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Articles 136171 - 136200 of 304313

Full-Text Articles in Physical Sciences and Mathematics

The Segal–Shale–Weil Representation, The Indices Of Kashiwara And Maslov, And Quantum Mechanics, Michael C. Berg Jan 2016

The Segal–Shale–Weil Representation, The Indices Of Kashiwara And Maslov, And Quantum Mechanics, Michael C. Berg

Mathematics, Statistics and Data Science Faculty Works

We produce a connection between the Weil 2-cocycles defining the local and adèlic metaplectic groups defined over a global field, i.e. the double covers of the attendant local and adèlic symplectic groups, and local and adèlic Maslov indices of the type considered by Souriau and Leray. With the latter tied to phase integrals occurring in quantum mechanics, we provide a formulation of quadratic reciprocity for the underlying field, first in terms of an adèlic phase integral, and then in terms of generalized time evolution unitary operators.

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Generalized Local And Nonlocal Master Equations For Some Stochastic Processes, Yanping Ma Jan 2016

Generalized Local And Nonlocal Master Equations For Some Stochastic Processes, Yanping Ma

Mathematics, Statistics and Data Science Faculty Works

In this paper, we present a study on generalized local and nonlocal equations for some stochastic processes. By considering the net flux change in a region determined by the transition probability, we derive the master equation to describe the evolution of the probability density function. Some examples, such as classical Fokker-Planck equations, models for Lévy process, and stochastic coagulation equations, are provided as illustrations. A particular application is a consistent derivation of coupled dynamical systems for spatially inhomogeneous stochastic coagulation processes.

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Garch(1,1) With Sifted Gamma-Distributed Errors, Alan C. Budd Jan 2016

Garch(1,1) With Sifted Gamma-Distributed Errors, Alan C. Budd

Electronic Theses and Dissertations

Typical General Autoregressive Conditional Heteroskedastic (GARCH) processes involve normally-distributed errors, and they model strictly-positive error processes poorly. This thesis will present a method for estimating the parameters of a GARCH(1,1) process with shifted Gamma-distributed errors, conduct a simulation study to test the method, and apply the method to real time series data.

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Modification Of The Fundamental Properties Of Light Through Interaction With Nanostructured Materials, David W. Keene Ii Jan 2016

Modification Of The Fundamental Properties Of Light Through Interaction With Nanostructured Materials, David W. Keene Ii

Electronic Theses and Dissertations

The field of photonics has been growing rapidly over the last few decades as it has endeavored to harness the potential of nanostructured materials to utilize the energy and momentum of electromagnetic radiation on the nanoscale. Using metal nanostructures provides the ability to take advantage of the sub-field of plasmonics which holds the promise of opening the world to vast increases in computational power by circumventing the limitations of conventional current that plague today’s processors. With a thorough understanding of this subject we also get one step closer to increasing the efficiency of solar technology, developing a finer scale of …

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Gorenstein Projective (Pre)Covers, Michael J. Fox Jan 2016

Gorenstein Projective (Pre)Covers, Michael J. Fox

Electronic Theses and Dissertations

The existence of the Gorenstein projective precovers is one of the main open problems in Gorenstein Homological algebra. We give sufficient conditions in order for the class of Gorenstein projective complexes to be special precovering in the category of complexes of R-modules Ch(R). More precisely, we prove that if every complex in Ch(R) has a special Gorenstein flat cover, every Gorenstein projective complex is Gorenstein flat, and every Gorenstein flat complex has finite Goenstein projective dimension, then the class of Gorenstein projective complexes, GP(C), is special precovering in Ch(R).

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Gallai-Ramsey Number Of An 8-Cycle, Jonathan Gregory Jan 2016

Gallai-Ramsey Number Of An 8-Cycle, Jonathan Gregory

Electronic Theses and Dissertations

Given a graph G and a positive integer k, define the Gallai-Ramsey number to be the minimum number of vertices n such that any k-edge-coloring of Kn contains either a rainbow (all different colored) triangle or a monochromatic copy of G. In this work, we establish the Gallai-Ramsey number of an 8-cycle for all positive integers.

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Stereographic Visualization Of Bose-Einstein Condensate Clouds To Measure The Gravitational Constant, Ed Wesley Wells Jan 2016

Stereographic Visualization Of Bose-Einstein Condensate Clouds To Measure The Gravitational Constant, Ed Wesley Wells

Electronic Theses and Dissertations

This thesis describes a set of tools that can be used for the rapid design of atom interferometer schemes suitable for measuring Newton's Universal Gravitation constant also known as "Big G". This tool set is especially applicable to Bose--Einstein--condensed systems present in NASA's Cold Atom Laboratory experiment to be deployed to the International Space Station in 2017. These tools include a method of approximating the solutions of the nonlinear Schrödinger or Gross--Pitaevskii equation (GPE) using the Lagrangian Variational Method. They also include a set of software tools for translating the approximate solutions of the GPE into images of the optical …

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Gorenstein Projective Precovers In The Category Of Modules, Katelyn Coggins Jan 2016

Gorenstein Projective Precovers In The Category Of Modules, Katelyn Coggins

Electronic Theses and Dissertations

It was recently proved that if R is a coherent ring such that R is also left n-perfect, then the class of Gorenstein projective modules, GP, is precovering. We will prove that the class of Gorenstein projective modules is special precovering over any left GF-closed ring R such that every Gorenstein projective module is Gorenstein flat and every Gorenstein flat module has finite Gorenstein projective dimension. This class of rings includes that of right coherent and left n-perfect rings.

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Combinatorial Optimization Of Subsequence Patterns In Words, Matthew R. Just Jan 2016

Combinatorial Optimization Of Subsequence Patterns In Words, Matthew R. Just

Electronic Theses and Dissertations

Packing patterns in words concerns finding a word with the maximum number of a prescribed pattern. The majority of the work done thus far is on packing patterns into permutations. In 2002, Albert, Atkinson, Handley, Holton and Stromquist showed that there always exists a layered permutation containing the maximum number of a layered pattern among all permutations of length n. Consequently, the packing density for all but two (up to equivalence) permutation patterns up to length 4 can be obtained. In this thesis we consider the analogous question for colored patterns and permutations. By introducing the concept of colored blocks …

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Geometric-Based Algorithm For A Full Row-Rank System Matrix Along Multiple Directions In Dt, Igor Lutsenko Jan 2016

Geometric-Based Algorithm For A Full Row-Rank System Matrix Along Multiple Directions In Dt, Igor Lutsenko

Electronic Theses and Dissertations

Discrete tomography (DT) is an image reconstruction procedure that deals with computational synthesis of a cross-sectional image of an object from either transmission or reflection data collected by penetrating an object with X-rays from a small number of different directions, and whose range of the underlying function is discrete. Image reconstruction using algebraic approach is time consuming and the computation cost depends on the size of the system matrix. More scanning directions provide an increase in the reconstructed image quality, however they increase the size of the system matrix dramatically. Deletion of linearly dependent rows of this matrix is necessary …

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Missing Data In Clinical Trial: A Critical Look At The Proportionality Of Mnar And Mar Assumptions For Multiple Imputation, Theophile B. Dipita Jan 2016

Missing Data In Clinical Trial: A Critical Look At The Proportionality Of Mnar And Mar Assumptions For Multiple Imputation, Theophile B. Dipita

Electronic Theses and Dissertations

Randomized control trial is a gold standard of research studies. Randomization helps reduce bias and infer causality. One constraint of these studies is that it depends on participants to obtain the desired data. Whatever the researcher can do, there is a possibility to end up with incomplete data. The problem is more relevant in clinical trials when missing data can be related to the condition under study. The benefits of randomization is compromised by missing data. Multiple imputation is a valid method of treating missing data under the assumption of MAR. Unfortunately this is an unverified assumptions. Current practice advise …

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Blow-Up Solution And Blow-Up Rate Of Bose-Einstein Condensates With Rotational Term, Nyla Basharat Jan 2016

Blow-Up Solution And Blow-Up Rate Of Bose-Einstein Condensates With Rotational Term, Nyla Basharat

Electronic Theses and Dissertations

In this thesis, we discuss the Gross Pitaevskii Equation (GPE) with harmonic potential and with an angular momentum rotational term in space R^2, which describes the model for Bose-Einstein Condensation. Local Well-Posedness of the equation and the conservation identities for mass, energy and angular momentum are presented. Using the virial identities, we derive the condition for blow-up solution in finite time. Then a threshold of L^2 norm of wave function is obtained for global existence, of GPE in term of ground state solution. This method allows us to obtain our main result ``Sharp sufficient condition for global …

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Up-Converted Emissions Of Er3+ Doped Gd2(Wo4)3 Phosphors, Grayson L. Wiggins Jan 2016

Up-Converted Emissions Of Er3+ Doped Gd2(Wo4)3 Phosphors, Grayson L. Wiggins

Electronic Theses and Dissertations

In this work, the up-conversion (UC) emissions of Er3+ in a gadolinium tungstate host was investigated to analyze the possible processes of up-conversion by 1500 nm and 980 nm excitation. Studies were conducted to see how the 4S3/2 -> 4I15/2 transition changed with varying current through the excitation source, varying excitation wavelength, and doping concentration. Power dependent studies revealed that under 1500 nm excitation the 4S3/2 -> 4I15/2 transition needed 3 photons, while 980 nm excitation could do the same transition with 2 photons. It was found that 1500 nm could produce more efficient red emission due to the 4I9/2 …

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A Partition Function Connected With The Göllnitz-Gordon Identities, Nicolas A. Smoot Jan 2016

A Partition Function Connected With The Göllnitz-Gordon Identities, Nicolas A. Smoot

Electronic Theses and Dissertations

Nearly a century ago, the mathematicians Hardy and Ramanujan established their celebrated circle method to give a remarkable asymptotic expression for the unrestricted partition function. Following later improvements by Rademacher, the method was utilized by Niven, Lehner, Iseki, and others to develop rapidly convergent series representations of various restricted partition functions. Following in this tradition, we use the circle method to develop formulas for counting the restricted classes of partitions that arise in the Gollnitz-Gordon identities. We then show that our results are strongly supported by numerical tests. As a side note, we also derive and compare the asymptotic behavior …

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Web Accessibility Compliance For E-Government Websites In The Gulf Region, Muhammad Saleem Jan 2016

Web Accessibility Compliance For E-Government Websites In The Gulf Region, Muhammad Saleem

Theses: Doctorates and Masters

The World Wide Web is a digital platform that helps people access and retrieve information in an accessible and equitable manner. However, people with disabilities can face a number of challenges when it comes to using the Web and accessing content on websites. According to Henry, web accessibility means “that people with disabilities can use the Web. More specifically, Web accessibility means that people with disabilities can perceive, understand, navigate, and interact with the Web, and that they can contribute to the Web” (2005, para.1). While different countries across the globe tackle issues of equitable access to the web via …

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Assessing Shoreline Change And Vegetation Cover Adjacent To Back-Barrier Shoreline Stabilization Structures In Georgia Estuaries, Katherine R. Wakefield Jan 2016

Assessing Shoreline Change And Vegetation Cover Adjacent To Back-Barrier Shoreline Stabilization Structures In Georgia Estuaries, Katherine R. Wakefield

Electronic Theses and Dissertations

Anthropogenic stabilization of erosional shorelines by hard-armoring structures is used for protection of property, especially if buildings, historical monuments, cultural resources, or other infrastructure are present. The post-installation effects of shoreline stabilization structures on adjacent shorelines in the back-barrier marshes of coastal Georgia are a concern, and interest in living shorelines as erosion control devices has increased because of their use of natural materials and vegetation. AMBUR shoreline analysis software was used to calculate pre-and post-installation shoreline change rates of shorelines adjacent to riprap and bulkhead structures. There was no significant difference between the post-installation shoreline change rates of the …

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An Alignment-Free "Metapeptide" Strategy For Metaproteomic Characterization Of Microbiome Samples Using Shotgun Metagenomic Sequencing, Damon H. May, Emma Timmins-Schiffman, Molly P. Mikan, H. Rodger Harvey, Elhanan Borenstein, Brook L. Nunn, William S. Noble Jan 2016

An Alignment-Free "Metapeptide" Strategy For Metaproteomic Characterization Of Microbiome Samples Using Shotgun Metagenomic Sequencing, Damon H. May, Emma Timmins-Schiffman, Molly P. Mikan, H. Rodger Harvey, Elhanan Borenstein, Brook L. Nunn, William S. Noble

OES Faculty Publications

In principle, tandem mass spectrometry can be used to detect and quantify the peptides present in a microbiome sample, enabling functional and taxonomic insight into microbiome metabolic activity. However, the phylogenetic diversity constituting a particular microbiome is often unknown, and many of the organisms present may not have assembled genomes. In ocean microbiome samples, with particularly diverse and uncultured bacterial communities, it is difficult to construct protein databases that contain the bulk of the peptides in the sample without losing detection sensitivity due to the overwhelming number of candidate peptides for each tandem mass spectrum. We describe a method for …

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Carbon Cycling In Santa Barbara Basin Sediments: A Modeling Study, David J. Burdige, Tomoko Komada, Cédric Magen, Jeffrey P. Chanton Jan 2016

Carbon Cycling In Santa Barbara Basin Sediments: A Modeling Study, David J. Burdige, Tomoko Komada, Cédric Magen, Jeffrey P. Chanton

OES Faculty Publications

The primary input of organic matter to almost all marine sediments comes from deposition at the sediment surface. However, in many continental margin settings, reduced carbon can also be added to sediments from below—for example, from “deep” geologic hydrocarbon reservoirs derived from ancient source rocks or from the decomposition of deeply buried gas hydrate deposits. To examine the impact of these two differing reduced carbon inputs on sediment biogeochemistry, a modified reaction-transport model for anoxic marine sediments is described here and applied to data from sediment cores in Santa Barbara Basin to a depth of 4.6 m. Excellent model fits …

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Effect Of 5-Hydroxymethylcytosine Modifications On Stability Of Vegf I-Motifs, Bethany Summerford Jan 2016

Effect Of 5-Hydroxymethylcytosine Modifications On Stability Of Vegf I-Motifs, Bethany Summerford

Honors Theses

DNA i-motifs are a secondary structure of DNA formed at low pH by internal folding of strands rich in cytosine. This study focuses on trying to determine if the DNA from the vascular endothelial growth factor (VEGF) promoter, which can form an i-motif, can be stabilized with the epigenetic modification to 5- hydroxymethylcytosine in four separate locations on the DNA strand, and to what extent the degree of stabilization depends on the location of the modification. Stability of the i-motif was determined by measuring pKa and melting point (Tm) of each VEGF modification using circular dichroism spectroscopy. The modified samples …

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Paleolithic Protection In A Western World: A Look Into Preagricultural Nutrition As A Remedy For The Diseases Of Civilization, Emilie R. Caron Jan 2016

Paleolithic Protection In A Western World: A Look Into Preagricultural Nutrition As A Remedy For The Diseases Of Civilization, Emilie R. Caron

Honors Theses

The aim of this investigation is to discover the associations of the Western diet to noncommunicable diseases and to determine if a reversion to a Paleolithic diet will provide treatment and prevention of these diseases. Noncommunicable diseases, otherwise known as Diseases of Civilization, are lifestyle influenced diseases and encompass obesity, diabetes mellitus, cardiovascular disease, and associated cancers. Incidences of these diseases have skyrocketed in the past century and show no signs of decline. Since 1900, the death rates due to heart disease and cancer have risen to account for 47% of total deaths in the United States in 2010. (Tippett, …

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Statistical Analysis Of Arsenic Concentrations In Subsurface Soils At The University Of Mississippi Field Station, David Thomas Webb Jan 2016

Statistical Analysis Of Arsenic Concentrations In Subsurface Soils At The University Of Mississippi Field Station, David Thomas Webb

Honors Theses

The purpose of this investigation is to determine how arsenic concentration varies in soils with respect to soil structures, grain size, soil type, and depth. The investigation was conducted at the University of Mississippi Field Station (UMFS). The UMFS is located in Abbeville, MS and is roughly 700 acres in size. It includes ponds and former agricultural fields, and lies within an internally draining basin. Seven boreholes were drilled using a direct push geoprobe and sampled. The cores obtained from the borings were then cut at one foot intervals, producing a total of 90 soil samples. Each sample was observed …

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Multidimensional Motion Capture Using Doppler Ultrasound, Forrest Nolan Gamble Jan 2016

Multidimensional Motion Capture Using Doppler Ultrasound, Forrest Nolan Gamble

Honors Theses

Ultrasonic waves are used to measure the velocity of a target object by measuring the Doppler shift of the reflected waves. In this work, ultrasonic Doppler Sonar (UDS) was used to measure the velocity of objects, including a pendulum and a battery on a turntable. The investigation focused on developing a method to measure motion in two and three dimensions, for applications in gait analysis and sports motion capture. By using multiple ultrasonic transducers and novel data processing techniques, the UDS captured motion in two and three dimensions. In order to test the accuracy of the velocity and position measurements, …

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Rhenium-Pyridyl-Nhcs For Photocatalytic Co2 Reduction, Emily Anne Sharpe Jan 2016

Rhenium-Pyridyl-Nhcs For Photocatalytic Co2 Reduction, Emily Anne Sharpe

Honors Theses

The ability to transform CO2 into a useable fuel source would have a remarkably positive impact on the environment by taking the vast amounts of previous unusable CO2 from the atmosphere and reducing it to CO, which can then be turned into fuel. This project involves the synthesis and testing of air and water stable Re (I) pyridyl N- heterocyclic carbene (NHC) compounds for photocatalytic reduction of CO2 into CO using a simulated solar spectrum. Previous research in this area focused on the use of Re(bpy)CO3X, which quickly became the benchmark of homogeneous CO2 reduction photocatalysts. The Re (I) pyridyl …

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A Computational Study Of High Energy Density Materials And Their Detection Using Surface-Enhanced Raman Spectroscopy, Emily N. Hugo Jan 2016

A Computational Study Of High Energy Density Materials And Their Detection Using Surface-Enhanced Raman Spectroscopy, Emily N. Hugo

Honors Theses

The purpose of this thesis is to theoretically predict the vibrational spectra of select high energy density materials (HEDMs) as well as some of their byproducts and to determine if using surface-enhanced Raman spectroscopy (SERS) could be a viable detection method for these compounds. Studying the vibrational patterns of these compounds will help in identifying them in the environment for remediation purposes. Because the byproducts are smaller and easier to model than the parent compounds, these were studied more in depth through analyzing their Infrared and Raman spectra. Ag2 was used to model the interactions between the Ag nanoparticles used …

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A Study On The Characterization And Implementation Of Tools For Advanced Ligo, Hunter Gabbard Jan 2016

A Study On The Characterization And Implementation Of Tools For Advanced Ligo, Hunter Gabbard

Honors Theses

The Laser Interferometer Gravitational Wave Observatory (LIGO) is aimed at directly detecting gravitational waves, small perturbations or ripples in the fabric of space-time. Because of their extreme sensitivity, the LIGO detectors are affected by many sources of non-astrophysical noise. In the first part of this thesis we test a pipeline designed for the identification of short-duration noise transients, called Omicron. We first inject simulated noise waveforms in engineering run data from the LIGO detector in Livingston, Louisiana and then determine Omicron efficiency by attempting to recover these injections. In the second part of this thesis, we present a novel method …

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Blue Cheese Cosmology: Lensing By Cosmic Strings, Jared Wofford Jan 2016

Blue Cheese Cosmology: Lensing By Cosmic Strings, Jared Wofford

Honors Theses

The light bending effects around cosmic strings in universes with varying rates of expansion are investigated. A relationship between the angular deflection and the expansion rate is found. This is made possible by the Blue Cheese model, which is a generalization to a cylindrical realm of the Swiss Cheese model

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Study Of An Active-State Cb1 Receptor Model And Jwh Compound Interactions To Predict New Emerging Synthetic Cannabinoids, Kelsey Leigh Pettus Jan 2016

Study Of An Active-State Cb1 Receptor Model And Jwh Compound Interactions To Predict New Emerging Synthetic Cannabinoids, Kelsey Leigh Pettus

Honors Theses

In recent years, a new class of compounds, called synthetic cannabinoids, have made their appearance in the market as a substitute for illegal marijuana or its constituent natural cannabinoids. These compounds, which are active at the same G- protein coupled receptors (GPCRS) as cannabinoids, are continuing to gain popularity because of the same cannabinoid-like effects they create. Though two cannabinoid receptors have been identified in humans, known as CB1 and CB2, synthetic cannabinoid activity at the CB1 receptor has been the focus of much research regarding synthetic cannabinoid ligand binding. In this study, the structure of the CB1 receptor is …

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Conformational Analysis Of A Furan, Thiophene Alternating Π System, Laura Cline Jan 2016

Conformational Analysis Of A Furan, Thiophene Alternating Π System, Laura Cline

Honors Theses

Organic materials with conjugated Ï€-electron networks are increasingly being studied as an alternative to inorganic semiconductors. In order to effectively transport charge as a semiconductor, the organic materials should maintain a planar conformation, exhibit Ï€ conjugation, and be rigid to rotational interconversion. Both furan and thiophene systems have been investigated as potential organic semiconductors but difficulties with solubility, synthesis, and effectiveness hampered these efforts. A novel furan-thiophene hybrid system that exhibits promising semiconducting properties is examined here. Full geometry optimizations and corresponding harmonic vibrational frequency computations were run on a diverse set of potential furan and thiophene oligomer structures using …

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The Synthesis Of Substituted Pentadentate Ligand Scaffolds And Their Future Application In Ruthenium-Catalyzed Water Oxidation, Manpreet Singh Jan 2016

The Synthesis Of Substituted Pentadentate Ligand Scaffolds And Their Future Application In Ruthenium-Catalyzed Water Oxidation, Manpreet Singh

Honors Theses

Rising global energy demands coupled with depleting natural resources have led to a strong emphasis on finding new sources of energy that are renewable and which limit the negative impact on the environment. One of the strongest candidates is utilizing solar energy to drive water oxidation to produce hydrogen as a fuel source. In order to do this, a better understanding of the mechanism involved in this process must be revealed. Homogenous molecular catalysts allow mechanistic studies and can be also used in Photoelectrochemical Cells (PECs) and other systems to produce chemical fuels. In this work, the new syntheses of …

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The Evolution Of The Sugarcoated American Food Market And The Paradox Of Artificial Sweeteners, Mary Moses Hitt Jan 2016

The Evolution Of The Sugarcoated American Food Market And The Paradox Of Artificial Sweeteners, Mary Moses Hitt

Honors Theses

Living in present-day America makes it hard to imagine an era when sugar was not as inexpensive and readily available as it is now. It is in little colorful packets on restaurant tables, filled to the brim in jars at coffee shops, or mixed into candy products located at the beginning of every cash register. Today, sugar is one of, if not, the most widely consumed food products in the world, but our love for sugar is nothing new. Humans have been experiencing the bliss triggered by sweet-tasting foods since their earliest diets, which included fruits and honey. Our diets …

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