Open Access. Powered by Scholars. Published by Universities.®

Digital Commons Network™

Open Access. Powered by Scholars. Published by Universities.®

Brigham Young University

Discipline
Keyword
Publication Year
Publication
Publication Type
File Type

Articles 1321 - 1350 of 8046

Full-Text Articles in Entire DC Network

Building An Ins-1 Cdna Library For A Genome-Wide Crispr-Cas9 Screen, Idongesit Ekpo Aug 2020

Building An Ins-1 Cdna Library For A Genome-Wide Crispr-Cas9 Screen, Idongesit Ekpo

Undergraduate Honors Theses

By the year 2040, an estimated 642 million people are expected to have diabetes globally. Diabetes results from an elevation of metabolic stressors, such as glucotoxicity, lipotoxicity, oxidative stress and apoptosis. In type 2 diabetes, these stressful conditions contribute to the malfunction and loss of functional insulin-producing β-cells. Current treatment methods for diabetes include insulin therapy, islet transplant and anti-diabetes medication. These treatments are not curative and ignore other factors that contribute to the pathogenesis of diabetes beyond insulin resistance and islet β-cell failure. Previous research on β-cells has focused on ways to replace functional β-cell mass, trigger β-cell proliferation, …

Go to article

Governing Dynamics Of Divalent Copper Binding By Influenza A Matrix Protein 2 His37 Imidazole, Kelly Lewis Mcguire Aug 2020

Governing Dynamics Of Divalent Copper Binding By Influenza A Matrix Protein 2 His37 Imidazole, Kelly Lewis Mcguire

Theses and Dissertations

Influenza A is involved in hundreds of thousands of deaths globally every year resulting from viral infection-related complications. Previous efforts to subdue the virus by preventing proper function of wild-type (WT) neuraminidase (N), and M2 proteins using oseltamivir and amantadine (AMT) or rimantadine (RMT), respectively, exhibited success initially. Over time, these drugs began exhibiting mixed success as the virus developed drug resistance. M2 is a proton channel responsible for the acidification of the viral interior which facilitates release of the viral RNA into the host. M2 has a His37-tetrad that is the selective filter for protons. This protein has been …

Go to article

A Method For Reconstructing Historical Destructive Earthquakes Using Bayesian Inference, Hayden J. Ringer Aug 2020

A Method For Reconstructing Historical Destructive Earthquakes Using Bayesian Inference, Hayden J. Ringer

Theses and Dissertations

Seismic hazard analysis is concerned with estimating risk to human populations due to earthquakes and the other natural disasters that they cause. In many parts of the world, earthquake-generated tsunamis are especially dangerous. Assessing the risk for seismic disasters relies on historical data that indicate which fault zones are capable of supporting significant earthquakes. Due to the nature of geologic time scales, the era of seismological data collection with modern instruments has captured only a part of the Earth's seismic hot zones. However, non-instrumental records, such as anecdotal accounts in newspapers, personal journals, or oral tradition, provide limited information on …

Go to article

Investigation Of Isotruss® Structures In Compression Using Numerical, Dimensional, And Optimization Methods, Hanna Belle Opdahl Aug 2020

Investigation Of Isotruss® Structures In Compression Using Numerical, Dimensional, And Optimization Methods, Hanna Belle Opdahl

Theses and Dissertations

The purpose of this research is to investigate the structural efficiency of 8-node IsoTruss structures subject to uniaxial compression using numerical, dimensional, and optimization methods. The structures analyzed herein are based on graphite/epoxy specimens that were designed for light-weight space applications, and are approximately 10 ft. (3 m) long and 0.3 lb. (0.14 kg). The principal failure modes considered are material failure, global buckling, local buckling at the bay level, and longitudinal strut buckling. Studies were performed with the following objectives: to correlate finite element predictions with experimental and analytical methods; to derive analytical expressions to predict bay-level buckling; to …

Go to article

Breaking The Organic Mold: Introducing Copper Into The Influenza A Arena With Neutral And Divalent Complexes, Jonathan D. Lynch Aug 2020

Breaking The Organic Mold: Introducing Copper Into The Influenza A Arena With Neutral And Divalent Complexes, Jonathan D. Lynch

Theses and Dissertations

Influenza A (IVA) continues to pose a growing global threat even as current medications are becoming less effective. One of the main avenues of research into new anti-IVA drugs is its homotetrameric Matrix 2 proton channel (M2A), without which the virus would be unable to release its viral RNA into the host cell. The drug amantadine used to bind and block M2A until near-ubiquitous resistance formed as an M2A-S31N mutation, starting around 1995 and proceeding to 2005 when amantadine was disallowed for use as an anti-IVA drug. The standard organic structure currently being used for M2A inhibitor research comprises an …

Go to article

Discovery Of A Novel Regulatory Mechanism Of Tnk1 By 14-3-3 And Its Ubiquitin Association Domain Provides A Potential Therapeutic Targeting Opportunity In Cancer, Tsz Yin Chan Aug 2020

Discovery Of A Novel Regulatory Mechanism Of Tnk1 By 14-3-3 And Its Ubiquitin Association Domain Provides A Potential Therapeutic Targeting Opportunity In Cancer, Tsz Yin Chan

Theses and Dissertations

While a relatively limited number of known oncogenes underlie a large percentage of cancers, a variety of new genes have emerged as low-frequency cancer drivers. Each of these new oncogenes represents a frontier for targeted therapy. However, the discovery of low-frequency targetable oncogenic drivers is challenging. This study focuses on the poorly understood Tyrosine kinase non-receptor-1 (TNK1), which has been reported to have both oncogenic and tumor suppressive functions. TNK1 has been identified to promote cancer cells survival and promote chemoresistance in multiple independent studies. On the other hand, whole-body constitutive deletion of TNK1 in mice caused an increase in …

Go to article

Linear And Nonlinear Dimensionality-Reduction-Based Surrogate Models For Real-Time Design Space Exploration Of Structural Responses, Gregory David Bird Aug 2020

Linear And Nonlinear Dimensionality-Reduction-Based Surrogate Models For Real-Time Design Space Exploration Of Structural Responses, Gregory David Bird

Theses and Dissertations

Design space exploration (DSE) is a tool used to evaluate and compare designs as part of the design selection process. While evaluating every possible design in a design space is infeasible, understanding design behavior and response throughout the design space may be accomplished by evaluating a subset of designs and interpolating between them using surrogate models. Surrogate modeling is a technique that uses low-cost calculations to approximate the outcome of more computationally expensive calculations or analyses, such as finite element analysis (FEA). While surrogates make quick predictions, accuracy is not guaranteed and must be considered. This research addressed the need …

Go to article

Analyzing Metacommunity Models With Statistical Variance Partitioning: A Review And Meta-Analysis, Kevin Vieira Lamb Aug 2020

Analyzing Metacommunity Models With Statistical Variance Partitioning: A Review And Meta-Analysis, Kevin Vieira Lamb

Theses and Dissertations

The relative importance of deterministic processes versus chance is one of the most important questions in science. We analyze the success of variance partitioning methods used to explain variation in β-diversity and partition it into environmental, spatial, and spatially structured environmental components. We test the hypotheses that 1) the number of environmental descriptors in a study would be positively correlated with the percentage of β-diversity explained by the environment, and that the environment would explain more variation in β-diversity than spatial or shared factors in VP analyses, 2) increasing the complexity of environmental descriptors would help account for more of …

Go to article

Non-Invasive Neurosurgeries Using Ultrasound And Mri, Steven P. Allen Aug 2020

Non-Invasive Neurosurgeries Using Ultrasound And Mri, Steven P. Allen

BYU Research Development Office Research Networking Conference

Medical Imaging Physics, Signal and Image Processing, Ultrasonics and Acoustics, Magnetic Resonance Imaging, Neurosurgeries

Go to article

Exploring The Louisiana Purchase And Its Borderlands: The Lewis And Clark, Hunter And Dunbar, Zebulon Pike, And Freeman And Custis Expeditions In Perspective [Part 1], Jay H. Buckley Aug 2020

Exploring The Louisiana Purchase And Its Borderlands: The Lewis And Clark, Hunter And Dunbar, Zebulon Pike, And Freeman And Custis Expeditions In Perspective [Part 1], Jay H. Buckley

Faculty Publications

When Americans contemplate the exploration of the Louisiana Purchase, the names Meriwether Lewis and William Clark quickly come to mind. Their historic journey was well conceived, well executed, and well documented. It was one of the first and longest U.S. government-backed explorations of the American West. The name Zebulon Pike, for some, conjures up notions of a lost explorer who was arrested by the Spanish as an alleged American spy. Fewer still have heard of the names William Dunbar, George Hunter, Thomas Freeman, and Peter Custis. Even those who have heard of these men may be hard-pressed to identify any …

Go to article

Zipperotf: Automatic, Precise, And Simple Data Race Detection For Task Parallel Programs With Mutual Exclusion, S. Jacob Powell Jul 2020

Zipperotf: Automatic, Precise, And Simple Data Race Detection For Task Parallel Programs With Mutual Exclusion, S. Jacob Powell

Theses and Dissertations

Data race in parallel programs can be difficult to precisely detect, and doing so manually can often prove unsuccessful. Task parallel programming models can help reduce defects introduced by the programmer by restricting concurrent functionalities to fork-join operations. Typical data race detection algorithms compute the happens-before relation either by tracking the order that shared accesses happen via a vector clock counter, or by grouping events into sets that help classify which heap locations are accessed sequentially or in parallel. Access sets are simple and efficient to compute, and have been shown to have the potential to outperform vector clock approaches …

Go to article

Clarque: Chatbot Recognizing Ambiguity In The Conversation And Asking Clarifying Questions, Shreeya Himanshu Mody Jul 2020

Clarque: Chatbot Recognizing Ambiguity In The Conversation And Asking Clarifying Questions, Shreeya Himanshu Mody

Theses and Dissertations

Recognizing when we need more information and asking clarifying questions are integral to communication in our day to day life. It helps us complete our mental model of the world and eliminate confusion. Chatbots need this technique to meaningfully collaborate with humans. We have investigated a process to generate an automated system that mimics human communication behavior using knowledge graphs, weights, an ambiguity test, and a response generator. It can take input dialog text and based on the chatbot's knowledge about the world and the user it can decide if it has enough information or if it requires more. Based …

Go to article

Age-Suitability Prediction For Literature Using Deep Neural Networks, Eric Robert Brewer Jul 2020

Age-Suitability Prediction For Literature Using Deep Neural Networks, Eric Robert Brewer

Theses and Dissertations

Digital media holds a strong presence in society today. Providers of digital media may choose to obtain a content rating for a given media item by submitting that item to a content rating authority. That authority will then issue a content rating that denotes to which age groups that media item is appropriate. Content rating authorities serve publishers in many countries for different forms of media such as television, music, video games, and mobile applications. Content ratings allow consumers to quickly determine whether or not a given media item is suitable to their age or preference. Literature, on the other …

Go to article

Optimal Learning Rates For Neural Networks, Tyler Moncur Jul 2020

Optimal Learning Rates For Neural Networks, Tyler Moncur

Theses and Dissertations

Neural networks have long been known as universal function approximators and have more recently been shown to be powerful and versatile in practice. But it can be extremely challenging to find the right set of parameters and hyperparameters. Model training is both expensive and difficult due to the large number of parameters and sensitivity to hyperparameters such as learning rate and architecture. Hyperparameter searches are notorious for requiring tremendous amounts of processing power and human resources. This thesis provides an analytic approach to estimating the optimal value of one of the key hyperparameters in neural networks, the learning rate. Where …

Go to article

A Derivation Of Scattered Intensity (Radiance) For Use In Optical Particle Counters, Brady S. Hales, Matthew R. Jones, Randy S. Lewis Jul 2020

A Derivation Of Scattered Intensity (Radiance) For Use In Optical Particle Counters, Brady S. Hales, Matthew R. Jones, Randy S. Lewis

Student Works

Mie scattering theory is often used to calculate the flux of light scattered off of small particles whose diameter is approximately the same order of magnitude as the wavelength of incident light. In many equations for the calculation of this flux, it is assumed that the area of interest is perpendicular to the ray of scattered light. This assumption does not apply to all cases such as low-cost (

Go to article

Heterogenity In Brain Injury: An Investigation Of The Efficacy Of Qualitative Comparative Analysis In Diffusion Tensor Imaging, Cooper Benton Hodges Jul 2020

Heterogenity In Brain Injury: An Investigation Of The Efficacy Of Qualitative Comparative Analysis In Diffusion Tensor Imaging, Cooper Benton Hodges

Theses and Dissertations

Traumatic brain injury (TBI) and its associated neural and cognitive sequelae are of increasing interest in military populations. Blast-related TBI is becoming more commonplace in military Service Members and Veterans since Operation Iraqi Freedom/Operation Enduring Freedom/Operation New Dawn and their following conflicts. It is currently unclear whether blast-related injuries cause unique neural and cognitive deficits. The present investigation, in Study 1, aims to investigate the differences in blast-related and non-blast related TBI using traditional statistical techniques. In Study 2, this study will demonstrate the use of Qualitative Comparative Analysis (QCA) in diffusion tensor imaging data. QCA is a relatively new …

Go to article

Applications Of Mathematical Optimization Methods To Digital Communications And Signal Processing, Spencer Giddens Jul 2020

Applications Of Mathematical Optimization Methods To Digital Communications And Signal Processing, Spencer Giddens

Theses and Dissertations

Mathematical optimization is applicable to nearly every scientific discipline. This thesis specifically focuses on optimization applications to digital communications and signal processing. Within the digital communications framework, the channel encoder attempts to encode a message from a source (the sender) in such a way that the channel decoder can utilize the encoding to correct errors in the message caused by the transmission over the channel. Low-density parity-check (LDPC) codes are an especially popular code for this purpose. Following the channel encoder in the digital communications framework, the modulator converts the encoded message bits to a physical waveform, which is sent …

Go to article

A Fmri Of Fear Conditioning And Auditory Looming In Autism Spectrum Disorder, David Nicholas Top Jr. Jul 2020

A Fmri Of Fear Conditioning And Auditory Looming In Autism Spectrum Disorder, David Nicholas Top Jr.

Theses and Dissertations

Many autistic adults experience debilitating anxiety that interferes with their daily functioning. Atypical sensory processing and intolerance of uncertainty are cognitive processes linked to atypical limbic system functioning and impaired fear conditioning as potential mediators of anxiety in autism. A previous fear conditioning study using fMRI found atypical amygdala functioning in autism when the threat stimulus was only partially reinforced. The first aim of this dissertation is a multimethod examination of brain and psychophysiological response in autistic and in neurotypical adults during a fear conditioning/extinction task with the threat stimulus reinforced 100% percent of the time. We were also interested …

Go to article

Teachers' Mathematical Meanings: Decisions For Teaching Geometric Reflections And Orientation Of Figures, Porter Peterson Nielsen Jul 2020

Teachers' Mathematical Meanings: Decisions For Teaching Geometric Reflections And Orientation Of Figures, Porter Peterson Nielsen

Theses and Dissertations

Teachers' instructional decisions are important for students' mathematics learning as they determine the learning opportunities for all students. This study examines teachers' decisions about the activities and tasks they choose for students' mathematics learning, the ordering and connecting of mathematics topics, and the mathematics within curricula not to cover. These decisions are referred to as curricular decisions. I also identify teachers' mathematical schemes, referred to as mathematical meanings, in relation to geometric reflections and orientation of figures and examine teachers' reasoning with their mathematical meanings as they make these curricular decisions. Additionally, based on the results of this study I …

Go to article

Facing The Hard Problems In Fgvc, Connor Stanley Anderson Jul 2020

Facing The Hard Problems In Fgvc, Connor Stanley Anderson

Theses and Dissertations

In fine-grained visual categorization (FGVC), there is a near-singular focus in pursuit of attaining state-of-the-art (SOTA) accuracy. This work carefully analyzes the performance of recent SOTA methods, quantitatively, but more importantly, qualitatively. We show that these models universally struggle with certain "hard" images, while also making complementary mistakes. We underscore the importance of such analysis, and demonstrate that combining complementary models can improve accuracy on the popular CUB-200 dataset by over 5%. In addition to detailed analysis and characterization of the errors made by these SOTA methods, we provide a clear set of recommended directions for future FGVC researchers.

Go to article

Implications Of Geochemistry And Textures Of Titanite For The Geologic Histories Of The Notch Peak Intrusion And Little Cottonwood Stock, Utah, Porter Henze Jul 2020

Implications Of Geochemistry And Textures Of Titanite For The Geologic Histories Of The Notch Peak Intrusion And Little Cottonwood Stock, Utah, Porter Henze

Theses and Dissertations

Textural and compositional variations in titanite, along with whole-rock geochemistry, provide constraints on the emplacement and cooling histories of two plutons: the Jurassic Notch Peak pluton and the Oligocene Little Cottonwood stock, both in Utah. Titanite textures observed with back-scattered electron (BSE) imaging along with their compositions were used to determine four periods of growth: cores, rims, interstitial overgrowths, and secondary replacements. Brightness in BSE images correlates mostly with rare earth elements (REE). REE patterns in cores and rims are compositionally similar in both plutons, although the Notch Peak intrusion tend to be slightly more enriched in REE. Overgrowths and …

Go to article

Effect Of Dilution On Sedimentational Separation Of Bacteria From Blood, Clifton M. Anderson, William G. Pitt Jul 2020

Effect Of Dilution On Sedimentational Separation Of Bacteria From Blood, Clifton M. Anderson, William G. Pitt

Faculty Publications

Bacteria must be separated from septic whole blood in preparation for rapid antibiotic susceptibility tests. This work improves upon past work isolating bacteria from whole blood by exploring an important experimental factor: Whole blood dilution. Herein, we use the continuity equation to model red blood cell sedimentation and show that overall spinning time decreases as the blood is diluted. We found that the bacteria can also be captured more efficiently from diluted blood, up to approximately 68 ± 8% recovery (95% confidence interval). However, diluting blood both requires and creates extra fluid that end users must handle; an optimal dilution, …

Go to article

Specialization: Do Your Job Well Helping Students Who Are Considering A Career In Programming Know How To Invest Their Time., Scott Pulley Jul 2020

Specialization: Do Your Job Well Helping Students Who Are Considering A Career In Programming Know How To Invest Their Time., Scott Pulley

Marriott Student Review

The article examines the effects of specialization on the hiring process for undergraduates studying programming whether in information systems or computer science.

Go to article

Use Of Viologens In Mediated Glucose Fuel Cells And In Aqueous Redox Flow Batteries To Improve Performance, Meisam Bahari Jul 2020

Use Of Viologens In Mediated Glucose Fuel Cells And In Aqueous Redox Flow Batteries To Improve Performance, Meisam Bahari

Theses and Dissertations

This dissertation presents my efforts to use viologens to improve the performance of glucose fuel cells and aqueous redox flow batteries. These two electrochemical systems have the potential to efficiently exploit renewable sources of energy. The contributions and significance of this work are briefly described below. Glucose Fuel cells. For glucose fuel cells, viologens were adopted as an electron mediator to facilitate the transfer of electrons from glucose to electrodes for power generation. Use of a mediator circumvents the need for precious metal electrodes to catalyze glucose oxidation. Both the oxidation efficiency and rate of glucose oxidation are important to …

Go to article

The Role Of The Chaperone Cct In Assembling Cell Signaling Complexes, Nicole C. Tensmeyer Jul 2020

The Role Of The Chaperone Cct In Assembling Cell Signaling Complexes, Nicole C. Tensmeyer

Theses and Dissertations

In order to function, proteins must be folded into their native shape. While this can sometimes occur spontaneously, the process can be hindered by thermodynamic barriers, trapped intermediates, and aggregation prone hydrophobic interactions. Molecular chaperones are proteins that help client proteins or substrates overcome these barriers so that they can be folded properly. One such chaperone is the chaperonin CCT, a large MDa protein made up of 16 paralogous subunits that form a double ring structure. CCT encapsulates its substrates in a central cavity, where they are sequestered and folded, using ATP binding and hydrolysis to drive conformational changes in …

Go to article

Survey Of 8 Uav Set-Covering Algorithms For Terrain Photogrammetry, Joshua Hammond, Cory Vernon, Trent Okeson, Benjamin Barrett, Samuel Arce, Valerie Newell, Joseph Janson, Kevin Franke, John Hedengren Jul 2020

Survey Of 8 Uav Set-Covering Algorithms For Terrain Photogrammetry, Joshua Hammond, Cory Vernon, Trent Okeson, Benjamin Barrett, Samuel Arce, Valerie Newell, Joseph Janson, Kevin Franke, John Hedengren

Faculty Publications

Remote sensing with unmanned aerial vehicles (UAVs) facilitates photogrammetry for environmental and infrastructural monitoring. Models are created with less computational cost by reducing the number of photos required. Optimal camera locations for reducing the number of photos needed for structure-from-motion (SfM) are determined through eight mathematical set-covering algorithms as constrained by solve time. The algorithms examined are: traditional greedy, reverse greedy, carousel greedy (CG), linear programming, particle swarm optimization, simulated annealing, genetic, and ant colony optimization. Coverage and solve time are investigated for these algorithms. CG is the best method for choosing optimal camera locations as it balances number of …

Go to article

Short-Term Effects Of Increased Body Mass And Distribution On Plantar Shear, Postural Control, And Gait Kinetics: Implications For Obesity, Hwigeum Jeong Jul 2020

Short-Term Effects Of Increased Body Mass And Distribution On Plantar Shear, Postural Control, And Gait Kinetics: Implications For Obesity, Hwigeum Jeong

Theses and Dissertations

Context: Obesity is a growing global health concern. The increased body mass and altered mass distribution associated with obesity may be related to increases in plantar shear that putatively leads to physical functional deficits. Therefore, measurement of plantar shear may provide unique insights on the effects of body mass and body distribution on physical function or performance. Purpose: 1) To investigate the effects of body mass and distribution on plantar shear; 2) To examine how altered plantar shear influences postural control and gait kinetics. Hypothesis: 1) a weighted vest forward distributed (FV) would shift the center of pressure (CoP) location …

Go to article

Links Between Eruptive Styles, Magmatic Evolution, And Morphology Of Low-Shield Volcanoes: Snake River Plain, Idaho, Katelyn J. Barton Jul 2020

Links Between Eruptive Styles, Magmatic Evolution, And Morphology Of Low-Shield Volcanoes: Snake River Plain, Idaho, Katelyn J. Barton

Theses and Dissertations

In this study, connections between chemical composition, eruption style, and topographic features of two shield volcanoes on the Snake River Plain, Idaho are examined. These relationships may then be applied to understanding silicate volcanic features throughout the inner solar system. Despite their similar ages and geographic locations, two young basaltic shield volcanoes—Kimama Butte (87 Ka) and Rocky Butte (95 Ka)—have strikingly different topographic profiles. The Kimama Butte shield has a diameter of 9 km and a height of 210 m. In contrast, Rocky Butte has a broad 36 km topographic shield that rises 140 m with less than 1° slopes. …

Go to article

Automated 3d Reconstruction Using Optimized View-Planning Algorithms For Iterative Development Of Structure-From-Motion Models, Samuel Arce, Cory Vernon, Joshua Hammond, Valerie Newell, Joseph Janson, Kevin Franke, John Hedengren Jul 2020

Automated 3d Reconstruction Using Optimized View-Planning Algorithms For Iterative Development Of Structure-From-Motion Models, Samuel Arce, Cory Vernon, Joshua Hammond, Valerie Newell, Joseph Janson, Kevin Franke, John Hedengren

Faculty Publications

Unsupervised machine learning algorithms (clustering, genetic, and principal component analysis) automate Unmanned Aerial Vehicle (UAV) missions as well as the creation and refinement of iterative 3D photogrammetric models with a next best view (NBV) approach. The novel approach uses Structure-from-Motion (SfM) to achieve convergence to a specified orthomosaic resolution by identifying edges in the point cloud and planning cameras that “view” the holes identified by edges without requiring an initial model. This iterative UAV photogrammetric method successfully runs in various Microsoft AirSim environments. Simulated ground sampling distance (GSD) of models reaches as low as 3.4 cm per pixel, and generally, …

Go to article

Vulnerability Analysis Of Infrastructure Systems, Sean Theodore Lane Jul 2020

Vulnerability Analysis Of Infrastructure Systems, Sean Theodore Lane

Theses and Dissertations

Complex cyber-physical systems have become fundamental to modern society by effectively providing critical services and improving efficiency in various domains. Unfortunately, as systems become more connected and more complex, they also can become more vulnerable and less robust. As a result, various failure modes become more common and easily triggered from both unanticipated and malicious perturbations. Research has been conducted in the area of vulnerability analysis for cyber-physical systems, to assist in locating these possible vulnerabilities before they can fail. I present two case studies on different forms of critical infrastructure systems to identify vulnerabilities and understand how external perturbations …

Go to article

First Prev Next Last