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Transparent polycrystalline ceramics at visible and infrared wavelenghts
Veselý, Jan ; Maca, Karel (referee) ; Trunec, Martin (advisor)
his thesis deals with preparation of transparent ceramic sheets made out of sub-µm alumina powder. Green bodies are prepared by ultraviolet (UV) curing of UV curable resin containing ceramic powder followed by debinding of organic parts at elevated temperature. High relative density of green bodies is essential for reduction of shrinkage during subsequent sintering process. Therefore high solids loading dispersions containing > 57 vol% ceramic particles are used. To reach transparent behaviour, porosity within the sheets must be reduced completely. Therefore hot isostatic pressing (HIP) is used as a final operation. Finally, light transmission and hardness measurements are presented. Possibilities of making high resolution microstructures using maskless lithography and some suggestions for use of the UV curing technique for production of complex-shaped 3D structures are briefly mentioned.
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Colonisation of Central Europe by benthic frehwater crustacean Asellus aquaticus (Isopoda, Crustacea)
Střížek, Antonín ; Sacherová, Veronika (advisor) ; Špaček, Jan (referee)
Longterm climate changes are an inseparable part of the evolution of Earth. In the last few milions of years the changing of glacials and interglacials was as ordinary and regular phenomenon as changing from day to night or from spring to summer. These cycles also have similar influance on evolution of nature on Earth. Eventhough the state of nature appears to us stable for the few last human generations, the reality from the long term point of view is differnt. During these cycles, the location of climatic zones, size of glaciers, deserts, savannahs, steppes or rainforests have changed. Organisms changed locations of their areas of distribution, many nowadays widespread species were pushed into isolated local populations. This Master's thesis reveals the impact of glacial cycles on a freshwater crustacean aquatic Isopod (Asellus aquaticus). Very variable mitochondrial COI gene was sequenced within 139 individuals of this species from 62 different localities in Europe. This data were included into an extensive scope of an already known phylogeographic structure of the continent. An Aquatic Sowbug shows a quite high rate of a genetic heterogenity (maximum Nucleotide Divergence discovered is 0,132 and average is 0,016) in the area of the Czech Republic. Where there are found representatives of two...
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Local dispersal of Golden-ringed dragonfly Cordulegaster boltonii
Hančíková, Barbora ; Černý, Martin (advisor) ; Dolný, Aleš (referee)
We carried out a pilot study of local dispersion and patterns of movement of Golden- ringed dragonfly Cordulegaster boltonii (Odonata: Cordulegasteridae). Cordulegasteridae is a family with many primitive traits present and rather restricted geographical distribution ranges (at least among European species). Their migration seems to be limited despite the body size that predetermines them to high mobility over large spatial scale. Linear habitat (upper parts of narrow forest streams) specialisation along with behavioural ecology (peculiar premating habit of scanning streams for females) is a unique life history, which bring lot of questions. We collected mark-release-recapture data during two adult flight seasons in year 2010 and 2011. We were simultaneously capturing patrolling males along three separate streams (Dračice, Koštěnický and Struha) in total length of 9.9 km in, located in the Natural park Česká Kanada, in the Southern Czech Republic. We captured and marked 440 individuals and recorded 113 recapture events (26 % recapture rate) in year 2010 and 355 individuals were marked, 171 recapture events made (48 % recapture rate) in 2011. Our data suggested high level of stream fidelity (only 10 inter stream dispersal events, 2.8 % dispersal rate). What was as well reflected in a closeness of...
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Dispersion of freshwater gastropods
Buďová, Jana ; Černý, Martin (advisor) ; Juřičková, Lucie (referee)
Freshwater gastropods (Mollusca: Gastropoda) belong to two tradional taxonomic groups: prosobranchs (Prosobranchia) and pulmonates (Pulmonata). Most of these molluscs are characterized by low vagility. Therefore they usually rely on passive dispersal. Their dispersal vectors are mostly birds and water. Animals can transport snails both externally and internally. Direct methods (capture.mark.recapture, radio - tracking) and genetic methods could be used to study dispersal. For genetic studies can be used many type of molecular markers, but the recently most popular are microsatellites. According to recent studies, the dispersal of freshwater gastropods is probably not as frequent and wide - spread as assumed before. Key words: freshwater snails, dispersal, dispersal vectors, capture - mark - recapture, molecular markers, population genetics
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Landscape factors and their influence on succession and distribution of woody species
Jablonská, Viola ; Vojta, Jaroslav (advisor) ; Tesnerová, Cecílie (referee)
The succession of temperate zone vegetation is a multi-layered process of exchange of plant dominants in which trees play a crucial role. To understand the processes that take place in the context of succession at the level of microhabitats, it is necessary to focus on the wider landscape context. This literature review seeks to answer questions of how factors such as the relief, topography, landscape structure and connectivity of habitat isolation, distance from the source or method of seed dispersal affect the occurrence, distribution and succession of species. The environmental aspects of the landscape are also taken into account and the disturbances that are part of the natural dynamics of ecosystems are briefly discussed. A specific factor is the method of using landscape, known under the term land use. Our handling of space, soil and other natural resources in the country leaves an indelible imprint, which is also reflected in changes in the structures of vegetation.
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Local dispersal of Golden-ringed dragonfly Cordulegaster boltonii
Hančíková, Barbora ; Černý, Martin (advisor) ; Dolný, Aleš (referee)
We carried out a pilot study of local dispersion and patterns of movement of Golden- ringed dragonfly Cordulegaster boltonii (Odonata: Cordulegasteridae). Cordulegasteridae is a family with many primitive traits present and rather restricted geographical distribution ranges (at least among European species). Their migration seems to be limited despite the body size that predetermines them to high mobility over large spatial scale. Linear habitat (upper parts of narrow forest streams) specialisation along with behavioural ecology (peculiar premating habit of scanning streams for females) is a unique life history, which bring lot of questions. We collected mark-release-recapture data during two adult flight seasons in year 2010 and 2011. We were simultaneously capturing patrolling males along three separate streams (Dračice, Koštěnický and Struha) in total length of 9.9 km in, located in the Natural park Česká Kanada, in the Southern Czech Republic. We captured and marked 440 individuals and recorded 113 recapture events (26 % recapture rate) in year 2010 and 355 individuals were marked, 171 recapture events made (48 % recapture rate) in 2011. Our data suggested high level of stream fidelity (only 10 inter stream dispersal events, 2.8 % dispersal rate). What was as well reflected in a closeness of...
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Colonisation of Central Europe by benthic frehwater crustacean Asellus aquaticus (Isopoda, Crustacea)
Střížek, Antonín ; Sacherová, Veronika (advisor) ; Špaček, Jan (referee)
Longterm climate changes are an inseparable part of the evolution of Earth. In the last few milions of years the changing of glacials and interglacials was as ordinary and regular phenomenon as changing from day to night or from spring to summer. These cycles also have similar influance on evolution of nature on Earth. Eventhough the state of nature appears to us stable for the few last human generations, the reality from the long term point of view is differnt. During these cycles, the location of climatic zones, size of glaciers, deserts, savannahs, steppes or rainforests have changed. Organisms changed locations of their areas of distribution, many nowadays widespread species were pushed into isolated local populations. This Master's thesis reveals the impact of glacial cycles on a freshwater crustacean aquatic Isopod (Asellus aquaticus). Very variable mitochondrial COI gene was sequenced within 139 individuals of this species from 62 different localities in Europe. This data were included into an extensive scope of an already known phylogeographic structure of the continent. An Aquatic Sowbug shows a quite high rate of a genetic heterogenity (maximum Nucleotide Divergence discovered is 0,132 and average is 0,016) in the area of the Czech Republic. Where there are found representatives of two...
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Dispersion of freshwater gastropods
Buďová, Jana ; Černý, Martin (advisor) ; Juřičková, Lucie (referee)
Freshwater gastropods (Mollusca: Gastropoda) belong to two tradional taxonomic groups: prosobranchs (Prosobranchia) and pulmonates (Pulmonata). Most of these molluscs are characterized by low vagility. Therefore they usually rely on passive dispersal. Their dispersal vectors are mostly birds and water. Animals can transport snails both externally and internally. Direct methods (capture.mark.recapture, radio - tracking) and genetic methods could be used to study dispersal. For genetic studies can be used many type of molecular markers, but the recently most popular are microsatellites. According to recent studies, the dispersal of freshwater gastropods is probably not as frequent and wide - spread as assumed before. Key words: freshwater snails, dispersal, dispersal vectors, capture - mark - recapture, molecular markers, population genetics
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Transparent polycrystalline ceramics at visible and infrared wavelenghts
Veselý, Jan ; Maca, Karel (referee) ; Trunec, Martin (advisor)
his thesis deals with preparation of transparent ceramic sheets made out of sub-µm alumina powder. Green bodies are prepared by ultraviolet (UV) curing of UV curable resin containing ceramic powder followed by debinding of organic parts at elevated temperature. High relative density of green bodies is essential for reduction of shrinkage during subsequent sintering process. Therefore high solids loading dispersions containing > 57 vol% ceramic particles are used. To reach transparent behaviour, porosity within the sheets must be reduced completely. Therefore hot isostatic pressing (HIP) is used as a final operation. Finally, light transmission and hardness measurements are presented. Possibilities of making high resolution microstructures using maskless lithography and some suggestions for use of the UV curing technique for production of complex-shaped 3D structures are briefly mentioned.
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