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Study of dark energy and modified gravity and their influence on the cosmological parameters of the universe
Vraštil, Michal ; Prouza, Michael (advisor) ; Heitmann, Katrin (referee) ; Heyrovský, David (referee)
Title: Study of dark energy and modified gravity and their influence on the cosmological parameters of the universe Author: Michal Vraštil Institute: Institute of Physics of the Czech Academy of Sciences Supervisor: RNDr. Michael Prouza, Ph.D., Institute of Physics of the Czech Academy of Sciences Abstract: Discovery of the accelerated expansion of the Universe poses a major theoretical puzzle. Although the assumption of a non-zero cosmological constant provides a minimal extension of general relativity that is consistent with observational data, many theories of modified gravity have been suggested as possible alternatives due to serious problems connected with the cosmological constant. Numerical predictions of structure formation for these models in the fully non-linear regime are very expensive and it is difficult, if not impossible, to explore such a huge space of models and parameters using high-resolution N-body simulations. Even in the mildly nonlinear regime, perturbative methods can become extremely complex. We explore whether simplified dynamical approximations, applicable for a certain set of cosmological probes, can be used to investigate models of modified gravity with acceptable accuracy in the latter instance. For the case of chameleon gravity, we found that it is screened away on scales...
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Search (approximate) methods for detecting human body alcohol
KOSTKOVÁ, Lucie
The topic of the thesis is Search (approximate) methods for detecting alcohol in the human body. The aim of the thesis was to evaluate and compare methods and technical means that are used to detect alcohol in the human body for forensic purposes, self-control, corporate control and other purposes. The theoretical part is focused on the description of the chemical properties of alcohol, its physiological effect, metabolism and occurrence in breath. The theoretical part includes also an overview of methods which are used to detect alcohol in the human body. The practical part of the thesis deals with the availability of detection tools and their basic sorting. On the basis of used methodology, which included a survey of domestic and foreign sources and targeted interview, all gained knowledge were thoroughly evaluated and systematically described. The thesis is structured in a way that it can be used as an overview of this issue for the general public, national institutions, companies and other organizations that try to prevent alcohol addiction and abuse of minors. The thesis could also be beneficial for education as a study material.
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