Thesis advisor: Kevin Bedell / Using the AdS/CFT correspondence, it has been shown that the ratio of shear viscosity to entropy density is bounded from below in strongly coupled field theories with a gravity dual. More recently, this bound has been shown to be grossly violated in novel non-Fermi liquids and the unitary Fermi gas in the presence of superfluid fluctuations above T_c. Nevertheless, a holographic approach to such systems which break the lower bound have been strongly reliant on AdS spacetimes with massive gravitons. In this work, we propose a violation of the viscosity over entropy bound in 3+1 dimensional AdS spacetimes that support stable black hole solutions with non-zero scalar field. Such a black hole is shown to be characterized by a novel phase transition at large negative mass, where the underlying thermodynamics agrees with the Larkin-Ovchinnikov-Fulde-Ferrell (LOFF)-like phase seen in the unitary Fermi gas near Tc and the bound is similarly broken. Such a work paves the way for a holographic description of strongly-entangled quantum fluids at high Reynolds number. / Thesis (BS) — Boston College, 2021. / Submitted to: Boston College. College of Arts and Sciences. / Discipline: Scholar of the College. / Discipline: Physics.

Influence diagrams (ID) are graphical frameworks for decision making in stochastic situations with mathematical models embedded in them. The goal of an optimal algorithm for an ID is to find a strategy that would maximize the expected utility. We will explain a few algorithms for influence diagrams in this thesis. There exists an obvious temporal ordering among decisions in an ID; and any information used in the past will always be available in the future: these two properties are respectively called the “regularity” and “noforgetting” assumptions. A limited memory influence diagram (LIMID) does not follow these two properties. The existing state-of-art depthirst-branch-and-bound (DFBnB) algorithm for solving influence diagrams does not scale very well due to the exponential increase of nodes proportional to the depth of the search (or total stages in the ID). In this paper, we propose and implement an algorithm that combines two widely used methods, depth first branch-andbound search (DFBnB) and value iteration with incremental pruning, for solving IDs and POMDPs, respectively. We describe an algorithm to convert the strategy tree to a strategy graph. Experiments show the effectiveness of these approaches. Algorithms for solving traditional influence diagrams are not easily generalized to solve LIMIDs, however, and only recently have exact algorithms for solving LIMIDs been developed. In this thesis, we provide an exact algorithm for solving LIMIDs that is based on branch-and-bound search. Our approach is related to the approach of solving an influence diagram by converting it to an equivalent decision tree, with the difference that the LIMID is converted to a much smaller decision graph that can be searched more efficiently.

Detailed analysis of the site-specific phosphorylation of a glucan phosphate from Saccharomyces cerevesiae has been carried out by 2D NMR techniques. Phosphorylation has been shown to be limited to the C-6 and C-2 positions, with the C-6 resonance showing two slightly different environments. Phosphorylation at C-4 is hindered due to proximity effects with the neighboring glucose ring oxygen. Noncovalently bound, nondialyzable phosphate appears to be coordinated to the nonphosphorylated HO-2 group of the helical polymer.

Indiana University-Purdue University Indianapolis (IUPUI) / In this thesis, we focus on two broad categories of problems, exciton condensation and bound states, and two complimentary approaches, real and momentum space, to solve these problems. In chapter 2 we begin by developing the self-consistent mean field equations, in momentum space, used to calculate exciton condensation in semiconductor heterostructures/double quantum wells and graphene. In the double quantum well case, where we have one layer containing electrons and the other layer with holes separated by a distance $d$, we extend the analytical solution to the two dimensional hydrogen atom in order to provide a semi-quantitative measure of when a system of excitons can be considered dilute. Next we focus on the problem of electron-electron screening, using the random phase approximation, in double layer graphene. The literature contains calculations showing that when screening is not taken into account the temperature at which excitons in double layer graphene condense is approximately room temperature. Also in the literature is a calculation showing that under certain assumptions the transition temperature is approximately \unit{mK}. The essential result is that the condensate is exponentially suppressed by the number of electron species in the system. Our mean field calculations show that the condensate, is in fact, not exponentially suppressed. Next, in chapter 3, we show the use of momentum space to solve the Schr\"{o}dinger equation for a class of potentials that are not usually a part of a quantum mechanics courses. Our approach avoids the typical pitfalls that exist when one tries to discretize the real space Schr\"{o}dinger equation. This technique widens the number of problems that can presented in an introductory quantum mechanics course while at the same time, because of the ease of its implementation, provides a simple introduction to numerical techniques and programming in general to students. We have furthered this idea by creating a modular program that allows students to choose the potential they wish to solve for while abstracting away the details of how the solution is found. In chapter 4 we revisit the single exciton and exciton condensation in double layer graphene problems through the use of real space lattice models. In the first section, we once again develop the equations needed to solve the problem of exciton condensation in a double layer graphene system. In addition to this we show that by using this technique, we find that for a non-interacting system with a finite non-zero tunneling between the layers that the on-site exciton density is proportional to the tunneling amplitude. The second section returns to the single exciton problem. In agreement with our momentum space calculations, we find that as the layer separation distance is increased the bound state wave function broadens. Finally, an interesting consequence of the lattice model is explored briefly. We show that for a system containing an electron in a periodic potential, there exists a bound state for both an attractive as well as repulsive potential. The bound state for the repulsive potential has as its energy $-E_0$ where $E_0$ is the ground state energy of the attractive potential with the same strength.

<p>In this thesis, we devise a new finite branch-and-bound algorithm for disjoint bilinear programs. In these problems, there are two vectors of variables, $\b{x}$ and $\b{y}$, and two polytopes $P_{\b{x}}$ and $P_{\b{y}}$ such that $\b{x}$ (resp. $\b{y}$) is chosen from $P_{\b{x}}$ (resp. $P_{\b{y}}$) so that a bilinear objective function is minimized. By a bilinear objective, we mean that the objective becomes linear when either one of $\b{x}$ or $\b{y}$ is fixed. </p> <p>  This branch-and-bound scheme uses a relaxation that is derived using the reformulation-linearization technique (RLT). The RLT relaxation is constructed by taking products of constraints and linearizing the bilinear terms using introduced variables. The quality of this relaxation improves as higher order products and the corresponding monomial terms are linearized. Although it is known that, as RLT relaxations are constructed with increasingly higher order linearizations, the relaxation eventually converges to the true optimal value. However, no finite convergence properties are known. In contrast, we show that the first level of the RLT hierarchy suffices to convexify the problem when one of the polytopes is a simplex. Then, using this insight we devise a new class of relaxations by combining RLT with a variant of the double description procedure, where the latter lifts a polytope into a simplex in a finite number of steps.  This leads us to a finite hierarchy of relaxations that converges to the optimal value. Although this hierarchy is finite, from a computational perspective, we find that the relaxations grow rapidly in size. However, we utilize the insight to derive a simplicial branch-and-bound scheme, that expresses each polytope as a union of simplices allowing us to converge finitely to the optimal solution for the problem. We perform preliminary numerical experiments to show that this approach holds promise and competes favorably with state-of-the-art methods on larger instances.</p>

By a tracer study, using ⁸²Br, it is demonstrated that bromine is bound to serum proteins in vivo. ⁸²Br⁻ of high specific activity was injected into rabbits and serum removed one day later. Approximately ½% of the total ⁸²Br in the serum was found to be protein-bound at this stage. The application of various separation methods (electrophoresis, bromide exchange, denaturation followed by desalting) showed that one-third of the protein-bound bromine is loosely attached whereas two-thirds are firmly bound. After partial and complete enzymatic hydrolysis the bromine was found in the amino acid fraction. On the basis of the elution pattern of the amino acids on calibrated cation exchange resin columns it is concluded that the main portion of the radioactivity appeared to be associated with 3-bromo-L-tyrosine. Little, if any, bromine was observed in the serum lipids and in the thyroxine fraction isolated from serum proteins. / Thesis / Doctor of Philosophy (PhD)

The purpose of this study was to investigate the perceptions of African American students on the impact of an Upward Bound Program on their academic performance, self-esteem, and the attitudes toward post-secondary educational success. Specifically, this study was concerned with the following variables: gender, family structure, and age as they related to the students aforementioned perceptions. A survey design was employed in this investigation to collect and analyze the data. Three hundred fifty-three (353) African American high school students participated in this empirical study. An instrument entitled “The Middleton Upward Bound Survey” was used to gather the data. The investigative instrument was validated by a group of Upward Bound professionals and university research professors. The instrument had an alpha coefficient of ¬¬.84 for the test as a whole. Moreover, the data was tested through the application of the One-Way Analysis of Variance and the Scheffe’ Multiple Comparison Test. Among the conclusions of this study were the following; in general it appeared the younger African American high school students are more favorable to his/her perceptions regarding the impact of an Upward Bound Programs on student academic achievement. African American high school students who reside with a guardian also tend to have more favorable perceptions regarding the impact of an Upward Bound Programs on their academic achievement. Regardless, of African American high school students’ age, gender or family structure, they tend to have similar perceptions regarding the impact of an Upward Bound Programs on their attitudes toward post-secondary educational success.

No description available.

Influenza epidemics continue to cause morbidity and mortality within the human population despite widespread vaccination efforts. This, along with the ominous threat of an avian influenza pandemic (H5N1), demonstrates the need for a much improved, more sophisticated influenza vaccine. Our group has developed an in vitro model system for producing a membrane-bound Cytokine-bearing Influenza Vaccine (CYT-IVAC). Numerous cytokines are involved in directing both innate and adaptive immunity and it is our goal to utilize the properties of individual cytokines and other immunomodulatory proteins to create a more immunogenic vaccine. Here we report methodologies for the construction of membrane-bound cytokine fusion constructs in which our cytokine of interest (mouse GM-CSF, mouse IL-2, mouse IL-4) was fused to the membrane anchoring regions of viral Hemagglutinin (HA). Progeny virions, produced from influenza infected MDCK cells expressing membrane-bound cytokines, readily incorporated membrane-bound cytokines during budding and these cytokines on the virus particles retained bioactivity following viral inactivation. In vivo vaccination studies in mice showed enhanced antibody titers and improved protection following lethal challenge in those mice vaccinated with IL-2 and IL-4-bearing CYT-IVAC's compared to the conventional wild-type vaccine without membrane-bound cytokines. In addition, the immune response induced by IL-2 and IL-4-bearing CYT-IVACs was skewed toward Th1 (cellular) mediated immunity compared to the Th2 (humoral) dominated response induced with wild-type vaccination. Cellular mediated immunity afforded by IL-2 and IL-4 CYT-IVACs was manifested as enhanced influenza specific T cell proliferation and activation. In conclusion, we have developed a novel methodology to introduce bioactive membrane-bound cytokines directly into virus particles in order to augment the immunogenicity of inactivated, whole virus influenza vaccines. / Ph. D.

Balanced truncation model reduction for linear systems yields reduced-order models that satisfy a well-known error bound in terms of a system's Hankel singular values. This bound is known to hold with equality under certain conditions, such as when the full-order system is state-space symmetric. In this work, we derive more general conditions in which the balanced truncation error bound holds with equality. We show that this holds for single-input, single-output systems that exhibit a generalized type of state-space symmetry based on the sign parameters corresponding to a system's Hankel singular values. We prove an additional result that shows how to determine this state-space symmetry from the arrowhead realization of a system, if available. In particular, we provide a formula for the sign parameters of an arrowhead system in terms of the off-diagonal entries of its arrowhead realization. We then illustrate these results with an example of an arrowhead system arising naturally in power systems modeling that motivated our study. / Master of Science / Mathematical modeling of dynamical systems provides a powerful means for studying physical phenomena. Due the complexities of real-world problems, many mathematical models face computational difficulties due to the costs of accurate modeling. Model-order reduction of large-scale dynamical systems circumvents this by approximating the large-scale model with a ``smaller'' one that still accurately describes the problem of interest. Balanced truncation model reduction for linear systems is one such example, yielding reduced-order models that satisfy a tractable upper bound on the approximation error. This work investigates conditions in which this bound is known to hold with equality, becoming an exact formula for the error in reduction. We additionally show how to determine these conditions for a special class of linear dynamical systems known as arrowhead systems, which arise in special applications of network modeling. We provide an example of one such system from power systems modeling that motivated our study.