National Repository of Grey Literature 122 records found  1 - 10nextend  jump to record: Search took 0.00 seconds. 
The use of stable isotopes in the trophic ecology of birds
Rusnáková, Michaela ; Hořák, David (advisor) ; Procházka, Petr (referee)
Recently, the use of stable isotope analysis has been becoming increasingly common in ecological studies of animals. This interesting method is based on the premise that the isotope composition of consumer's tissues is related to the isotope composition of the sustenance consumed. This allows us to explore the contribution of individual food sources to the diet of species, populations or individuals, and at the same time to study their position in the trophic chains. The method enables us to research even omnivores, consuming variable food with different nutrients and isotope composition. Nevertheless, isotope values can differ depending on diet preferences, species physiology and the tissue type used for the analysis. This review summarizes current knowledge and results in the topic of stable isotope analysis, particularly in ornithological studies where the approach in question has been used to study the diet and trophic position. Powered by TCPDF (
Historical walk around the town Dačice (school project)
Procházka, Petr ; Mikeska, Tomáš (advisor) ; Parkan, František (referee)
The diploma thesis is about the preparation, implementation and feedback of a school project. The first part is focused on the territory, regional history and its application in teaching. The following topic introduces the history of town Da ice, the most important monuments and personages of this town. The main part of the diploma thesis describes several-day project lessons carried out directly in the town and its data processing in connection with next utilization of the beginning project for the school, next classes, whole town and last but not least territory. The main task of the diploma thesis has been fulfilled. I have created the methodical manual for teachers from primary and secondary schools how to make an excursion through the town (or city).
New environment grings new interaction:coexistence of closely related birds in urban mosaic
Sedláček, Ondřej ; Fuchs, Roman (advisor) ; Grim, Tomáš (referee) ; Procházka, Petr (referee)
I I New environment brings new interaďions: coexistence of closely related birds in urban mosaic ondřej Sedláček 1. SUMMARYOF THE THESIS The ongoingurbanizationrapidlychangesenvironmentsof mostplantand animal species worldwideand ecologistshave recentlyincreasedtheir attentionto biodiversiýconservationin man-affected|andscapes.HoWeVer,besidesspecia|ised species,whichdisappeardue to dramatichabitatconversion,manyorganismsare ableto changetheirbehaviour,physiologyand life historiesand haveadaptedto humanproximity.Citiesthereforeprovidea,,natura||aboratoý.,whichenablesusto studyecologicaland physiologicaladaptationsof synanthropicorganisms.Urban environmentsare a|soýpica|for theirhabitatheterogeneiý'Thanksto the mosaic natureof diversehabitats,specieswith differenthabitatselectioncometo close contaďin cities.ThisphenomenonWasa re|ative|yneg|eďedresearchareain urban ecology.A good model for this kind of investigationseemsto be a coupleof congenericbirdspecies,whicharerecentlycommonin urbanhabitatsacrossEurope - Black Redstart (Phoenicurusochruros)and Redstaft (P. phoenicurus).The two specieshavesimilarnestingandforagingecologybutoccupydifferenthabitatsunder naturalconditions.The BlackRedstartprimarilybreedsin open,rockyrerrainin mountaineousareas.This relativelyspecia|habitatýpe has spreadacrossEurope with...
A range-wide assessment of carry-over effects within the full annual cycle of the Great Reed Warbler with a focus on sex and population differences
Brlík, Vojtěch ; Procházka, Petr (advisor) ; Bauer, Silke (referee)
Movements of long-distance migratory birds are frequently well timed and routed in order to maximise individual fitness. However, individual timing of events or environmental conditions experienced have a potential to carry over into subsequent annual cycle stages and may have delayed fitness consequences. Therefore, knowledge of these seasonal interactions is crucial to identify key periods and regions that limit survival beyond the breeding period and thus to fully understand population dynamics of migratory species. Despite current evidence for seasonal interactions, there is no detailed knowledge of the complex of relationships within the full annual cycle, differences between sexes and populations or impact of environmental conditions during moult in one species. To unveil this system of seasonal interactions within the annual cycle, we directly tracked 103 great reed warblers (Acrocephalus arundinaceus) using light-level geolocators from five breeding sites across the breeding range to obtain information on timing and positions of annual cycle events. We then combined this information with various remotely sensed habitat condition metrics and stable isotopic composition of feathers from the non-breeding grounds to identify and quantify carry-over effects within the full annual cycle. Our...
Yellowhammer as a model species for studies on passerine dialects
Diblíková, Lucie ; Petrusková, Tereza (advisor) ; Procházka, Petr (referee)
Even though birdsongs and bird dialects have been subject to considerably intense scientific research, the domain of bird dialects is still worth attention of scientists. There is a large number of hypotheses about the emergence of bird dialects which separately or combined explain their origin. Dialects can be classified on the basis of the structure of a birdsong which they are related to or according to a geographical scale (micro and macrodialects). Research on bird dialects belongs to such type of studies that require great amount of data and thus large amount of time and finance is needed. Nonetheless, this obstacle can be avoided by involving general public into the research, however choosing a suitable model species is necessary. Yellowhammer (Emberiza citrinella), which was chosen in this study, is undoubtedly a convenient species for its common occurrence and distinguishable birdsong. Yellowhammer males sing during a large part of the season and their dialects can be easily recognized. Moreover, some scientists differentiate between macrodialects, that should be divided across western and eastern Europe, and could be used to make the research more attractive for general public. Till now yellowhammer dialects have been thoroughly explored in Denmark and in some parts of Germany, but in other...
The effect of nest quality for breeding success in Great Reed Warbler
Jelínek, Václav ; Procházka, Petr (advisor) ; Fuchs, Roman (referee)
Nests are key structures for the reproduction of majority of avian species and as such they should be subject to natural selection. Six hypotheses have been suggested to explain variance in avian nest size. In my master thesis I evaluate their validity in the Great Reed Warbler (Acrocephalus arundinaceus). First two hypotheses describe responses of nest size to predation and brood parasitism. These two selection pressures may lead to the reduction of nest size, but no evidence of their impact on nest dimensions was obtained. However, I found a significant but negative relationship between the probability of nest predation and soft nest height. No such relationship was found between the probability of brood parasitism and nest size characteristics. The incidence of brood parasitism was affected only by nest visibility from the nearest cuckoo perch site and distance from open water. More visible nests suffered heavier parasitism while those located deeper in reed beds were better protected from cuckoo parasitism. Another four hypotheses describe selection pressures which favour large nests or some of their functional parts. The thermoregulatory hypothesis, the sexual display hypothesis and the nest support hypothesis did not explain nest size variation. I found support for the clutch size hypothesis,...
Ecology and behaviour of two European pipit species
Petrusková, Tereza ; Fuchs, Roman (advisor) ; Procházka, Petr (referee) ; Matyjasiak, Piotr (referee)
Brief overview of the thesis The thesis consists of íntroductionand five chapters (four published articles and one unpublished manuscript), which deal with two topics unified by the studied species. The first part of the thesis focuses on mechanisms allowing coexistence of tree and meadow pipits, and on the territorial and aggressive behaviour of meadow pipit males. The second part of the thesis analyzes tree pipit song and singing behaviour. Short introduction to the first part presentsbríefbackground on mechanisms allowing coexistence of closely related territorial bird species, and first two chapters focus on local co- occunence of ecologically and morphologically very similar congeneric species: the tree pipit (Anthus trivialis) and the meadow pipít(A. praten'sis).First, we evaluate habitat preferences of these species in syntopy and on two allopatric localities, and show that both species select different habitats in coexistence. ln the next chapter,we test by playback experiments for the presence ofinterspecific territoriality, and conclude that habitat preferences,and not interspecific aggression, are important for territorial selection of the two studied species. In addition, we demonstratethat overexcitation by conspecific song is a factor strongiy influencing behaviour of testedanimals, and...
DC/DC converters for industrial power supplies
Chudý, Andrej ; Cipín, Radoslav (referee) ; Procházka, Petr (advisor)
This diploma thesis deals with design and comparison of selected DC/DC converters, where the better of them is practically realized. The first part of the diploma thesis is focused on the general analysis of DC/DC power converters. The following part is theoretical analysis focused on the first selected topology – step-up converter. The second analysed topology is forward converter with full bridge on the primary side. The theoretical analysis also includes a description of synchronous rectifier, the differences between hard and soft switching, and the types of secondary rectifiers. Another part specializes in the detailed calculation of main components of selected converters and their subsequent power dimensioning. Both designed topologies are compared according to the required aspects. The selected better topology is supplemented by the design of control circuits and an auxiliary power supply. Practical realization of converter and commissioning follows. The diploma thesis ends with verification measurements on the realized converter and their subsequent analysis.
Switched Mode Power Supplies
Španěl, Petr ; Lettl,, Jiří (referee) ; Kadaník,, Petr (referee) ; Procházka, Petr (advisor)
This thesis deals with switched mode power supplies based on resonant principle to achieve high efficiency. Several ways of switched mode power supplies optimalisation are described as part of the work to achieve better efficiency. Priparily, the new generation of switching elements based on SiC and resonant topology are used to achieve significant switching loss minimization. The selected resonant topology is simualted in detail and then built with focus on high efficiency. The main content of the work consists in the design and realization of the switched mode power supply with selected control algorithms and their comparison. The problems associated with usage of new SiC MOSFET generation in TO-247-4L package are being solved within the design and implementation of the power source. To solve the main problems, new 3rd SiC MOSFET gate driver was developer for working with switching frequencies in hundreds of kHz and resisting very high voltage stress on the controlled transistor. The next part of the gate driver is the overcurrent protection. The overcurrent limit can be set easily by changing one component. This protection reacts very quickly in hundreds of nanoseconds, so it is capable of saving the converter even in branch failure and going to hard short circuit. The functional sample of the series resonant converter was built and revated in the work. The converter based on 3. Generation of SiC MOSFET transistors from Cree in a modern case TO-247-4L was built. For this inverter, it was also necessary to develop both the control scheme and the resonance frequency tracking to achieve accurate switching and thus achieve the use of the resonant principle of the converter to the maximum extent possible. The result of this work is up to 3 kW converter with adjustable output voltage while maintaining high efficiency up to 96%.
Design of single-purpose assembly machine for assembly of gas distributor in gas grill
Procházka, Petr ; Pavlík, Jan (referee) ; Knoflíček, Radek (advisor)
Objective of this thesis is creating the construction of one-purpose assembly machine for combination of gas switchboard in gas grill assembly, which is top part of the gas cooking grill, consisting of stainless steel plate and burners. There are three types of burners, one small type, two medium types and one big type. Each consists of aluminium body, nozzle, ignition electrode and gas leakage protection fuse. Prior to construction itself,  variant solutions of the assembly operations arrangement are designated. From those, the most appropriate one is chosen based on multicriteria weighting method. Construction of assembly line is created using 3D modelling program with necessary design calculations. For selected assemblies and parts, a drawing documentation has been created. Risk analysis and security of the machine’s normal operation is an integral part of the thesis. Risk analysis is created for the machine’s normal operation. In conclusion, the costs of purchasing the assembly line are calculated and the return of the investment for purchasing the machine is assessed.

National Repository of Grey Literature : 122 records found   1 - 10nextend  jump to record:
See also: similar author names
35 Prochazka, Petr
3 Procházka, P.
48 Procházka, Pavel
16 Procházka, Pavel P.
2 Procházka, Přemysl
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