We begin with a result on the refocussing of null geodesics in space-times. We show that all oriented refocussing 2-dimensional Lorentz manifolds are also strongly refocussing. We also introduce a theory of virtual Legendrian knots. We show that...
Partially ordered sets. ; Convex polytopes. ; Representations of groups.
This thesis deals with geometric representations of ordered sets. In a geometric representation, each element of the ordered set is assigned a geometric object, with two elements incomparable in the ordered set if and only if the corresponding...
NAD (Coenzyme) -- Metabolism. Nicotinamide -- Mechanism of action. Genetic regulation. Nicotinamide-beta-riboside.
NAD+ is an essential co-enzyme for hydride transfer enzymes and a consumed substrate of multiple signaling enzymes including the sirtuins, a family of protein lysine deacetylases shown to regulate longevity in a wide array of organisms. We have...
Many protocols for adoptive T cell therapy (ACT) include preparative conditioning strategies to deplete host lymphocytes prior to T cell infusion. Total body irradiation and high-dose chemotherapy regimens not only relieve immunosuppression, but...
The purpose of this thesis is to describe methods for detecting hidden crevasses on glaciers in Polar regions. Crevasses form in ice sheets as a result of forces imposed upon the brittle ice. The crevasses are hidden from view by bridges of soft...
Si/SiGe quantum dots (QDs) are promising candidates for spin-based quantum bits (qubits) as a result of the reduced spin-orbit coupling as well as the Si isotopes with zero nuclear spin. Meanwhile qubit readout is a challenge related to...
Cyclin-dependent kinases (CDKs) and their associated cyclins are key regulators of cell cycle progression. Caenorhabditis elegans has two predicted A- type cyclins, encoded by the genes cya-1 and cya-2. Cyclin A has been shown to be required for...
We study the bijective combinatorics of reduced words. These are fundamental objects in the study of Coxeter groups. We restrict our focus to reduced words of permutations and signed permutations. Our results can all be situated within the context...
Constructibility (Set theory). Trees (Graph theory).
This thesis investigates possible initial segments of the degrees of constructibility. Specifically, we completely characterize the structure of degrees in generic extensions of the constructible universe L via forcing with Souslin trees. Then we...
Protein phosphorylation is an important regulatory mechanism for the control of countless processes in living systems. The delicate management of phosphate attachment to, and removal from, serine, threonine and tyrosine residues in proteins...
Studies presented in this dissertation focus on the transcriptional targets and cellular functions of [Delta]Np63[alpha], the predominant TP63 isoform expressed in epithelial stem cell compartments. TP63, a member of the p53 family of...
Temperature has powerful effects on all scales of biological organization from biochemical reactions to ecosystem processes. Despite the well-appreciated influence and thorough understanding of the physiological and population consequences of...
This thesis constitutes the first steps in the author's program to investigate the question of when a homotopy of 2-cocycles Ï‰ = {Ï‰[subscript t]}[subscript tâˆŠ[0,1]] on a locally compact Hausdorff groupoid Æ“ induces an isomorphism of the...
It has been well established that physical exercise has broad impacts across the lifespan, including improved cognition, brain function, and mental health. Studies investigating the mechanism underlying the cognitive enhancing effect of exercise...
In this thesis, we characterize and enumerate the permutations which are realized by the orbits of signed shifts, a family of discrete dynamical systems on words. The permutations, which are called patterns of the signed shifts, are given by the...
In Chapter 2 we look at the distribution of permutation statistics in the context of pattern-avoiding permutations. The first part of this chapter deals with a recursively defined bijection of Robertson [37] between 123- and 132-avoiding...
Visual searches for a conjunction of features (e.g., a particular combination of color and shape) are ordinarily slow and difficult. However, search efficiency for a particular conjunction can improve dramatically within a few hundred practice...
G protein coupled receptors (GPCRs) make up somewhere between 30-50% of all current drug targets, yet the structural characterization of these receptors has been moderate at best. Until recently, structural data were almost nonexistent and...
From deciding what to eat first or what stock to invest in, the order in which we prefer to experience events and the amount of risk we are willing to undertake are factors that influence our choices. However, the mechanisms underlying order and...
For many scientific applications, the data set cannot entirely fit in main memory. The data must reside out-of-core, i.e., on parallel disks. For many basic data-movement operations such as permuting, if the programmer does not design efficient...
Drosophila melanogaster is a model organism often used when studying the complex processes of neuronal signaling and neurodegeneration. The short life cycle, malleable genetics, amenability to in vivo electrophysiological assays and sensitivity to...
The Euler '-function and Carmichael -function are extremely important in modern number theory, and much work has been devoted to studying the distribution and arithmetic properties of the values of each function. One interesting unresolved question...
Face perception -- Physiological aspects. Face perception -- Social aspects. Sex differences (Psychology). Neuropsychology.
The general objective of the current thesis was to investigate the neural substrates underlying the perception of opposite-sex faces. Building on what is already known about the distributed network of brain areas supporting various dimensions of...
Robots -- Control systems -- Design and construction. Mobile robots. Robots -- Dynamics.
This thesis examines the issues of vehicle and information dynamics in the control of a multi-robot system using a radial-basis potential function controller. Distributed control of multi-robot systems requires each robot to communicate state...
Information retrieval -- Mathematical models. ; Electronic information resource searching. ; Computer algorithms. ; Decision making -- Data processing. ; Mathematical optimization.
This thesis presents a unified method for simultaneous solution of three problems in Information Retrieval--metasearch (the fusion of ranked lists returned by retrieval systems to elicit improved performance), efficient system evaluation (the...
Does early and sustained experience with two languages in childhood modify how language is processed in the adult bilingual brain? Does extensive exposure to two languages influence language processing in the bilingual brain as compared to...