The aim of this study was to investigate the effects of silicon in alleviating cadmium stress in maize plants grown in a nutrient solution and to evaluate the potential of the spectral emission parameters and the ratio of red fluorescence (Fr) to far-red fluorescence (Ffr) in assessing the beneficial effects of Si. An experiment was carried out using a nutrient solution with a toxic dose of Cd and six doses of Si; biomass, Cd, Si, and photosynthetic pigments of the plants were measured. Chlorophyll (Chl) a fluorescence analysis demonstrated that Si alleviated Cd toxicity in plants. Chl fluorescence measurements were sensitive in detecting such effects even when significant changes in biomass production and concentrations of photosynthetic pigments were not observed. The spectral emission and the Fr/Ffr ratio were sensitive to the effects of Si. Silicon caused a reduction in the translocation of Cd to the shoots of maize plants., A. J. Silva, C. W. A. Nascimento, A. S. Gouveia-Neto., and Obsahuje seznam literatury
Isogeometric analysis (IGA) has been recently introduced as a viable alternative to the standard, polynomial-based finite element analysis. One of the fundamental performance issues of the isogeometric analysis is the quadrature of individual components of the discretized governing differential equation. The capability of the isogeometric analysis to easily adopt basis functions implies that high order numerical quadrature schemes must be employed. This may become computationally prohibitive because the evaluation of the high degree basis functions and/or their derivatives at individual integration points is quite demanding. The situation tends to be critical in three-dimensional space where the total number of integration points can increase dramatically. The aim of this paper is to compare computational efficiency of several numerical quadrature concepts which are nowadays available in the isogeometric analysis. Their performance is asessed on the assembly of stifness matrix of B-spline based problems with special geometrical arrangement allowing to determine minimum number of integration points leading to exact results. and Článek zahrnuje seznam literatury a na str. 257-259 Appendix
Empirical formulae are often used in practice to quickly and cheaply determine the hydraulic conductivity of soil. Numerous relations based on dimensional analysis and experimental measurements have been published for the determination of hydraulic conductivity since the end of 19th century. In this paper, 20 available empirical formulae are listed, converted and re-arranged into SI units. Experimental research was carried out concerning hydraulic conductivity for three glass bead size (diameters 0.2 mm, 0.5 mm and 1.0 mm) and variable porosity. The series of experiments consisted of 177 separate tests conducted in order to obtain relevant statistical sets. The validity of various published porosity functions and empirical formulae was verified with the use of the experimental data obtained from the glass beads. The best fit was provided by the porosity function n3/(1–n)2. In the case of the estimation of the hydraulic conductivity of uniform glass beads, the best fit was exhibited by formulae published by Terzaghi, Kozeny, Carman, Zunker and Chapuis et al.
Based on the examination and quantitative comparison of the approaches used to assess the energy partitioning in photosystem II, the unified method was proposed to calculate the contribution of the components of nonphotochemical quenching. and D. Kornyeyev, C. R. Guadagno, N. D’Ambrosio.
In the marketing area, new trends are emerging, as customers are not only interested in the quality of the products or delivered services, but also in a stimulating shopping experience. Creating and influencing customers' experiences has become a valuable differentiation strategy for retailers. Therefore, understanding and assessing the customers' emotional response in relation to products/services represents an important asset. The purpose of this paper consists of investigating whether the customer's facial expressions shown during product appreciation are positive or negative and also which types of emotions are related to product appreciation. We collected a database of emotional facial expressions, by presenting a set of forty product related pictures to a number of test subjects. Next, we analysed the obtained facial expressions, by extracting both geometric and appearance features. Furthermore, we modeled them both in an unsupervised and supervised manner. Clustering techniques proved to be efficient at differentiating between positive and negative facial expressions in 78\% of the cases. Next, we performed more refined analysis of the different types of emotions, by employing different classification methods and we achieved 84\% accuracy for seven emotional classes and 95\% for the positive vs. negative.
While including gradual long-term flooding of individual residual mining pits, the re-vitalization program of the Podkrušnohorská brown-coal basin area has to assure - beside general water quality standards - satisfactory stability level of future lake banks and their wider environment as required for safe usage of future water lakes. General assessment of factors and conditions influencing bank and/or slope stability of future lakes was realized within the frames of the Czech Republic Academy of Sciences grant project. The grant project solutions include a study of exogenous processes on localities where the mining has been terminated. Also, prognoses were developed on behaviour of future banks during flooding and subsequent operation of future lakes. The presented paper is focused on assessment of mayor factors that participate on initiation and intensity of the bank abrasion and sliding deformations., Tamara Spanilá, Zdeněk Kudrna, Vladislav John, Filip Hartvich and Vladimír Chour., and Obsahuje bibliografické odkazy
Twenty-five genotypes of early CIMMYT hexaploid wheat were screened for salt tolerance in a glasshouse experiment using photosynthetic capacity and water relation parameters as selection criteria. Under salt stress (150 mM NaCl) the genotypes Frontana, Norin-10, Mayo-54, Noreste-66, and Yaktana-54 excelled all other lines in shoot dry mass, and Na(20)TPP, Penjamo-62, Inia-66, Frontana, Siete Cerros, and Jaral-66 in grain yield per plant in both absolute and relative (percent of control) terms. Although net photosynthetic rate (PN) declined in all genotypes due to salt stress, it was not helpful in discriminating among genotypes according to salt tolerance. Similarly, no positive relationships of salt tolerance of the genotypes with stomatal conductance, leaf water potential, or turgor pressure were found. Every genotype used its own specific mechanism to tolerate salt stress. However, a large amount of variation in salt tolerance observed in 25 early CIMMYT wheat genotypes can be of considerable practical value for improving salt tolerance in the existing commercial hexaploid wheats. and M. Ashraf, M. Shahbaz.
Increased parasympathetic tone achieved with endurance training may provide cardioprotection after menopause. To compare heart rate variability (HRV) from rest through maximal exercise and recovery in trained postmenopausal women. Thirtysix postmenopausal women who self-reported training at either moderate (MOD; 3-5.9 METS; 58.9±4.4 year) or vigorous (VIG; >6 METS; 59.7±5.2 year) intensities participated. HRV was measured for 5 min in the supine position, in the last minute of the VO2max test and after 2 min of active recovery. HRV in MOD and VIG was compared using a factorial ANOVA with repeated measures on time. MOD and VIG responded similarly over the three time periods for root mean square of sequential deviations (rMSSD), and high (HF) and low frequency (LF) power (p>0.05). Maximal exercise lowered rMSSD (3.3±0.08 vs. 1.2±0.06) and lnLF (4.1±0.05 vs. 3.3±0.13) and increased lnHF (3.3±0.14 vs. 4.0±0.10; p<0.01) from resting. However, active recovery restored lnHF (3.3±0.11) and lnLF (4.1±0.08) from maximal values (p<0.01). Our findings suggest that moderate and vigorous exercise training may enhance HRV recovery following one bout of maximal exercise in older women., J. C. Orri, E. M. Hughes, D. G. Mistry, A. Scala., and Obsahuje bibliografii
This case study presents the verification of two surface subsidence prediction models for longwall mining at depths greater than 400 m. The surface subsidence points were surveyed and compared for both models. The first model uses empirical calculations to predict the surface subsidence. This method is reliable for predicting surface subsidence at shallower depths. At present, however, coal mining has progressed to great depths. The second model is the 2-dimensional finite element method to predict surface subsidence. In contrast to the first method, this method is based on the regional parameters and uses the rock mass properties to evaluate surface subsidence for multi-seams at any depth. Results show that the finite element method gives a better approximation of the measured surface subsidence than the Knothe method. The maximum surface subsidence, which was determined by the FEM method, was used to adjust the extraction coefficient in the Knothe's method. The predicted value differs from the measured value by 8 %. The slope of the predicted subsidence trough was within the range of 2‒8 % from the surveyed subsidence. This case study proposes a procedure for using both models to successfully predict the surface subsidence.