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Human impact on the holocene vegetation development in North Macedonia.
Koubský, Karel ; Abraham, Vojtěch (advisor) ; Pokorný, Petr (referee)
This thesis aims to reconstruct the Holocene vegetation development in North Macedonia in relation to human activities; specifically, it focuses on the late Holocene period, when changes in land-use and settlement strategy were simultaneously taking place, which lead to an increased human pressure on the surrounding environment. To describe the vegetation development, a sedimentary profile from a small lake in the Pelister Mountains was chosen for analysis. A total of 25 samples were processed and analysed under a light microscope for the presence of pollen and non-pollen objects. Based on the results of pollen stratigraphy and radiocarbon dating, it was confirmed that the vegetation record covers the entire Holocene period. The early Holocene is characterized by a gradual increase in forest vegetation and a decrease in steppe vegetation. In the middle Holocene, secondary anthropogenic indicators show up in higher numbers. The late Holocene is already showing signs of continuous human presence. Compared to the lowlands, the mountain record shows a rather discontinuous presence of primary indicators, which nevertheless appear after the 5th millennium before present. High percentages of secondary indicators indicate continuous human influence in the mountains. Overall, it has been confirmed that...
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Reactivity of pulmonary vessels to hypoxia
Koubský, Karel ; Herget, Jan (advisor) ; Červenka, Luděk (referee) ; Neckář, Jan (referee)
Hypoxic pulmonary vasoconstriction (HPV) is a physiological mechanism that maintains optimal oxygenation of blood in the lungs. However, chronic hypoxia causes hypoxic pulmonary hypertension (HPH). Increased reactive oxygen species (ROS) participate in the pathogenesis of HPH. Oxidative stress can cause NO synthase uncoupling and subsequent production of superoxide instead of NO. Increase in intracellular Ca2+ concentration in pulmonary smooth muscle cells is required for pulmonary vasoconstriction. However, vessel tone can also be regulated by vascular smooth muscle cells' calcium sensitivity (without Ca2+ concentration changes). Increase of calcium sensitivity plays a role in HPV and HPH. This study focuses on three mechanisms to influence the increased calcium sensitivity in HPV a HPH: (1) Rho kinase inhibition, (2) effort to re-couple NO synthase, and (3) vasorelaxant effect of tyrosine kinase inhibitors. Normobaric hypoxic chamber (10% O2) or the combination of hypoxia and vascular endothelial growth factor receptor blockade was used to induce pulmonary hypertension in rats. (1) The effect of acute and chronic Rho kinase inhibition was studied on pressure-flow relationship (P/Q) in isolated perfused lungs. Acute Rho kinase inhibition decreased the basal tone of pulmonary vessels in HPH...
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Paleoenvironmental evolution around Lake Ohrid in the context of ancient settlement
Koubský, Karel ; Hošek, Jan (advisor) ; Abraham, Vojtěch (referee)
Lake Ohrid, the oldest lake in Europe, is an ideal place to study the response of the terrestrial ecosystems to many climatic and environmental changes during the Quaternary. It is also a useful source of information regarding the interactions between man and environment during the Holocene - this applies especially to the Late Bronze Age period and the beginning of the Iron Age, when there were profound changes in landscape management and when lakeside settlements were suddenly abandoned, which is also evident in the palaeobotanical record. This work summarizes the existing knowledge on this issue and presents various possibilities for studying paleoenvironmental development in this area. Key words: Holocene - Lake Ohrid - paleoenvironmental reconstruction - settlement - Bronze Age
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Reactivity of pulmonary vessels to hypoxia
Koubský, Karel ; Herget, Jan (advisor) ; Červenka, Luděk (referee) ; Neckář, Jan (referee)
Hypoxic pulmonary vasoconstriction (HPV) is a physiological mechanism that maintains optimal oxygenation of blood in the lungs. However, chronic hypoxia causes hypoxic pulmonary hypertension (HPH). Increased reactive oxygen species (ROS) participate in the pathogenesis of HPH. Oxidative stress can cause NO synthase uncoupling and subsequent production of superoxide instead of NO. Increase in intracellular Ca2+ concentration in pulmonary smooth muscle cells is required for pulmonary vasoconstriction. However, vessel tone can also be regulated by vascular smooth muscle cells' calcium sensitivity (without Ca2+ concentration changes). Increase of calcium sensitivity plays a role in HPV and HPH. This study focuses on three mechanisms to influence the increased calcium sensitivity in HPV a HPH: (1) Rho kinase inhibition, (2) effort to re-couple NO synthase, and (3) vasorelaxant effect of tyrosine kinase inhibitors. Normobaric hypoxic chamber (10% O2) or the combination of hypoxia and vascular endothelial growth factor receptor blockade was used to induce pulmonary hypertension in rats. (1) The effect of acute and chronic Rho kinase inhibition was studied on pressure-flow relationship (P/Q) in isolated perfused lungs. Acute Rho kinase inhibition decreased the basal tone of pulmonary vessels in HPH...
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