Constraints on models with warped extra dimensions

It has been known for some time that warped extra dimensions offer a potential explanation of the large hierarchy that exists between the electroweak scale and the Planck scale. The majority of this work has focused on a five dimensional slice of AdS space. This thesis attempts to address the question, what possible spaces offer phenomenologically viable resolutions to this gauge hierarchy problem. In order for a space to offer a potential resolution to the hierarchy problem two conditions must be met: Firstly one should be able to demonstrate that the space can be stabilised such that a small effective electroweak scale (or large effective Planck scale) can be obtained. Secondly one must demonstrate that the space allows for a Kaluza Klein (KK) scale that is small enough such that one does not reintroduce a hierarchy in the effective theory. Here we focus on the second condition and examine the constraints, on the KK scale, coming from corrections to electroweak observables and flavour physics which arise when gauge fields propagate in an additional dimension. We study a large class of possible spaces of different geometries and dimensionalities. In five dimensions it is found that such constraints are generically large. In more than five dimensions it is found that a significant proportion of such spaces suffer from either a high density of KK modes or alternatively strongly coupled KK fields. The latter would not offer viable resolutions to the hierarchy problem. Models in which the Higgs propagates in the bulk are also studied, in the context of models with a ‘soft wall’ and it is found these have significantly reduced constraints from flavour physics as well as a notion of a minimum fermion mass

The recent development of South African short film making

Student Number : 9905214K - MA research report - School of Dramatic Art - Faculty of ArtsSouth Africa’s film industry presently has huge, unrealised potential for growth. Currently one of the most vibrant sectors of the local industry is short filmmaking. This research’s main contention is that, for a number of reasons the short form is the most viable form for film-making development to take. The short film’s value as a training tool and essential building block for local film-making is scrutinized. To this end the research incorporates a content and form analysis of selected short films, with special reference made to the modes and economic conditions of production that affect the film industry. To conclude, I take the position that film-making, as a form of artistic and cultural dialogue, has tremendous possibilities for the development of a national identity, the creation and perpetuation of local myths and the fostering of social cohesion. For these reasons the short form is worthy of more concerted institutional support

Analysis of Nanomaterial Physiochemical Property Influences on Lymph Node Accumulation and Leukocyte Association

Lymph nodes house high concentrations of immune cells, and are critical tissues for regulating and priming the adaptive immune response. Thus, these tissues are an important therapeutic target for treatments that modulate immune activity, including but not limited to vaccination, induction of tolerance, and cancer immunotherapy. However, lymph nodes are also highly structured with physical and cellular barriers that can limit therapeutic access to important immune cell targets housed within them. Nanomaterial delivery approaches have been established to increase accumulation within the lymph node via locoregional methods of administration, but nanomaterials that highly efficiently accumulate within lymphatics are also restricted from entering the lymph node’s deeper regions in a size-dependent manner, limiting their delivery to lymphocytes. This motivates the need for better understanding and control over therapeutic access to cells within the lymph node, which is the overall objective of this thesis work. As such, work in the first part of this thesis quantifies the influences of lymphatic transport barriers on access of locoregionally administered nanomaterials to immune cell subsets within the tissue, and describes engineered biomaterial approaches to mitigate these barrier influences. Delivery to the lymph node from the blood supply via intravenous administration is next explored as a means to alter route of entrance to the lymph node and therefore distribution of cells accessed. Intravenous delivery is also standard practice for many cancer immunotherapies in the clinical setting, but delivery to the lymph node from this administration method is not well characterized, so nanomaterial properties favorable for intravenous delivery to immune cells within the lymph node are thoroughly studied. Finally, a cell-targeted antibody nanoparticle conjugate approach is employed to enhance delivery to T cells subsets specifically relevant in cancer immunotherapy. As a whole, this work provides new insights into therapeutic considerations for delivery to specific immune cell subsets within the lymph node and informs biomaterial design approaches to improve therapeutic outcomes.Ph.D

A transputer based implementation of a quick look processor for an airborne SAR system

Includes bibliographical references.The purpose of this thesis is to describe the development of a transputer based real-time Synthetic Aperture Radar (SAR) processor called the Quick Look Processor (QLP). The QLP is required to produce medium resolution, real-time images at a wavelength of 2.5m for the airborne South African SAR (SASAR) system which is under development at the University of Cape Town (UCT). The required azimuth resolution for the QLP is 30m and system is required to process 2048 range bins at a rate of 39 range lines per second. The algorithm used was developed at UCT, and works on the principle of dividing up the synthetic aperture into subapertures with appropriate phase corrections. This method is used in order to reduce computational loading (for real-time processing), but at the same time achieve medium resolution processing. One of the fundamental issues concerning this algorithm is its efficiency as the required azimuth resolution is increased. The system is designed around a host PC and a network of nine transputers. The host PC communicates with the other SASAR subsystems via an Ethernet network. It is responsible for displaying and saving the SAR image, receiving and displaying geocoding information and configuring the transputer network. The transputer network is responsible for processing the SAR data. The network is connected in a pipeline configuration with a master transputer controlling the other eight slave transputers. Each slave transputer concurrently processes a section of the swath width. This method allows for easy scalability

John Paul Archer in a Senior Piano Recital

This is the program for the senior piano recital of John Paul Archer. Baritone Wordy Buckner and Lillie McKnight assisted the performance. The recital took place on January 13, 1959, in Mitchell Hall Auditorium

Constraints on DD Dimensional Warped Spaces

In order to investigate the phenomenological implications of allowing gauge fields to propagate in warped spaces of more than five dimensions, we consider a toy model of a space warped by the presence of a anisotropic bulk cosmological constant. After solving the Einstein equation, three classes of solutions are found, those in which the additional ($D>5$) dimensions are growing, shrinking or remaining constant. It is found that gauge fields propagating in these spaces have a significantly different Kaluza Klein (KK) mass spectrum and couplings from that of the Randall and Sundrum model. This leads to a greatly reduced lower bound on the KK scale, arising from electroweak constraints, for spaces growing towards the IR brane.Comment: 6 pages, 5 figures PASCOS2010 International Symposium proceedin

The van Hove distribution function for Brownian hard spheres: dynamical test particle theory and computer simulations for bulk dynamics

We describe a test particle approach based on dynamical density functional theory (DDFT) for studying the correlated time evolution of the particles that constitute a fluid. Our theory provides a means of calculating the van Hove distribution function by treating its self and distinct parts as the two components of a binary fluid mixture, with the `self' component having only one particle, the `distinct' component consisting of all the other particles, and using DDFT to calculate the time evolution of the density profiles for the two components. We apply this approach to a bulk fluid of Brownian hard spheres and compare to results for the van Hove function and the intermediate scattering function from Brownian dynamics computer simulations. We find good agreement at low and intermediate densities using the very simple Ramakrishnan-Yussouff [Phys. Rev. B 19, 2775 (1979)] approximation for the excess free energy functional. Since the DDFT is based on the equilibrium Helmholtz free energy functional, we can probe a free energy landscape that underlies the dynamics. Within the mean-field approximation we find that as the particle density increases, this landscape develops a minimum, while an exact treatment of a model confined situation shows that for an ergodic fluid this landscape should be monotonic. We discuss possible implications for slow, glassy and arrested dynamics at high densities.Comment: Submitted to Journal of Chemical Physic