National Repository of Grey Literature 40 records found  1 - 10nextend  jump to record: Search took 0.00 seconds. 
Importance of ecological stoichiometry in soil development.
Veselá, Hana ; Frouz, Jan (advisor) ; Hruška, Jakub (referee) ; Bonkowski, Michael (referee)
Ecological stoichiometry is a useful tool for understanding of ecological dynamics and related processes. There are only rare informations about nutrient cycling and nutrient dynamics in plant- soil system in restoration areas after coal mining. Different plant species have developed own strategies and treat differently with nutrients which can influence nutrient cycling and consequent nutrient return to the soil. In thesis, I investigated ecological stoichiometry as one of key factors which controls soil development in post mining sites. In general introduction, known facts are summarized about e.g. plant traits, decomposition process, nutrient cycling and consequences for soil development and restoration practices. But still, relationship between leaves, plant litter, and soil is poorly understood in restoration areas. The results of a doctoral thesis are presented in five papers, out of which three have been published, one has been already submitted and one manuscript is prepared for publication in an international journal with impact factor. In the first presented publication, the influence of soil fauna was studied (especially earthworms) on soil development. Soil development differed significantly between sites afforested with different tree species and it is strongly influenced by the...
Sediments of Bohemian Forest lakes and their use in paleoenvironmental research
Vondrák, Daniel ; Tátosová, Jolana (advisor) ; Hruška, Jakub (referee) ; Kyška Pipík, Radovan (referee)
Sediments of Bohemian Forest lakes are important natural archives. Their sedimentary record covers postglacial history of the lakes as well as history of natural processes in a wider region. It also documents local settlements and changes in landscape management. The lake sediments have attracted the interest of the scientific community since the end of the 19th century. Despite of the fact that modern paleolimnological and paleoecological investigations were already performed in the second half of the 20th century in the Bohemian Forest Mts., the great potential of the lake sediments was not fully utilized in scientific research so far. The ultimate objective of this thesis is to deepen knowledge of these natural archives and support their utilization in future studies. Several specific objectives have been set to achieve the ultimate objective: i) to compare age of the Bohemian Forest lake sediments with the recent knowledge of local deglaciation at the end of the last ice age, ii) to integrate chronostratigraphic marker horizons as one of the tools of Late Glacial sediment dating, iii) to assess the role of bioerosion in chitinous subfossil freshwater invertebrate remains on the record representativeness, and iv) to prove the presumed dystrophic nature of the lakes during the Holocene using...
Research on inflence of SO2 and NOx on spruce growth
Hruška, Jakub ; Oulehle, Filip ; Kolář, Tomáš
Radial growth of Norway spruce (Picea abies) in Krušné and Jizerské Mts.responded qiuckly on the decline of SO2 and NOx emissions and S deposition. At the end of 1990´s it was equal to growh measured before the period of high emissions. The best correlation was founded with ambient SO2 concentrations, then with S atmosperic deposion and less important correlation was found with soil chemistry as it is correlated with deposition levels. At present there is no evidence of influence of SO2 and NOX on decline of radial growht. Observed decline in last decade is most probably attributed to climatic conditions.
Tree species influence on soil acidification: long-term trends and modeling
Oulehle, Filip ; Hruška, Jakub (advisor) ; Borůvka, Luboš (referee) ; Šantrůčková, Hana (referee)
Forest ecosystems belong to the part of environment most affected by the anthropogenic acidification. The structure of Central European forests was historically converted mostly into the Norway spruce monocultures. Such a forests received elevated acidic deposition since 1950s, from which large parts of mountain forests were killed by air pollution in 1970s and 1980s. After reduction of acidic deposition the forest soils were significantly delayed in chemical recovery compared to stream chemistry (Alewell et al., 2000). In this thesis we focused on long-term changes in soil chemistry at highly polluted area of Ore Mts., with particular interest in the tree species influence on soil acidification. The presented results including measurements of biogeochemical cycles within forest ecosystem at the Norway spruce (Picea abies [L.]) stand in the period 1992-2005 and at the European beech (Fagus sylvatica [L.]) stand between 2003-2005. The desorption of previously stored sulfur and the decrease of Ca deposition are the main factors controlling the recovery of soil solution at spruce stand. The reduction in Ca availability resulted in lower uptake by tree assimilatory tissues, measured as concentration in needles. The unexpected disappearing of nitrogen leaching from soil was undoubtedly the most...
Effect of global climate change on hydrological patterns in headwater catchments
Lamačová, Anna ; Hruška, Jakub (advisor) ; Tesař, Miroslav (referee) ; Kalvová, Jaroslava (referee)
The aims of this theses were (i) to evaluate trends in spring yields in the Czech Republic (period 1971-2007) and trends in runoff from small forested catchments of the GEOMON network during the period 1994-2011, (ii) evaluate the impact of climate change on streamwater chemistry in acid-sensitive catchment (Lysina), and (iii) estimate the impact of anticipated climate change projected according to different CO2 emission scenarios on flow patterns forested (GEOMON) and alpine headwater (Skalnaté Lake) catchments in the periods 2021-2050 and 2071-2100. Significant negative trends on the annual level were observed at 18% of springs while positive trends at only less than 0.5% of 157 tested objects and 4 of 18 regions revealed significant decreasing trend. To these regions belonged the zones of Carpathian Cretaceous and Paleogene sediments in the southeast and northeast of the Czech Republic, the zones of tertiary and Cretaceous basins in the southeast and Proterozoic and Paleozoic crystalline rocks in the central part of the Czech Republic. Most spring yields were decreasing within the summer months June- August (on average 24%) and least between February and April (on average 15%) (Paper I). There were no general patterns found indicating either significant increases or decreases in runoff on either...
Multielement analysis of flue gas residues from secondary lead smelting
Šebek, Ondřej ; Mihaljevič, Martin (advisor) ; Rychlovský, Petr (referee) ; Hruška, Jakub (referee)
Multielement analysis of flue gas residues from secondary lead smelting was tested using seven decomposition methods on four different flue gas residues and certified reference materials (CRM) CPB-2 (Pb concentrate, CCRMP). The studied samples contained both silicates and also high contents of phases with Pb, primarily Pb chlorides and sulphates. Solutions prepared by various decomposition methods were analysed using ICP OES (Al, As, Ba, Be, Bi, Ca, Cd, Co, Cr, Cu, Fe, K, Li, Mg, Mn, Mo, Na, Ni, P, Pb, Sb, Se, Si, Sn, Sr, Ti, Tl, V, Zn). Greater yields were found for most of the elements by combined decomposition (with fusion) and decomposition by sintering. Nonetheless, both methods exhibited major losses of volatile elements (As, Bi, Sb, Tl). Thus, one of these methods must always be combined with a method of decomposition in a closed system. The work also demonstrates that, for investigation of untraditional waste geological materials (e.g. flue residues from high- temperature industrial processes), it will be necessary in the future to produce new certified reference materials with anomalous chemical and mineralogical compositions, which are not currently available on the market. Laboratory extraction tests were performed on two different types of flue residues - kinetic (30 days) with ratio L/S...
Historical occurrence of bark beetle (Coleoptera: Scolytinae) in the Bohemian Forest, Czech Republic, and possibility of its study in lake sediments
Vytisková, Markéta ; Hořická, Zuzana (advisor) ; Hruška, Jakub (referee)
The bachelor's project is closely related to the problem of bark beetle calamities in the Bohemian Forest National Park in the Czech Republic, and to a possible use of paleolimnological methods for their historical reconstruction. The importance of subfossil beetles as a proxy in assessing past changes in the nature is growing, and the occurrence of remains of Scolytinae in lake sediments has been confirmed - also in the Bohemian Forest paleolake Stará jímka. The thesis is a literature review of (1) the relationship between spruce forests and bark beetle gradations in the area, and (2) chitinous remains of bark beetle and other Scolytinae preserved in lake sediments, and their paleoecological implications. Key words Bohemian Forest (Czech Republic), spruce forests, bark beetle, paleolimnology, subfossil Coleoptera, paleolake Stará jímka
Generating Methods in GR and Properties of the Resulting Solutions
Hruška, Jakub
The use of conformal transformation as a method for generating solutions of Einstein's equations has been mainly studied in the cases where the original spacetime is vacuum. The generated spacetimes then frequently belong to the class of pp-waves. In the present work, the electrovacuum spacetimes are stud- ied, i.e the solutions of coupled Einstein's and Maxwell's equations. By using the conformal transformation, it is possible to circumvent solving the later equa- tions. This method is concretely studied for null Einstein-Maxwell fields and it turns out that the admissible spacetimes are pp-waves again. However, if the method is generalized, it is possible to enlarge the class of conformal null Einstein-Maxwell fields to a wider family of Kundt spacetimes. 1
Generating Methods in GR and Properties of the Resulting Solutions
Hruška, Jakub ; Žofka, Martin (advisor) ; Pravdová, Alena (referee) ; Gürlebeck, Norman (referee)
The use of conformal transformation as a method for generating solutions of Einstein's equations has been mainly studied in the cases where the original spacetime is vacuum. The generated spacetimes then frequently belong to the class of pp-waves. In the present work, the electrovacuum spacetimes are stud- ied, i.e the solutions of coupled Einstein's and Maxwell's equations. By using the conformal transformation, it is possible to circumvent solving the later equa- tions. This method is concretely studied for null Einstein-Maxwell fields and it turns out that the admissible spacetimes are pp-waves again. However, if the method is generalized, it is possible to enlarge the class of conformal null Einstein-Maxwell fields to a wider family of Kundt spacetimes. 1

National Repository of Grey Literature : 40 records found   1 - 10nextend  jump to record:
See also: similar author names
14 HRUŠKA, Jan
1 HRUŠKA, Jaroslav
14 Hruška, Jan
1 Hruška, Jindřich
2 Hruška, Jiří
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