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The biology of aging in Nothobranchius fishes
Žák, Jakub
The aging human population and consequent unprecedented demographic changes in society have inevitably led to more scientists focusing their research on aging. Senescence, in the narrowest biological sense, is age related decline in an organism's function and survival. The majority of senescence research is performed in the laboratory environment. The basic biology of wild counterparts of model organisms is therefore relatively unstudied, despite its importance for proper interpretation of laboratory outcomes. This dissertation, via a series of 6 first-authored and 5 second-authored papers, combines field and laboratory research on senescence and senescence-related life history traits using a short-lived fish Nothobranchius furzeri. An age at the maturity of 14 days post hatching in wild N. furzeri is presented in this thesis as well as extremely fast growth of wild fish. Both life history traits have important consequences for senescence. The following section is focused on how the environment modulates senescence. In the first step, preferred body temperatures of Mozambican Nothobranchius fish were measured and descriptions of environmental and behavioural fluctuations within a 24 hours periodicity were completed. Based on this knowledge, ecologically relevant thermal fluctuations were simulated...
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Methods of study habitats and microhabitats preferences of freshwater fishes of Central Europe
Žák, Jakub ; Švátora, Miroslav (advisor) ; Drozd, Bořek (referee)
Small streams are a common habitat in Central Europe with unstable, rapidly-changing conditions. We can examine habitats on three different scales: microhabitat, mesohabitat and macrohabitat. Habitat preferences were among the fields of interest of Antonín Frič as he tried to describe the changing gradient of fish assemblages from source to the river's mouth on the macrohabitat scale. Habitat preferences are examined from a spatial point of view (substrate, depth, shelter), temporal point of view (season, day/night), biotic point of view (interspecies and intraspecies competition) and abiotic point of view (dissolved chemicals, velocity). For obtaining data of good quality, it is necessary to choose the right location and select the opti- mal strategy of examining fish assemblages (e.g. electrofishing, radiotelemetry, cameras). All variables which can affect habitat preferences in fish are measured. Multivariate statistical methods (e.g. PCA, RDA, CCA, CA) are used for evaluation of obtained datasets. Currently, we live in a fast developing period of this scientific area because of the need of evaluation of the human impact on freshwater biotope. The aim of this bachelor thesis is to introduce variables which influence habitat pref- erences of fish, to propose a modern review of methods commonly...
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The Sexual Segregation of fish from family Cyprinidae in the Řimov Reservoir
Žák, Jakub ; Prchalová, Marie (advisor) ; Čech, Martin (referee)
The sexual segregation, defined as different use of space by sexes is widespread phenomenon in the animal tree of life. As a result of segregation there is a different use of resources such as habitat, prey items or different threat by predation. Nevertheless it is not well studied in fish taxa except in marine environment. The common and widespread freshwater species such as a bream (Abramis brama), a bleak (Alburnus alburnus) and a roach (Rutilus rutilus) so far have not never been studied from the perspective of sexual segregation too. This thesis aims to examine the sexual segregation of these species and to test premises of sexual segregation such as sexual size dimorphism, age composition and differences in food. Afterwards the different space use of sexes in the Římov reservoir was tested. The gillnet sampling was used to collect data. Gillnets were installed to four localities in longitudinal gradient of reservoir in epilimnion where is the highest abundance of fish. Sampling was performed in August from 2009 to 2016. Results of this thesis show that females and males have different life histories and that bleak and roach are significantly bigger and older than males. The size dimorphism in bream was confirmed but not age difference between sexes. Sexes of bream had different diet. Males...
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The biology of aging in Nothobranchius fishes
Žák, Jakub ; Reichard, Martin (advisor) ; Valenzano, Dario Riccardo (referee) ; Sedláček, Ondřej (referee)
The aging human population and consequent unprecedented demographic changes in society have inevitably led to more scientists focusing their research on aging. Senescence, in the narrowest biological sense, is age related decline in an organism's function and survival. The majority of senescence research is performed in the laboratory environment. The basic biology of wild counterparts of model organisms is therefore relatively unstudied, despite its importance for proper interpretation of laboratory outcomes. This dissertation, via a series of 6 first-authored and 5 second-authored papers, combines field and laboratory research on senescence and senescence-related life history traits using a short-lived fish Nothobranchius furzeri. An age at the maturity of 14 days post hatching in wild N. furzeri is presented in this thesis as well as extremely fast growth of wild fish. Both life history traits have important consequences for senescence. The following section is focused on how the environment modulates senescence. In the first step, preferred body temperatures of Mozambican Nothobranchius fish were measured and descriptions of environmental and behavioural fluctuations within a 24 hours periodicity were completed. Based on this knowledge, ecologically relevant thermal fluctuations were simulated...
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Chess Program with Various Chess Variations with Various Set of Figures
Škandera, František ; Žák, Jakub (referee) ; Rozman, Jaroslav (advisor)
The goal of this thesis was to create a chess program able to play various chess variations with various set of figures. The first part of the work deals with the general matters of creating a chess program and implementing a chess artificial intelligence. In the second part we analyze individual chosen chess variations and suggest strategies for their implementation. Eventually we describe the implementation of the created application itself and its structure.
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Motivation and Remuneration of Factory Workers in a Selected Company
Žák, Jakub ; Schüller, David (referee) ; Konečný, Štěpán (advisor)
This diploma thesis describes and analyses the proces of motivation and remuneration of employees in selected company. The theoretical part is dedicated to explanation of basic terms of this topic.In the practical part i tis focused on the concrete company mentioned above. It is analysed its methods of motivation and remuneration of employees. The aim of this diploma thesis is to detect actual motivational instruments of this company and examine its quality and utilization. The final part presents some suggestions in order to improve the actual processes that would lead to higher satisfatcion of the employees.
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The Sexual Segregation of fish from family Cyprinidae in the Řimov Reservoir
Žák, Jakub ; Prchalová, Marie (advisor) ; Čech, Martin (referee)
The sexual segregation, defined as different use of space by sexes is widespread phenomenon in the animal tree of life. As a result of segregation there is a different use of resources such as habitat, prey items or different threat by predation. Nevertheless it is not well studied in fish taxa except in marine environment. The common and widespread freshwater species such as a bream (Abramis brama), a bleak (Alburnus alburnus) and a roach (Rutilus rutilus) so far have not never been studied from the perspective of sexual segregation too. This thesis aims to examine the sexual segregation of these species and to test premises of sexual segregation such as sexual size dimorphism, age composition and differences in food. Afterwards the different space use of sexes in the Římov reservoir was tested. The gillnet sampling was used to collect data. Gillnets were installed to four localities in longitudinal gradient of reservoir in epilimnion where is the highest abundance of fish. Sampling was performed in August from 2009 to 2016. Results of this thesis show that females and males have different life histories and that bleak and roach are significantly bigger and older than males. The size dimorphism in bream was confirmed but not age difference between sexes. Sexes of bream had different diet. Males...
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Bullying in labour law relations
Žák, Jakub ; Soušková, Milena (advisor) ; Spirit, Michal (referee)
Problematics of bullying in labour law relations is very actual topic. The main aim of this thesis is to demonstrate that presence of bullying in Czech labour law relations is not on retreat but quite opposite despite all efforts to eradicate it. First of all, in first two chapters there are defined basic concepts closely linked to problematics of bullying and then there are examinations of bullying related legislation on international, European and national levels. Result of third chapter is comprehensive summary of available means which victims of discrimination or bullying in work space can use to defend themselves. Practical part based on survey from years 2011, 2013 and 2015 deals with individual occurrences of bullying incidents in Czech labour law relations, average frequency and duration of those incidents and also ways victims of bullying in work space proceed in solving it.
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Methods of study habitats and microhabitats preferences of freshwater fishes of Central Europe
Žák, Jakub ; Švátora, Miroslav (advisor) ; Drozd, Bořek (referee)
Small streams are a common habitat in Central Europe with unstable, rapidly-changing conditions. We can examine habitats on three different scales: microhabitat, mesohabitat and macrohabitat. Habitat preferences were among the fields of interest of Antonín Frič as he tried to describe the changing gradient of fish assemblages from source to the river's mouth on the macrohabitat scale. Habitat preferences are examined from a spatial point of view (substrate, depth, shelter), temporal point of view (season, day/night), biotic point of view (interspecies and intraspecies competition) and abiotic point of view (dissolved chemicals, velocity). For obtaining data of good quality, it is necessary to choose the right location and select the opti- mal strategy of examining fish assemblages (e.g. electrofishing, radiotelemetry, cameras). All variables which can affect habitat preferences in fish are measured. Multivariate statistical methods (e.g. PCA, RDA, CCA, CA) are used for evaluation of obtained datasets. Currently, we live in a fast developing period of this scientific area because of the need of evaluation of the human impact on freshwater biotope. The aim of this bachelor thesis is to introduce variables which influence habitat pref- erences of fish, to propose a modern review of methods commonly...
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