National Repository of Grey Literature 35,357 records found  beginprevious35348 - 35357  jump to record: Search took 0.80 seconds. 

Application of optimization methods in hydrological modeling
Jakubcová, Michala ; Máca, Petr (advisor) ; Hanel, Martin (referee)
Finding the optimal state of reality is the main purpose of the optimization process. The best variant from many possibilities is selected, and the effectiveness of the given system increases. Optimization has been applied in many real life engineering problems as in hydrological modelling. Within the hydrological case studies, the optimization process serves to estimate the best set of model parameters, or to train model weights in artificial neural networks. Particle swarm optimization (PSO) is relatively recent optimization technique, which has only a few parameters to adjust, and is easy to implement to the selected problem. The original algorithm was modified by many authors. They focused on changing the initialization of particles in the swarm, updating the population topology, adding new parameters into the equation, or incorporating shuffling mechanism into the algorithm. The modifications of PSO algorithm improve the performance of the optimization, prevent the premature convergence, and decrease computation time. Therefore, the main aims of the presented doctoral thesis consist of proposal of a new PSO modification with its implementation in C++ programming language. More PSO variants were compared and analysed, and the best methods based on benchmark problems were applied in two hydrological case studies. The first case study focused on utilization of PSO algorithms in inverse problem related to estimation of parameters of rainfall-runoff model Bilan. In the second case study, combination of artificial neural networks with PSO methods was introduced for forecasting the Standardized precipitation evapotranspiration drought index. It was found out, that particle swarm optimization is a suitable tool for solving problems in hydrological modelling. The most effective PSO modifications are the one with adaptive version of parameter of inertia weight, which updates the velocity of particles during searching through the multidimensional space via feedback information. The shuffling mechanism and redistribution of particles into complexes, at which the PSO runs separately, also significantly improve the performance. The contribution of this doctoral thesis lies in creation of new PSO modification, which was tested on benchmark problems, and was successfully applied in two hydrological case studies. The results of this thesis also extended the utilization of PSO methods in real life engineering optimization problems. All analysed PSO algorithms are available for later use within other research projects.

The effect of mycorrhizal nad saprotrophic fungi on yield properties and nitrogen uptake of tomato and leek plants
Kudláčková, Marta ; Albrechtová, Jana (advisor) ; Baláž, Milan (referee)
Currently looking for alternative approaches to crop production which would be in accord with sustainable development. The present thesis was aimed on testing of organic cultivation of tomato (Solanum lycopersicum L.) and leek (Allium porrum L.) by using amendment with organic maize biomass (Zea mays L.), mycorrhizal fungi and saprotrophic fungi. The effects of different combinations of microbial inoculations on nitrogen uptake, plant growth and yield were investigated in greenhouse conditions. Supplied 15 N-labelled organic matter was separated from the root system by a nylon mesh which permitted only fungal hyphae to pass through but not plant roots. In the first year experiments the treatments differed in the presence or absence of three factors: organic matter, saprotrophic fungus Agrocybe sp. and mycorrhizal fungus Glomus mosseae (Nicolaj & Gerd.) Gerd. & Trappe. Plant inoculation with Agrocybe sp. alone or together with G. mosseae increased plant growth of tomato in the presence of organic matter. Tomato yield were not increased significantly. Shoot dry weight of leek increased when plants were treated with mycorrhizal fungus G. mosseae and organic matter. Microbial inoculation did not influence nitrogen (15 N) uptake from the organic source. In following experiments, all treatments contained...

Applications of capillary electrophoresis in life sciences
Křížek, Tomáš ; Coufal, Pavel (advisor) ; Pacáková, Věra (referee) ; Tůma, Petr (referee)
Tomáš Křížek: Applications of Capillary Electrophoresis in Life Sciences (Dissertation thesis) ABSTRACT This thesis is focused on the applications of capillary electrophoresis in two important areas of life sciences, proteomics and enzyme assays. In the first part, Pluronic F-127 copolymer was studied as a sieving matrix for proteomic applications of capillary gel electrophoresis. The effect of thermoassociation of Pluronic F-127 on the separation selectivity was investigated and no difference in selectivity of the separation below, inside and above the thermoassociation temperature region was observed. The performance of Pluronic F-127 in capillary gel electrophoresis was compared with dextran as a commonly used sieving matrix. The results showed, that Pluronic F-127 offers superior performance for low-molecular-mass proteins because it provides higher separation power than dextran with significantly lower viscosity of the background electrolyte. The lower viscosity makes the polymer easier to replace after each analysis, which leads to remarkably higher repeatability of the experiments. On the other hand, dextran, due to its higher viscosity, was shown to be more convenient for separations of protein digests, where extremely high separation efficiency is required. The second part focuses on...

Phylogeography of mountain butterfly ??Bicyclus anisops in West Africa
PETRŮ, Vojtěch
The Gulf of Guinea Highlands is a unique mountane range of volcanic origin, situated on the African mainland in the borther of Nigeria and Cameroon, and the Gulf of Guinea islands of Bioko, S?o Tomé and Príncipe. This area is highly unique as the only large mountains in central and western Africa. The high degree of isolation of these mountains generated high degree of endemism of many groups of organisms; the whole region is thus one of the world biodiversity hotspots (known as the West African Forests). Despite its tremnedous conservation importance, this mountain range is under strong anthropogenic influence, as one of the most densely populated areas in tropical Africa. Despite all these factors, the conservation efforts in West Africa focused mainly on lowland areas of rain forests, whilst only few conservation effort is focused to the mountain habitats. As the other result, the lack of comprehensive biogeographic and phytogeographical studies of mountain flora and fauna is obvious. In this work, I have summarized the results of all crucial studies of the biogeography of the Gulf of Guinea Highlands. I also obtained sequences of three mitochondrial genes (COI, COII, and ND1) of an endemic montane butterfly Bicyclus anisops. Variability in the studied genes was relatively low. Phylogenetic analyses separated haplotypes into 7 well-established groups (1st Mt. Cameroon, 2nd Nkogam I, 3rd Nkogam II, 4th Bakossi-Kupe-Manengouba-Bani, 5th Mbam, 7th Hosséré Enla Fabo 6th all others localities (tj. Bamenda-Banso Mts., Acha Tugi, Mbam, Ngel Nyaki, Gotel Mts.)) but did not significantly resolved relationships among them. Based on the hyplotype diversity of B. anisops as an umbrella species, Mt. Cameroon, Nkogam, Mbam Massif, Mbiame, Hosséré Enla Fabo, Mt. Manengouba, Mt. Kupe and Mt. Oku are considered as localities of the highest conservation importance.

The electrochemical study of the degradation of the natural dyes from historical objects
Ramešová, Šárka ; Schwarzová, Karolina (advisor) ; Navrátil, Tomáš (referee)
The oxidation of quercetin (3,3',4',5,7-pentahydroxyflavone) and luteolin (3',4',5,7-tetrahydroxyflavone) has been studied. These intensively coloured polyphenolic compounds belong to a large group of naturally occuring flavonoid compounds. They were used with advantage as colourants in old tapestries. The study concerns the analysis of degradation processes of the original dyes. Degradation products formed during the ageing process can be used as fingerprints for the determination of the original colours. The degradation processes of flavonoid compounds were studied by electrochemical methods, absorption spectrometry and separation methods in aqueous media. The oxidation mechanism involves electron transfer coupled with chemical reaction and is influenced by the acidobasic properties of quercetin. The dissociation constants pK1 and pK2 of quercetin and pK1 and pK2 of luteolin were determined by combining of independent methods: acid-base titration and UV-Vis spectroscopy. The stability of both compounds significantly depends on the presence of the oxygen. The distribution of the oxidation products of quercetin in aqueous media within the exposure to oxygen was monitored by LC-MS/MS and LC- DAD analysis.

Characterization of separation systems for determination of enantiomers
Geryk, Radim
(EN) The dissertation thesis is focused on the research and characterization of retention and enantiorecognition mechanisms of chiral stationary phases based on derivatized polysaccharides. The separation systems with a variety of modern stationary phases (both achiral and chiral) were characterized in detail to provide a comprehensive view of the interactions participating in the separation process. The study of the retention/separation behavior significantly facilitates the development and the optimization of new enantioselective methods for a wide variety of compounds. The work deals with the comparison of enantioselective performance of polysaccharide-based chiral stationary phases. The objectives are to show the differences of separation behavior among these chiral stationary phases, as they differ by the nature of the polysaccharide backbone (amylose versus cellulose), by binding of chiral polymer to silica support (coated versus immobilized stationary phase) and by the phenyl moiety in the reversed and normal phase HPLC. In both separation modes amylose-based chiral stationary phases exhibited higher enantioselectivity, especially for acidic and bifunctional analytes. Chiral stationary phases based on derivatized cellulose showed higher enantiodiscrimination potential for basic analytes....

Factors predisposing to the development of allergies X.
Bártová, Lenka ; Jílek, Petr (advisor) ; Kudláčková, Zděnka (referee)
1 SUMMARY The prevalence of atopic disorders has been increasing at last years. One of the notions is that this is caused by unsatisfactory stimulation of immune system by infectious diseases ("the hygiene hypothesis"). The aim of our study was determine the influence of infectious diseases, the adenoidectomy, tonsillectomy, using of antibiotics on the development of atopic diseases. We availed the questionnaire survey which included 2050 children born approximately on 1994, who attended a primary school at various places of Czech Republic. We separate them to allergic and nonallergic, according to certain criteria. We asked about three periods: the first two years of life, period when child moved from a kindergarten to a primary school (years 1999, 2000) and last two years before answer on our questionnaire. We found, that the allergic children significantly more than the nonallergic suffered from: otitis media (49,6% vs. 42.5%; 44.5% vs. 25.7%; 13.3% vs. 6.0%), sinusitis (12.5% vs. 5.2%; 26.2% vs. 9.2%; 18.2% vs. 6.2%), nasopharyngitis or rhinitis (88.5% vs. 79.5%; 94.1% vs. 81.4%; 88.4% vs. 76.7%), bronchitis (65.8% vs. 38.4%; 72.9% vs. 35.3%; 46.0% vs. 20.8%), pneumonia (14.3% vs. 6.0%; 21.1% vs. 7.5%; 3.8% vs. 1.5%), influenza or other virosis with increased body temperature (80.4% vs. 72.0%; 91.3% vs....

Morphological characterization of monolithic columns
Širc, Jakub
1 High performance liquid chromatography (HPLC) is currently one of the most widely used analytical separation techniques. Although the most of applications use standard chromatographic columns packed with particles, these stationary phases has some disadvantages and limits. A promising alternative are monolithic columns. In contrast to the packed stationary phase consisting of many particles, monoliths are composed of one block of porous material. Monoliths are characteristic with communitating macropores, instead of the interparticle spaces of packed columns, which allow the flow of mobile phase carrying the analyte molecules, and small mesopores providing sufficient surface for active sites of stationary phase. The character of the porous structure of the monolith, its specific surface area, quantity, size and shape of pores significantly affect the properties of monolithic columns. The aim of this thesis is to manage the preparation of monolithic chromatographic columns by in situ polymerization within the columns and a description of factors influencing the morphology of the resulting monoliths. Second part of the work is focused on the characterization of the morphology of prepared monoliths, which is essential for the understanding of chromatographic processes that run through them. Describe the...

Faktory ovlivňující výběr boxu dojnicemi českého strakatého plemene skotu
Večeřa, Milan
The objective of the dissertation thesis was to analyse factors affecting preference of cubicle of Czech Fleckvieh dairy cows. Monitoring was carried in farm GenAgro Ricany a. s., a period of 12 months (June 2011 -- May 2012). The objective of monitoring was one section - one quarter of stable (n = 98 cows). Total of 47 040 observations were analysed. Statistical evaluation of data was performed by STATISTICA 10.0. In the sectionwas comprised of 103 comfortable stalls (cubicles) distributed into 3 rows.. Row A -- closest to feeding table (32 cubicles); row B -- in the midle section (33 cubicles); row C -- close to the side wall (38 cubicles). In all factors (number and stage of lactation, milk yield, number of arrival from milking parlour, temperature and humidity in stable and THI, height in the cross) was found significantly influence (p < 0,01) on preference of cubicle row. In evaluation of preference of boxes it was found out, that the lowest occupation rate in whole observing was in those boxes, which are on the edge of rows. Also lower amount of visits was noted in boxes, which are surrounded from more than one side by wooden partition separating space for lying (box) from waterhole. On the contrary mostly occupied boxes were those, which are located in the middle of box rows. Further higher preference rate of left side when lying was found in all observed influences, identically at both outer rows. On the contrary dairy cows preferred right side when lying in middle row.

The office spaces development in Prague after 1989
Císař, Milan ; Heřmanová, Eva (advisor) ; Sýkora, Luděk (referee)
In the nineties of the twentieth century the Prague office space market looked totally different from its current situation. The demand significantly exceeded the supply on the market and there was an entire lack of high-quality office places, which were built mostly in the city centre. There were predominating small projects of office and residential reconstructions which were limited by historical monument regulation and lack of space in the city centre. As of now the supply is prevailing on the Prague office space market and the situation for developers and tenants has totally changed. The competition of developers has rapidly increased and further increase is expectable. The development of new office buildings has moved from the city centre to the inner and outer city and the developers have focused on the multifunctional complexes, conversion of brownfields and construction of large city districts instead of separate office buildings. Prague office development is comparable with the development in Budapest and Warsaw. Commercialization of the city centre and suburbanization is even typical for all four capital cities in Central and Eastern Europe.