Management of reservoirs for drinking water supply should be based on a thorough knowledge of water quality changes within variable conditions of hydrology, climate, nutrient loading and water storage. The two-dimensional longitudinal water quality model CE-QUAL-W2 was tested for its ability to predict concentrations of organic matter and trophic conditions in Rimov Reservoir, a small dimictic reservoir (volume 33,000,000 m3, maximum depth 43 m, hydraulic retention time 40 to 160 d) suffering from seasonally increased concentrations of humic substances and symptoms of eutrophication. The model was calibrated on two seasonal courses differing in hydrology and validated on a 1074 day period. The averages of absolute mean errors between simulated and measured vertical profiles of temperature, and concentrations of dissolved organic matter, dissolved oxygen and chlorophyll a in the validation run were 0.9 °C, 0.8 mg l-1, 1.2 mg l-1 and 0.008 mg l-1, respectively. Analysis of results and sensitivity analysis of modelling phytoplankton and phosphorus showed suitability of the mathematical description of their dynamics in the photic zone but not in the deeper layers. In spite of this partial problem, the model was found appropriate for the reliable predictions of water quality dynamics in Rimov Reservoir. and Hospodaření s vodou ve vodárenských nádržích by mělo být založeno na podrobné znalosti vlivu hydrologických, klimatických a limnologických veličin na kvalitu vody. Možnosti matematického modelování změn kvality vody byly testovány pro nádrž Římov na Malši za pomoci dvourozměrného modelu kvality vody CE-QUAL-W2. Model byl zkalibrován na dvou sezónních řadách dat pro hydrologicky různá období a poté byl uplatněn na 1074-denní řadě dat. Byly vyhodnoceny rozdíly mezi měřenými a simulovanými vertikálními profily teploty, koncentrací rozpuštěných organických látek, rozpuštěného kyslíku a chlorofylu. Tyto rozdíly vyjádřené jako velikost absolutní střední chyby byly 0,9 °C, 0,8 mg l-1 , 1,2 mg l-1 a 0.008 mg l-1 . Analýza získaných výsledků a citlivostní analýza modelu ukazují dobrou shodu mezi naměřenou a simulovanou dynamikou zmíněných veličin v eufotické zóně, v nižších a tmavších vrstvách nádrže dochází k nárůstu odchylek modelu od reality. Přes tyto dílčí problémy byl model shledán jako užitečný a nenahraditelný pomocník při úlohách řešících dopad vnějších vlivů na kvalitu vody v nádrži.
Measurement of leaf area is commonly used in many horticultural research experiments, but it is generally destructive, requiring leaves to be removed for measurement. Determining the individual leaf area (LA) of bedding plants like pot marigold (Calendula officinalis L.), dahlia (Dahlia pinnata), sweet William (Dianthus barbatus L.), geranium (Pelargonium × hortorum), petunia (Petunia × hybrida), and pansy (Viola wittrockiana) involves measurements of leaf parameters such as length (L) and width (W) or some combinations of these parameters. Two experiments were carried out during spring 2010 (on two pot marigold, four dahlia, three sweet William, four geranium, three petunia, and three pansy cultivars) and summer 2010 (on one cultivar per species) under greenhouse conditions to test whether a model could be developed to estimate LA of bedding plants across cultivars. Regression analysis of LA versus L and W revealed several models that could be used for estimating the area of individual bedding plants leaves. A linear model having LW as the independent variable provided the most accurate estimate (highest R2, smallest mean square error, and the smallest predicted residual error sum of squares) of LA in all bedding plants. Validation of the model having LW of leaves measured in the summer 2010 experiment coming from other cultivars of bedding plants showed that the correlation between calculated and measured bedding plants leaf areas was very high. Therefore, these allometric models could be considered simple and useful tools in many experimental comparisons without the use of any expensive instruments. and F. Giuffrida ... [et al.].
Leaf area estimation is an important biometrical observation recorded for evaluating plant growth in field and pot experiments. In this study, conducted in 2009, a leaf area estimation model was developed for aromatic crop clary sage (Salvia sclarea L.), using linear measurements of leaf length (L) and maximum width (W). Leaves from four genotypes of clary sage, collected at different stages, were used to develop the model. The actual leaf area (LA) and leaf dimensions were measured with a Laser Area meter. Different combinations of prediction equations were obtained from L, W, product of LW and dry mass of leaves (DM) to create linear (y = a + bx), quadratic (y = a + bx + cx2), exponential (y = aebx), logarithmic (y = a + bLnx), and power models (y = axb) for each genotype. Data for all four genotypes were pooled and compared with earlier models by graphical procedures and statistical measures viz. Mean Square Error (MSE) and Prediction Sum of Squares (PRESS). A linear model having LW as the independent variables (y = -3.4444 + 0.729 LW) provided the most accurate estimate (R 2 = 0.99, MSE = 50.05, PRESS = 12.51) of clary sage leaf area. Validation of the regression model using the data from another experiment showed that the correlation between measured and predicted values was very high (R 2 = 0.98) with low MSE (107.74) and PRESS (26.96). and R. Kumar, S. Sharma.
The aim of this study was to determine the accuracy and precision of McMaster method with Raynaud's modification in the detection of the eggs of the nematodes Toxocara canis (Werner, 1782) and Trichuris ovis (Abildgaard, 1795) in faeces of dogs. Four variants of McMaster method were used for counting: in one grid, two grids, the whole McMaster chamber and flotation in the tube. One hundred sixty samples were prepared from dog faeces (20 repetitions for each egg quantity) containing 15, 25, 50, 100, 150, 200, 250 and 300 eggs of T. canis and T. ovis in 1 g of faeces. To compare the influence of kind of faeces on the results, samples of dog faeces were enriched at the same levels with the eggs of another nematode, Ascaris suum Goeze, 1782. In addition, 160 samples of pig faeces were prepared and enriched only with A. suum eggs in the same way. The highest limit of detection (the lowest level of eggs that were detected in at least 50% of repetitions) in all McMaster chamber variants were obtained for T. canis eggs (25-250 eggs/g faeces). In the variant with flotation in the tube, the highest limit of detection was obtained for T. ovis eggs (100 eggs/g). The best results of the limit of detection, sensitivity and the lowest coefficients of variation were obtained with the use of the whole McMaster chamber variant. There was no significant impact of properties of faeces on the obtained results. Multiplication factors for the whole chamber were calculated on the basis of the transformed equation of the regression line, illustrating the relationship between the number of detected eggs and that of the eggs added to the sample. Multiplication factors calculated for T. canis and T. ovis eggs were higher than those expected using McMaster method with Raynaud modification.
The previously developed thoracic finite element model [8, 9] was used to investigate the human thoracic dynamic responses associated with the frontal, lateral and oblique loading and to predict injuries of the thorax associated with the frontal loading. The thoracic model was developed [8, 9] to improve the human articulated rigid body model ROBBY (the model of an average adult male) [13, 14], which was previously developed at the University of West Bohemia in cooperation with ESI Group (Engineering Simulation for Industry). There are implemented deformable models of the thorax and abdomen in the ROBBY model. The geometries of individual thoracic organs were based on the cadaver tomography data and color cross-section photographs obtained from Visible Human Project (VHP) [33]. The thoracic model material properties were obtained either by virtue of cooperation with ESI Group or from public sources (articles, Internet, books). Thoracic model includes the models of the sternum, ribs, costal cartilages, vertebrae, lungs, heart, trachea, main vessels (aorta, vena cava superior), intercostal muscles, diaphragm, flesh and skin. The presented study deals with the dynamic response and validation of the whole thoracic model and with the prediction of thoracic injuries by virtue of this model. The results of simulations are compared with the experimental results. and Obsahuje seznam literatury
Biomechanics has widely expanded in the last decades. The last development of computers provides new possibilities in this field. Problems can be solved faster and can be more extensive. One of these problems is the biomechanical model of human body. Its realisaton is practically impossible without using computers, because it is necessary to solve systems of thousands of equations.
There are several software packages that enable human body modeling. One of them is the PAM environment [15] developed by the ESI Group International. This computational system is based on the Finite Element Method and is one of the mostly used systems for crash test simulations.
Various human body models for various purposes are developed. Pregnant female model serve to optimize safety systems in cars to be more friendly to pregnant abdomen. and Obsahuje seznam literatury
Semi-dry grasslands are of high nature conservation interest both at national and European scales due to their high biodiversity and species richness. For effective conservation, however, the variation in floristic composition and distribution of these grasslands need first to be described. In Hungary, there is currently no comprehensive survey and classification of semi-dry grasslands. Therefore, the aim of this study was to (i) describe the variation in species composition of Hungarian semi-dry grasslands by a country-scale cluster analysis based on a large database; (ii) describe the types (clusters) and compare these descriptions with those in the phytosociological literature, and finally (iii) formulate a new syntaxonomical system for Hungarian semi-dry grasslands. For this analysis 699 relevés were selected in which the percentage cover of at least one of the grasses Brachypodium pinnatum, Bromus erectus, Danthonia alpina, Avenula adsurgens, A. pubescens or A. compressa reached >10%. A geographical stratification of the dataset was performed and then it was split randomly into two equal parts (training and test datasets). Following outlier exclusion and noise elimination, clustering was performed separately for both datasets. The optimal number of clusters was determined by validation. The number of valid clusters was the highest at the level of ten clusters, where seven clusters appeared to be valid. The valid clusters are separated geographically; however, there are considerable overlaps in the species compositions. According to our results, all the grasslands belong to the Cirsio-Brachypodion alliance. The seven valid clusters are assigned to five main groups of semi-dry grasslands in Hungary: 1. Brachypodium pinnatum (and partly Bromus erectus) dominated, species rich meadow-steppe-like grasslands occurring on deep loess in central Pannonia, identified as Euphorbio pannonicae-Brachypodietum Horváth 2009; 2. Brachypodium pinnatum dominated mountain grasslands restricted to the Bükk Mountains; identified as Polygalo majoris-Brachypodietum Wagner 1941; 3. mostly Bromus erectus dominated grasslands on shallow, calcium/rich soils of the Dunántúl region, proposed as a new association Sanguisorbo minoris-Brometum erecti Illyés, Bauer & Botta-Dukát 2009; 4. Brachypodium pinnatum and Danthonia alpina dominated stands occurring mainly in the Északi-középhegység Mts, characterized by species of nutrient poor soils, proposed as a new association Trifolio medii-Brachypodietum pinnati Illyés, Bauer & Botta-Dukát 2009; 5. transition towards meadows and successional stands dominated mainly by Brachypodium pinnatum.
Accurate and nondestructive methods to determine individual leaf areas of plants are a useful tool in physiological and agronomic research. Determining the individual leaf area (LA) of rose (Rosa hybrida L.) involves measurements of leaf parameters such as length (L) and width (W), or some combinations of these parameters. Two-year investigation was carried out during 2007 (on thirteen cultivars) and 2008 (on one cultivar) under greenhouse conditions, respectively, to test whether a model could be developed to estimate LA of rose across cultivars. Regression analysis of LA vs. L and W revealed several models that could be used for estimating the area of individual rose leaves. A linear model having L×W as the independent variable provided the most accurate estimate (highest r2, smallest MSE, and the smallest PRESS) of LA in rose. Validation of the model having L×W of leaves measured in the 2008 experiment coming from other cultivars of rose showed that the correlation between calculated and measured rose LA was very high. Therefore, this model can estimate accurately and in large quantities the LA of rose plants in many experimental comparisons without the use of any expensive instruments. and Y. Rouphael ... [et al.].
Nondestructive approach of modeling leaf area could be useful for plant growth estimation especially when number of available plants is limited and/or experiment demands repeated estimation of leaf area over a time scale. A total of 1,280 leaves were selected randomly from eight different morphotypes of som (Persea bombycina) established at randomized complete block design under recommended cultural regimes in field. Maximum leaf laminar width (B), length (L) and their squares B2, L2; leaf area (LA), and lamina length × width (L×B) were determined over two successive seasons. Leaf parameters were significantly affected by morphotypes; but seasons had nonsignificant impacts on tested features. Therefore, pooled seasonal morphotype means of each parameter were used to establish relationship with LA. L and its square L2 did not provide accurate models for LA predictions. Considerably better models were obtained by using B (y = 2.984 + 7.9664 x, R2 = 0.615, P≥0.001, n = 119) and B2 (y = 12.784+ 0.9604 x, R2 = 0.605, P≥0.001, n = 119) as independent variables. However, maximum accuracy of prediction of LA could be achieved through a simple linear relationship of L×B (y = 8.2203 + 0.4224 x, R2 = 0.843, P≥0.0001, n = 119). The model (LA:L×B) was validated with randomly selected leaf samples (n = 360) of som morphotypes and highly significant (P≤0.001) linear function was found between actual and predicted LAs. Therefore, the last model may consider adequate to predict leaf area of all cultivars of som with sufficient fidelity. and S. Chattopadhyay ... [et al.].
Biomechanical simulation activities are seen to undergo considerable growth in volume and scope. More complex and more complete models are now being generated. Biomechanical simulations are considered and extended well into the fields of transport vehicle occupant safety, biomedicine and virtual surgery, ergonomics and into the fields of leisure and sports article manufacture.
For an impact application like a car to pedestrian impact, correct modeling of a knee joint is important for description of the global response and dynamics after the impact. It is also useful for description of possible injuries. Based on the large research of available sources done in [3] in order to create an adequate knee joint, a simple articulated rigid body knee model is introduced. The model is based on the nonlinear joint accommodating flexion-extension and lateral rotation and translation. Joint characteristics are based on public experimental data. Dynamical validation of the new model is provided. The model is implemented into existing human articulated rigid body model ROBBY2 [2] and the frontal impact of a van versus a pedestrian is simulated including comparison to experiment.
The pre-crash activity of the human body is also essential from the point of influencing the global body motion. Hence, the influence of active muscles on the impact kinematics is investigated and comparison to passive model is provided. and Obsahuje seznam literatury