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Effects of litter raking on plant-soil interactions
Husinecká, Tereza ; Münzbergová, Zuzana (advisor) ; Hadincová, Věroslava (referee)
Plant litter creates variously sized layer on soil and provides significant source of nutrients, especially carbon and nitrogen, for the whole ecosystem. Decomposition of plant litter forms the main source of soil organic matter and is an essential part of the global nutrient cycle. It also provides habitat for many organisms living on the boundary of soil. Also, plant litter makes a barrier which the light is unable to penetrate. Terrestrial ecosystems are affected by human activity and are subject to disturbances, including litter raking. Litter raking has been an integral part of forest management for several centuries in the past, significantly affecting the character of vegetation and the soil environment. The aim of this work is to summarize the findings of studies dealing with the effects of litter raking on the interaction between plants and soil. The first part of the paper is devoted to the litter, soil environment and its components, which are connected to the litter and second part of the paper is devoted to the effect of litter raking on the nutrient cycle, acidification, plant diversity and seed germination.
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Parallelization of Ultrasound Simulations Using 2D Decomposition
Nikl, Vojtěch ; Dvořák, Václav (referee) ; Jaroš, Jiří (advisor)
This thesis is a part of the k-Wave project, which is a toolbox for the simulation and reconstruction of acoustic wave felds and one of its main contributions is the planning of focused ultrasound surgeries (HIFU). One simulation can take tens of hours and about 60% of the simulation time is taken by the calculation of the 3D Fast Fourier transforms. Up until now the 3D FFT has been calculated purely by the FFTW library and its 1D decomposition, whose major limitation is the maximum number of employable cores. Therefore we introduce a new approach, called the 2D hybrid decomposition of the 3D FFT (HybridFFT), where we combine both MPI processes and OpenMP threads to reach as best performance as possible. On a low number of cores, on the order of a few hundreds, we are about as fast or slightly faster than FFTW and pure MPI 2D decomposition libraries (PFFT and P3DFFT). One of the best results was achieved on a 512^3FFT using 512 cores, where our hybrid version run 31ms, FFTW run 39ms and PFFT run 44ms. The most significant performance advantage should be seen when employing around 8-16 thousand cores, however we haven't had an access to a machine with such resources. Almost a linear scalability has been proven for up to 2048 employed cores.
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Longer-term Yield Decomposition: an analysis of the Czech Government Yield Curve
Kučera, Adam ; Dvořák, Michal ; Komárek, Luboš ; Komárková, Zlatuše
The term structure of yields is an important source of information on market expectations about future macroeconomic developments and investors’ risk perceptions and preferences. This paper presents the methodology used by the Czech National Bank to obtain such information. It describes the decomposition of the Czech government bond yield curve into its components. The evolution of those components is interpreted in relation to the macro-financial environment, as embodied by selected variables. The practical use of the decomposition in estimating and interpreting the responses of the Czech government bond yield curve to macroeconomic and financial shocks is presented using a vector autoregression model.
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Effect of emergent micropolutants on the denitrification activity of activated sludge
Mosná, Silvia ; Stříteský, Luboš (referee) ; Hrich, Karel (advisor)
Diploma thesis Effect of emergent micropolutants on the denitrification process through activated sludge is focused on three specific substances. The substances under investigation are atrazine, terbutylazine and sulfametaxazole. Atrazine and terbutylazine are pesticides, particularly herbicides. Sulfametaxazole was chosen as a common antibiotic. The thesis is summarized into 10 chapters and conclusion. The work consists essentially of theoretical and practical part. Part of the theoretical part of the thesis is legislation that deals with the matters of the problem with micropolutants. The next chapter is an introduction to the issue, where we want to familiarize the reader with the current situation. There are also chapters on emergent micropolutants, denitrification and investigated substances. If we look at the practical part, there are chapters on sampling, evaluation of BATCH tests and evaluation of inhibition tests. There are also chapters on BATCH tests and respiratory inhibition test, which describe procedures of how we performed this test. Laboratory test reports are included in the Annex.
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Water Management Analysis of Storage Capacity of the Vranov Reservoir
Vítková, Lucie ; Havlík, Martin (referee) ; Marton, Daniel (advisor)
The current persistent drought and changes in the climate system have raised water managers expert questions about how to manage water resources in the future. The manifestation of climate change in hydrological series and their influence on the magnitude of threats to the storage functions of reservoirs are more often investigated. Already today, long-term shortages of storage capacity in reservoirs lead to the introduction of special manipulations on water structures. The aim of the thesis is to perform the analysis of time series, respectively decomposition of hydrological series average annual and monthly discharges. Create extended hydrological bases using synthetic discharge series generators and develop a comprehensive analysis of storage volume without considering losses even with the introduction of losses from the water surface vapor in the UNCE RESERVOIR program. The created discharge series are compared and evaluated on the basis of statistical characteristics and reservoir storages results with the real discharge series. The practical app is conducted on the Vranov reservoir in the Dyje River Basin.
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Peat formation and peat meadow restoration
Krejčová, Jana ; Frouz, Jan (advisor) ; Picek, Tomáš (referee)
This work aims to clarify and describe the necessary conditions of the peat soil horizon formation. The following three types of locations were compared. Drained locations that were revitalized afterwards. Locations which were drained and never revitalized. And lastly undrained localities where the original peat horizons are still presented. It has been proven that the grounwater level differs in drained and undrained areas. However, there was no significant differrence between revitalized and non-revitalized areas in drained types of locations. The results confirmed that Sphagnum spp., which is the most important species in peat formation, dominates the plant community where the groundwater level is higher than 25 cm. If the grounwater level is lower than 25 cm below the surface, Sphagnum spp. disappears very quickly and degrades peat soil horizons. The work also proved the groundwater level directly affects plant comunities that more or less promote carbon accumulation in the soil but water level and anaerobic conditions have no direct affect on soil carbon accumulation and only affect the vegetation composition of the peat soil horizon.
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Use of nanomagnets treated materials in study of decomposition
Vyhnálek, Michal ; Frouz, Jan (advisor) ; Veselá, Hana (referee)
In study of soil organic matter, many methods of carbon labeling are used, mostly using carbon isotope 13 C, which are reliable, but require expensive devices. Magnetic nanoparticles could provide low-cost alternative, which can be prepared in most laboratories with basic equipment. The upside of nanoparticles usage is the fact, that we could monitor fate of individual particles added to soil, including their chemical transformations or changes in microbial communities. The goal of this paper was to test the usage of magnetic nanoparticles and prove the reliability of carbon labeling through experiment. KEY WORDS Magnetic nanoparticles, decomposition, soil organic matter
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Hydrological Time Series Analysis for Chosen Sub Catchment in Morava River Basin
Černý, Vojtěch ; Benáčková, Kateřina (referee) ; Marton, Daniel (advisor)
Current climate conditions raise questions about how climate change should affect the hydrological regime of the Czech Republic. The main questions are: I) Is climate change serious and is it already tangible in hydrological series? II) Are there significant changes in the climatic conditions, or in the flow of the river network? III) How does climate change affect hydrological conditions in the catchment? IV) Are there non-stationary tendencies in the hydrological series caused by climate change? The aim of this work was to perform a basic analysis of hydrological time series and estimated its possible changes. The analysis was done with using autocorrelation function, spectral density, moving averages methods, statistical characteristics, empirical line of probability of exceeding and last but not least by decomposing the time series. The practical application was applied on time series of average monthly flows determined in the hydrometric profile of Dalečín in the Svratka river basin.
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Modules over string algebras
Löwit, Jakub ; Šťovíček, Jan (advisor) ; Žemlička, Jan (referee)
The aim of this thesis is to investigate the categories of modules over the so called string algebras. In particular, we try to understand the cotorsion pairs in these categories, which boils down to understanding the decompositions of extensions of such modules. For string algebras with some oriented tree for the underlying quiver, we describe some classes given by these cotorsion pairs in terms of purely combinatorial closure properties. For any string algebras, the combinatorics appears to be similar, althought more complicated.
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The lowest-mortality countries: their specifics and trends of development
Stýblová, Julie ; Burcin, Boris (advisor) ; Maláková, Kateřina (referee)
The lowest-mortality countries: their specifics and trends of development Abstract The main objective of this work is to analyze mortality rates in countries with the lowest mortality rates between 1990 and 2013 for each gender separately. The life expectancy at birth indicator was used to assess the developmental trends of overall mortality, followed by the probability of death, which allowed for the expression of age-related mortality changes, and the contribution of individual age groups to the change in life expectancy at birth was determined by one-dimensional decomposition. For a more detailed look, the mortality rate of selected group of death causes was assessed using a standardized mortality rate. The two-dimensional decomposition allowed to quantify the contribution of age groups and the main causes of death and thus to evaluate how the age group and cause of death contributed to the change in life expectancy at birth. In all countries, the overall mortality rate is decreasing and no interruption of this trend is observed. The results show that the states are getting closer to each other and do not show much differences. All selected countries are characterized by a decline in mortality, mainly in older age groups. The states also change the order of the most important causes of death, when a...
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