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Litter decomposition and its role in biogeochemical cycles
Vicena, Jakub ; Frouz, Jan (advisor) ; Picek, Tomáš (referee) ; Krištůfek, Václav (referee)
Decomposition of litter is a key process in the soil nutrient cycle. It is a very complex process that is influenced by a number of factors. This dissertation studies these key factors influencing the rate of organic matter mineralization using modern analytical methods. The results of the dissertation are presented in four publications in international journals with IF and one manuscript ready for publication. The first publication shows a strong positive correlation between microbial diversity and organic matter decomposition per gram of carbon. In contrast, microbial respiration per gram soil was negatively correlated with bacterial diversity and positively correlated with fungal biomass. Thus, the relationship between microbial diversity and decomposition rate is context dependent. The second study (in manuscript form) shows that microbial respiration correlates with C/N of fallout only at the beginning of the experiment, but not at the end. However, respiration during litter decomposition at the beginning and end of the experiment is strongly negatively correlated with the C/N ratio of green leaves. This suggests that the stoichiometric C/N ratio may influence decomposition indirectly through correlation with other unknown parameters such as leaf morphology. The third study examined the...
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Olfactory adaptations in the deep-sea fishes
Kamrla, Jaroslav ; Musilová, Zuzana (advisor) ; Stopková, Romana (referee)
The goal of this work was to summarize the present knowledge about olfaction in deep-sea fishes. The research on this topic is seldom, however, few interesting studies suggest the importance of olfaction in these inhospitable conditions. After a short introduction of how the olfaction works, individual description of deep-sea adaptations follows. Implications on the importance of a specific sense can be made based on comparisons between individual brain areas responsible for the input of each sense. The importance of individual senses was investigated in mesopelagic and demersal species. Ontogenetic shift in sensory importance is one of the adaptations. Furthermore, sexual dimorphism in the olfactory system. Enlarged olfactory organs in males are most likely responsible for easier localisation of a female. Regarding the olfactory receptor repertoire, a whole genome of a hadal fish from the Mariana trench marked a massive loss of olfactory genes but highlighted their specificity. My own data included in this thesis estimate the number of the olfactory genes in deep-sea fishes for which we lack the high-quality genome. The estimates (albeit with large confidence intervals) suggest rather smaller numbers of genes in most of the species, while there are some species with putatively expanded gene...
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The role of SGIP1 protein interaction with cannabinoid receptor 1 in nociception under pathological conditions.
Dresslerová, Denisa ; Špicarová, Diana (advisor) ; Zímová, Lucie (referee)
The cannabinoid receptor type 1 (CB1) is a component of the endocannabinoid system and is abundantly expressed in the central nervous system. CB1 receptor has been extensively studied primarily due to its inhibitory role in neurotransmitter release from presynaptic terminals, and this process subsequently modulates postsynaptic currents and postsynaptic neuron excitation. Its interaction with the Src homology domain 3 growth factor 2 receptor binding protein (SGIP1) has recently been investigated in the context of nociception modulation (Hájková et al., 2016b). However, the role of this CB1 regulatory protein, SGIP1, in pathological pain conditions has not yet been described. Clarification of the role of SGIP1 interaction with CB1 receptor may help future research based on the use of cannabinoids as potential therapeutics. The thesis is structured into two parts, theoretical and practical. In the theoretical part of the thesis, knowledge of the given topic is summarized. First, pain is described from an anatomical-physiological perspective, followed by a description of the endocannabinoid system, where a part is dedicated to the CB1 cannabinoid receptor itself, and then another part is dedicated to the SGIP1 protein and its interaction with the CB1 receptor. In the practical part, the role of SGIP1...
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3D modelování jako prostředek rozvoje tvořivosti žáků 2. stupně základní školy
SOSNA, Tomáš
The dissertation deals with the issue of creativity development using 3D modeling. In the introductory, theoretical part of the work, defining the concept of creativity is the first step towards understanding its essence and mechanisms. Defining the term 3D modeling is key to understanding its role and importance in the context of work. Although the connection of creativity with 3D modeling has great potential in the field of education and development of pupils' abilities, it is practically unexplored. At the same time, the teaching of 3D modeling is slowly but surely entering the curriculum of elementary schools and appears to be a good and modern means of teaching technical subjects that can develop the creativity of pupils. In addition, the possibility of the influence of a curricular document from the field of technology on creativity was investigated. The overlap with the planned major revisions of the RVP ZV is also mentioned, especially in the area of 3D modeling. In order to clarify the relationship between 3D modeling and creativity, quantitative research was carried out in the practical part of the work among pupils of the 2nd grade of primary schools. The research was divided into two areas A and B. In part A, the development of creativity in the control group, in which the teaching of technical education took place in the classic way, was compared with the development of creativity in the experimental group, in which the teaching took place with the support of 3D modeling tools. In part B, the development of creativity in the control group with 3D modeling lessons was compared with the development of creativity in the experimental group, in which the 3D modeling lessons were additionally supplemented with specially designed creative tasks. Data collection took place in the form of testing students using Torrance's Figural Test of Creative Thinking. The obtained results were processed using the Wilcoxon paired test and the Mann and Whitney U-test in the statistical program R. The main part of the work describes the results of the research, which are discussed from the perspective of the goal of the work and partial steps. In addition, the final summary discusses the possibilities for further research, which emerged from the results of this work, and identified recommendations for further investigation.
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Speciation analysis of arsenic based on volatile species generation and dielectric barrier discharge plasma atomization
Plecháč, Matěj ; Kratzer, Jan (advisor) ; Kaňa, Antonín (referee)
SPECIATION ANALYSIS OF ARSENIC BASED ON VOLATILE SPECIES GENERATION AND DIELECTRIC BARRIER DISCHARGE PLASMA ATOMIZATION Bc. Matěj Plecháč 2024 Abstract Volatile species generation (VSG) comprises a group of techniques based on analyte derivatization in order to form a volatile compound prior to spectrometric detection. Selective analyte conversion from liquid to gas phase results in enhanced analyte introduction efficiency, but also in matrix separation and reduced risk of interferences. Moreover, VSG step can be utilized during speciation analysis or analyte preconcentration. The most frequent atomizers of volatile species are externally heated quartz tubes (QTA). Dielectric barrier discharge (DBD) atomizers have proved to be alternative hydride atomizers to QTA. The significant difference in toxicity of various species of the same element leads to the urgent need to develop new strategies for speciation analysis. Various approaches to speciation analysis of toxicologically relevant arsenic species including inorganic iAsIII and iAsV , monomethylarsonic acid (MMA), dimethylarsinic acid (DMA) and trimethylarsine oxide (TMAsO) by hydride generation atomic absorption spectrometry (HG-AAS) were investigated in this work. All these species can be converted to volatile compounds. i.e. arsane and its methylated...
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Kindergarten climate as a starting point for a child - centred model
Reslová, Dagmar ; Uhlířová, Jana (advisor) ; Ristić, Petra (referee)
The thesis deals with the climate in kindergarten and the personality-oriented model. The aim of the thesis is to explore the relationship between the kindergarten climate and the personality-oriented philosophy. In a narrower focus, the thesis examines personal well-being, the setting of the kindergarten teacher, and her interaction with the children. In the theoretical part, the author defines the concept of school climate, personal well-being, the personality- oriented model and its characteristics, the personality of the child, the personality of the teacher, and the relationships in kindergarten in connection with the implementation of the personality-oriented model. In the research part, the correlation and interconnectedness of these relationships are examined in the operation of three selected kindergartens. The correlations are examined through classroom observations and based on individual interviews with teachers and school principals. The collected data show different settings and approaches in individual schools and classrooms, various methods of work and communication of teachers with children, and also a different depth of understanding of the topic of the personality-oriented model. The conclusion of the thesis summarizes the research results. Furthermore, the predetermined research...
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Mg-hydroxyapatite composite materials prepared by powder metallurgy
Řičánek, Adam ; Doskočil, Leoš (referee) ; Buchtík, Martin (advisor)
This bachelor thesis focuses on the preparation of magnesium-hydroxyapatite composite by powder metallurgy methods. The theoretical part of bachelor thesis deals with magnesium, magnesium alloys and magnesium materials. Furthermore, the theoretical part of the bachelor thesis deals with the basics of powder metallurgy, processing of materials prepared by powder metallurgy and metal matrix composites. In the experimental part of the bachelor thesis, two series of composites were made with different quantities of hydroxyapatite. Composites were made by mixing Mg with filler and by mixing and milling Mg with filler. Both series of composites were characterised by investigation of microstructure and element composition, hardness, compressive strength and corrosion resistance. Composites of mixed and milled series showed a highly homogenous structure. Hardness, compressive strength and corrosion resistance increased with increasing amounts of hydroxyapatite. Composites of mixed series showed heterogeneous structures. Hardness did not increase with increasing amount of hydroxyapatite. Corrosion resistance slightly increased with increasing amount of filler. Compression strength decreased with the increasing amount of filler due to lower cohesion and incompactness of the structure.
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Laser preheating during of cobalt alloy cladding
Nevřivý, David ; Slováček, Marek (referee) ; Šebestová, Hana (advisor)
In this work, the possibility of using a laser beam for local preheating in combination with the MIG method in the cladding of Stellite 6 cobalt alloy on X12Cr13 steel was investigated. The surface temperature during heating by the laser beam, the temperature cycles and the cooling rate in the heat afected zone at different beam-arc distances were measured. The patterns were assessed based on the geometry and dilution achieved. The structure was evaluated in terms of macro and microstructure. The microhardness achieved was measured for its distribution throughout the entire clad with a focus on the heat affected zone. The performance parameters of the welding source were varied to evaluate their impact on the resulting dilution and changes in the geometry of the design. To achieve higher process efficiency, the cladding speed was increased and the clads were evaluated in terms of macrostructure and resulting clads geometry.
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Assessing Economic Situation of a Company and Proposals for Its Improvement
Hynek, Jan Jaroslav ; Franková, Tereza (referee) ; Doubravský, Karel (advisor)
The master’s thesis deals with the assessment of the financial situation of XZY s.r.o. using financial analysis and statistical methods. The theoretical part is divided into financial and statistical theory. In these parts, it presents the definition of selected financial ratios and statistical methods, which include time series regression and correlation analysis. The theoretical part is followed by an analytical part in which the financial situation of the selected company is evaluated along with the prediction of selected ratios. Furthermore, the selected ratios are subjected to correlation analysis where the interdependence between them is examined. The paper concludes with suggestions for improving the financial situation of the enterprise.
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Evaluation of the Company´s Financial Performance using Benchmarking Approach
Toman, Martin ; Štukavec, Jiří (referee) ; Bartoš, Vojtěch (advisor)
This diploma thesis is focused on the evaluation of the business and financial performance of the company SWIETELSKY stavební s.r.o. using the benchmarking method. The thesis is divided into four main parts. The first part contains the theoretical background necessary for addressing the given issue. The following chapter characterizes the examined company and also describes the strategic analysis of the enterprise. In the third part of this thesis, the actual benchmarking of the company with appropriately chosen competitive enterprises is conducted. The final part includes a detailed description of proposals for improving the business and financial performance of the company.
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