Topologica Defects and Corrections to the Nambu Action

The effective action of a (1+2)-dimensional defect is obtained as an expansion in powers of the thickness.Considering non-straight solutions as the zero order term, the corrections to the Nambu action are found to depend on the curvature scalar and on the gaussian curvature .Comment: UNB.FIS.FM-002/92, Marcos@FNAL, 12 pages, Late

Hypersensitivity Reactions To Ixodes Scapularis Bites And Protection Against Tick-Borne Infection

Background: Salivary proteins from insect bites result in a wide array of complex immune interactions within a bitten host. In the case of the deer tick, Ixodes scapularis, previous research has demonstrated that tick-induced hypersensitivity reactions may interfere with the transmission of Lyme disease. There are no prospective studies in humans regarding the spectrum of hypersensitivity reactions that occur with I. scapularis bites. Methods: We analyzed data obtained from a prospective enrollment of the first 102 individuals who reported tick bite to a medical practice in Mansfield, Connecticut from 2005-2008. Clinical responses were recorded and subject based diaries were utilized to classify and analyze whether certain reactions reduced tick-borne pathogen transmission. Results: No subjects developed serious clinical manifestations or systemic reactions. The most common localized reactions were local erythema (88%), swelling (64%), itch (48%), and a delayed type hypersensitivity reaction (27%). None of these responses were associated with the presence or absence of a previous episode of Lyme disease. Conclusion: Hypersensitivity reactions to I. scapularis bites generally are mild. Although they may help to prevent tick-borne infection, we did not observe an association between tick-bite reaction and the presence or absence of Lyme disease. An expanded and modified surveillance study is needed to determine if there is an association between hypersensitivity reactions and the development of tick-borne infection

Doctor of Philosophy

dissertationThe effects of iron chemistry dominate the visual landscape of southwestern Utah, producing not only the well-known red rock scenery, but also a broad variety of other colorful features. Diagenetic coloration is perhaps best displayed in the magnificent cliffs of the Jurassic Navajo Sandstone, where selective chemical alteration by subsurface fluids has enriched the rock with iron in some areas (iron oxide cement precipitation), and locally depleted the rock of iron in others (chemical bleaching). This study examines the complex interrelationships between these coloration facies in a regional context in order to better understand the large-scale stratigraphic, hydrodynamic, and tectonic mechanisms that produced them. Primary goals of the study are to map diagenetic coloration facies, analyze geospatial relationships, establish the timing of major diagenetic events, and evaluate the impact of iron oxide cementation on reservoir architecture. Results indicate that the Navajo Sandstone has a prolonged and complex diagenetic history. At least four major events have occurred on a regional scale: (1) precipitation of primary grain coats to produce primary red rock; (2) bleaching of the upper Navajo Sandstone; (3) precipitation of dense concentrations of iron oxide (up to 30% by weight) in the lower formation; and (4) brightly colored secondary cementation along joints in the upper formation. Hierarchal taxonomies are presented for classifying and interpreting the major types of diagenetic features that are present. Sandstone bleaching patterns are influenced by multiple factors including variations in eolian bedform morphology, higher percent grainflow stratification in the upper formation, and the localized superimposition of horizontally contiguous bleached facies (loosely akin to sedimentary facies relationships of Walther's law). Dense concentrations of concretionary iron oxide cement occur primarily as discontinuous subhorizontal horizons in the lower portion of the formation. The wide occurrence of these horizons in southwestern Utah may indicate a relationship with regional tectonic processes, with cementation resulting from fluctuating geochemical conditions. Iron oxide precipitation locally follows previously high-permeability bedding features that, upon cementation, become barriers to subsequent fluid flow ("permeability inversion"). These relationships have application for both characterizing reservoir architecture and understanding the diagenetic history of the region

Quadratic Dynamical Decoupling with Non-Uniform Error Suppression

We analyze numerically the performance of the near-optimal quadratic dynamical decoupling (QDD) single-qubit decoherence errors suppression method [J. West et al., Phys. Rev. Lett. 104, 130501 (2010)]. The QDD sequence is formed by nesting two optimal Uhrig dynamical decoupling sequences for two orthogonal axes, comprising N1 and N2 pulses, respectively. Varying these numbers, we study the decoherence suppression properties of QDD directly by isolating the errors associated with each system basis operator present in the system-bath interaction Hamiltonian. Each individual error scales with the lowest order of the Dyson series, therefore immediately yielding the order of decoherence suppression. We show that the error suppression properties of QDD are dependent upon the parities of N1 and N2, and near-optimal performance is achieved for general single-qubit interactions when N1=N2.Comment: 17 pages, 22 figure

Macroscopic open strings and gravitational confinement

We consider classical solutions for strings ending on magnetically charged black holes in four-dimensional Kaluza-Klein theory. We examine the classical superstring and the global vortex, which can be viewed as a nonsingular model for the superstring. We show how both of these can end on a Kaluza-Klein monopole in the absence of self-gravity. Including gravitational back-reaction gives rise to a confinement mechanism of the magnetic flux of the black hole along the direction of the string. We discuss the relation of this work to localized solutions in ten dimensional supergravity.Comment: 14 pages latex (JHEP style), 2 figure

High Fidelity Adiabatic Quantum Computation via Dynamical Decoupling

We introduce high-order dynamical decoupling strategies for open system adiabatic quantum computation. Our numerical results demonstrate that a judicious choice of high-order dynamical decoupling method, in conjunction with an encoding which allows computation to proceed alongside decoupling, can dramatically enhance the fidelity of adiabatic quantum computation in spite of decoherence.Comment: 5 pages, 4 figure

On expansion in the width for domain walls

The well-known idea to construct domain wall type solutions of field equations by means of an expansion in the width of the domain wall is reexamined. We observe that the problem involves singular perturbations. Hilbert-Chapman-Enskog method is used to construct a consistent perturbative expansion. We obtain the solutions to the second order in the width without introducing an effective action for the domain wall. We find that zeros of the scalar field in general do not lie on a Nambu-Goto trajectory. As examples we consider cylindrical and spherical domain walls. We find that the spherical domain wall, in contradistinction to the cylindrical one, shows an effective rigidity.Comment: 21 pages, LaTe