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Alternative powertrains of vehicles
Filip, Vojtěch ; Kučera, Pavel (referee) ; Píštěk, Václav (advisor)
The aim of this thesis is the analysis of most common alternative drive systems currently used in cars, their comparison with the current gasoline and diesel engines. Familiarization with the technical solutions of drives, their categorization into several groups according to the specific key features. It also deals the most important components of an alternative fuels automobiles, respecting their strengths and also weaknesses that currently hinder expansion of these propulsions, economically as well as technically.
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Modern hybrid drive of passenger vehicles
Švoma, Jan ; Blaťák, Ondřej (referee) ; Vančura, Jan (advisor)
This bachelor thesis deals with the current hybrid-drives in passenger cars. The thesis contains the categorization of hybrid systems according to structure and use. It also discusses the analysis of individual components and describes their suitability for use in different situations. It is focused on current offering of hybrid vehicles and development opportunities. At the end of are evaluated economic aspects and prospects for the use of these systems in the future.
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Evolution of intraspecific diversity of invasive pathogen of alder Phytophthora ×alni
Pecka, Štěpán ; Koukol, Ondřej (advisor) ; Sedlářová, Michaela (referee)
Phytophthora alni s. l. (Peronosporomycetes: Stramenopila) is an invasive pathogen causing phytophthora root and collar rot in alders. It has been known from Europe since the '90s and from the Czech Republic since 2001. Three species were found are known within species complex P. alni s. l. Two of these species hybridized in Europe and created third triploid species called Phytophthora ×alni (Phytophthora alni subsp. alni). Dozens of genotypes have been identified with the help of microsatellites in previous studies, nevertheless only one genotype (Pxa-1) was dominating and most of other genotypes were closely related to it. The trend of increasing or decreasing incidence of this genotype differed among these studies. This thesis compares changes in the P. ×alni population in Vltava basin over the last 14 years during which a significant decrease in number of available hosts of this pathogen took place. Multilocus genotypes were determined using a set of 10 microsatellite markers. Among the 94 P. ×alni isolates reliably genotyped, 23 were of different genotypes. None of these genotypes, however, were found on the same localities repeatedly (except the dominant genotype). Incidence of the dominant genotype increased over time (from 63 % to 86 %). Most of the other genotypes were only slightly...
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Commercialization of civil society organizations from the perspective of managers in the field of elderly care in the Czech Republic
Čechurová, Helena ; Šťovíčková Jantulová, Magdaléna (advisor) ; Moree, Dana (referee)
The diploma thesis focuses on the commercialization of civil society organizations (CSOs), specifically the institutional isomorphism that makes CSOs "business like" as well as the relationship between CSOs and the commercial sector in the context of commercialization. The purpose of this thesis is to gain an understanding of the manager's perspectives representing CSOs in the field of elderly care in the Czech Republic, with a particular emphasis on the institutional isomorphism and the relationships mentioned above. The findings of the study were obtained from narrative and semi-structured interviews with seven selected managers in the field of elderly care in the Czech Republic. The findings indicate that the participants regard the institutional isomorphism (coercive) as unfair and meaningless; patchy and outdated. The examination of the level of relationships between CSOs and the commercial sector resulted in the Relationships Typology. The typology presents three foundations based on need, reputation, and crisis that have been identified as the foundations for developing relationships between CSOs and the commercial sector. Each foundation conceals the unique nature of relationships visible in commercialized CSOs as reflected by selected managers. Key words: business-like, hybridization,...
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Evolution of the genus Malus with a particular reference to old and local cultivars
Polcar, Václav ; Urfus, Tomáš (advisor) ; Macková, Lenka (referee)
The following work deals with the genus Malus in terms of the significant diversity that this genus represents. It summarizes a basic knowledge about the taxonomic position and world centers of the genus evolution. Part of the thesis also discussed reproductive mechanisms as a source of the genus diversity. The thesis then focuses on the species Malus domestica, its evolution and the hybrid origin. In this context, old varieties of apple trees, their significance and pomologically important regions of the Czech Republic are presented. An integral part of this work is also devoted to the protection of old varieties, its limits and possibilities. The protection of old varieties also encompasses the extensive orchard as an important agroecosystem. Finally, different Czech regions are compared with respect to the quantity of reported old varieties.
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Hybridization as a source of threat to Urtica kioviensis
Pekařová, Michaela ; Urfus, Tomáš (advisor) ; Štěpánek, Jan (referee)
Hybridization can have a negative impact on native taxa, which means a risk to plant biodiversity. Urtica kioviensis (2x) is a rare species of that grows in mixed populations together with two cytotypes (2x and 4x) of the closely related taxon Urtica dioica (stinging nettle). The presence of hybrids has been described in the past. Here I studied hybridization at localities in the Czech Republic (PR Plačkův les a říčka Šatava, NPR Ranšpurk), Slovakia (PR Jurský Šúr), and Hungary (Kóny, Fehér-tó). These taxa and their hybrids were studied by flow cytometry and morphometric analysis. Both methods provided evidence of ongoing hybridization. The continuous pattern at the diploid level suggests homoploid hybridization and subsequent introgression affecting mainly U. kioviensis. The possibility of backcrossing at the diploid level was also confirmed by analyses of pollen fertility or staining. Triploid individuals were also detected, showing differences in relative genome sizes and different positions relative to the parental taxa in morphometric analyses. Based on these results, it's not possible to reliably determine their origin. Heteroploid hybridization is likely to occur, but its presence cannot be definitely confirmed or excluded. Hybrids are common in mixed populations of U. kioviensis and mean a...
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Speciation mechanisms and the role of reinforcement in mammals
Horký, Jakub ; Hulva, Pavel (advisor) ; Reifová, Radka (referee)
Speciation, the process of the formation of new species, comprises a diverse range of microevolutionary mechanisms acting in unison, which lead to the gradual formation of reproductive barriers between populations. The study of speciation has significantly progressed since its origins around the midpoint of the nineteenth century, owing to progressively improving analytical methods and the data said methods obtained, allowing us to observe previously invisible patterns and form new hypotheses on their basis. From traditional to modern research, this review's goal is to describe the contemporary understanding of speciation's concepts and mechanisms, focusing on those which are most relevant to mammals. Modern understanding of spatial contexts, prezygotic and postzygotic isolating mechanisms, and character displacement, including a type of reproductive character displacement dubbed reinforcement, are discussed. Significant emphasis is placed on the topics of maladaptive and adaptive hybridization, which, together with reinforcement and development of new genomic methods, has this review identified as the current frontier of speciation research. Keywords: reproductive isolating mechanisms, microevolution, character displacement, hybridization, reinforcement, speciation
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Mechanisms of reproductive isolation between two hybridizing passerine species, the common nightingale and the thrush nightingale
Poignet, Manon ; Reifová, Radka (advisor) ; Choleva, Lukáš (referee) ; Kratochvíl, Lukáš (referee)
iv - ABSTRACT (in English) - A key step in the origin of new species is the evolution of the reproductive isolation mechanisms separating the gene pools of newly emerging species. Despite a growing number of studies, we still know very little about the molecular, physiological and genetic mechanisms underlying reproductive isolation. Hybrid zones represent useful examples of ongoing species differentiation and can provide information about the nature of reproductive isolation separating the species and mechanisms facilitating or limiting the hybridization. Using two naturally hybridizing passerine species, the common nightingale (Luscinia megarhynchos) and the thrush nightingale (L. luscinia), we evaluated several mechanisms of reproductive isolation at the chromosomal, phenotypic, and genetic levels, with a focus on postmating prezygotic (PMPZ) and postzygotic isolation mechanisms. These nightingale species diverged ~1.8 Mya and currently hybridize in a secondary contact zone running across Central and Eastern Europe. First, we analysed the genetic composition of the secondary contact zone, demonstrating that parental forms are predominant in the hybrid zone, with few F1 hybrids (3.4%), early backcross hybrids (3.1%) and the absence of F2 hybrids. This suggests strong but incomplete reproductive isolation....
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Určování říčních populací lakušníku štítnatého (\kur{Ranunculus peltatus)}
DOLEJŠEK, Vojtěch
In some Czech rivers hybridogenous populations of pond water-crowfoot (Ranunculus peltatus) were detected. These populations are morphologicaly similar to the parental pond water-crowfoot and it is sometimes difficult to tell them apart. Such hybridogenous populations are not detectable via flow cytometry and are only detectable via sequencing. In this thesis I was trying to find out whether the hybridogenous populations could be clearly distinguished based on their morphology from the parental species pond water-crowfoot.
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The formation and maintenance of odd ploidy level cytotypes in the heteroploid system and their contribution to the heteroploid gene flow in invasive perennial species
Dýbová, Markéta ; Slovák, Marek (advisor) ; Šrámková, Gabriela (referee)
Polyploidy is one of the crucial evolutionary factors in the evolution of vascular plants. Polyploid cytotypes are mostly reproductively isolated from their diploid counterparts; however, there exists the possibility of gene exchange between different ploidies/species via heteroploid geneflow. The heteroploid gene exchange might be mediated through the odd and aneuploid cytotypes, which evolved via hybridisation but also de novo via the fusion of reduced and unreduced gametes. The primary focus of the thesis will be to review knowledge about the formation of odd cytotypes in heteroploid systems and evaluate their contribution to gene exchange between given ploidies. The particular focus will be on gene flow between higher ploidy levels in perennial invasive species complexes. Attention will also be paid to mechanisms enabling their maintenance in the population and the consequence of their long term persistence on between ploidy (species) hybridisation on their invasive potential. Key words: odd ploidy level, invasive plants, hybridization, life strategy
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