simple diffusion of L-amino acids and to establish the effective dosage of HgCl2 for completely blocking carrier-mediated L-amino acid transport in porcine jejunal enterocyte brush border membrane vesicles. Jejunal mucosa was scraped from three pigs weighing 26 kg. Enterocyte brush border membrane vesicles, with an average enrichment of 24-fold in sucrase specific activity, were prepared by Mg2+-precipitation and differential centrifugation. In vitro uptake was measured by the fast filtration manual procedure. HgCl2 blocked the carrier-mediated initial transport of L-threonine and L-glutamine under Na+-gradient condition in a dose-dependent manner. At the minimal concentration of 0.165 mmol HgCl2 mg-1 protein, carrier-mediated L-threonine and L-glutamine transport was completely inhibited. The apparent L-threonine and L-glutamine diffusion was estimated to be 8.6±0.7 and 12.4±1.0 % of the total uptake at the substrate concentrations of 5 mM (L-threonine) and 50 mM (L-glutamine). Therefore, the treatment of porcine brush border membrane vesicles with a minimum of 0.165 mmol HgCl2 mg-1 protein completely blocks carrier-mediated L-amino acid transport and enables the direct estimation of apparent L-amino acid diffusion in enterocyte brush border membrane vesicles., M. Z. Fan, O. Adeola, E. K. Asem., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
7896. Estimation of natural direct groundwater recharge in southwest Ghana using water balance simulations
- Creator:
- Darko, Philip K.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- groundwater recharge, base flow, hydrologic budget, interflow, conceptual modelling, doplňování podzemní vody, základní odtok, hydrologická bilance, hypodermický odtok, and koncepční modelování
- Language:
- Slovak
- Description:
- The Sacramento soil moisture-accounting model has been used to simulate the discharges of a major catchment (Pra river basin) in southern Ghana. Through the simulation it was possible to assess the temporal variability of evapotranspiratio, base flow proportions and groundwater in storage, as well as the average groundwater recharge to the weathered aquifers. Groundwater recharge was estimated by considering the measured discharge of groundwater across the boundary of the basin over periods of equivalent storage, to be equal to the net recharge inside the catchment. The direct groundwater recharge rate over the basin of area 22,836 km2 amounted to an annual average of 50 mm. This represented 4 % of mean annual rainfall of 1300 mm, giving natural groundwater resources potential of 1.6 l s-1 km-2. For regional groundwater resources assessment, the results obtained could be applied to other river basins in southwest Ghana. and Použitím SAC-SMA modelu byly simulovány odtoky z povodí řeky Pra v jižní části Ghany. Tímto bylo možno odhadnout časové tměny evapotranspirace, podzemního odtoku a zásoby podzemní vody, i průměrné doplňování podzemní vody do zvětralé zóny hydrogeologických kolektorů. Doplňování podzemní vody bylo stanoveno s uvážením měřených odtoků podzemní vody přes hranice povodí tak, aby se v obdobích stejné zásoby rovnaly výslednému doplňování uvnitř infiltrační oblasti. Roční průměr přirozeného doplňování podzemní vody v povodí s plochou 22 836 km2 činilo 50 mm. To odpovídá 4 % ročního průměru srážky (1300 mm) a 1,61 s-1 km-2 specifického odtoku podzemní vody. Dosažené výsledky mohou být aplikovány na další povodí v jihozápadní Ghaně pro regionální odhad zásoby podzemní vody.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
7897. Estimation of Nutrient Concentrations in Runoff from Beef Cattle Feedlot using Adaptive Neuro-Fuzzy Inference Systems
- Creator:
- Simsek, H., Cemek, B., Odabas, M. S., and Rahman, S.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- nutrient concentration, cattle feedlot, grid partition based fuzzy inference system (ANFIS-GP), and subtractive clustering based fuzzy inference system (ANFIS-SC)
- Language:
- English
- Description:
- Nutrient concentrations in runoff from beef cattle feedlots were estimated using two different adaptive network-based fuzzy inference systems (ANFIS), which were: (1) grid partition (ANFIS-GP) and (2) subtractive clustering based fuzzy inference system (ANFIS-SC). The input parameters were pH and electrical conductivity (EC); and the output parameters were total Kjeldahl nitrogen (TKN), ammonium-N (NH4-N), orthophosphate (ortho-P), and potassium (K). Models performances were evaluated based on root mean square error, mean absolute error, mean bias error, and determination coeficient statistics. For the same dataset, the ANFIS model outputs were also compared with a previously published nutrient concentration predictability model for runoff using artificial neural network (ANN) outputs. Results showed that both ANFIS-GP and ANFIS-SC models successfully predicted the runoff nutrient concentration. The comparison results revealed that the ANFIS-GP model performed slightly better than ANFIS-SC model in estimating TKN, NH4-N, ortho-P, and K. When compared with the ANN model for the same dataset, ANFIS outperformed ANN in nutrient concentration prediction in runoff.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
7898. Estimation of phase errors of laser observations of artificial Earth satellites
- Creator:
- Matveev, D. T.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- laser observations, artificial Earth satellites, and error estimations
- Language:
- Czech
- Description:
- Error estimations arising from phase-wave fluctuations on laser beam propagation through turbulent atmosphere are given. The phase error value increases with the distance of satellite and is up to 8 cm for satellites with synchronous orbit in the daytime.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
7899. Estimation of photorespiration rate by simultaneous measurements of CO2, gas exchange rate, and chlorophyll fluorescence quenching in the C3 plant Vigna radiata (L.) Wilczek and the C4 plant Amaranthus mongostanus L.
- Creator:
- Yoshimura, Y., Kubota, F., and Hirao, K.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- electron transport rate, photosynthesis, photosystem 2, mungbean, and quantum yield
- Language:
- Multiple languages
- Description:
- So far the photorespiration rate (RP) in a leaf has been determined as the difference between the net photosynthetic rates (PN) measured in 21 % O2 air (PN21%) and 3 % O2 air (PN3%). In the C3 plant Vigna radiata and the C4 plant Amaranthus mongostanus L., PN and chlorophyll fluorescence quenching in leaves were monitored simultaneously. RP of leaves in situ was estimated as termed RPE from the electron transport rates through photosystem 2 (PS2), and compared with RPO (PN3% - PN21%). In V. radiata RPO was 11.9 µmol(CO2) m-2 s-1 and the ratio of RPO to PN21% was 42.2 %, whereas the ratio of RPE to PN21% was 25.7 %. This suggests that RPO may be over-estimated for the real RP in normal air. In A. mongostanus, PN was almost not changed with a decrease in O2 concentration from 21 to 3 %, whereas the quantum yield of PS2 was evidently affected by the change in O2 concentration. This fact shows the presence of photorespiration in this C4 species, where RPE was equivalent to 3.8 % of PN21%. and Y. Yoshimura, F. Kubota, K. Hirao.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
7900. Estimation of photosynthetic activity from the electron transport rate of photosystem 2 in a film-sealed leaf of sweet potato, Ipomoea batatas Lam.
- Creator:
- Haimerong, Kubota, F., and Yoshimura, Y.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- C3-leaf, chlorophyll fluorescence, irradiance, leaf age, leaf-sealing method, leaf temperature, oxygen concentration, photorespiration, and respiration
- Language:
- Multiple languages
- Description:
- In order to evaluate the photosynthetic activity of a C3 leaf from the electron transport rate (ETR) of photosystem 2 (PS2), a new method was devised and examined using leaves of sweet potato. In this method, both surfaces of a leaf were sealed with transparent films to stop the gas exchange between the leaf and the atmosphere; hence the functions of both photosynthetic assimilation (CO2 uptake) and photorespiration (CO2 release) are restricted to the inside of the leaf. After both functional rates became equally balanced, ETR of the sealed leaf (ETRseal) was determined from the chlorophyll fluorescence. The measurements were conducted at different irradiances and leaf temperatures and by using leaves of different age. Under each measurement condition, ETRseal showed a close positive relationship with the photosynthetic potential, or the gross photosynthetic rate measured in the air of 2 % O2 (PG2%) before sealing. ETRseal may become an indicator to estimate or evaluate the photosynthetic activity of C3 leaves. and Haimeirong, F. Kubota, Y. Yoshimura.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public