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171.
Hana Kopackova Karel Michalek Karel Cejna 《Universal Access in the Information Society》2010,9(1):51-61
This article focuses on the accessibility of local e-government web pages. Accessibility is herein considered in a broader
perspective, taking also into account that information must be findable within the Internet through conventional fulltext
search engines. Based on this assumption, an analysis of 39 local e-government websites in the Czech Republic was carried
out in two testing periods (March 2006 and April 2008). The web pages were analysed both from a citizen’s point of view (with
disadvantage due to disability or to technical equipment) and from the point of view of fulltext search engines. In the analysis
of results, there is an overall evaluation and comparison between testing periods and recommendations for improvement of the
current conditions. 相似文献
172.
Maria Vass Iva Diblikova Eloise Kok Kamil Stastny Karla Frgalova Karel Hruska Milan Franek 《Food Additives & Contaminants》2008,25(8):930-936
An enzyme-linked immunosorbent assay (ELISA) method is described for the semi-quantitative determination of semicarbazide (SEM), the marker residue for the banned nitrofuran drug, nitrofurazone, in chicken eggs. The sample homogenate is subjected to acid hydrolysis and derivatisation with o-nitrobenzaldehyde, followed by ethyl acetate/hexane extraction and detection by ELISA. The ELISA procedure has been validated using 0.3, 1.0 and 3 microg kg(-1) of SEM in fortified samples. Detection capability (CC(ss)) was based on the acceptance of 5% false compliant results for a given concentration level according to Commission Decision 2002/657/EC and was determined to be 0.3 microg kg(-1) with a respective limit of detection of 0.13 microg kg(-1). A validated LC-MS/MS method was used for the analysis of incurred egg samples and the results compared with ELISA. A good correlation between the results obtained from ELISA and LC-MS/MS within the concentration range 0.12-20.3 microg kg(-1) was observed in samples collected from chickens fed with a medicated ration of nitrofurazone (r = 0.992, n = 14). Validated ELISA enabled reliable monitoring of SEM levels in eggs collected from incurred chickens over a 90-day period. 相似文献
173.
Jiří Pecha Tomáš Fürst Karel Kolomazník Veronika Friebrová Petr Svoboda 《American Institute of Chemical Engineers》2012,58(7):2010-2019
Biostimulants are substances which promote plant metabolism and are able to increase yields of various crops. However, their efficiency at field can be affected by climatic conditions. A novel mathematical model based on diffusion transport mechanism is proposed to predict the biostimulant uptake at different climatic conditions. The main input model parameter is experimentally measured effective diffusion coefficient of the biostimulant. The model is applied to a biostimulant prepared from leather waste by enzymatic hydrolysis. Simulations show that climatic conditions have significant impact on biostimulant penetration and should not be neglected in biostimulant application and further research. The suggested model is able to explain observed differences between laboratory and field biostimulant investigations, as well as draw recommendations for protein biostimulant application. The model also shows that the theoretical tools of chemical engineering can be used for optimization of biostimulant performance. © 2011 American Institute of Chemical Engineers AIChE J, 2012 相似文献
174.
Andrea Ďuračková Helena Valentová Miroslava Dušková-Smrčková Karel Dušek 《Polymer Bulletin》2007,58(1):201-211
Summary Gel point conversions and equilibrium tensile moduli of polyester-based polyurethane networks were determined for different
dilutions during network formation. Also, the limiting dilution beyond which the network was not formed at full conversion
of functional groups was determined. It ranged between 92 and 94% of diluent. The scaling dependences against the reference
states – the ring-free case and the limiting dilution case – showed that the excluded volume effects were operative and structural
changes associated with cyclization affected the rates of both the intramolecular and the intermolecular reactions. 相似文献
175.
The absorption and reflection spectra of a Grätzel-type solar cell were evaluated in terms of heat losses. Using these experimental data, the temperature distribution inside the solar cell was calculated. The temperature-controlling process in this cell is the heat transfer from the cell to the environment. Assuming the environment temperature of 25°C, the natural air convection leads to the temperature of 46.9°C inside the TiO2 layer. Forced air convection causes the decrease, up to 30.1°C at the wind speed of 10 m s−1. Variations in the cell dimensions, except the active layer length, have only a small effect on the temperature field, compared to the variations in the heat transfer coefficients. 相似文献
176.
Hidalgo-Rosa Yoan Mena-Ulecia Karel Treto-Suárez Manuel A. Schott Eduardo Páez-Hernández Dayán Zarate Ximena 《Journal of Materials Science》2021,56(24):13684-13704
Journal of Materials Science - The structural and photophysical properties of the [Cd2(H2L)2(H2O)5].5H2O (where H4L is the ligand 5,5'-((thiophene-2,5-dicarbonyl)bis(azanediyl))diisophthalic... 相似文献
177.
Krist P Vannucci L Kuzma M Man P Sadalapure K Patel A Bezouska K Pospísil M Petrus L Lindhorst TK Kren V 《Chembiochem : a European journal of chemical biology》2004,5(4):445-452
GlcNAc-coated glycodendrimers, which are polyvalent glycomimetics, display strong in vitro affinity for the rat natural killer cell protein-1A (NKR-P1A), a C-type lectin-like receptor of natural killer (NK) cells in rats, humans and some strains of mice. Administration of these compounds in vivo results in a substantial increase in the antitumour activity with involvement of the natural cell immunity. To clarify the in vitro and in vivo fate of these molecules, we synthesized labelled glycodendron analogues of the previously studied glycodendrimers. Labelling with fluorescent tags enabled the localization of the glycodendrons in white blood cells, tumours and other tissues by using different imaging techniques such as fluorescence and confocal microscopy. These studies are useful for probing the mechanism of action and fate of artificial ligands and the cell receptors involved. 相似文献
178.
An image analysis algorithm for dendritic spines 总被引:5,自引:0,他引:5
The structure of neuronal dendrites and their spines underlie the connectivity of neural networks. Dendrites, spines, and their dynamics are shaped by genetic programs as well as sensory experience. Dendritic structures and dynamics may therefore be important predictors of the function of neural networks. Based on new imaging approaches and increases in the speed of computation, it has become possible to acquire large sets of high-resolution optical micrographs of neuron structure at length scales small enough to resolve spines. This advance in data acquisition has not been accompanied by comparable advances in data analysis techniques; the analysis of dendritic and spine morphology is still accomplished largely manually. In addition to being extremely time intensive, manual analysis also introduces systematic and hard-to-characterize biases. We present a geometric approach for automatically detecting and quantifying the three-dimensional structure of dendritic spines from stacks of image data acquired using laser scanning microscopy. We present results on the measurement of dendritic spine length, volume, density, and shape classification for both static and time-lapse images of dendrites of hippocampal pyramidal neurons. For spine length and density, the automated measurements in static images are compared with manual measurements. Comparisons are also made between automated and manual spine length measurements for a time-series data set. The algorithm performs well compared to a human analyzer, especially on time-series data. Automated analysis of dendritic spine morphology will enable objective analysis of large morphological data sets. The approaches presented here are generalizable to other aspects of neuronal morphology. 相似文献
179.
Recently, the adaptive finite element methods have gained a very important position among numerical procedures for solving ordinary as well as partial differential equations arising from various technical applications. While the classical a posteriori error estimates are oriented to the use in h-methods the contemporary higher order hp-methods usually require new approaches in a posteriori error estimation. 相似文献
180.
Recent studies have indicated that companies are increasingly experiencing Data Quality (DQ) related problems as more complex data are being collected. To address such problems, the literature suggests the implementation of a Total Data Quality Management Program (TDQM) that should consist of the following phases: DQ definition, measurement, analysis and improvement. As such, this paper performs an empirical study using a questionnaire that was distributed to financial institutions worldwide to identify the most important DQ dimensions, to assess the DQ level of credit risk databases using the identified DQ dimensions, to analyze DQ issues and to suggest improvement actions in a credit risk assessment context. This questionnaire is structured according to the framework of Wang and Strong and incorporates three additional DQ dimensions that were found to be important to the current context (i.e., actionable, alignment and traceable). Additionally, this paper contributes to the literature by developing a scorecard index to assess the DQ level of credit risk databases using the DQ dimensions that were identified as most important. Finally, this study explores the key DQ challenges and causes of DQ problems and suggests improvement actions. The findings from the statistical analysis of the empirical study delineate the nine most important DQ dimensions, which include accuracy and security for assessing the DQ level. 相似文献