With the advent of supergravity and superstring theory, it is of great importance to study higher-dimensional solutions to the Einstein equations. In this dissertation, we study the higher dimensional Kerr-AdS metrics, and show how they admit further generalisations in which additional NUT-type parameters are introduced. The choice of coordinates in four dimensions that leads to the natural inclusion of a NUT parameter in the Kerr-AdS solution is rather well known. An important feature of this coordinate system is that the radial variable and the latitude variable are placed on a very symmetrical footing. The NUT generalisations of the highdimensional Kerr-AdS metrics obtained in this dissertation work in a very similar way. We first consider the Kerr-AdS metrics specialised to cohomogeneity 2 by appropriate restrictions on their rotation parameters. A latitude coordinate is introduced in such a way that it, and the radial variable, appeared in a very symmetrical way. The inclusion of a NUT charge is a natural result of this parametrisation. This procedure is then applied to the general D dimensional Kerr-AdS metrics with cohomogeneity [D/2]. The metrics depend on the radial coordinate r and [D/2] latitude variables µi that are subject to the constraint Ei µ2i = 1. We find a coordinate reparameterisation in which the µi variables are replaced by [D/2]−1 unconstrained coordinates yα, and put the coordinates r and yα on a parallel footing in the metrics, leading to an immediate introduction of ([D/2]−1) NUT parameters. This gives the most general Kerr-NUT-AdS metrics in D dimensions. We discuss some remarkable properties of the new Kerr-NUT-AdS metrics. We show that the Hamilton-Jacobi and Klein-Gordon equations are separable in Kerr- NUT-AdS metrics with cohomogeneity 2. We also demonstrate that the general cohomogeneity-n Kerr-NUT-AdS metrics can be written in multi-Kerr-Schild form. Lastly, We study the BPS limits of the Kerr-NUT-AdS metrics. After Euclideanisation, we obtain new families of Einstein-Sassaki metrics in odd dimensions and Ricci-flat metrics in even dimensions. We also discuss their applications in String theory.

The Reactor Accelerator Coupling Experiments (RACE) are a set of neutron source driven subcritical experiments under temperature feedback conditions. These experiments will involve coupling an accelerator driven neutron source to a TRIGA reactor system in a subcritical configuration. The accelerator source will consist of a 40 MeV electron linear accelerator (LINAC) and a heavy metal target. The electrons from the accelerator produce bremsstrahlung radiation in the target which in turn produces a source of neutrons via photonuclear reactions. The available core at the The University of Texas at Austin (UT) with standard TRIGA fuel will be used to carry out these studies. The primary objective of this thesis was to study the feasibility of RACE especially with respect to the heat generation rates capable of placing the reactor in a temperature feedback regime. First, the accelerator target (or neutron source) was optimized for size, shape, and type of material to be used. Analyses were then performed for several arrangements of this target in the UT TRIGA reactor. One of these arrangements was found to provide heat generation rates well into the temperature feedback regime of the fuel. Lastly, a multi-target system [named the Texas Transmutation System (TTS)] was designed to allow for more detailed accelerator driven systems (ADS) studies. It was shown that this system would allow for operation over a wide-range of subcriticalities and with a wide-range of heat loads. Thus, the feasibility for these experiments has been proven, and it is recommended that continued study and implementation of these experiments be performed.

With the advent of supergravity and superstring theory, it is of great importance to study higher-dimensional solutions to the Einstein equations. In this dissertation, we study the higher dimensional Kerr-AdS metrics, and show how they admit further generalisations in which additional NUT-type parameters are introduced. The choice of coordinates in four dimensions that leads to the natural inclusion of a NUT parameter in the Kerr-AdS solution is rather well known. An important feature of this coordinate system is that the radial variable and the latitude variable are placed on a very symmetrical footing. The NUT generalisations of the highdimensional Kerr-AdS metrics obtained in this dissertation work in a very similar way. We first consider the Kerr-AdS metrics specialised to cohomogeneity 2 by appropriate restrictions on their rotation parameters. A latitude coordinate is introduced in such a way that it, and the radial variable, appeared in a very symmetrical way. The inclusion of a NUT charge is a natural result of this parametrisation. This procedure is then applied to the general D dimensional Kerr-AdS metrics with cohomogeneity [D/2]. The metrics depend on the radial coordinate r and [D/2] latitude variables µi that are subject to the constraint Ei µi² = 1. We find a coordinate reparameterisation in which the µi variables are replaced by [D/2] - 1 unconstrained coordinates yα, and put the coordinates r and yα on a parallel footing in the metrics, leading to an immediate introduction of ([D/2] - 1) NUT parameters. This gives the most general Kerr-NUT-AdS metrics in D dimensions. We discuss some remarkable properties of the new Kerr-NUT-AdS metrics. We show that the Hamilton-Jacobi and Klein-Gordon equations are separable in Kerr- NUT-AdS metrics with cohomogeneity 2. We also demonstrate that the general cohomogeneity-n Kerr-NUT-AdS metrics can be written in multi-Kerr-Schild form. Lastly, We study the BPS limits of the Kerr-NUT-AdS metrics. After Euclideanisation, we obtain new families of Einstein-Sassaki metrics in odd dimensions and Ricci-flat metrics in even dimensions. We also discuss their applications in String theory.

No description available.

Submitted to the Faculty of Education in fulfillment of the requirements for the Master of Education in the Department of Educational Psychology and Special Education at the University of Zululand, South Africa, 2010. / One of the most devastating diseases in. modem history as measured in terms of loss of human life is the HIV/AIDS pandemic - Approximately 200 million people have already died. Sub- Sahara Africa is the most affected with South Africa severely affected with an estimated 6 million HIV positive South Africans and 2.5 million already dead from AIDS or related illnesses. This study, located at several primary and secondary schools in the deep rural areas of the Scottsburgh circuit, KwaZulu-Natal, South Africa, was undertaken to investigate the trend that, despite a higher level of knowledge and exposure to information about HIV/AID amongst educators and despite comprehensive campaigns to fight HIV/AIDS, an increasing number of educators are still dying from the disease. In this study it is assumed that knowledge alone is not enough and that attitude change is central to HIV/AIDS prevention since attitudes influence the way in which persons behave. The following research questions are asked: What is the nature of educators' attitudes towards HIV/AIDS, and, are the educators' attitudes towards HIV/AIDS influenced by variables such as age, gender, religion, experience and qualification? Thus the study aims to: determine the nature of educators' attitudes towards HIV/AIDS, and find out whether or not educators' attitudes towards HIV/AIDS are influenced by characteristics such as, gender, age, experience, religion, and qualification. To determine this, a quantitative study was conducted with 71 secondary and primary school educators in the rural area of KwaZulu Natal, Scottsburgh district. The survey, a cross sectional design, involved administering a fixed response questionnaire (Likert scale type) categorized into five scales, which described the nature of educators' attitudes towards HIV/AIDS. The study revealed that there was no significant difference amongst the sampled educators' attitudes towards HIV/ADS, and that these attitudes were mostly negative. This difference was also not influenced by educators' age, gender, qualification, experience or religion. The study found that educators were still discriminating, reluctant to test themselves and disclose their HIV/AIDS status, which may be related to the failure of HIV/AIDS prevention strategies. The campaign to stop the spread of HIV/AIDS in schools and m communities appears to be jeopardized by such attitudes of educators. The following was recommended: the cascading system of training educators did not work and therefore the Department of Education must ensure that every educator has an opportunity to receive training in HIV/AIDS information; that support systems (emotional, psychological, medical) for those educators infected and affected by HFV/AIDS be made available; financial allocations to HIV/AIDS prevention programmes should be increased but with better fmancial control; employment of full-time co-ordinators who are knowledgeable; provision of incentives to encourage educators to test for HIV/AIDS and programmes that provide social skills training needed for behavioural change, as well as those that aim at reducmg stigraatization, ostracism and discrimination of individuals infected. The researcher suggests that an immediate, urgent strategy to address educator attitudes towards the disease is required from the relevant government departments.

L'objet de cette thèse est l'étude de certaines propriétés de théories des champs à fort couplage via la dualité avec la théorie des cordes, dans la limite de supergravité. L'analyse expérimentale du plasma de quarks et de gluons produit au RHIC et au LHC tend en effet à indiquer que cet état de la matière se comporte comme un fluide quasiment parfait. Les méthodes perturbatives de la QCD sont impuissantes à décrire ses propriétés et la chromodynamique quantique sur réseau fait face à des problèmes tant techniques que conceptuels pour calculer les observables dynamiques d'un tel système. La correspondance AdS/CFT offre par conséquent un outil unique permettant d'étudier en première approximation cette phase de la QCD. L'un des aspects de cette thèse consiste en la description par une équation stochastique de Langevin d'un parton massif se propageant dans un plasma de Yang--Mills maximalement supersymétrique. Bien que cette théorie semble décrire de manière satisfaisante la phase déconfinée de la QCD, il est toutefois désirable de chercher un dual en théorie des cordes rendant compte des aspects de la QCD à basse énergie. L'autre axe directeur de cette thèse propose ainsi de rendre compte de solutions de moindre supersymétrie, sans invariance conforme, et avec confinement. On obtient le dual gravitationnel d'états metastables de telles théories. En particulier, on dérive une contribution au potentiel inflationnaire dans le cadre d'un modèle cosmologique générique de la théorie des cordes. / In this thesis, we apply the gauge/string duality in its supergravity limit to infer some properties of field theories at strong coupling. Experiments at RHIC and at the LHC indeed suggest that the quark--gluon plasma behaves as one of the most perfect fluid ever achieved in any controlled experimental setup. Perturbative approaches fail at accounting for its properties, whereas lattice QCD methods face technical as well as conceptual difficulties in computing dynamical aspects of this new state of matter. As a result, the AdS/CFT correspondence currently is the best tool at our disposal for analytically modelling this phase of QCD. One of the contributions of this thesis amounts to deriving a stochastic Langevin equation for a heavy quark moving across a maximally supersymmetric Yang--Mills plasma at strong coupling. Even though this theory seems to describe in a surprisingly satisfactory way the high--energy, deconfined phase of QCD, it is also of much interest to try and search for a string theory dual making closer contact with QCD at lower energies. As such, the other main focus of this thesis deals with supergravity solutions of lesser supersymmetry, without conformal invariance and exhibiting confinement. We build for the first time the gravity dual to metastable states of such theories. In particular, we find the contribution from anti--branes to the inflation potential in some general scenario of string cosmology.

SANTOS, Victor Pereira do Nascimento. Dinâmica de solitons em superfluidos holográficos. 2010. 62 f. Dissertação (Mestrado em Física) - Programa de Pós-Graduação em Física, Departamento de Física, Centro de Ciências, Universidade Federal do Ceará, Fortaleza, 2010. / Submitted by Edvander Pires (edvanderpires@gmail.com) on 2015-06-23T20:57:29Z No. of bitstreams: 1 2010_dis_vpnsantos.pdf: 969083 bytes, checksum: 66187abe576db7775b0fcfd1ae693c87 (MD5) / Approved for entry into archive by Edvander Pires(edvanderpires@gmail.com) on 2015-06-23T21:04:21Z (GMT) No. of bitstreams: 1 2010_dis_vpnsantos.pdf: 969083 bytes, checksum: 66187abe576db7775b0fcfd1ae693c87 (MD5) / Made available in DSpace on 2015-06-23T21:04:21Z (GMT). No. of bitstreams: 1 2010_dis_vpnsantos.pdf: 969083 bytes, checksum: 66187abe576db7775b0fcfd1ae693c87 (MD5) Previous issue date: 2010 / We numerically study the formation and dynamics of domain-wall-like topological defects in superfluids, using a (3+1)-dimensional abelian Maxwell-Higgs model, under the AdS/CFT correspondence. We obtain the bulk-boundary propagators, as well as the correlation functions on the boundary for a scalar field, both in massive and non-massive cases. If we impose that the fields depends only on a boundary coordinate and the bulk radial coordinate, we obtain in the dual theory the domain wall solutions found in literature. From these solutions we found that the superfluid is characterized by two length scales, one for the order parameter and other for the charge density. We also study the change of charge density in the region near the interface of the defect, and finally we investigate the modifications needed in theory to study the dynamics of these solutions. / Neste trabalho, estudamos numericamente a formação e a dinâmica de defeitos topológicos do tipo parede de domínio em superfluidos em um modelo (3+1)-dimensional do tipo Maxwell-Higgs abeliano, no contexto da correspondência AdS/CFT. Obtemos os propagadores bulk-fronteira, assim como as funções de correlação na fronteira, para um campo escalar nos casos massivo e não-massivo. Se impusermos que os campos dependem apenas da coordenada radial no bulk e de uma coordenada na fronteira, conseguimos obter na teoria dual as soluções do tipo parede de domínio encontradas na literatura. A partir dessas soluções, estudamos suas propriedades, verificando que o superfluido é caracterizado por duas escalas de comprimento, uma para o parâmetro de ordem e outra para a densidade de carga. Estudamos também a variação da densidade de carga na região próxima à interface do defeito, e por fim, investigamos as modificações necessárias na teoria para se estudar a dinâmica dessas soluções.

Diploma thesis is focused on creating a strategy and evaluating an effectivity of PPC campaigns of the e-shop called Factcool. Introduction of the diploma thesis is dedicated to the currently most used online advertising systems Google Ads and Facebook Ads. The PPC strategy is created based on the worked-out analysis of the current state.Thestrategy andcampaignseffectivity are evaluated with use of analytical platforms. The main goal of the diploma thesis is to find any drawbacks of the strategy and to come up with ideas for improvement not only for the specific e-shop, but also for the whole industry.

No description available.

We aim to have a comprehensive understanding of holographic correspondence and to demonstrate how the holographic correspondence (or renormalization) can be applied. Thus this thesis is divided into two parts. The first part is devoted to the former purpose (chapters 1 to 4 including appendix A,B, and C), and the second part is dedicated for the latter purpose (chapter 5 to 7). In Part I, the structure of the AdS/CFT correspondence is analyzed, and the properties of the AdS spacetime is studied in the context of the AdS/CFT correspondence; Here, we investigate the isometry group, the conformal structure, and generation of asymptotic solution near the conformal boundary. This solution yields significant convenience for the process of holographic renormalization. Moreover the properties of the Minkowski spacetime are compared to those of the AdS spacetime. To develop a greater understanding of the Lifshitz/quantum critical theory correspondence, the quantum phase transition is studied. Furthermore The holographic renormalization is briefly reviewed. In part II, the holographic renormalization associated with the Mann-Marolf (MM) counterterm is investigated for the asymptotically Minkowski spacetime in (n+3) dimensions. As a boundary condition, the cylindrical coordinate is considered. The solution of the MM-counterterm is obtained by solving the given algebraic equation, and from the counterterm solution, the boundary stress tensor is calculated. It is proven that the formula for conserved quantities via the boundary stress tensor holds. Next, we investigate deformations of Lifshitz holography with the Gauss-Bonnet term in (n+1) dimensional spacetime. To admit the non-trivial solution of the sub-leading orders, a value of the dynamical critical exponent z is restricted by z= n-1-2(n-2)α̃, where is the (redefined) Gauss-Bonnet coupling constant. Such solution of sub-leading orders correspond to the marginally relevant modes for the massive vector field and are generated by Λ~0, at the asymptotic region. A generic black hole solution, which is characterized by the horizon flux of the vector field and α̃, is considered in the bulk. We explore its thermodynamic properties, which depend on temperature, by varying n and α̃. As a result, the contribution of the marginally relevant mode is found in a function of Λ^z/T, and the relation between the free energy density and the energy density is numerically recovered when the marginally relevant mode is turned off (Λ=0), is obtained.