Flow variability plays an important role in structuring lotic communities, yet comparatively little is known about processes governing assemblage dynamics in stream ecosystems with stable environmental conditions, such as spring-fed rivers. Volcanic spring-fed rivers (hereafter spring-fed rivers) occur in geologically active landscapes of the western USA and around the globe. We sampled invertebrate assemblages and quantified primary productivity and habitat characteristics of spring-fed and runoff rivers in northern California over 4 seasons. We predicted that abiotic factors would be more stable and nutrient availability greater and that invertebrate density would be greater and diversity lower in spring-fed than in runoff rivers. Runoff rivers exhibited high variability in discharge and temperature, whereas spring-fed rivers were relatively stable with high naturally occurring nutrient levels. On average, NO3- and PO43- concentrations were 40x greater in spring-fed than in runoff rivers. Spring-fed rivers supported nearly 7 to 16x greater densities of invertebrates than runoff systems, depending on season. However, invertebrate species richness was greater in runoff rivers in all seasons. Spring-fed river invertebrate assemblages were strongly correlated with elevated nutrient concentrations and basal C sources, whereas runoff assemblages were associated with discharge variability and median substrate size. We suggest that strong differences in abiotic variability between spring-fed and runoff rivers play an important role in determining invertebrate assemblage structure. Because spring-fed rivers exhibit more stable temperatures throughout the year and lower temperatures during the summer than runoff rivers, they may provide essential refugia for coldwater taxa in a warming climate.

LL.M. (International Law) / Since 1945 there has been a noticeable broadening of what constitutes a threat to international peace and security. Traditionally, the definition of “threat to international peace” was limited to a conflict among nations, which were conflicts common in the world. The core threat to international peace used to be organized inter-state conflicts only. Today however, the nature of threats to international peace has changed drastically to include internal conflicts – as there are examples of cases where these have spread across the borders or have led to massive refugee situations. In this dissertation, I review the mandate of the United Nation’s inter alia the changing definition of ‘threat to international peace’.

This thesis explores Shi’a-Sunni relations in Gulf politics during a period of regional upheaval, starting with the 2003 invasion of Iraq through the Arab revolts of early 2011. It seeks to understand the conditions under which sectarian distinctions become a prominent feature of the Gulf political landscape, focusing on the three Gulf countries that have been affected most by sectarian tensions: Bahrain, Saudi Arabia, and Kuwait. The study analyzes the contagion effect of the civil war in Iraq, the 2006 war in Lebanon, and the Arab Spring on local sectarian dynamics in the three states. Specifically, it explores the role of domestic institutions—parliaments and other quasi-democratic structures, the media, and clerical establishments—in tempering or exacerbating sectarianism. It finds that the maturity and strength of participatory institutions in each state played a determinant role in the level of sectarianism resulting from dramatic shifts in the regional environment since the 2003 invasion of Iraq. I conclude, therefore, that the real roots of the so-called “rise of the Shi’a” phenomena lie in the domestic political context of each state, rather than in the regional policies of Iran or the contagion effect of events in Iraq or Lebanon. Although the Gulf Shi’a took a degree of inspiration from the actions of their co-religionists in Iraq, Iran and Lebanon, they ultimately strove for greater rights in a non-sectarian, nationalist framework. The rise of sectarianism in the Gulf has been largely the product of excessive alarm by entrenched Sunni elites or the result of calculated attempts by regimes to discredit Shi’a political actors by portraying them as proxies for Iran, Iraq, or the Lebanese Hizballah. What is qualitatively different about the post-2003 period is not the level of mobilization by the Shi’a, but rather the intensity of threat perception by Gulf regimes and Sunni Islamists.

The dynamic properties of several rectangular and V-shaped microcantilevers were investigated. Particular attention was paid to the higher flexural eigenmodes of oscillation. The potential of the higher flexural modes was demonstrated through the use of cantilevers as standalone sensors for adsorbed mass. The mass adsorbed on the surface of a cantilever was in the form of a homogeneous water layer measured as a function of relative humidity. The minimum detectable water layer thicknesses were 13.7 Å, 3.2 Å, 1.1 Å, and 0.7 Å for the first four modes of a rectangular cantilever, clearly demonstrating enhanced accuracy for the higher eigenmodes of oscillation. These thicknesses correspond to minimum detectable masses of 33.5 pg, 7.8 pg, 2.7 pg and 1.7 pg for the first four modes. For quantitative applications the spring constants of each cantilever must be determined. Many methods exist but only a small number can calibrate the higher flexural eigenmodes. A method was developed to simultaneously calibrate all flexural modes of microcantilever sensors. The method was demonstrated for the first four eigenmodes of several rectangular and V-shaped cantilevers with nominal fundamental spring constants in the range of 0.03 to 1.75 N/m. The spring constants were determined with accuracies of 5-10 %. Spring constants of the fundamental mode were generally in agreement with those determined using the Sader method. The method is compatible with existing AFM systems. It relies on a flow of gas from a microchannel and as such poses no risk of damage to the cantilever beam, its tip, or any coating. A related method was developed for the torsional modes of oscillation. Preliminary results are shown for the fundamental mode of a rectangular cantilever. The method can be easily extended to the higher torsional modes, V-shaped cantilevers, and potentially, the flapping modes of the legs of V-shaped microcantilevers.

In this thesis, a model based on the continuous-time Markov process is built and implemented and later applied on an one chosen collective game. An extensive analysis of available data is carried out to build a regression model to estimate parameters of the game model. An usableness of the game model is shown by a simulation process. Pros and cons are evaluated in a comparison analysis against the application of the discrete-time Markov chains, how it was described in my bachelor thesis [Roman Zákutný (2007)]. In conclusion are discussed possible extensions for other collective games.

This thesis starts with the introduction of the general historic moments of postwar Czechoslovakia. Attention is paid to the February 1948, Prague Spring and the events of August 1968. These dates established two waves of emigration from Czechoslovakia. In this context, there are presented personalities of Jiří Pelikán and Pavel Tigrid as leading personalities of exile. The analytical part focuses on the comparison of Tigrid's Svědectví and Listy published by Jiří Pelikán. Analysis is based on important events in postwar history. The thesis is mainly focused on the different perceptions of the Prague Spring and Charta 77.

This diploma thesis is focusing on analyzing a possible influence of new media on politics with an emphasis on the three most popular social networks as Facebook, Twitter and YouTube. The main methods used in this thesis are analysis and subsequent comparison of acquired facts. This thesis has two subtopics. Firstly, it is the action and the access of Czech and world politicians on the social networks. Secondly, it analyses the events of the Arab Spring in the years 2010 and 2011. This thesis is based both on professional literature of Czech and foreign authors, that follows up mass media, mass communication and new media, as well as on studies analyzing social networks as Facebook, Twitter and YouTube, on Czech and foreign newspapers, TV broadcasts and post electoral studies.

The acceptance and the use of cold-formed steel sections has significantly increased in recent years due to advantages such as consistency and accuracy of profile, ease of fabrication, high strength and stiffness to the lightness in the weight. For thin-walled columns, made by folding a plane plate into a section, it is possible that when they are subjected to compression loads they may buckle either locally, if the member is very short, or globally if the member is very long. In addition to local and global buckling, a thin-walled member of an open cross section may also show buckling involving a “distortion” of the cross section. Compared to local and global buckling, distortional buckling is not very familiar and has been discovered only in thin-walled members of open cross sections such as cold-formed steel section columns. The objective of this study is to investigate the behavior of polygonal semi-closed cross-section with pure compression. The study comprise to only elastic buckling and the methodology is consisted by using CUFSM analysis. In order to execute CUFSM of polygonal profiles, the scripts have created which match the Matlab script files (m-files) downloaded from CUFSM 4 open source. The distortional buckling mode is governing as a buckling failure, which occur and dominate in the cases where spring values are 100 kN or higher. However, the contrary result reveals by a decreasing of the spring values. The behavior of the cross-section is dependent on how the interaction of different buckling modes prevails at the corresponding critical half-wavelength. Considering the predomination of distortional buckling mode indicates that the most of polygonal cross-section do not behave as rigid, i.e. as whole cross-section. A reducing of distortional mode and increasing of local mode as well as global mode gives indication that the behavior of the cross-section has changed and turned significantly into more rigid and thus is expected to behave more as whole cross-section.  The more spring values decrease, the higher global mode arises and dominates for the lower slenderness range. The critical half-wavelength for each profile illustrates the needed density between bolts on the longitudinal part of the member. In the interest of eliminating distortional buckling failure, due the fact that distortional buckling is unpredictable, the bolt-density should be lower than the corresponding half-wavelength for the profile where the distortional mode is predominating.

Abstract For most of the Cold War, the United States attempted to maintain friendly relations with the Communist nations comprising the Eastern Bloc, but with no other Soviet satellite was the relationship as close as it was with Romania. No other member nation of the Warsaw Pact took to the United States’ overtures so eagerly. Diplomatic relations between the United States and the Romanian Communist government were established relatively early, almost immediately following the end of the Second World War. However, it was not until 1968, when Romanian dictator Nicolae Ceauşescu denounced the Warsaw Pact invasion of Czechoslovakia, that the Romanians finally gained the Americans’ trust. Ceauşescu’s 1968 speech attacking the Warsaw Pact invasion of Czechoslovakia, and the diplomatic maneuverings surrounding it, was the pivotal moment in the relationship between the two nations, fostering an amicable relationship that would last well into the 1980s.

Cette thèse contribue à l'étude des aimants à effet ressort, connu sous le nom de "Exchange Spring Magnets" (ESM). Nous avons divisé nos travaux en deux parties : une première dite expérimentale et une seconde dite théorique. Dans la première partie, nous avons étudié la synthèse de ESM. Le processus de fabrication débute par le mélange des nano-poudres magnétiques dures et douces. Cette étape a été réalisé par broyage mécanique ainsi que par ultrasons. Les mélanges sont ensuite frittés via la technique de frittage par plasma d'arc (Spark Plasma Sintering (SPS)) afin d'obtenir des aimants massifs. La structure ainsi que les propriétés magnétiques de ces aimants sont étudiées. Les structures obtenues présentent des phases intermédiaires ainsi qu'une réduction de la phase magnétique dure. Nous avons trouvé que ces aimants ont des cycles magnétiques à deux phases indiquant un couplage faible entre les phases précurseurs. De plus, les aimants obtenus à partir du mélange à ultrasons possèdent des meilleurs propriétés magnétiques que ceux obtenus par broyages mécanique ainsi qu'une plus grande capacité à obtenir un meilleur couplage. Dans la seconde partie, nous avons étudié l'utilité des ESM pour l'enregistrement magnétique perpendiculaire. Il a été montré qu'en y appliquant un faible champ micro-onde , l'ESM présente un basculement facilité ainsi qu'une meilleur stabilité thermique, ce qui est désirable pour l'enregistrement magnétique. Nous avons étudié les dynamiques non-linéaires de basculement magnétique dans un ESM perpendiculaire en utilisant l'équation de Landau-Lifshitz. A partir d'un nouveau code FORTRAN basé sur la méthode des différences finies, nous avons étudié les solutions numériques de cette équation. Le système bi-couche présente des solutions stables nommés modes-P globaux et une diminution du champ nécessaire au basculement pour une grande gamme de fréquence. Le profil de la magnétisation dans le système étendu à été étudié numériquement. L'étude analytique des dynamiques est commentée en faisant l'approximation que deux modes-P sont couplés par un champ d'interaction. L'"ansatz" utilisé pour décrire le champ d'interaction est validé par comparaison avec les résultats numériques. Cette approche s'est révélée être équivalente à l'étude de deux macro-spins couplés. / This thesis is divided into two parts, experimental part presenting the synthesis of exchange spring magnets and theoretical part showing the magnetization dynamics of exchange spring magnets. For the synthesis, ferrite and metal alloy based magnets using mechanical milling and ultrasonic mixing are studied. This part discusses the difficulty in controlling the microstructure during synthesis. Several samples with varying volume fractions of the soft phase are synthesized. It is found that mechanical milling initiates a reaction and this leads to disintegration of the ferrite phase into its intermediate phases. Samples prepared using ultrasonic mixing however show presence of the ferrite phase up to very large volume fraction of the soft alloy phase which provides better perspective for the synthesis. Dynamics of the exchange spring system is studied theoretically using micromagnetic theory. Microwave assisted magnetization reversal are studied in the bulk bilayer exchange coupled system. We investigate the nonlinear magnetization reversal dynamics in a perpendicular exchange spring media using the Landau-Lifshitz equation. In the limit of the infinite thickness of the system, the propagation field leads the reversal of the system. The reduction of the switching field and the magnetization profile in the extended system are studied numerically. The possibility to study the dynamics analytically is discussed and an approximation where two P-modes are coupled by an interaction field is presented. The ansatz used for the interaction field is validated by comparison with the numerical results. This approach is shown to be equivalent to two exchange coupled macrospins.