Analyses of the light variation of the 6 Scuti star CC Andromedae and of the radial velocity variation of the ß Canis Majoris star 6 Scorpii, a single -line spectroscopic binary, indicate that the long period modulations exhibited are caused by tidal deformations induced in the hydrogen and /or helium ionization zones of each primary by a faint companion, resulting in surface zonal variations of the amplitude and phase of each primary's normal radial pulsations. The variations in the tide raising potential calculated at the center of the apparent disk of o Scorpii correlate very strongly with the observed variations in the phase zero -point of the fundamental pulsation. It is suggested that all the ß Canis Majoris and 6 Scuti stars exhibiting long period modulation, and probably also the RR Lyrae stars showing a Blazhko effect, do so because of tidal perturbations induced by faint companions.

A significant component of recent space exploration has been unmanned mission to comets and asteroids. The increase in interest for these bodies necessitates an increase in demand for higher fidelity trajectory simulations in order to assure mission success. Most available methods for simulating trajectories about asymmetric bodies assume they are of uniform density. This thesis examines a hybrid method that merges a mass concentration ("mascon") model and a spherical harmonic model using the "Brillouin sphere" as the interface. This joint model will be used for simulating trajectories about variable density bodies and, in particular, contact binary asteroids and comets. The scope of this thesis is confined to the analysis and characterization of the spherical harmonic modeling method in which three bodies of increasing asymmetrical severity are used as test cases: Earth, asteroid 101955 Bennu, and asteroid 25143 Itokawa. Since the zonal harmonics are well defined for Earth, it is used as the initial baseline for the method. Trajectories in the equatorial plane and inclined to this plane are simulated to analyze the dynamical behavior of the environment around each of the three bodies. There are multiple degrees of freedom in the spherical harmonic modeling method which are characterized as follows: (1) The radius of the Brillouin sphere is varied as a function of the altitude of the simulated orbit, (2) The truncation degree of the series is chosen based upon the error incurred in the acceleration field on the chosen Brillouin sphere, and (3) The gravitational potential and acceleration field are calculated using the determined radial location of the Brillouin sphere and the truncation degree. An ideal Brillouin sphere radius and truncation degree are able to be determined as a function of a given orbit where the error in the acceleration field is locally minimized. The dual-density model for a contact binary is found to more accurately describe the dynamical environment around Asteroid 25143 Itokawa compared to the single density model.

The study explores binary classification with Support Vector Machines as means to predict a satisfaction score based on customer surveys in the customer supportdomain. Standard feature selection methods and their impact on results are evaluated and a feature scoring metric Log Odds Ratio is implemented for addressingasymmetrical class distributions. Results show that the feature selection andscoring methods implemented improve performance significantly. Results alsoshow that it is possible to get decent predictive values on test data based onlimited amount of training observations. However mixed results are presentedin a real-world application example as a there is a significant error rate fordiscriminating the minority class. We also show the negative effects of usingcommon metrics such as accuracy and f-measure for optimizing models whendealing with high-skew data in a classification context.

This thesis focuses on the Binary Integer Modulo-Division Algorithm that is essential for the permutation process in Sunar-Koc ONB Type II Multiplier and also for other general purposes. This thesis explains the new algorithm developed based on the systolic array architecture which gives a systematic approach to the iterative process for the Modulo-Division. The scheduling and projection timing functions are proposed for the processor array allocation and the matlab code has been implemented to verify the efficiency of the algorithm. The thesis also explores the possibility of word based algorithm for design optimisation. / Graduate / 0544 / 0984 / m.shubha8@gmail.com

Virginia’s Department of Conservation and Recreation (DCR) assigns all of Virginia localities to Regional Offices to help conserve the natural resources in a certain region. In this paper, we present a mathematical model for optimizing such assignments by minimizing the travel time and cost of these assignments. With the growing increase in fuel costs and tighter budgets, our solution finds alternate assignments that will help cut costs by 14% annually. We have used integer programming techniques to find optimal assignments which satisfy requirements, respect limitations and minimize cost. Several plans are suggested, some keeping soil and water conservation districts together and some without.

This exploratory investigation examined the relationship between states' educational standardization and voter turnout, using cultural and critical theory lenses. The study documented the problem of low voter participation and current education standardization policies. The study used a complementarity mixed-methods design with sequential quantitative and qualitative components. The quantitative component developed a tool for measuring states' levels of educational standardization, the Standardized Education Index (SEI). Data for voter age population (VAP) and voter eligible population (VEP) in state presidential elections between 2000 and 2012 were used as measures of voter turnout. A weak correlation was found between the SEI and voter turnout for VEP in 2000 and VAP in 2000, 2004, and 2008, with between 6% and 14% of variability explained. While no evidence of a positive relationship between higher levels of SEI and higher voter turnout was found, no counter argument could be established either. The qualitative component utilized case studies of exemplars of states with high SEI/low voter turnout and high SEI/low voter turnout, which were Arkansas and New Hampshire, respectively. Investigated elements were educational Administrative Rules, voting regulations, and cultural/geographic and demographic attributes. Data were compiled and compared. A binary sort, a Dichotomous Sort of Accountability Concepts, framed the critical analysis of educational standards data. Arkansas was found to be a location of standardized education and restrictive voting regulations. New Hampshire was a location of more differentiated education supporting civic engagement with easier access to voting. This study's results are a baseline for further investigation of the relationship of educational standardization to voter participation. If standards based reform has a positive effect on voter participation, then future correlation analysis will produce a moderate to strong positive relationship. If the relationship remains negative, then it will provide evidence that standards reform does not engender an informed electorate.

Clostridium difficile infection (CDI) is a serious problem within the healthcare environment where the bacterium causes symptoms ranging from mild diarrhoea to life-threatening colitis. In addition to its principal virulent factors, Toxin A and Toxin B, some C. difficile strains produce a binary toxin (CDT) composed of two subunits namely CDTa and CDTb that are produced and secreted from the cell as two separate polypeptides. Once in the gut, these fragments have the potential to combine to form a potent cytotoxin whose role in the pathogenesis of CDI is presently unclear. This thesis is a step towards understanding structural and functional aspects of the binary toxin produced by C. difficile. The first half of this thesis (chapter I and II) provides a brief introduction to the method of structure determination of proteins molecules, i. e. X-ray crystallography and a detailed overview of C. difficile and the three known toxins from C. difficile namely – Toxin A, Toxin B and the binary toxin. Chapter II further focuses on C. difficile binary toxin and other related toxins. These toxins, known as the ADP-ribosylating toxins (ADPRTs) form a big family of potent toxins which includes Cholera, Pertussis and Diphtheria toxins and are capable of transferring the ADP-ribose part of NAD/NADPH to a varity of substrates in the target cell which ultimately results in cell death. The second half of the thesis comprises of experimental procedures that were carried out during the course of this study and their results. Cloning and expression methods for recombinant CDTa and CDTb in bacterial system followed by their purification are described with the abnormal behaviour exhibited by CDTb (chapter III). We show for the first time that purified CDTa and CDTb can combine to form an active CDT which is cytotoxic to Vero cells (Chapter IV). The purification processes described yielded milligram quantities of binary toxin fragments of high purity that led to the successful crystallisation of the proteins (chapter IV) for further functional and structural studies. High resolution crystal structures of CDTa in its native form (at pH 4.0, 8.5 and 9.0) and in complex with the ADP ribose donors -NAD and NADPH (at pH 9.0) have been determined (chapter V). The crystal structures of the native protein show ‘pronounced conformational flexibility’ confined to the active site region of the protein and ‘enhanced’ disorder at low pH while the complex structures highlight significant differences in ‘ligand specificity’ compared with the enzymatic subunit of a close homologue, Clostridium perfringens Iota toxin (Ia). These structural data provide the first detailed information on protein-donor substrate complex stabilisation in CDTa which may have implications in understanding CDT recognition. Crystallisation of CDTb yielded preliminary crystals. The optimisation of these crystallisation conditions is underway. The thesis concludes with some thoughts and discussion on future directions of this research.

As the endpoints of stars less massive than roughly eight solar masses, the population of Galactic white dwarfs (WD) contain information about complex stellar evolution processes. Associated pairs of WDs add an extra degree of leverage; both WDs must have formed and evolved together. The work presented in this dissertation uses various populations of double WDs (DWD) to constrain evolution of both single and binary stars. One example is the set of low-mass WDs with unseen WD companions, which are formed through a dynamically-unstable mass loss process called the common envelope. To work toward a quantitative understanding of the common envelope, we develop and apply a Bayesian statistical technique to identify the masses of the unseen WD companions. We provide results which can be compared to evolutionary models and hence a deeper understanding of how binary stars evolve through a common envelope. The statistical technique we develop can be applied to any population of single-line spectroscopic binaries. Binaries widely separated enough that they avoid any significant interaction independently evolve into separate WDs that can be identified in photometric and astrometric surveys. We discuss techniques for finding these objects, known as wide DWDs. We present a catalog of 142 candidate wide DWDs, combining both previously detected systems and systems we identify in our searches in the Sloan Digital Sky Survey. Having been born at the same time, the masses and cooling ages of the WDs in wide DWDs, obtained with our spectroscopic follow-up campaign can be used to constrain the initial-final mass relation, which relates a main sequence star to the mass of the WD into which it will evolve. We develop a novel Bayesian technique to interpret our data and present our resulting constraints on this relation which are particularly strong for initial masses between two and four solar masses. During this process, we identified one wide DWD, HS 2220+2146, that was peculiar since the more massive WD in this system evolved second. We construct an evolutionary formation scenario in which the system began as a hierarchical triple in which the inner binary merged (possibly due to Kozai-Lidov oscillations) forming a post-blue straggler binary. The system then evolved into the DWD we observe today. We further discuss the potential for identifying more wide DWDs, including peculiar systems like HS 2220+2146, in future surveys such as Gaia.

We consider the computational complexity of evaluating the Tutte polynomial of three particular classes of greedoid, namely rooted graphs, rooted digraphs and binary greedoids. Furthermore we construct polynomial-time algorithms to evaluate the Tutte polynomial of these classes of greedoid when they're of bounded tree-width. We also construct a Möbius function formulation for the characteristic polynomial of a rooted graph and determine the computational complexity of computing the coefficients of the Tutte polynomial of a rooted graph.

A kinetic study of the reactions of Group VI-B hexacarbonyls with primary amine and halide ligands was undertaken in order to determine the possible mechanisms of these reactions. As well as the expected dissociative pathway, the reactions with the primary amines were seen to proceed by a concurrent pathway which was dependent upon the ligand concentration. Since nitrogen donor ligands are expected to be poor donor ligands, the mechanism proposed was a "dissociative interchange" mechanism which should not be too dependent upon the nucleophilicity of the ligand. Comparison of the rate constants for the amines studied as well as those of the previously investigated Lewis base ligands indicated all such reactions may proceed through the same mechanism. The similarity in rate constants for the ligand-independent and ligand-dependent pathways supports this mechanism. The rate of formation of the final product was seen to be dependent upon the square of the mercuric halide concentration. Therefore, the conversion of Fe(CO)4(HgX)2 to the final product was proposed to proceed by the successive abstraction by each HgX group of two molecules of mercuric halide. These oxidative elimination reactions are related to a chemical model for the intermediate step in the reduction of dinitrogen to ammonia and their similarities and differences are discussed.