Physical Sciences and Mathematics Commons^™

Increased Hydrologic Variability Near The Paleocene-Eocene Boundary (Piceance Creek Basin, Colorado, U.S.A.)), Anna Lesko

WWU Graduate School Collection

The Paleocene Eocene Thermal Maximum (PETM) was a rapid global warming event that occurred approximately 56 million years ago and represents the largest and most abrupt warming event of the Cenozoic Era. The PETM caused mean annual temperatures to increase at least 5°C globally above the already warm, greenhouse climate state of the early Paleogene. The warming and associated perturbation of the carbon cycle had numerous consequences for paleoenvironments and paleobiologic systems. This study investigates the hydrologic response to the PETM within the interior of North America and presents a new d¹³C bulk organic record. This study generates …

Progress Towards The Substrate-Bound Structure Of Streptococcus Pneumoniae Sortase A, Nicholas M. Horvath

WWU Graduate School Collection

Sortases are cysteine transpeptidases found primarily on the cell surface of Gram-positive bacteria. Sortase-mediated ligations have become an attractive option for protein modification chemistry, enabling the synthesis of a wide range of non-natural polypeptide derivatives. Attempts at understanding how these enzymes recognize and bind substrates are integral to furthering their usefulness in protein engineering and, potentially, treatment of bacterial diseases. However, the variable substrate specificity and activity between homologs of these enzymes is not yet fully understood. Of specific interest to us is sortase A from Streptococcus pneumoniae (SrtA_pneu), as it demonstrates a broad substrate tolerance not …

Validation Of Predicted Tsunami Inundation For The Inland Coast Of The Salish Sea Associated With Cascadia Subduction Zone Earthquakes, Paige Morkner

WWU Graduate School Collection

The Cascadia subduction zone is understood to produce large, Mw 9.0, earthquakes every 300-1000 years. As a result of large ruptures along the fault, Washington, Oregon and Northern California, are susceptible large tsunamis along the coast. Hazard modeling and mapping along the Cascadia subduction zone has concluded that large tsunamis are able to travel through the Strait of Juan de Fuca and inundate coastal regions of the Salish Sea and Puget Sound. However, to improve modeling efforts, field validation of models is required. Tsunamis can move material from the near shore and beach and deposit in low-laying coastal marshes and …

Dendroclimatology Of Yellow Cedar (Callitropsis Nootkatensis) And Late Holocene Temperature Variability On The Western Slopes Of The North Cascades In Washington State, Christopher A. (Chrisopher Anthony) Trinies

WWU Graduate School Collection

Subalpine tree growth in the Washington Cascades is often limited by both growing season temperatures and persistence of the winter snowpack, making paleoclimate inferences on temperature alone difficult. Here I expand on three yellow cedar chronologies on the west slopes of the North Cascades and build chronologies for two co-dominant species at one of the sites. I used the VIC hydrologic model to include biologically relevant proxies for water stress, including evapotranspiration deficit, and snow cover in a climate-growth analysis. The co-dominant species, specifically mountain hemlock, showed a climate response reminiscent of a high-elevation, energy-limited environment with an interaction between …

Assessing Coastal Vulnerability To Storm Surge And Wave Impacts With Projected Sea Level Rise Within The Salish Sea, Nathan R. Vanarendonk

WWU Graduate School Collection

Sea level rise (SLR) in the Salish Sea, a large inland waterway shared between Canada and the United States, is expected to be 0.3 to 1.8 m by the year 2100. Uncertainty in greenhouse gas emissions, global ice sheet loss, and other controls such as vertical land movement all contribute to this range. Valuable property, infrastructure, and critical habitats for shellfish and threatened salmon populations are at risk to coastal changes associated with SLR. Additionally, development in Washington State is expected to accelerate through the end of the 21st century adding extra pressure on protecting ecosystems and people from natural …

Springtime Benthic Fluxes In The Salish Sea: Environmental Parameters Driving Spatial Variation In The Exchange Of Dissolved Oxygen, Inorganic Carbon, Nutrients, And Alkalinity Between The Sediments And Overlying Water, Emma I. Rigby

WWU Graduate School Collection

Recent decades have seen changes to biogeochemical cycles in the Salish Sea, including alterations in water column nutrients, an expansion of hypoxic zones, and bottom water acidification. Marine sediments can be a major contributor to these biogeochemical cycles by exchanging solutes with bottom water. In an effort to understand the sediment biogeochemistry of the Salish Sea further, benthic fluxes of dissolved oxygen (DO), dissolved inorganic carbon (DIC), pH, total alkalinity (TA), and nutrients (ammonium, nitrate+nitrite, phosphate, silicate) between the sediment and the overlying water were directly measured using incubated flux cores at 42 sites in April and early May 2018. …

Under What Conditions Could Eelgrass Measurably Drawdown Carbon? Relating Carbon Drawdown To Pco2, Irradiance, And Leaf Area Index Of Zostera Marina, Tyler Tran

WWU Graduate School Collection

Seagrass meadows, common to coastal habitats, have been identified as potential short-term refugia for calcifying organisms from ocean acidification (OA). In nearshore, soft-sediment habitats of the Salish Sea, eelgrass (Zostera marina L.) is the dominant seagrass species, and several studies have found that eelgrass is effective at taking up inorganic carbon and may be carbon-limited, potentially increasing uptake potential in the future. However, irradiance levels vary throughout a day and can therefore influence rates of carbon uptake and release through the relative rates of photosynthesis and respiration. Eelgrass meadows vary in terms of meadow size, shoot density and morphology, …

Surface Modified Gold Nanorods Based Mercury Sensor, Tianqi Luan

WWU Graduate School Collection

The high toxicity of mercury in the form of inorganic vapor and organic compounds has become a major concern leading scientists to investigate more accurate and effective methods for the quantification of residue mercury in drinking water, aquaculture products and industrial wastes. In this research, we designed a mercury sensor based on the amalgamation between mercury and gold nanorods (AuNRs) which relate the longitudinal surface plasmon resonance (LSPR) peak shift induced by aspect ratio (AR) change after amalgamation. However, most of AuNRs synthesized based on seed mediated methods use either citrate or hexadecyl trimethyl ammonium bromide (CTAB) as surface stabilizing …

Development Of A Rangeland Degradation Risk Model For The Peruvian Andes, Colin Schmidt

WWU Graduate School Collection

This study developed a Rangeland Degradation Risk Model for the Peruvian Andes based on the Unit Stream Powered Erosion Deposition Model using globally available datasets. A supervised land cover classification was conducted to identify suitable grazing areas and to conduct a regional analysis of susceptibility to erosion. Field data were collected from two different study sites, Huascaran National Park and Nor Yauyos Cochas Landscape Reserve, and were used to assess the model’s accuracy in different ecosystems and land use types. Field data were also leveraged to identify additional data needs and other potential drivers of degradation not taken into account …

Slip And Strain Accumulation Along The Sadie Creek Fault, Olympic Peninsula, Washington, Cody Duckworth

WWU Graduate School Collection

Upper-plate faulting in the Olympic Peninsula of Washington State reflects the interaction of crustal blocks within the Cascadia forearc as well as contributions from various earthquake cycle processes along the Cascadia subduction zone (CSZ). These processes include interseismic coupling, megathrust earthquakes, and aseismic slow slip events. In this study I utilize high resolution airborne lidar, field mapping of deformed surficial deposits and landforms, optically stimulated luminescence (OSL) dating and radiocarbon dating to reconstruct fault slip rates since Late Pleistocene deglaciation on the Sadie Creek fault (SCF), located north of the Olympic Mountains. This mapping reveals the SCF as a ~14 …

Isopeptide Ligations Catalyzed By Streptococcus Suis Sortase A, Sarah Bowersox

WWU Graduate School Collection

Chemically modified proteins are critical components of modern therapeutics and basic research. To generate non-natural protein derivatives, bacterial sortase enzymes have been effective due to their ability to catalyze selective ligations between protein targets and functional groups that are uncommon in nature. Thus far, the enzymatic approach using sortase has been limited to modifications at the termini of peptide chains. Here we describe efforts to develop a sortase-mediated strategy for the formation of isopeptide bonds at the side chains of internal lysine residues. To this end, we have identified a sortase A homolog from Streptococcus suis (SrtA_suis) that …

The Structural Information Filtered Features Potential For Machine Learning Calculations Of Energies And Forces Of Atomic Systems., Jorge Arturo Hernandez Zeledon

Graduate Theses, Dissertations, and Problem Reports

In the last ten years, machine learning potentials have been successfully applied to the study of crystals, and molecules. However, more complex materials like clusters, macro-molecules, and glasses are out reach of current methods. The input of any machine learning system is a tensor of features (the most universal type are rank 1 tensors or vectors of features), the quality of any machine learning system is directly related to how well the feature space describes the original physical system. So far, the feature engineering process for machine learning potentials can not describe complex material. The current methods are highly inefficient …

Deep Learning For Image Restoration And Robotic Vision, Yixin Du

Graduate Theses, Dissertations, and Problem Reports

Traditional model-based approach requires the formulation of mathematical model, and the model often has limited performance. The quality of an image may degrade due to a variety of reasons: It could be the context of scene is affected by weather conditions such as haze, rain, and snow; It's also possible that there is some noise generated during image processing/transmission (e.g., artifacts generated during compression.). The goal of image restoration is to restore the image back to desirable quality both subjectively and objectively. Agricultural robotics is gaining interest these days since most agricultural works are lengthy and repetitive. Computer vision is …

Design Of Experiment And Analysis Techniques For Fuel Consumption Data Using Heavy-Duty Diesel Vehicles And On-Road Testing, Sarah Ann Mills

Graduate Theses, Dissertations, and Problem Reports

Chassis dynamometer and on-road testing are usually employed to test vehicle operation. Testing on a chassis dynamometer reduces data variability compared to on-road testing due to the controlled environment but it does not account for other important variables that affects real-world vehicle operation. This study used on-road testing to investigate the differences between two test fuels under real-world conditions. Three heavy-duty diesel vehicles were driven on different routes for a period of three months. Each vehicle was instrumented with flow meters to gather fuel consumption data, which was then compared to the fuel rate broadcasted by the engine control unit …

Empirical Studies Related To Open Questions Regarding Geomagnetic Storms, Bruce Patrick Tepke

Graduate Theses, Dissertations, and Problem Reports

Earth’s magnetosphere is subject to disturbances, as evidenced by variations of the geomagnetic field in space and on the ground. It is generally understood that most such disturbances are controlled by variations in the solar wind, with interplanetary magnetic field orientations directed southward opposite to Earth’s dipole magnetic axis being most conducive to energy transfers into the magnetosphere, thus resulting in more disturbed intervals. However, the exact functional form for solar wind driving of the magnetosphere has been widely studied, with proposed functional forms varying from the simple half-wave electric rectifier to expressions with a much more complicated dependence upon …

Multimodal Approach For Malware Detection, Jarilyn M. Hernandez Jimenez

Graduate Theses, Dissertations, and Problem Reports

Although malware detection is a very active area of research, few works were focused on using physical properties (e.g., power consumption) and multimodal features for malware detection. We designed an experimental testbed that allowed us to run samples of malware and non-malicious software applications and to collect power consumption, network traffic, and system logs data, and subsequently to extract dynamic behavioral-based features. We also extracted code-based static features of both malware and non-malicious software applications. These features were used for malware detection based on: feature level fusion using power consumption and network traffic data, feature level fusion using network traffic …

Intelligent Malware Detection Using File-To-File Relations And Enhancing Its Security Against Adversarial Attacks, Lingwei Chen

Graduate Theses, Dissertations, and Problem Reports

With computing devices and the Internet being indispensable in people's everyday life, malware has posed serious threats to their security, making its detection of utmost concern. To protect legitimate users from the evolving malware attacks, machine learning-based systems have been successfully deployed and offer unparalleled flexibility in automatic malware detection. In most of these systems, resting on the analysis of different content-based features either statically or dynamically extracted from the file samples, various kinds of classifiers are constructed to detect malware. However, besides content-based features, file-to-file relations, such as file co-existence, can provide valuable information in malware detection and make …

Experimental And Modeling Investigation Of The Oh-Initiated Oxidation Of Semi-Solid And Aqueous Saccharide Aerosols, Hanyu Fan

Graduate Theses, Dissertations, and Problem Reports

My research focuses on investigating the impact of moisture-induced and oligomer-induced viscosity changes on OH-initiated oxidation of semi-solid aerosols,and the role of gas-liquid interfaces in regulating aqueous aerosol chemistry. Saccharides, which are a major constituent of aqueous atmospheric aerosols, are chosen as model molecules to form highly oxygenated organic aerosols. The experiments are performed using an atmospheric pressure flow-tube reactor with both online VUV-AMS (Vacuum-Ultraviolet Aerosol Mass Spectrometer) and offline GC-MS analysis techniques. The decay rates of saccharide are determined by measuring the loss signal of saccharide in the particle phase as a function of OH exposure (time-integrated total concentration …

Object-Based Supervised Machine Learning Regional-Scale Land-Cover Classification Using High Resolution Remotely Sensed Data, Christopher A. Ramezan

Graduate Theses, Dissertations, and Problem Reports

High spatial resolution (HR) (1m – 5m) remotely sensed data in conjunction with supervised machine learning classification are commonly used to construct land-cover classifications. Despite the increasing availability of HR data, most studies investigating HR remotely sensed data and associated classification methods employ relatively small study areas. This work therefore drew on a 2,609 km2, regional-scale study in northeastern West Virginia, USA, to investigates a number of core aspects of HR land-cover supervised classification using machine learning. Issues explored include training sample selection, cross-validation parameter tuning, the choice of machine learning algorithm, training sample set size, and feature selection. A …

Discerning The Diets Of Sweep-Feeding Eurypterids Through Analyses Of Mesh-Modified Appendage Armature, Emily Samantha Hughes

Graduate Theses, Dissertations, and Problem Reports

Eurypterids were a group of aquatic chelicerates that lived throughout most of the Paleozoic. While swimming eurypterids are generally considered to be active predators, the benthic stylonurine eurypterids appear to have had a mode of life similar to modern horseshoe crabs with the exception of two clades, the Stylonuroidea and the Mycteropoidea, both of which independently evolved modifications for sweep-feeding on their anterior appendages. Among extant suspension feeders, it has been shown that there is a linear correlation between the average spacing of feeding structures and prey sizes. This relationship was extrapolated to the sweep-feeding stylonuroid and mycteropoid eurypterids in …

Sediment Provenance Study Of The Lower Hamilton Group: An Analysis Of The Organic-Rich Facies And Its Depositional History, Luke Patrick Fritz

Graduate Theses, Dissertations, and Problem Reports

Currently, insufficient geological models exist to explain the variability and distribution of TOC in the Marcellus Shale, within the Hamilton Group. TOC is one of the several limiting factors for natural gas production within the Marcellus Shale basin. One possible explanation for the low TOC regions is that detrital dilution was variable across the basin, with different sediment sources contributing detritus to low TOC areas, compared to surrounding regions with higher TOC. This hypothesis is tested by analyzing the source composition of inorganic detritus, using elemental and mineralogical proxies, with two cores in the Hamilton Group. The Armstrong #1 core …

A Machine-Aided Seismic Signal Analysis Workflow For Subsurface Faults And Facies Visualization And Interpretation, South Central Anadarko Basin, Oklahoma, Wade Martin

Graduate Theses, Dissertations, and Problem Reports

Seismic attribute analysis enhances the understanding of subsurface geology and has continually gained traction in the oil and gas industry since the 1970’s. Many seismic attributes are available for petroleum geoscientists. This research intends to provide insight to an analytical attribute workflow for rock property estimation in the Anadarko basin of Oklahoma that is prolific in oil and gas exploration, with a particular focus on seismic texture. 3-D volumes processed for seismic texture facies and structure enhance geophysical investigation and interpretation of amplitude data. This study will contribute valuable insight to reservoir studies and the potential for texture attribute well …

Compound-Specific Isotope Analysis Of Amino Acids In Biological Tissues: Applications In Forensic Entomology, Food Authentication And Soft-Biometrics In Humans, Mayara Patricia Viana De Matos

Graduate Theses, Dissertations, and Problem Reports

In this work we demonstrate the power of compound-specific isotope analysis (CSIA) to analyze proteinaceous biological materials in three distinct forensic applications, including: 1) linking necrophagous blow flies in different life stages to their primary carrion diet; 2) identifying the harvesting area of oysters for food authentication purposes; and 3) the ability to predict biometric traits about humans from their hair.

In the first application, we measured the amino-acid-level fractionation that occurs at each major life stage of Calliphora vicina (Robineau-Desvoidy) (Diptera: Calliphoridae) blow flies. Adult blow flies oviposited on raw pork muscle, beef muscle, or chicken liver. Larvae, pupae …

Non-Target Analyses Of Novel Psychoactive Substances; Inherent Variation In Gcms Relative Abundances And Gas Phase Hydrogen Deuterium Exchange Isomer Discrimination, Kristin Michelle Kelly

Graduate Theses, Dissertations, and Problem Reports

Novel psychoactive substances (NPSs) are synthetically derived compounds designed to mimic the effects of other illicit drugs. An endless cycle of NPSs continually reach the drug market due to limitations in drug legislation creating two problems: (1) non-availability of standards and (2) multiple isobars indistinguishable even to high resolution mass spectrometry. Gas chromatography-mass spectrometry (GCMS) is the most common instrument used for compound identification in non-targeted seized drug analysis. Compound identification using this technique relies on mass spectra where the percent relative abundances (%RAs) of all m/z values are compared manually or searched against a library database. Lacking standards, laboratories …

Using Social Media To Combat Opioid Epidemic, Yiming Zhang

Graduate Theses, Dissertations, and Problem Reports

Opioid addiction has become one of the largest and deadliest epidemics in the United States. To combat such deadly epidemic, there is an urgent need for novel tools and methodologies to gain new insights into the behavioral processes of opioid abuse and addiction. The role of social media in biomedical knowledge mining has turned into increasingly significant in recent years. The data from social media may contribute information beyond the knowledge of domain professionals (e.g., psychiatrists and epidemics researchers) and could potentially assist in sharpening our understanding toward the behavioral process of opioid addiction and treatment.

In this thesis, we …

Evaluation Of Ufp Number Concentrations Near A Natural Gas Transmissions Station, John M. Thornsbury

Graduate Theses, Dissertations, and Problem Reports

Identifying UFP number concentrations near a natural gas compressor station is key to understanding ambient exposures associated with the transmission station. Developing an atmospheric survey to characterize these concentrations was key in understanding ambient exposures. The aims of this study are to compare and contrast number concentrations taken in a hollow, near the transmission station to those of the background. From this, it would be possible to identify whether or not the compressor station was a contributing factor to peaks and spikes in number concentrations.

This study begins with a review of what UFPs are, how they react in different …

The Impact Of Hii Regions On The Interstellar Medium Of Our Galaxy, Matteo Luisi

Graduate Theses, Dissertations, and Problem Reports

The interstellar medium (ISM) of our Galaxy contains low-density diffuse ionized gas known as the warm ionized medium (WIM). O- and B-type stars emit large amounts of ionizing radiation and it is believed that a fraction of this radiation escapes from their fully ionized HII regions and into the ISM where it is responsible for maintaining the ionization of the WIM. Here we aim to better understand how the radiation produced by OB stars is able to leak from the HII regions, how the radiation field changes during this process, and how the radiation affects the ambient ISM. Using Green …

Impacts Of Climate Change On Water Balance Components In The Central Appalachian Mountains, Usa, Brandi Anne Gaertner

Graduate Theses, Dissertations, and Problem Reports

This research investigated the impact of climate and land cover on water balance components including evapotranspiration and runoff in the mountainous central Appalachian region of the United States. The first studyanalyzed trends in climatologic, hydrologic, and growing season length variables, identified the important variables effecting growing season length changes, and evaluated the influence of a lengthened growing season on increasing evapotranspiration trends. The results showed that growing season length has increased, on average, by ~22 days and evapotranspiration has increased ~12 mm. The second study quantified long-term historical and future climate trends, evaluated water balance sensitivity to change, and quantified …

Structural Style And Stratigraphic Architecture Of The Northeastern Brooks Range, Alaska, Benjamin G. Johnson

Graduate Theses, Dissertations, and Problem Reports

The Arctic Alaska–Chukotka microplate is a large Mesozoic–Cenozoic composite terrane that resides at the northern limit of the North American Cordillera. Although its Mesozoic origins are assuredly linked to the opening of the Amerasian Basin of the Arctic Ocean, its Paleozoic origins can be linked to at least three separate paleocontinents, including northern Laurentia, Baltica, and Siberia. Across the Arctic Alaska portion of the microplate, an internal, mid-Paleozoic suture zone presumably separates rocks of the North Slope subterrane (Laurentian affinity) from a collection of smaller subterranes in the southern Brooks Range and Seward Peninsula (Baltic affinity).

The mountains of the …

Stream Salamander And Benthic Macroinvertebrate Community Responses To Imidacloprid Exposure, Sara M. Crayton

Graduate Theses, Dissertations, and Problem Reports

The insecticide imidacloprid is widely used to mitigate hemlock (Tsuga spp.) mortality resulting from the invasive hemlock woolly adelgid (HWA), but evidence suggests that

imidacloprid can have negative effects on adjacent stream systems. Imidacloprid exposure causes physiological changes, bioaccumulation, and reduced survival in anurans, and induces physiological impairment and reduced survival in benthic macroinvertebrates. In this thesis, we assessed whether HWA treatments using imidacloprid affect stream salamander abundances and benthic macroinvertebrate community composition. We also investigated whether imidacloprid or its metabolites bioaccumulate in benthic macroinvertebrates or salamanders and cause sublethal effects. We conducted this study in two National Park …