Physical Sciences and Mathematics Commons^™

Magnetism In Curved Geometries, Robert Streubel, Peter Fischer, Florian Kronast, Volodymyr P. Kravchuk, Denis D. Sheka, Yuri Gaididei, Oliver G. Schmidt, Denys Makarov

Robert Streubel Papers

Extending planar two-dimensional structures into the three-dimensional space has become a general trend in multiple disciplines, including electronics, photonics, plasmonics and magnetics. This approach provides means to modify conventional or to launch novel functionalities by tailoring the geometry of an object, e.g. its local curvature. In a generic electronic system, curvature results in the appearance of scalar and vector geometric potentials inducing anisotropic and chiral effects. In the specific case of magnetism, even in the simplest case of a curved anisotropic Heisenberg magnet, the curvilinear geometry manifests two exchange-driven interactions, namely effective anisotropy and antisymmetric exchange, i.e. Dzyaloshinskii-Moriya-like interaction. As …

Evidence Of The Excitation Of A Ring-Like Gravity Wave In The Mesosphere Over The Andes Lidar Observatory, F. Vargas, G. Swenson, A. Liu, Pierre-Dominique Pautet

All Physics Faculty Publications

On 23 March 2012, our all-sky imager recorded a concentric, ring-like gravity wave pattern. The wave arose within the area covered by images of both OH and O(1S) nightglow emissions taken at the Andes Lidar Observatory (ALO), Chile (30.3ÁS, 70.7ÁW). We have estimated the observed and intrinsic parameters of the event and located the wave source within the lower mesosphere altitude range using a reverse ray tracing method. By the analysis of GOES and LIS satellite images, we have not found evidence of neither convective nor lightning activity nearby ALO, indicating that the source of the ring-like wave was not …

Using Ecological Production Functions To Link Ecological Processes To Ecosystem Services, Randall Jf Bruins, Timothy J. Canfield, Clifford Duke, Larry Kapustka, Amanda M. Nahlik, Ralf B. Schäfer

United States Environmental Protection Agency: Publications

Ecological production functions (EPFs) link ecosystems, stressors, and management actions to ecosystem services (ES) production. Although EPFs are acknowledged as being essential to improve environmental management, their use in ecological risk assessment has received relatively little attention. Ecological production functions may be defined as usable expressions (i.e., models) of the processes by which ecosystems produce ES, often including external influences on those processes. We identify key attributes of EPFs and discuss both actual and idealized examples of their use to inform decision making. Whenever possible, EPFs should estimate final, rather than intermediate, ES. Although various types of EPFs have been …

U.S. Drought Monitor, August 16, 2016, David Miskus

United States Agricultural Commodities in Drought Archive

Drought map of U.S. for August 16, 2016 (8/16/16) plus: U.S. crop areas experiencing drought (map), Approximate percentage of crop located in drought, by state (bar graph), Percent of crop area located in drought, past 52 weeks (line graph) for: Corn, Soybeans, Hay, Cattle, Winter wheat.

Electron Correlations In Local Effective Potential Theory, Viraht Sahni, Xiao-Yin Pan, Tao Yang

Publications and Research

Local effective potential theory, both stationary-state and time-dependent, constitutes the mapping from a system of electrons in an external field to one of the noninteracting fermions possessing the same basic variable such as the density, thereby enabling the determination of the energy and other properties of the electronic system. This paper is a description via Quantal Density Functional Theory (QDFT) of the electron correlations that must be accounted for in such a mapping. It is proved through QDFT that independent of the form of external field, (a) it is possible to map to a model system possessing all the basic …

Beam-Energy Dependence Of Charge Balance Functions From Au+Au Collisions At Energies Available At The Bnl Relativistic Heavy Ion Collider, L. Adamczyk, James K. Adkins, G. Agakishiev, M. M. Aggarwal, Z. Ahammed, I. Alekseev, J. Alford, A. Aparin, D. Arkhipkin, E. C. Aschenauer, G. S. Averichev, A. Banerjee, R. Bellwied, A. Bhasin, A. K. Bhati, P. Bhattarai, J. Bielcik, J. Bielcikova, L. C. Bland, I. G. Bordyuzhin, J. Bouchet, A. V. Brandin, I. Bunzarov, T. P. Burton, J. Butterworth, H. Caines, M. Calderón De La Barca Sánchez, J. M. Campbell, D. Cebra, M. C. Cervantes, Renee H. Fatemi, Suvarna Ramachandran

Physics and Astronomy Faculty Publications

Balance functions have been measured in terms of relative pseudorapidity (Δη) for charged particle pairs at the BNL Relativistic Heavy Ion Collider from Au + Au collisions at √^s_NN = 7.7GeV to 200 GeV using the STAR detector. These results are compared with balance functions measured at the CERN Large Hadron Collider from Pb + Pb collisions at √^s_NN = 2.76 TeV by the ALICE Collaboration. The width of the balance function decreases as the collisions become more central and as the beam energy is increased. In contrast, the widths of the balance functions …

Use Of Distance Weighted Metrics To Investigate Landscape-Stream Temperature Relationships Across Different Temporal Scales, Eric Craig Watson

Dissertations and Theses

Stream ecosystems have experienced significant negative impacts from land use, resource exploitation, and urban development. Statistical models allow researchers to explore the relationships between these landscape variables and stream conditions. Weighting the relevant landscape variables based on hydrologically defined distances offers a potential method of increasing the predictive capacity of statistical models. Using observations from three grouped watersheds in the Portland Metro Area (n=66), I have explored the use of three different weighting schemes against the standard method of taking an areal average. These four different model groups were applied to four stream temperature metrics: mean seven-day moving average maximum …

Asymmetric Interiors For Small Black Holes, Daniel N. Kabat, Gilad Lifschytz

Publications and Research

We develop the representation of infalling observers and bulk fields in the CFT as a way to understand the black hole interior in AdS. We first discuss properties of CFT states which are dual to black holes. We then show that in the presence of a Killing horizon bulk fields can be decomposed into pieces we call ingoing and outgoing. The ingoing field admits a simple operator representation in the CFT, even inside a small black hole at late times, which leads to a simple CFT description of infalling geodesics. This means classical infalling observers will experience the classical geometry …

Using Simulations Of Black Holes To Study General Relativity And The Properties Of Inner Accretion Flow, Janie Katherine Hoormann

Arts & Sciences Graduate Student Theses and Dissertations

While Albert Einstein’s theory of General Relativity (GR) has been tested extensively in our solar system, it is just beginning to be tested in the strong gravitational fields that surround black holes. As a way to study the behavior of gravity in these extreme environments, I have used and added to a ray-tracing code that simulates the X-ray emission from the accretion disks surrounding black holes. In particular, the observational channels which can be simulated include the thermal and reflected spectra, polarization, and reverberation signatures. These calculations can be performed assuming GR as well as four alternative spacetimes. These results …

A Study Of The Effects Of Pair Production And Axionlike Particle Oscillations On Very High Energy Gamma Rays From The Crab Pulsar, Avery Michael Archer

Arts & Sciences Graduate Student Theses and Dissertations

Pulsars are highly-magnetized rapidly-rotating neutron stars that emit energy throughout the electromagnetic spectrum. Despite decades of study, the emission mechanisms of pulsars are not well understood. New observations at the highest energy end of the spectrum can provide strong constraints on theoretical models of pulsar emission. The strong magnetic fields of pulsar magnetospheres accelerate charged particles to relativistic energies and these particles emit very high energy (VHE; E > 100 GeV) gamma rays. In addition to creating conditions to emit gamma rays, the magnetic fields are powerful enough to attenuate gamma rays through pair production. The attenuation of gamma rays limits …

Green's Function Application For Pairing Correlations And The Optical Potential, Dong Ding

Arts & Sciences Graduate Student Theses and Dissertations

Pairing in asymmetric nuclear matter has been studied incorporating the effect of finite total momentum. We employ the generalized Cooper eigenvalue equation, which can be used to demonstrate the pairing instability and also generates reasonable pairing gaps compared to the traditional Bardeen-Cooper-Schrieffer (BCS) gap equation. From phase space arguments and the resulting strength of the pairing gap, we learn that the Larkin-Ovchinnikov-FuldeFerrell phase with a finite total momentum is favored over the conventional phase in asymmetric nuclear matter, but not in symmetric nuclear matter. To address open questions in neutron star cooling, neutron matter pairing gaps of the 1S0 and …

Synthesis Of Simplified Ym-254890 Analogs, Derek Thomas Rensing

Arts & Sciences Graduate Student Theses and Dissertations

G Protein Coupled Receptors (GPCR’s) are responsible for a multitude of physiological, cellular, and disease processes. GPCR’s signal through non-receptor based heterotrimeric G proteins and since G proteins effectively mediate GPCR signal transduction they are attractive therapeutic targets. However, little is known about the signaling pathways associated with individual G proteins. For this reason, there is intense interest in the development of chemical probes that can help identify the downstream biochemistry of individual G proteins.One small molecule natural product that shows promise along these lines is YM-254890 (YM). YM has been shown to specifically and potently inhibit the α subunit …

Nanostructured Thin Film Synthesis By Aerosol Chemical Vapor Deposition For Energy Storage Applications, Tandeep Singh Chadha

McKelvey School of Engineering Graduate Student Theses & Dissertations

Renewable energy sources offer a viable solution to the growing energy demand while mitigating concerns for greenhouse gas emissions and climate change. This has led to a tremendous momentum towards solar and wind-based energy harvesting technologies driving efficiencies higher and costs lower. However, the intermittent nature of these energy sources necessitates energy storage technologies, which remain the Achilles heel in meeting the renewable energy goals. This dissertation focusses on two approaches for addressing the needs of energy storage: first, targeting direct solar to fuel conversion via photoelectrochemical water-splitting and second, improving the performance of current rechargeable batteries by developing new …

Calcium Carbonate Formation In Energy-Related Subsurface Environments And Engineered Systems, Qingyun Li

McKelvey School of Engineering Graduate Student Theses & Dissertations

Geologic CO2 sequestration (GCS) in subsurface saline aquifers is a promising strategy to mitigate climate change caused by increasing anthropogenic CO2 emissions from energy production. At GCS sites, interactions between fluids and geomedia are important because they can affect CO2 trapping efficiency and the safety of CO2 storage. These interactions include the dissolution and precipitation of minerals. One of the most important minerals is calcium carbonate, because it can permanently trap CO2.

In this work, Portland cement was used as a model geomedium to investigate the chemical reactions, mechanical alterations, transport of reactive fluids, and the interplay of all these …

Geometric Inference With Microlens Arrays, Ian Schillebeeckx

McKelvey School of Engineering Graduate Student Theses & Dissertations

This dissertation explores an alternative to traditional fiducial markers where geometric

information is inferred from the observed position of 3D points seen in an image. We offer an alternative approach which enables geometric inference based on the relative orientation

of markers in an image. We present markers fabricated from microlenses whose appearance

changes depending on the marker's orientation relative to the camera. First, we show how

to manufacture and calibrate chromo-coding lenticular arrays to create a known relationship

between the observed hue and orientation of the array. Second, we use 2 small chromo-coding lenticular arrays to estimate the pose of …

Continuum Nuclear Structure Of Light Nuclei, Kyle Wayne Brown

Arts & Sciences Graduate Student Theses and Dissertations

In this work, the continuum decay of proton-rich nuclei with mass number A ≤ 17 was studied. The nuclear structure of these nuclei was assessed by measuring the decay energy, width, and momentum correlations between the decay fragments. In particular the Isobaric Analog State in 8B, the ground-state and excited states of 16Ne, the T = 3/2 states in the A = 7 isobaric chain, and the excited states of 9C and 17Ne were all studied. In addition a first measurement of 17Na was made. These states decay by emission of 1 or more protons and were populated through knockout …

Survival Analysis In A Clinical Setting, Yunzhao Liu

Arts & Sciences Graduate Student Theses and Dissertations

With the fast paced advancement of modern medicine, cancer treatments have improved greatly over the past few decades; however, the overall survival rate has not improved for head neck squamous cell carcinoma (HNSCC). Traditionally, the general affected population of HNSCC was male over 50-60 years of age, whom have had history of alcohol and tobacco use. Conversely, in the recent decades, HNSCC has exhibited significant rise in younger patients, largely due to the increase in human papillomavirus (HPV) infection among young adults. Generally, HPV as the most prevalent sexually transmitted disease, consisted of strains that do not cause harm to …

Synthesis Of Two-Dimensional Copper Indium Disulfide Nanocrystals And Study Of Exciton Splitting In Thin Nanosheets, Linjia Mu

Arts & Sciences Graduate Student Theses and Dissertations

This dissertation presents the preparation of two-dimensional (2D) CuInS2 nanocrystals by the ion-exchange method and the exciton splitting observed in thin CuInS2 nanosheets. After monitoring the one-pot synthesis of CuInS2 by energy-dispersive X-ray spectroscopy (EDS), an ion-exchange method is developed as an improvement for the synthesis of CuInS2 nanocrystals, to control the morphology and size. CuInS2 nanocrystals are prepared by ion exchange with template Cu2-xS nanoplatelets and InX3 [X = chloride, iodide, acetate (OAc), or acetylacetonate (acac)]. The morphologies of the resultant nanocrystals depend on the InX3 precursor and the reaction temperature. Exchange with InCl3 at 150 °C produces CuInS2 …

Anodic Electrochemistry: Controlling The Reactivity Of Radical Cation Intermediates, Robert John Perkins

Arts & Sciences Graduate Student Theses and Dissertations

Radical cations are highly reactive intermediates which when formed can lead to a variety of interesting and efficient synthetic transformation. Electrochemical oxidations may be used to generate radical cations from electron rich, nucleophilic functional groups, triggering intramolecular cyclization reactions. These intramolecular anodic olefin coupling reactions are a powerful synthetic tool for coupling electron-rich olefins with a second nucleophile to form complex ring systems. However, they do not all work well. The main focus of this dissertation research is to diagnose the main causes of failed anodic olefin coupling reactions, devise new methods to overcome or circumvent these causes, and then …

Spectral Properties Of Fractional Quantum Hall Hamiltonians, Amila Weerasinghe

Arts & Sciences Graduate Student Theses and Dissertations

The fractional quantum Hall (FQH) effect plays a prominent role in the study of topological phases of matter and of strongly correlated electron systems in general. FQH systems have been demonstrated to show many interesting novel properties such as fractional charges, and are believed to harbor even more intriguing phenomena such as fractional statistics. However, there remain many interesting questions to be addressed in this regime. The work reported in this thesis aims to push the envelope of our understanding of the low-energy properties of FQH states using microscopic principles. In the first part of the thesis, we present a …

Actin-Based Feedback Circuits In Cell Migration And Endocytosis, Xinxin Wang

Arts & Sciences Graduate Student Theses and Dissertations

In this thesis, we study the switch and pulse functions of actin during two important cellular processes, cell migration and endocytosis. Actin is an abundant protein that can polymerize to form a dendritic network. The actin network can exert force to push or bend the cell membrane. During cell migration, the actin network behaves like a switch, assembling mostly at one end or at the other end. The end with the majority of the actin network is the leading edge, following which the cell can persistently move in the same direction. The other end, with the minority of the actin …

Development Of A Long-Period Torsion Balance For Tests Of Einstein's Equivalence Principle And A Search For Normal Mode Torsional Oscillations Of The Earth, Michael David Abercrombie

Arts & Sciences Graduate Student Theses and Dissertations

This thesis describes the development of a torsion balance experiment designed to test Einstein's equivalence principle with unprecedented sensitivity, while also taking a novel approach to directly observe the normal mode torsional oscillations of the Earth. Accordingly, a model of the signal expected from a potential equivalence principle violation has been developed, as well as a multi-slit auto-collimating optical lever which possesses a resolution on the order of a nanoradian and a range of observation of 10 milliradians and is used to monitor the torsion balance. A torsion balance with a natural torsional frequency of ~104 Hz, signi_cantly below the …

Shining Light On Beta-Lactam Synthesis: The Photochemical Synthesis Of 3-Oh-Beta-Lactams, Tyler L. Morse

Arts & Sciences Graduate Student Theses and Dissertations

No abstract provided.

Ionophoric Polyphenols Selectively Bind Cu2+, Display Potent Antioxidant And Anti-Amyloidogenic Properties, And Are Non-Toxic Toward Tetrahymena Thermophila, Alberto Martinez, Ralph Alcendor, Tanzeen Rahman, Magdalena Podgorny, Ismaila Sanogo, Rebecca Mccurdy

Publications and Research

Alzheimer’s disease (AD) is the most common form of dementia affecting more than 28 million people in the world. Only symptomatic treatments are currently available. Anticipated tri-fold increase of AD incidence in the next 50 years has established the need to explore new possible treatments. Accumulation of extracellular amyloid-b (Ab) plaques, intracellular tangles in the brain, and formation of reactive oxygen species (ROS) are the major hallmarks of the disease. The active role of some metal ions, especially Cu²⁺, in promoting both Ab aggregation and reactive oxygen species formation has rendered ionophoric drugs as a promising treatment strategy. …

Comprehensive All-Sky Search For Periodic Gravitational Waves In The Sixth Science Run Ligo Data, B. P. Abbott, R. Abbott, T. D. Abbott, Teviet Creighton, Mario C. Diaz, Soma Mukherjee, Volker Quetschke, Malik Rakhmanov, Joseph D. Romano

Physics & Astronomy Faculty Publications

We report on a comprehensive all-sky search for periodic gravitational waves in the frequency band 100-1500 Hz and with a frequency time derivative in the range of [-1.18,+1.00]×10-8 Hz/s. Such a signal could be produced by a nearby spinning and slightly nonaxisymmetric isolated neutron star in our galaxy. This search uses the data from the initial LIGO sixth science run and covers a larger parameter space with respect to any past search. A Loosely Coherent detection pipeline was applied to follow up weak outliers in both Gaussian (95% recovery rate) and non-Gaussian (75% recovery rate) bands. No gravitational wave signals …

Toward Autonomous Multi-Rotor Indoor Aerial Vehicles, Connor Brooks

Mahurin Honors College Capstone Experience/Thesis Projects

In this project, we worked to create an indoor autonomous micro aerial vehicle (MAV) using a multi-layer architecture with modular hardware and software components. We required that all computing was done onboard the vehicle during time of flight so that no remote connection of any kind was necessary for successful control of the vehicle, even when flying autonomously. We utilized environmental sensors including ultrasonic sensors, light detection and ranging modules, and inertial measurement units to acquire necessary environment information for autonomous flight. We used a three-layered system that combined a modular control architecture with distributed on-board computing to allow for …

The Rise Of Nuclear Energy In Arab States: Future Impacts, Brittany Broder

Mahurin Honors College Capstone Experience/Thesis Projects

The signing of the Iranian nuclear deal during the Summer of 2015 highlighted the threat of nuclear proliferation from foreign powers, but largely overlooked the rise of nuclear energy in the Middle East and North Africa (MENA). With growing energy demands and heightened environmental regulations, countries in this region are turning to nuclear power to fuel their next generation. However, the rise of nuclear power in the MENA region holds serious implications for the future of the area’s energy, economic, and social reforms that have largely gone unexplored as a whole thus far. The purpose of this thesis is to …

Freedom Through Inquiry, Francis Su

All HMC Faculty Publications and Research

I delivered this speech at the Inquiry‐Based Learning Forum & 19th Annual Legacy of R.L. Moore Conference on August 4, 2016. It is partly an homage to an influential teacher, partly an excuse to articulate what makes some styles of teaching so effective, and partly an excuse to talk about difficult issues facing our nation and our classrooms today.

Low Florida Coral Calcification Rates In The Plio-Pleistocene, Thomas C. Brachert, Markus Reuter, Stefan Kruger, James S. Klaus, Kevin P. Helmle, Janice M. Lough

Marine & Environmental Sciences Faculty Articles

In geological outcrops and drill cores from reef frameworks, the skeletons of scleractinian corals are usually leached and more or less completely transformed into sparry calcite because the highly porous skeletons formed of metastable aragonite (CaCO3) undergo rapid diagenetic alteration. Upon alteration, ghost structures of the distinct annual growth bands often allow for reconstructions of annual extension ( =  growth) rates, but information on skeletal density needed for reconstructions of calcification rates is invariably lost. This report presents the bulk density, extension rates and calcification rates of fossil reef corals which underwent minor diagenetic alteration only. The corals derive from …

Synthesis And Characterization Of Amphiphiles For Mammalian Cell Transfection And Antimicrobial Activity, Joseph William Meisel

Dissertations

Amphiphiles are molecules that contain both water-soluble and water-insoluble components. The dual nature of these molecules engenders remarkable properties including the ability to self-assemble into ordered structures. Cell membranes are composed of amphiphilic phospholipids that organize into a bilayer motif. Synthetic amphiphiles can interact with natural membranes and influence the transport of molecules across the cell membrane. The work elaborated in this report employs amphiphiles to co-assemble with DNA and transport the genetic material across cell membranes. First, a simplified method for interacting DNA with amphiphiles was developed. Second, a series of known ion-transporting compounds were assayed for their interaction …