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Universal solutions in gravity, electrodynamics and nonabelian gauge theories
Kuchynka, Martin ; Pravdová, Alena (advisor) ; Hervik, Sigbjorn (referee) ; Švarc, Robert (referee)
The presented thesis spans over a number of related topics with a com- mon theme - the so-called universality. Classical fields exhibiting this property serve as exact solutions to virtually any higher-order theory irrespective of the particular form of the field equations, being thus of particular interest in ef- fective field theories. The aim of this work is to study various aspects of such solutions in the context of gravity, electrodynamics, as well as more general nonabelian gauge theories. The results are concentrated in four chapters, the first of which is devoted to what we call the almost universal spacetimes. Due to their nice curvature properties, these spacetimes provide an efficient method for simplifying and solving the field equations of higher-order gravity theories. We illustrate this feature of almost universal metrics by finding new vacuum solutions to quadratic gravity and six-dimensional conformal gravity. In the second chapter, we shift our attention towards electrodynamics. Following up on recent results on universal electromagnetic fields, we deal with Einstein- Maxwell fields which simultaneously solve also any higher-order modification of the Einstein-Maxwell theory. In particular, we identify solutions with this remarkable property as plane-fronted gravitational and...
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Visualization of root apoplastic pH in plants
Wernerová, Daša ; Fendrych, Matyáš (advisor) ; Paris, Nadine (referee)
Plant oriented movements, or tropisms allow the plant to actively respond to environmental stimuli to get more light, better access to nutrients and to grow roots deeper into the soil. Gravitropism drives the growth of roots along the gravity vector. Perception of gravity is triggered by the sedimentation of statoliths in columella root cap, but the exact signalling pathway behind this process is not known. Perception of gravity results in an unequal redistribution of the phytohormone auxin in the outer cell layers which leads to different rate of growth on the root's upper and lower side and bending of the root. The changes in auxin redistribution are accompanied by changes in apoplastic pH. Knowing an exact pattern of these pH changes could shed light on the mechanisms laying behind the gravitropic response pathway. While microelectrodes can be used to measure pH precisely, they are not suitable for the long-term imaging of growing roots. In the past few years, several pH sensitive dyes and genetically encoded sensors emerged. These can be used for long-term live in vivo imaging of pH changes in growing roots. In this thesis, I analysed the performance of several published pH sensitive genetically encoded sensors and available dyes in the roots of Arabidopsis thaliana. I observed that dyes varied...
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Evaluation of rock masses on planetary surfaces
Boldbaatar, Dayansetsen ; Kletetschka, Günther (advisor) ; Mikuláš, Radek (referee)
The understanding of rock mass has great benefits in engineering and geology. This understanding can benefit in the field of colonizing and terraforming other planetary bodies. To achieve this task, we can begin by using current methods to see if we can evaluate rock mass and if these can be inferred to understanding rock mass on other planetary bodies. Therefore, this bachelor's thesis is sought to examine if the use of compositional and volume information in order to figure out the mass of a rock pebbles on planetary bodies. For this purpose, 3D computing Photogrammetry method and X-ray Fluorescence methods were used to derive the necessity physical quantities for the mass computing. Five rocks where used in this study. Data was collected and analyzed using the two methods, software program and instruments. The results showed use of the two methods were accurate and efficient. Compare to the classic methods, these two methods proved as efficient and accurate.
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Evaluation of rock masses (pebbles) on planets
Boldbaatar, Dayansetsen ; Kletetschka, Günther (advisor) ; Mikuláš, Radek (referee)
This research is science engineering topic based on compositional and volume information to figure out the mass of a rock pebbles on a planetary surface. For this purpose, 3D computing Photogrammetry method and X-ray Fluorescence methods were used to derive the necessity physical quantities for the mass computing First section discusses the moon, its characteristics and possibility of terraforming. The second half of this bachelor's thesis is focused on modeling and its techniques. The final part summarizes the results derived from modeling chapter.
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Analysis of Free Trade Agreements Between European Union and Latin American Countries
Macháček, Martin ; Semerák, Vilém (advisor) ; Palanský, Miroslav (referee)
Bibliographic note Macháček Martin. Analysis of Free Trade Agreements Between European Union and Latin American Countries. 35. Bachelor thesis. Charles University, Fac- ulty of Social Sciences, Institute of Economic Studies. Supervisor Ing. Vilém Semerák M.A., Ph.D. Abstract The aim of this paper is to examine if free trade agreements between Latin American countries and the European Union have positive effect on trade flow between the two. For this purpose, we use gravity models, specifically Ordi- nary Least Squares and Poisson Pseudo Maximum Likelihood estimations with time and country-pair fixed effects. We apply these methods on five studied countries: Argentina, Brazil, Chile, Colombia and Mexico. The results show that the agreements with the European Union for the first four mentioned countries have positive impact, although lower than the impact of other agreements signed by these countries. For Mexico, the effect is negative, which corresponds with the reports of the EU, which is negotiating modernization of their agreement. JEL Classification C51, F12, F14, F21, H25 Keywords International trade, gravity model, European Union, Latin America Author's e-mail mhmachacek@gmail.com Supervisor's e-mail vilem.semerak@fsv.cuni.cz
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VR Innovative Game Demo in UE4
Doležal, Josef ; Chlubna, Tomáš (referee) ; Milet, Tomáš (advisor)
The task of this bachelor thesis is to create a demo application for virtual reality using Unreal engine 4. Main mechanics are gravity sfere, simulating custom gravity and mirror portals with an ability to teleport a player to a previous or any other destination. All prefabs are free to be used in another Unreal engine 4 projects.
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Border Effect and Openness of Chinese Economy
Zacharuk, Pavel ; Semerák, Vilém (advisor) ; Cazachevici, Alina (referee)
The ratio of China's aggregate exports and aggregate imports to GDP has been decreasing in recent years, which seems to contradict many claims about China striving for increased openness about their economy. Our hypothesis is that the decrease might be connected with the development of GVCs and asymmetric improvement of transportation in China, driven by evolution of infrastructure. We have used simplified regionalization methods and regional input-output analysis in order to identify trend of interregional trade. The results show increase in interregional trade which does not refute this hypothesis.
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Algebraically special spacetimes - geometrical properties
Kuchynka, Martin ; Pravdová, Alena (advisor) ; Švarc, Robert (referee)
In the thesis, we set out to study a certain class of algebraically special spacetimes in arbitrary dimension. These are the so-called spacetimes of Weyl and traceless Ricci type N. Our work can be divided into two parts. In the first part, we study general geometrical properties of spacetimes under consideration. In particular, we are interested in various properties of aligned null directions - certain significant null directions associated with algebraic structure of the Weyl and the Ricci tensor. Since the obtained results are of geometric nature, they are theory-independent and thus hold in Einstein's gravity as well as in its various generalizations. In the second part of our work, we apply these general results in the Einstein-Maxwell p-form theory, within which spacetimes of traceless Ricci type N emerge naturally as a part of a solution of the Einstein-Maxwell equations with a null Maxwell field. Powered by TCPDF (www.tcpdf.org)
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