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Articles 2911 - 2940 of 4195
Full-Text Articles in Physical Sciences and Mathematics
The Arctic Game, Sarah E. Nuernberger
The Arctic Game, Sarah E. Nuernberger
Electronic Theses and Dissertations
Since outsiders first visited the Arctic, they have believed in man's ability to conquer the region. Today's Arctic conquest is not one of heroic exploration, but rather one of ownership and exploitation. This paper illustrates contestation in the Arctic through the metaphor of a game, with attendant prizes, players, and rules. It focuses on how to prevent the future destruction of the Arctic given the interactions of the Arctic's landscape, prizes, players, and current management frameworks. In the wake of renewed resource exploitation and escalating climate change impacts, the current frameworks and mindsets are inadequate to support the precarious balance …
Plasma Spectroscopic Techniques Applied To Biological And Environmental Matrices, Morgan Steele Schmidt
Plasma Spectroscopic Techniques Applied To Biological And Environmental Matrices, Morgan Steele Schmidt
Electronic Theses and Dissertations
The purpose of this research was to apply the use of direct ablation plasma spectroscopic techniques, including spark-induced breakdown spectroscopy (SIBS) and laser-induced breakdown spectroscopy (LIBS), to a variety of environmental matrices. These were applied to two different analytical problems. SIBS instrumentation was adapted in order to develop a fieldable monitor for the measurement of carbon in soil. SIBS spectra in the 200 nm to 400 nm region of several soils were collected, and the neutral carbon line (247.85 nm) was compared to total carbon concentration determined by standard dry combustion analysis. Additionally, Fe and Si were evaluated in a …
Structural Polymorphism In Tau Filaments: An Implication For Neurodegenerative Diseases, Ayisha Siddiqua
Structural Polymorphism In Tau Filaments: An Implication For Neurodegenerative Diseases, Ayisha Siddiqua
Electronic Theses and Dissertations
Tau filaments are the pathological hallmark of >20 neurodegenerative diseases including Alzheimer's disease, Pick's disease, and progressive supranuclear palsy. In the adult human brain, six isoforms of tau are expressed that differ by presence or absence of the second of the four semiconserved repeats. As a consequence, half of the tau isoforms have three repeats (3R tau), whereas the other half has four repeats (4R tau).
Site-directed spin labeling of recombinant tau in conjunction with electron paramagnetic resonance spectroscopy was used to obtain structural insights into tau filaments. The studies showed that the filaments of 4R tau and 3R tau …
Analysis Of Interphase Chromatin Motion In Hela Cells, Matthew Joel Westacott
Analysis Of Interphase Chromatin Motion In Hela Cells, Matthew Joel Westacott
Electronic Theses and Dissertations
Motion of particles under influencing forces may be observed under light microscopy techniques. Variations in mobility of particles may give relevant biophysical information. Automated high resolution single particle tracking techniques were used to characterize interphase chromatin mobility in the cell nucleus. Interphase chromatin undergo replication prior to cell division with the assistance of replication proteins (machinery) which modify chromatin mobility. Using dual color imaging of flourescently tagged chromatin and proliferating cell nuclear antigen (PCNA) were followed through interphase. Chromatin motion was modelled as a two dimensional random walk. Reduction in chromatin mobility was observed during S phase was dependent on …
On The Nature Of Weak Intermolecular Forces: A First Principles Approach To Hydrogen Bonding And Pi-Type Interactions, Kari Lorene Copeland
On The Nature Of Weak Intermolecular Forces: A First Principles Approach To Hydrogen Bonding And Pi-Type Interactions, Kari Lorene Copeland
Electronic Theses and Dissertations
Computational quantum chemistry is a branch of chemistry that is based on quantum mechanics. In this field, chemical phenomena is represented in mathematical form and computers are used to provide numerical solutions to rigorous mathematical equations. Through this medium, the properties of atoms and molecules are calculated with high accuracy. Chapter 1 opens with a general discussion of science, the development of atomic theory and computational chemistry. Electronic structure theory is more extensively reviein Chapter 2. Hydrogen bonding and dispersion forces are defined in Chapter 3, and the procedures used to computationally study these type interactions are considered. Chapter 4 …
Using Geophysics To Evaluate Levee Stability, Laura Mcconnell Dalton
Using Geophysics To Evaluate Levee Stability, Laura Mcconnell Dalton
Electronic Theses and Dissertations
Shallow slough slides have occurred along the river \side slope of Mississippi River Levees for over sixty years. Shallow slough slides also occur along smaller levees that protect tributaries of the Mississippi River. This investigation takes place along a section of the Coldwater River Levee, a tributary levee of the Mississippi River. Field observation, soil samples, and geophysical data were collected at two field sites located on the border of Tate and Tunica County, MS. The first site consists of a developed shallow slough slide that had occurred that has not yet been repaired and the second site is a …
Characterizations Of Zero Divisor Graphs Determined By Equivalence Classes Of Zero Divisors, Amanda Catherine Acosta
Characterizations Of Zero Divisor Graphs Determined By Equivalence Classes Of Zero Divisors, Amanda Catherine Acosta
Electronic Theses and Dissertations
We study zero divisor graphs of commutative rings determined by equivalence classes of zero divisors, specifically for a Noetherian ring R. We study the classification of these graphs. Specifically, we add more criteria to the list of characterizations that disqualify a graph as the zero divisor graph of a ring. We also briefly discuss Sage, a mathematical software, which was an aid in providing visual pictures for the graphs under study.
The Distribution Of Individual Stock Returns In A Modified Black-Scholes Option Pricing Model, Daniel Lee Richey
The Distribution Of Individual Stock Returns In A Modified Black-Scholes Option Pricing Model, Daniel Lee Richey
Electronic Theses and Dissertations
Author's abstract: There have been many attempts to find a model that can accurately price options. These models are built on many assumptions, including which probability distribution stock returns follow. In this paper, we test several distributions to see which best fit the log returns of 20 different companies over a period between November 1, 2006 to October 31, 2011. If a "best" distribution is found, a modified Black-Scholes model will be defined by modifying the Weiner process. We use Monte Carlo simulations to generate estimated prices under specified parameters, and compare these prices to those simulated by the model …
Infeasible Full-Newton-Step Interior-Point Method For The Linear Complementarity Problems, Antré Marquel Drummer
Infeasible Full-Newton-Step Interior-Point Method For The Linear Complementarity Problems, Antré Marquel Drummer
Electronic Theses and Dissertations
In this tesis, we present a new Infeasible Interior-Point Method (IPM) for monotone Linear Complementarity Problem (LPC). The advantage of the method is that it uses full Newton-steps, thus, avoiding the calculation of the step size at each iteration. However, by suitable choice of parameters the iterates are forced to stay in the neighborhood of the central path, hence, still guaranteeing the global convergence of the method under strict feasibility assumption. The number of iterations necessary to find -approximate solution of the problem matches the best known iteration bounds for these types of methods. The preliminary implementation of the method …
Temporal And Spatial Assessment Of Pahs In Water, Sediment, And Oysters As A Result Of The Deepwater Horizon Oil Spill, Meghan Christina Dailey
Temporal And Spatial Assessment Of Pahs In Water, Sediment, And Oysters As A Result Of The Deepwater Horizon Oil Spill, Meghan Christina Dailey
Electronic Theses and Dissertations
On April 20, 2010, BP's Deepwater Horizon oil rig exploded leaking over 200 million gallons of crude oil into the Gulf of Mexico for 84 days. Exposure to oil-associated polycyclic aromatic hydrocarbons (PAHs) in the water and sediment could severely impact the aquatic organisms inhabiting the Gulf of Mexico (i.e. developmental defects, reproductive effects, death, etc.). Therefore, water, sediment and oyster, Crassostrea virginica, samples were collected approximately bimonthly between May 26 and November 30, 2010 from multiple sites along the Gulf Coast, namely, two sites in Mobile Bay (Denton and Sand Reefs at 1 or 0.1 m above the bay …
Infrasound As Upper Atmospheric Monitor, Jelle Daniel Assink
Infrasound As Upper Atmospheric Monitor, Jelle Daniel Assink
Electronic Theses and Dissertations
Understanding and specification of the higher altitudes of the atmosphere with global coverage over all local times is hampered by the challenges of obtaining direct measurements in the upper atmosphere. Methods to measure the properties of the atmosphere above the stratopause is an active area of scientific research. In this thesis, we revisit the use of infrasound as a passive remote sensing technique for the upper atmosphere. Signals from the Tungurahua volcano in Ecuador are used to investigate the behavior of the upper atmosphere. Depending on the atmospheric conditions, stratospheric, mesospheric and thermospheric arrivals are observed during intervals of explosive …
Multidoman Piezo-Ceramic Cantilever, David Paul Sedorook
Multidoman Piezo-Ceramic Cantilever, David Paul Sedorook
Electronic Theses and Dissertations
PZT-5H is a ferroelectric and piezoelectric material that has many applications that are the subjects of current research. As a ferroelectric, PZT-5H has a permanent electrical polarization that arises from ferroelectric domains. In this thesis, numerical simulations were conducted via the well know Finite Element Method of several types of piezoelectric cantilevers that were made of PIC-181, a high quality PZT-5H made in Germany. Single crystal cantilever models with multiple polarization vectors were investigated with Q factors ranging from Q = 50 to Q = 1200, where the acoustical displacements were calculated. Further, the displacements were calculated for a multidomain …
Stratigraphy And Sedimentology Of The Smackover Formation, Southwest Alabama, Andrew Wilbourn
Stratigraphy And Sedimentology Of The Smackover Formation, Southwest Alabama, Andrew Wilbourn
Electronic Theses and Dissertations
The Smackover Formation is a highly productive producer of hydrocarbons throughout the United States Gulf Coast region. More than four million barrels of oil and five billion cubic feet of gas have been produced from the Smackover Formation in the Barnett Field in southwest Alabama. Paleohighs formed during the Paleozoic and salt tectonic relief features control sediment distribution of the Smackover Formation in southwest Alabama. The Smackover in Barnett Field is entirely dolomitized, but the carbonate texture at the time of deposition is still visible in thin section. The Smackover carbonates in Barnett Field were deposited in the near-shore area …
Investigations Of Noncovalent Interactions Using Raman Spectroscopy And Electronic Structure Computations, Ashley Wright
Investigations Of Noncovalent Interactions Using Raman Spectroscopy And Electronic Structure Computations, Ashley Wright
Electronic Theses and Dissertations
This dissertation research focuses on the effects of noncovalent interactions on vibrational energy levels. Vibrational spectroscopy is a powerful tool for the study of the effects of weak intermolecular interactions such as hydrogen bonding and interactions with the environment, including solvation effects. Changes in the vibrational spectra of interacting molecules allow us to ascertain exactly which atoms and bonds are affected and to what extent they are affected. Quantum mechanical methods, ab initio theory and density functional theory, are employed to model molecular geometries, properties, and subtle interactions between molecules. Much of this research centers on the comparison of these …
Theoretical And Spectroscopic Studies Of Molecular Systems For Charge Transfer And Energy Storage And Transfer, Debra Scardino
Theoretical And Spectroscopic Studies Of Molecular Systems For Charge Transfer And Energy Storage And Transfer, Debra Scardino
Electronic Theses and Dissertations
Efficient charge transfer and energy storage and transfer have become increasingly important in many areas of research and development. This is especially true for the development of optoelectronic devices, molecular electronics, and solar voltaic cells. Characterization of the photophysical properties of new molecular systems for these applications has emerged as an important field of research. Many molecular building blocks have been developed and understanding the properties of these systems at a fundamental level is essential for their successful implementation. This dissertation focuses on experimental and theoretical studies of some of these newly-developed molecular systems. Oxygen substituted dihydrobenzvalene is studied theoretically …
Networking And Security Solutions For Vanet Initial Deployment Stage, Baber Aslam
Networking And Security Solutions For Vanet Initial Deployment Stage, Baber Aslam
Electronic Theses and Dissertations
Vehicular ad hoc network (VANET) is a special case of mobile networks, where vehicles equipped with computing/communicating devices (called "smart vehicles") are the mobile wireless nodes. However, the movement pattern of these mobile wireless nodes is no more random, as in case of mobile networks, rather it is restricted to roads and streets. Vehicular networks have hybrid architecture; it is a combination of both infrastructure and infrastructure-less architectures. The direct vehicle to vehicle (V2V) communication is infrastructure-less or ad hoc in nature. Here the vehicles traveling within communication range of each other form an ad hoc network. On the other …
Turtle Cam: Live Multimedia Interaction For Engaging Potential Visitor Population To Canaveral National Seashore, Brian Alfred Tortorelli
Turtle Cam: Live Multimedia Interaction For Engaging Potential Visitor Population To Canaveral National Seashore, Brian Alfred Tortorelli
Electronic Theses and Dissertations
This project expands the outreach of the Canaveral National Seashore to its visitors, potential visitors, and virtual visitors through its goals in conservancy and preservation of its natural resources. This paper is involved with the current iteration of a series of digital media projects, the Sea Turtle Nest Camera, also known as, Turtle Cam. It details how and why this project was designed to be an ongoing initiative to assist in those goals.
Characterization And Application Of Isolated Attosecond Pulses, Michael Chini
Characterization And Application Of Isolated Attosecond Pulses, Michael Chini
Electronic Theses and Dissertations
Tracking and controlling the dynamic evolution of matter under the influence of external fields is among the most fundamental goals of physics. In the microcosm, the motion of electrons follows the laws of quantum mechanics and evolves on the timescale set by the atomic unit of time, 24 attoseconds. While only a few time-dependent quantum mechanical systems can be solved theoretically, recent advances in the generation, characterization, and application of isolated attosecond pulses and few-cycle femtosecond lasers have given experimentalists the necessary tools for dynamic measurements on these systems. However, pioneering studies in attosecond science have so far been limited …
Assessment Of Molecular Interactions Via Magnetic Relaxation: A Quest For Inhibitors Of The Anthrax Toxin, Oscar Santiesteban
Assessment Of Molecular Interactions Via Magnetic Relaxation: A Quest For Inhibitors Of The Anthrax Toxin, Oscar Santiesteban
Electronic Theses and Dissertations
Anthrax is severe disease caused by the gram-positive Bacillus anthracis that can affect humans with deadly consequences. The disease propagates via the release of bacterial spores that can be naturally found in animals or can be weaponized and intentionally released into the atmosphere in a terrorist attack. Once inhaled, the spores become activated and the anthrax bacterium starts to reproduce and damage healthy macrophages by the release of the anthrax toxin. The anthrax toxin is composed of three virulent factors: (i) anthrax protective antigen (APA), (ii) anthrax lethal factor (ALF), and (iii) anthrax edema factor (AEF) that work in harmony …
A Study Of Localization And Latency Reduction For Action Recognition, Syed Zain Masood
A Study Of Localization And Latency Reduction For Action Recognition, Syed Zain Masood
Electronic Theses and Dissertations
The success of recognizing periodic actions in single-person-simple-background datasets, such as Weizmann and KTH, has created a need for more complex datasets to push the performance of action recognition systems. In this work, we create a new synthetic action dataset and use it to highlight weaknesses in current recognition systems. Experiments show that introducing background complexity to action video sequences causes a significant degradation in recognition performance. Moreover, this degradation cannot be fixed by fine-tuning system parameters or by selecting better feature points. Instead, we show that the problem lies in the spatio-temporal cuboid volume extracted from the interest point …
Low Voltage Blue Phase Liquid Crystal Displays, Linghui Rao
Low Voltage Blue Phase Liquid Crystal Displays, Linghui Rao
Electronic Theses and Dissertations
From cell phones, laptops, desktops, TVs, to projectors, high reliability LCDs have become indispensable in our daily life. Tremendous progress in liquid crystal displays (LCDs) has been made after decades of extensive research and development in materials, device configurations and manufacturing technology. Nowadays, the most critical issue on viewing angle has been solved using multidomain structures and optical film compensation. Slow response time has been improved to 2-5 ms with low viscosity LC material, overdrive and undershoot voltage, and thin cell gap approach. Moving image blur has been significantly reduced by impulse driving and frame insertion. Contrast ratio in excess …
Detecting, Tracking, And Recognizing Activities In Aerial Video, Vladimir Reilly
Detecting, Tracking, And Recognizing Activities In Aerial Video, Vladimir Reilly
Electronic Theses and Dissertations
In this dissertation, we address the problem of detecting humans and vehicles, tracking them in crowded scenes, and finally determining their activities in aerial video. Even though this is a well explored problem in the field of computer vision, many challenges still remain when one is presented with realistic data. These challenges include large camera motion, strong scene parallax, fast object motion, large object density, strong shadows, and insufficiently large action datasets. Therefore, we propose a number of novel methods based on exploiting scene constraints from the imagery itself to aid in the detection and tracking of objects. We show, …
Computational Methods For Analyzing Rna Folding Landscapes And Its Applications, Yuan Li
Computational Methods For Analyzing Rna Folding Landscapes And Its Applications, Yuan Li
Electronic Theses and Dissertations
Non-protein-coding RNAs play critical regulatory roles in cellular life. Many ncRNAs fold into specific structures in order to perform their biological functions. Some of the RNAs, such as riboswitches, can even fold into alternative structural conformations in order to participate in different biological processes. In addition, these RNAs can transit dynamically between different functional structures along folding pathways on their energy landscapes. These alternative functional structures are usually energetically favored and are stable in their local energy landscapes. Moreover, conformational transitions between any pair of alternate structures usually involve high energy barriers, such that RNAs can become kinetically trapped by …
4d-Ct Lung Registration And Its Application For Lung Radiation Therapy, Yugang Min
4d-Ct Lung Registration And Its Application For Lung Radiation Therapy, Yugang Min
Electronic Theses and Dissertations
Radiation therapy has been successful in treating lung cancer patients, but its efficacy is limited by the inability to account for the respiratory motion during treatment planning and radiation dose delivery. Physics-based lung deformation models facilitate the motion computation of both tumor and local lung tissue during radiation therapy. In this dissertation, a novel method is discussed to accurately register 3D lungs across the respiratory phases from 4D-CT datasets, which facilitates the estimation of the volumetric lung deformation models. This method uses multi-level and multi-resolution optical flow registration coupled with thin plate splines (TPS), to address registration issue of inconsistent …
Evolution Through The Search For Novelty, Joel Lehman
Evolution Through The Search For Novelty, Joel Lehman
Electronic Theses and Dissertations
I present a new approach to evolutionary search called novelty search, wherein only behavioral novelty is rewarded, thereby abstracting evolution as a search for novel forms. This new approach contrasts with the traditional approach of rewarding progress towards the objective through an objective function. Although they are designed to light a path to the objective, objective functions can instead deceive search into converging to dead ends called local optima. As a significant problem in evolutionary computation, deception has inspired many techniques designed to mitigate it. However, nearly all such methods are still ultimately susceptible to deceptive local optima because they …
Elemental And Isotopic Analysis Of Sediments From Oxbow Lakes In The Mississippi Delta, Pragya Chakravarty
Elemental And Isotopic Analysis Of Sediments From Oxbow Lakes In The Mississippi Delta, Pragya Chakravarty
Electronic Theses and Dissertations
No abstract provided.
Electrochemistry, Transport Properties And Electronic Spectroscopy Of Lanthanide Solutes In Bis(Trifluoromethylsulfonyl)Imide-Based Ionic Liquids, Yunfeng Pan
Electronic Theses and Dissertations
No abstract provided.
On K-Trees And Special Classes Of K-Trees, John Wheless Estes
On K-Trees And Special Classes Of K-Trees, John Wheless Estes
Electronic Theses and Dissertations
The class of k-trees is defined recursively as follows: the smallest k-tree is the k-clique. If G is a graph obtained by attaching a vertex v to a k-clique in a k-tree, then G is also a k-tree. Trees, connected acyclic graphs, are k-trees for k = 1. We introduce a new parameter known as the shell of a k-tree, and from the shell special subclasses of k-trees, tree-like k-trees, are classified. Tree-like k-trees are generalizations of paths, maximal outerplanar graphs, and chordal planar graphs with toughness exceeding one. Let fs = fs( G) be the number of independent sets …
Donor-Sigma-Acceptor (D-Sigma-A) Molecules With Perylenebisimide Acceptors Having Alkyl Or Peg Swallowtails With Sulfur Or Hydroxyl Anchors: Synthesis And Applications In Langmuir-Blodgett Films, Single Molecule Spectroscopy (Sms), G-Quadruplex Studies And Passivation Of Gold Nanoparticles, Rajesh Kota
Electronic Theses and Dissertations
Use of single molecules as electronic devices is presently considered a potential alternative to semiconductor-based nanoscale electronics. The ability to study a single molecule or a small group of molecules provides a great opportunity to build electronic devices at the molecular level. It is vital to understand the parameters that control the device properties such as molecular structure, conformation and arrangement at the surface. Ari Aviram and Mark A. Ratner proposed the construction of a single organic molecule as an organic rectifier. Donor-Sigma-Acceptor (D-?-A ) molecules, when arranged with a proper orientation as Langmuir-Blodgett (LB) films and fixed between two …
Stochastic Models For Evolutionary Genetic Problems, Wei Liao
Stochastic Models For Evolutionary Genetic Problems, Wei Liao
Electronic Theses and Dissertations
Two stochastic models are designed for answering evolutionary genetic problems. The first study shows that inbreeding-environment interactions increase extinction risk. The second research demonstrates that 1) the carrying capacity and initial population growth rate is critical to determine the population persistence time; 2) increasing the advantageous mutation rate reduces the extinction risk although its effects are usually shadoby population size and fitness; 3) the new mutation correlation among environments rises during the evolution process, but it has compromised effects on population fate. Being able to accurately estimate the persistence time of populations of endangered plants and animals is central to …