Physical Sciences and Mathematics Commons^™

Sediment Transport Model Including Short-Lived Radioisotopes: Model Description And Idealized Test Cases, Justin J. Birchler,, Courtney K. Harris, Christopher R Sherwood, Tara A. Kniskern

VIMS Articles

Geochronologies derived from sediment cores in coastal locations are often used to infer event bed characteristics such as deposit thicknesses and accumulation rates. Such studies commonly use naturally occurring, short-lived radioisotopes, such as Beryllium-7 (Be-7) and Thorium-234 (Th-234), to study depositional and post-depositional processes. These radioisotope activities, however, are not generally represented in sediment transport models that characterize coastal flood and storm deposition with grain size patterns and deposit thicknesses. We modified the Community Sediment Transport Modeling System (CSTMS) to account for reactive tracers and used this capability to represent the behavior of these short-lived radioisotopes on the sediment bed. …

Associated Dataset: Ocean Circulation Causes Strong Variability In The Mid-Atlantic Bight Nitrogen Budget, Marjorie A.M. Friedrichs, Pierre St-Laurent

Data

The dataset includes model outputs used in the associated publication (Friedrichs et al.), which used the United States Eastern Continental Shelf (USECoS) biogeochemical model embedded in the Regional-Ocean-Modeling-System (ROMS) to examine the impact of the oceanic circulation on the nitrogen budget of the Mid-Atlantic Bight (MAB). The model simulation covers the period 2004 to 2008 and is fully described in the associated publication. The model simulation highlights that the horizontal along-shelf and across-shelf fluxes dominate the spatiotemporal variability of net community production (NCP) in the MAB. The highest NCP is found in a year when inorganic nitrogen entering from across …

Symbiotic Unicellular Cyanobacteria Fix Nitrogen In The Arctic Ocean, K. Harding, K. A. Turk-Kubo, Rachel E. Sipler, M. M. Mills, D. A. Bronk

VIMS Articles

Biological dinitrogen (N2) fixation is an important source of nitrogen (N) in low-latitude open oceans. The unusual N2-fixing unicellular cyanobacteria (UCYN-A)/haptophyte symbiosis has been found in an increasing number of unexpected environments, including northern waters of the Danish Straight and Bering and Chukchi Seas. We used nanoscale secondary ion mass spectrometry (nanoSIMS) to measure 15N2 uptake into UCYN-A/haptophyte symbiosis and found that UCYN-A strains identical to low-latitude strains are fixing N2 in the Bering and Chukchi Seas, at rates comparable to subtropical waters. These results show definitively that cyanobacterial N2 fixation is not constrained to subtropical waters, challenging paradigms and …

Building Capacity For Protection Of Wetland Resources In Virginia - Track One, Virginia Department Of Environmental Quality, Center For Coastal Resources Management - Virginia Institute Of Marine Science

Reports

DEQ continues to make significant progress in the development of a comprehensive nontidal wetland regulatory program; refinement of our permitting/compliance database to track impacts, compliance, and compensation by watershed; and continued refinement of our wetland monitoring and assessment tools for use in management decision-making and integration within our water quality programs. This project focused on development of strategies and extension of outreach to improve understanding and protection of high ecological value aquatic resources such as headwater resources and wetlands that may provide added value in improving impaired waters in Virginia. Project activities specifically addressed three of the priority elements in …

Strong Electron-Boson Coupling In The Iron-Based Superconductor Bafe1.9pt0.1as2 Revealed By Infrared Spectroscopy, Zhen Xing, Shanta Saha, J. Paglione, M. M. Qazilbash

Arts & Sciences Articles

Understanding the formation of Cooper pairs in iron-based superconductors is one of the most important topics in condensed matter physics. In conventional superconductors, the electron-phonon interaction leads to the formation of Cooper pairs. In conventional strong-coupling superconductors like lead (Pb), the features due to electron-phonon interaction are evident in the infrared absorption spectra. Here we investigate the infrared absorption spectra of the iron arsenide superconductor BaFe1.9Pt0.1As2. We find that this superconductor has fully gapped (nodeless) Fermi surfaces, and we observe the strong-coupling electron-boson interaction features in the infrared absorption spectra. Through modeling with the Eliashberg function based on Eliashberg theory, …

Exploring New Paradigms For Mobile Edge Computing, Yutao Tang

Dissertations, Theses, and Masters Projects

Edge computing has been rapidly growing in recent years to meet the surging demands from mobile apps and Internet of Things (IoT). Similar to the Cloud, edge computing provides computation, storage, data, and application services to the end-users. However, edge computing is usually deployed at the edge of the network, which can provide low-latency and high-bandwidth services for end devices. So far, edge computing is still not widely adopted. One significant challenge is that the edge computing environment is usually heterogeneous, involving various operating systems and platforms, which complicates app development and maintenance. in this dissertation, we explore to combine …

Firefighter Hood Contamination: Efficiency Of Laundering To Remove Pahs And Frs, Ac Mayer, Kw Fent, S Bertke, Gp Horn, Dl Smith, K Kerber, Mark J. La Guardia

VIMS Articles

Firefighters are occupationally exposed to products of combustion containing polycyclic aromatic hydrocarbons (PAHs) and flame retardants (FRs), potentially contributing to their increased risk for certain cancers. Personal protective equipment (PPE), including firefighter hoods, helps to reduce firefighters’exposure to toxic substances during fire responses by providing a layer of material on which contaminants deposit prior to reaching the firefighters skin.However, over time hoods that retain some contamination may actually contribute to fire-fighters’systemic dose. We investigated the effectiveness of laundering to reduce or remove contamination on the hoods, specifically PAHs and three classes of FRs: polybrominateddiphenyl ethers (PBDEs), non-PBDE flame retardants (NPBFRs), …

Targeted Living Shoreline Management Planning For Virginia State Parks In Chesapeake Bay Summary Report, Donna A. Milligan, C. Scott Hardaway Jr., Christine A. Wilcox

Reports

The Commonwealth of Virginia owns numerous tidal, waterfront properties along Chesapeake Bay and its tributaries including state parks, natural area preserves, and wildlife management areas. Many of these parks have eroding shorelines and are at risk from coastal hazards such as tidal flooding, waves, and sea level rise. These environmental threats impact the safety of park visitors and the mission of the parks.

In an effort to address these issues for the parks as well as provide education to the public on living shoreline management strategies, eleven state parks with tidal shoreline along the Chesapeake Bay and its tributaries were …

Living Shoreline Sea-Level Resiliency: Performance And Adaptive Management Of Existing Sites, C. Scott Hardaway Jr., Donna A. Milligan, Christine A. Wilcox

Reports

The goal of this project is to monitor effectiveness of nature-based resiliency projects such as those that use living shoreline management strategies. Living shoreline strategies can effectively control shoreline erosion while providing water quality benefits and maintaining natural habitat and coastal processes. These ecosystem-based management systems have been the preferred alternative for stabilizing tidal shorelines in the Commonwealth of Virginia since 2011. However, a recent analysis has shown that between 2011 and 2016 only 24% of the permits granted for shore protection were considered living shorelines (ASMFC, 2016). These types of systems may be relatively new to many landowners and …

Stormsense: A Blueprint For Coastal Flood Forecast Information & Automated Alert Messaging Systems, Jon Derek Loftis, Sridhar Katragadda, Sokwoo Rhee, Cuong Nguyen

VIMS Articles

Increased availability of low-cost water level sensors communicating through the Internet of Things (IoT) has expanded the horizons of publicly-ingestible data streams available to modern smart cities. StormSense is an IoT-enabled inundation forecasting research initiative and an active participant in the Global City Teams Challenge seeking to enhance flood preparedness in the smart cities of Hampton Roads, VA for flooding resulting from storm surge, rain, and tides. In this study, we present the a blueprint and series of applicable protocols through the use of the new StormSense water level sensors to help establish a regional resilience monitoring network. In furtherance …

Effects Of Density‐Driven Flows On The Long‐Term Morphodynamic Evolution Of Funnel‐Shaped Estuaries, Matiane Olabarrieta, W. Rockwell Geyer, Giovanni Coco, Carl T. Friedrichs

VIMS Articles

Subtidal flows driven by density gradients affect the tide‐averaged sediment transport in estuaries and, therefore, can influence their long‐term morphodynamic evolution. The three‐dimensional Coupled Ocean‐Atmosphere‐Wave‐Sediment Transport modeling system is applied to numerically analyze the effects of baroclinicity and Earth's rotation on the long‐term morphodynamic evolution of idealized funnel‐shaped estuaries. The morphodynamic evolution in all the analyzed cases reproduced structures identified in many tide‐dominated estuaries: a meandering region in the fluvial‐tidal transition zone, a tidal maximum area close to the head, and a turbidity maxima region in the brackish zone. As the morphology of the estuaries evolved, the tidal propagation (including …

Oyster Bag Sill Construction And Monitoring At Two Sites In Chesapeake Bay, Donna A. Milligan, C. Scott Hardaway Jr., Christine A. Wilcox, Walter I. Priest

Reports

The use of oyster shell bags as a means of shore protection along fetchlimited shorelines in Chesapeake Bay is growing. This method is an innovative use of a byproduct of the seafood industry and can provide habitat creation, water quality improvement, and shore protection. The landowner can install the bags themselves, and with the new living shoreline general permit in Virginia, these projects are easier than ever to afford and install. However, oyster shells are a limited resource that are needed for largescale oyster reef restoration with the Chesapeake Bay watershed, so determining the effectiveness of this shore protection strategy …

Shorescape-Level Factors Drive Distribution And Condition Of A Salt Marsh Facilitator (Geukensia Demissa), Robert E. Isdell, Donna M. Bilkovic, Carl Hershner

VIMS Articles

Ribbed mussels (Geukensia demissa) are a highly abundant bivalve filter feeder throughout the salt marshes of the U.S. Atlantic Coast. These mussels form a mutualistic relationship with smooth cordgrass Spartina alterniflora wherein the grass provides habitat and shade to the mussels, and the mussels stabilize the sediment and fertilize the grass. Salt marshes are, however, rapidly changing and eroding as humans modify the coast, and the rate of sea level rise is accelerating. In order to understand how ribbed mussels may respond to their changing habitat, we collected mussel density and distribution data from 30 marshes covering the range of …

Impact Of Seabed Resuspension On Oxygen And Nitrogen Dynamics In The Northern Gulf Of Mexico: A Numerical Modeling Study, Julia M. Moriarty, Courtney K. Harris, Marjorie A.M. Friedrichs, Katja Fennel, Kehui Xu

VIMS Articles

Resuspension affects water quality in coastal environments by entraining seabed organic matter into the water column, which can increase remineralization, alter seabed fluxes, decrease water clarity, and affect oxygen and nutrient dynamics. Nearly all numerical models of water column biogeochemistry, however, simplify seabed and bottom boundary layer processes and neglect resuspension. Here we implemented HydroBioSed, a coupled hydrodynamic-sediment transport-biogeochemical model to examine the role of resuspension in regulating oxygen and nitrogen dynamics on timescales of a day to a month. The model was implemented for the northern Gulf of Mexico, where the extent of summertime hypoxia is sensitive to seabed …

Restoring The Eastern Oyster: How Much Progress Has Been Made In 53 Years?, Ab Hernandez, Rochelle Brumbaugh, P Fredrick, R Grizzle, Mark Luckenbach, Ch Peterson, C Angelini

VIMS Articles

Coastal ecosystem restoration is accelerating globally as a means of enhancing shoreline protection, carbon storage, water quality, fisheries, and biodiversity. Among the most substantial of these efforts have been those focused on re-establishing oyster reefs across the US Atlantic and Gulf coasts. Despite considerable investment, it is unclear how the scale of and approaches toward oyster restoration have evolved. A synthesis of 1768 projects undertaken since 1964 reveals that oyster substrate restoration efforts have primarily been concentrated in the Chesapeake Bay and the Gulf Coast, have been heavily reliant on oyster shell, and have re-established 4.5% of the reef area …

Overcoming Early Career Barriers To Interdisciplinary Climate Change Research, Christopher J. Hein, John E. Ten Hoeve, Sathya Gopalakrishnan, Et Al

VIMS Articles

Climate-change impacts are among the most serious and complex challenges facing society, affecting both natural and social systems. Addressing these requires a new paradigm of interdisciplinary collaboration which incorporates tools, techniques, and insights from across the social, natural, and engineering sciences. Yet, a wide range of intrinsic and extrinsic hurdles need to be overcome to conduct successful, integrated interdisciplinary research. The results of a bibliometric analysis and survey of early to mid-career scientists from 56 countries who were involved with the interdisciplinary DISsertations initiative for the advancement of Climate Change ReSearch (DISCCRS) emphasize the particular challenges faced by early career …

Future Response Of Global Coastal Wetlands To Sea-Level Rise, M. Schuerch, T. Spencer, S. Temmerman, Matthew L. Kirwan, Et Al

VIMS Articles

The response of coastal wetlands to sea-level rise during the twenty-first century remains uncertain. Global-scale projections suggest that between 20 and 90 per cent (for low and high sea-level rise scenarios, respectively) of the present-day coastal wetland area will be lost, which will in turn result in the loss of biodiversity and highly valued ecosystem services(1-3). These projections do not necessarily take into account all essential geomorphological(4-7) and socio-economic system feedbacks(8). Here we present an integrated global modelling approach that considers both the ability of coastal wetlands to build up vertically by sediment accretion, and the accommodation space, namely, the …

Probe Of Electroweak Interference Effects In Non-Resonant Inelastic Electron-Proton Scattering, James Franklyn Dowd

Dissertations, Theses, and Masters Projects

The Qweak collaboration at Jefferson Lab made the first direct measurement of the proton's weak charge, Q_W^p, via a measurement of the parity-violating asymmetry in elastic e ⃑p scattering with low four-momentum transfer. to meet the high-precision goals, energy-dependent electroweak radiative corrections were applied to the measured asymmetry. The γZ box, □_γZ, where a photon and a Z-boson are simultaneously exchanged, was the most problematic of these corrections. It could not be calculated through the same perturbative methods as the rest of the corrections. The □_γZ correction depends on theoretical models of the γZ interference structure functions, F_1,2^γZ, for which …

Stoichiometric N:P Ratios, Temperature, And Iron Impact Carbon And Nitrogen Uptake By Ross Sea Microbial Communities, Jl Spackeen, Da Bronk, Rachel E. Sipler, Em Bertrand, Da Hutchins, Ae Allen

VIMS Articles

The Southern Ocean is one of the most biologically important ecosystems on our planet. Microscopic plants, called phytoplankton, form the base of the food web in the Southern Ocean and play a direct role in regulating how much and how fast elements like nitrogen and carbon are cycled throughout the world ocean. The goal of this research was to determine how predicted changes in the environment will impact how fast phytoplankton use these elements. The conditions that we tested included elevated temperature, addition of iron, and the proportion of nitrogen to phosphorus in the seawater. These parameters were selected because …

Living Shorelines Support Nearshore Benthic Communities In Upper And Lower Chesapeake Bay, Tm Davenport, Rochelle D. Seitz, Ke Knick, N Jackson

VIMS Articles

Human population growth and sea-level rise are increasing the demand for protection of coastal property against shoreline erosion. Living shorelines are designed to provide shoreline protection and are constructed or reinforced using natural elements. While living shorelines are gaining popularity with homeowners, their ability to provide ecological services (e.g., habitat provision and trophic transfer) is not well understood, and information is needed to improve coastal and resource management decision-making. We examined benthic community responses to living shorelines in two case-study subestuaries of Chesapeake Bay using a before-after control-impact study design. At Windy Hill, a bulkhead was removed and replaced by …

Estimating Hypoxic Volume In The Chesapeake Bay Using Two Continuously Sampled Oxygen Profiles, Aaron J. Bever, Marjorie A.M. Friedrichs, Carl T. Friedrichs, Malcolm E. Scully

VIMS Articles

Low levels of dissolved oxygen (DO) occur in many embayments throughout the world and have numerous detrimental effects on biota. Although measurement of in situ DO is straightforward with modern instrumentation, quantifying the volume of water in a given embayment that is hypoxic (hypoxic volume (HV)) is a more difficult task; however, this information is critical for determining whether management efforts to increase DO are having an overall impact. This paper uses output from a three‐dimensional numerical model to demonstrate that HV in Chesapeake Bay can be estimated well with as few as two vertical profiles. In addition, the cumulative …

Shrinking Suburbs In A Time Of Crisis, Justin B. Hollander, Colin Polsky, Dan Zinder, Daniel M. Runfola

Arts & Sciences Book Chapters

The Routledge Companion to the Suburbs provides one of the most comprehensive examinations available to date of the suburbs around the world. International in scope and interdisciplinary in nature, this volume will serve as the definitive reference for scholars and students of the suburbs.

This volume brings together the leading scholars of the suburbs researching in different parts of the world to better understand how and why suburbs and their communities grow, decline, and regenerate. The volume sets out four goals: 1) to provide a synthesis and critical appraisal of the historical and current state of understanding about the development …

Development Of Large-Scale Unstructured Grid Storm Surge And Sub-Grid Inundation Models For Coastal Applications, Zhuo Liu

Dissertations, Theses, and Masters Projects

Storm surge and inundation induced by hurricanes and nor'easters pose a profound threat to coastal communities and ecosystems. These storm events with powerful winds, heavy precipitation, and strong wind waves can lead to major flooding for cities along U.S. Coasts. Recent examples of Hurricane Irene (2011) in North Carolina and Virginia and Hurricane Sandy (2012) in New York City not only demonstrated the immense destructive power by the storms, but also revealed the obvious, crucial need for improved forecasting of storm tide and inundation. in part I, a large-scale unstructured-grid 3-D barotropic storm tide model SCHISM (Semi-implicit Cross-scale Hydroscience Integrated …

Impact Of Submerged Aquatic Vegetation On Water Quality In Cache Slough Complex, Sacramento-San Joaquin Delta: A Numerical Modeling Study, Xun Cai

Dissertations, Theses, and Masters Projects

Submerged aquatic vegetation (SAV) plays a significant role in many aquatic systems, and impacts both physical and ecological quantities. It can baffle currents, attenuate waves, recycle nitrogen and phosphorus from the sediment bed, perform ecosystem function as a primary producer, and provide critical habitat for many aquatic species. Conversely, the invasive SAV, Egeria densa (Brazilian waterweed), in the San Francisco Bay & Delta has been a nuisance since its introduction into the system in the 1960s. It has displaced most of the native submersed aquatic plant species in the Delta and restructured the ecosystem, thus threatening the survival of several …

Exotic Phases In Attractive Fermions: Charge Order, Pairing, And Topological Signatures, Peter Rosenberg

Dissertations, Theses, and Masters Projects

Strongly interacting many-body systems remain a central challenge of modern physics. Recent developments in the field of ultra-cold atomic physics have opened a new window onto this enduring problem. Experimental progress has revolutionized the approach to studying many-body systems and the exotic behaviors that emerge in these systems. It is now possible to engineer and directly measure a variety of models that can capture the essential features of real materials without the added complexity of disorder, impurities, or complicated or irregular geometries. The parameters of these models can be freely tuned with tremendous precision. These experimental realizations are an ideal …

Quantifying And Explaining Causal Effects Of World Bank Aid Projects, Jianing Simulation Zhao

Dissertations, Theses, and Masters Projects

In recent years, machine learning methods have enabled us to predict with good precision using large training data, such as deep learning. However, for many problems, we care more about causality than prediction. For example, instead of knowing that smoking is statistically associated with lung cancer, we are more interested in knowing that smoking is the cause of lung cancer. With causality, we can understand how the world progresses and how impacts are made on an outcome by influencing the cause. This thesis explores how to quantify the causal effects of a treatment on an observable outcome in the presence …

Computational Investigations Of The Structure And Spectroscopy Of Small Biomolecules In The Gas Phase, Zachary Michael Smith

Dissertations, Theses, and Masters Projects

Small biomolecule systems were interrogated using infrared multiple photon dissociation (IRMPD) action spectroscopy and corresponding quantum chemical calculations with a particular focus on peptide fragmentation and protonation site preference. b2+ and b3+ fragment ions with a terminal lysine homolog residue were investigated using IRMPD in the fingerprint region (1000 cm-1 – 2000 cm-1) and a variety of computational methods. We present the first spectroscopic confirmation of b-ion formation with a lactam structure. Infrared spectra for b2+ fragment system indicate the presence of a mixture of structures, though final determination will require further investigation. The b3+ fragment ion infrared spectra show …

A Measurement Of Nuclear Effects In Deep Inelastic Scattering In Neutrino-Nucleus Interactions, Anne Norrick

Dissertations, Theses, and Masters Projects

Neutrino-Nucleus Deep Inelastic Scattering (DIS) events provide a probe into the structure of nucleons within a nucleus that cannot be accessed via charged lepton-nucleus interactions. The MINERvA experiment is stationed in the Neutrinos from the Main Injector (NuMI) beam line at Fermi National Accelerator Laboratory. With the recent increase in average neutrino energy and the greatly increased intensity of the NuMI beam line, projected sensitivities for DIS cross section ratio analyses using MINERvA's suite of nuclear targets (C, CH, Fe and Pb) are greatly increased. an analysis of theMINERvA DIS data on carbon, iron, lead, and plastic has been conducted …

Dynamics Of Systems With Hamiltonian Monodromy, Daniel Salmon

Dissertations, Theses, and Masters Projects

A system is said to have monodromy if, when we carry the system around a closed circuit, it does not return to its initial state. The simplest example is the square-root function in the complex plane. A Hamiltonian system is said to have Hamiltonian monodromy if its fundamental action-angle loops do not return to their initial topological state at the end of a closed circuit. These changes in topology of angle loops carry through to other aspects of these systems, including the classical dynamics of families of trajectories, quantum spectra and even wavefunctions. This topological change in the evolution of …

Extensions Of The Standard Model Higgs Sector, Richard Keith Thrasher

Dissertations, Theses, and Masters Projects

The Standard Model is regarded as one of the most successful scientific theories, but there is compelling evidence that it is an incomplete theory of particle physics. There is currently no understanding of the observed baryon asymmetry, the nature of dark matter, and dark energy. Field theoretic considerations indicate parameters in the Standard Model are extremely fine-tuned. This suggests the existence of new physics, accessible at higher energies, to explain these seemingly unnatural tunings. to solve these puzzles, and others not addressed by the Standard Model, many extensions of the Standard Model have been proposed. It is of great importance …