Physical Sciences and Mathematics Commons^™

Nitrate-Stimulated Release Of Naturally Occurring Sedimentary Uranium, Jeffrey Westrop, Pooja Yadav, Pj Nolan, Kate M. Campbell, Rajesh Singh, Sharon E. Bone, Alicia H. Chan, Anthony Kohtz, Donald Pan, Olivia Healy, John R. Bargar, Daniel D. Snow, Karrie A. Weber

Department of Earth and Atmospheric Sciences: Faculty Publications

Groundwater uranium (U) concentrations have been measured above the U.S. EPA maximum contaminant level (30 μg/L) in many U.S. aquifers, including in areas not associated with anthropogenic contamination by milling or mining. In addition to carbonate, nitrate has been correlated to uranium groundwater concentrations in two major U.S. aquifers. However, to date, direct evidence that nitrate mobilizes naturally occurring U from aquifer sediments has not been presented. Here, we demonstrate that the influx of high-nitrate porewater through High Plains alluvial aquifer silt sediments bearing naturally occurring U(IV) can stimulate a nitrate-reducing microbial community capable of catalyzing the oxidation and mobilization …

On Bayesian Methods And Functional Registration Of Fmri, Xiaoxuan Wang

Major Papers

The application of functional magnetic resonance imaging (fMRI) has greatly improved our comprehension of the human brain and behaviour. However, after anatomical alignment, there remains large inter-individual variability in brain anatomy and functional localization, which is one of the obstacles to conducting group studies and performing group-level inference. This major paper addresses this problem by applying a new method (Bayesian Functional Registration) to decrease misalignment in functional brain systems between people by spatially transforming each subject’s functional data into a common reference map. The proposed approach allows us to assess differences in brain function across subjects. It also creates a …

Investigating The Cut-Off Effect Of N-Alcohols On Lipid Movement: A Biophysical Study, Michael H.K. Nguyen, Dominik Dziura, Mitchell Dipasquale, Stuart R. Castillo, Elizabeth G. Kelley, Drew Marquardt

Chemistry and Biochemistry Publications

Cellular membranes are responsible for absorbing the effects of external perturbants for the cell’s survival. Such perturbants include small ubiquitous molecules like n-alcohols which were observed to exhibit anesthetic capabilities, with this effect tapering off at a cut-off alcohol chain length. To explain this cut-off effect and complement prior biochemical studies, we investigated a series of nalcohols (with carbon lengths 2-18) and their impact on several bilayer properties, including lipid flip-flop, intervesicular exchange, diffusion, membrane bending rigidity and more. To this end, we employed an array of biophysical techniques such as time-resolved small angle neutron scattering (TRSANS), small angle X-ray …

Modeling Titan’S Atmosphere Through Investigation Of Low-Temperature Kinetics And Branching Of N (^2d) And C2h4 Towards Cyclic-2h-Azirine (C-Ch2nch), Ruby Neisser, Sophia Haile

Undergraduate Research Awards

Excerpt from paper: "Understanding the rate coefficients and branching of reactions in extraterrestrial atmospheres is of vital importance because it allows us to build a more complete picture of the overall chemical makeup and photochemical behavior in these alien environments. Gaining insight into these exotic reactions is crucial not only for understanding extraterrestrial environments, but also for providing a better understanding of reactions on Earth. The atmosphere of Titan, Saturn’s largest moon, is notably rich in nitrogen compounds and chemical reactions, which makes it an immensely important environment to study.1 Titan’s reducing atmosphere resembles that of early Earth (the first …

Semantic Enhanced Markov Model For Sequential E-Commerce Product Recommendation, Mahreen Nasir, C. I. Ezeife

Computer Science Publications

To model sequential relationships between items, Markov Models build a transition probability matrix P of size n× n, where n represents number of states (items) and each matrix entry p(i,j) represents transition probabilities from state i to state j. Existing systems such as factorized personalized Markov chains (FPMC) and fossil either combine sequential information with user preference information or add the high-order Markov chains concept. However, they suffer from (i) model complexity: an increase in Markov Model’s order (number of states) and separation of sequential pattern and user preference matrices, (ii) sparse transition probability matrix: few product purchases from thousands …

Integrating Human Dimensions In Decadal-Scale Prediction For Marine Social Ecological Systems: Lighting The Grey Zone, Jess Melbourne-Thomas, Desiree Tommasi, Marion Gehlen, Eugene J. Murphy, Jennifer Beckensteiner, Francisco Bravo, Tyler D. Eddy, Mibu Fischer, Elizabeth Fulton, Mayya Gogina, Eileen Hofmann, Maya Ito, Sara Mynott, Kelly Ortega-Cisneros, Anna N. Osiecka, Mark R. Payne, Romeo Saldívar-Lucio, Kim J.N. Scherrer

CCPO Publications

The dynamics of marine systems at decadal scales are notoriously hard to predict-hence references to this timescale as the "grey zone" for ocean prediction. Nevertheless, decadal-scale prediction is a rapidly developing field with an increasing number of applications to help guide ocean stewardship and sustainable use of marine environments. Such predictions can provide industry and managers with information more suited to support planning and management over strategic timeframes, as compared to seasonal forecasts or long-term (century-scale) predictions. The most significant advances in capability for decadal-scale prediction over recent years have been for ocean physics and biogeochemistry, with some notable advances …

The Response Of Sea Ice And High-Salinity Shelf Water In The Ross Ice Shelf Polynya To Cyclonic Atmosphere Circulations, Xiaoqiao Wang, Zhaoru Zhang, Michael S. Dinniman, Petteri Uotila, Xichen Li, Meng Zhou

CCPO Publications

Coastal polynyas in the Ross Sea are important source regions of high-salinity shelf water (HSSW) – the precursor of Antarctic Bottom Water that supplies the lower limb of the thermohaline circulation. Here, the response of sea ice production and HSSW formation to synoptic-scale and mesoscale cyclones was investigated for the Ross Ice Shelf Polynya (RISP) using a coupled ocean–sea ice–ice shelf model targeted on the Ross Sea. When synoptic-scale cyclones prevailed over RISP, sea ice production (SIP) increased rapidly by 20 %–30 % over the entire RISP. During the passage of mesoscale cyclones, SIP increased by about 2 times over …

Seasonal Variations In Circumpolar Deep Water Intrusions Into The Ross Sea Continental Shelf, Yufei Wang, Meng Zhou, Zhaoru Zhang, Michael S. Dinniman

CCPO Publications

Intrusions of the warm and nutrient-rich Circumpolar Deep Water (CDW) across the Ross Sea shelf break play an important role in providing heat for ice shelf basal melting and setting the physical environment for biochemical processes. Several mechanisms driving CDW intrusions into the Ross Sea were proposed such as mesoscale eddies, tidal rectification, and interactions between Antarctic Slope Current (ASC) and topographic features. The seasonal variations in the poleward transport of CDW are investigated using ERA-Interim wind data and a Ross Sea circulation model based on the Regional Ocean Modeling System (ROMS) between September 1999 and September 2014. The analyses …

Shellfish, Shorelines, Seagrass And Schism How Virginia Became A Leader In Coastal Marine Science, George Mapp

Miscellaneous

Since the 1930s, when William and Mary professor Donald Davis proposed hiring a state-funded biologist to address fisheries issues, Virginia marine scientists have diagnosed shellfish diseases, rejuvenated the oyster and clam fisheries, preserved wetlands and shorelines, restored seaside seagrass, and accurately modeled Chesapeake Bay circulation. This informal history looks back at the lives of the many dedicated marine scientists, advisory personnel, and administrators who led the Commonwealth through difficult times: collapse of the oyster industry, James River toxic pesticide pollution, Chesapeake Bay water quality degradation, crab and striped bass population declines, and the current challenges brought about by climate change …

The Impact Of Big Data Utilization On Quality Improvement In Inpatient Facilities, Lakyn Hare

Theses, Dissertations and Capstones

Introduction: Poor quality in healthcare has resulted in avoidable patient complications, including readmission rates. Big data in healthcare can be analyzed and built into a tools, with machine learning, to aid in reduced readmission rates and overall positive patient outcomes.

Purpose of the Study: The intention of this study was to evaluate the ways that big data can be analyzed to improve healthcare, specifically readmissions, patient outcomes, and show cost savings. This study examined different ways that big data could be used in concordance with machine learning, including predictive analysis, to make these improvements.

Methodology: The hypothesis was the …

Stratigraphy Of The Metamorphic Rocks Of Niğde Massif And New Evidence Of Triassic Rifting Of The Inner Tauride Ocean (Central Anatolia, Türkiye), Mustafa Kemal Özkan, Metin Beyazpi̇ri̇nç, Ali Ekber Akçay, Muhamed Çoban, Osman Candan, Osman Ersin Koralay, Meftun Kerem Sönmez, Halil Yusufoğlu

Bulletin of the Mineral Research and Exploration

Metamorphites of Niğde Massif, which form the basis of the study area covering the Niğde vicinity in Central Anatolia, are composed of Late Devonian Gümüşler, Carboniferous-early Permian Kaleboynu late Permian Kızıldağ formation and unconformable Triassic-Late Cretaceous cover units from bottom to the top, which are separated from each other with unconformities. The Triassic succession (Söğütlüdere formation) of phyllite-marble-schist alternations with common amphibolite levels is first distinguished in this study, unconformably overlies the Paleozoic succession. Thick homogeneous marbles of Jurassic-Cretaceous period, is defined by quartzite at the bottom representing the unconformity at the base, is defined as the Kırtepe formation. The …

R-Process Nucleosynthesis: Identifying The Significant Nuclear Properties, Sabina Gaia Tomasicchio

2023 REYES Proceedings

We provide a theoretical overview of r-process nucleosynthesis. We then identify the nuclear properties that have the greatest astrophysical impact according to recent sensitivity studies as: nuclear masses, β decays and neutron capture rates. Finally, we briefly discuss how the NuCRL model can enhance the performance of the relevant simulations.

Identification And Biosynthetic Study Of The Siderophore Lysochelin In The Biocontrol Agent Lysobacter Enzymogenes, Amanda Lynn Miller, Shanren Li, Catherine D. Eichhorn, Yongbiao Zheng, Liangcheng Du

Liangcheng Du Publications

Lysobacter is a genus of bacteria emerging as new biocontrol agents in agriculture. Although iron acquisition is essential for the bacteria, no siderophore has been identified from any Lysobacter. Here, we report the identification of the first siderophore, N1,N8-bis(2,3-dihydroxybenzoyl)spermidine (lysochelin), and its biosynthetic gene cluster from Lysobacter enzymogenes. Intriguingly, the deletion of the spermidine biosynthetic gene encoding arginine decarboxylase or SAM decarboxylase eliminated lysochelin and the antifungals, HSAF and its analogues, which are key to the disease control activity and to the survival of Lysobacter under oxidative stresses caused by excess iron. The production of …

Multiplatform Untargeted Metabolomics, Micah J. Jeppesen, Robert Powers

Robert Powers Publications

Metabolomics samples like human urine or serum contain upwards of a few thousand metabolites, but individual analytical techniques can only characterize a few hundred metabolites at best. The uncertainty in metabolite identification commonly encountered in untargeted metabolomics adds to this low coverage problem. A multiplatform (multiple analytical techniques) approach can improve upon the number of metabolites reliably detected and correctly assigned. This can be further improved by applying synergistic sample preparation along with the use of combinatorial or sequential non-destructive and destructive techniques. Similarly, peak detection and metabolite identification strategies that employ multiple probabilistic approaches have led to better annotation …

Assessing The Unionid Assemblage Of The Robert C. Byrd Pool, Ohio River, Ethan Hunter Bellamy

Theses, Dissertations and Capstones

Unionid mussels are the most imperiled taxa in the United States and are vastly understudied. The entire Robert C. Byrd (RCB) pool of the Ohio River is the study area. I selected sites from the 2019 and 2013 ORSANCO RCB pool assessments that utilize random site selection across the pool. I used SCUBA to survey and collect data on unionid diversity, reproduction, and habitat. I collected 1,083 individuals over 19 species in RCB pool. I compared results from RCB pool survey to two similar surveys conducted in Greenup Pool. Both richness and abundance in the Upper Section of Greenup Pool …

Scheduling Electric Vehicle Charging For Grid Load Balancing, Zhixin Han, Katarina Grolinger, Miriam Capretz, Syed Mir

Electrical and Computer Engineering Publications

In recent years, electric vehicles (EVs) have been widely adopted because of their environmental benefits. However, the increasing volume of EVs poses capacity issues for grid operators as simultaneously charging many EVs may result in grid instabilities. Scheduling EV charging for grid load balancing has a potential to prevent load peaks caused by simultaneous EV charging and contribute to balance of supply and demand. This paper proposes a user-preference-based scheduling approach to minimize costs for the user while balancing grid loads. The EV owners benefit by charging when the electricity cost is lower, but still within the user-defined preferred charging …

New Features In Landyne 5 - A Software Suite For Materials Characterization And Crystallography By Transmission Electron Microscopy, Xing-Zhong Li

Nebraska Center for Materials and Nanoscience: Faculty Publications

Landyne software suite (version 5) includes fifteen standalone computer programs for materials characterization and crystallography by transmission electron microscopy [1]. A launcher interface is provided for users to access all components conveniently. The purpose of this software suite is twofold: i) as research tools to analyze experimental results, ii) as teaching tools to explore the varieties of electron diffraction methods and crystallographic image processing principles.

The Landyne suite previously included: PTable, an interactive periodic table of elements; SVAT, a structural visual and analytical tool; SAED and PCED, simulation and analysis of electron diffraction (spot and ring) patterns; QSAED and QPCED, …

Structural, Electronic, And Magnetic Properties Of Cofevge-Based Compounds: Experiment And Theory, Parashu Kharel, Zachary Lehmann, Gavin Baker, Lukas Stuelke, Shah R. Valloppilly, Paul M. Shand, Pavel V. Lukashev

Nebraska Center for Materials and Nanoscience: Faculty Publications

We have carried out a combined theoretical and experimental investigation of both stoichiometric and nonstoichiometric CoFeVGe alloys. In particular, we have investigated CoFeVGe, Co_1.25Fe_0.75VGe, Co_0.75Fe_1.25VGe, and CoFe_0.75VGe bulk alloys. Our first principles calculations suggest that all four alloys show ferromagnetic order, where CoFeVGe, Co_1.25Fe_0.75VGe, and Co_0.75Fe_1.25VGe are highly spin polarized with spin polarization values of over 80%. However, the spin polarization value of CoFe_0.75VGe is only about 60%. We have synthesized all four samples using arc melting and high-vacuum annealing …

Tem Studies Of A New Modulated Structure In Mn2Rusn Alloy And Intermetallic Phases In Fe3+XCo3–XTi2 (X = 0, 1, 2, 3) Alloys, Xing-Zhong Li, Shah R. Valloppilly

Nebraska Center for Materials and Nanoscience: Faculty Publications

Heusler compounds are a remarkable class of intermetallic materials with wide-ranging and tunable properties. The Mn₂RuSn Heusler compound was reported as an L2₁B-type cubic phase, a = 0.62195 nm, distinguishing from the original L2₁ structure (or L2₁A-type). The L2₁B-type structure is a disordered variant of the inverse Heusler structure, XA-type (Prototype-CuHg₂Ti, space group No. 216, F4–3m).

In our recent work [1], we observed a new modulated structure derived from the XA-type structure and its orthogonal domains in the Mn₂RuSn Heusler alloy. The structural characterization was carried out …

Entropy-Driven Structural Transition From Tetragonal To Cubic Phase: High Thermoelectric Performance Of Cucdinse3 Compound, Tingting Luo, Yihao Hu, Shi Liu, Fanjie Xia, Junhao Qiu, Haoyang Peng, Keke Liu, Quansheng Guo, Xingzhong Li, Dongwang Yang, Xianli Su, Jinsong Wu, Xinfeng Tang

Nebraska Center for Materials and Nanoscience: Faculty Publications

Cu based chalcopyrite is an important class of thermoelectric materials with excellent electronic properties, however, the thermal conductivity is relatively high due to the simple tetragonal structure with highly ordered configuration on cation sites, limiting the thermoelectric performance. Herein, we realize that the modulation of entropy via alloying CdSe achieves the structural transition from tetragonal structure with ordered configuration on cations sites in CuInSe₂ compound to cubic CuCdInSe₃. CuCdInSe₃ crystallizes in a zinc blende (ZnS) structure where Cu, Cd and In cations randomly occupy the Zn site with the occupancy fraction 1/3. This entropy driven order-disorder …

Math Department 2022-2023 Newsletter, Mathematics Department

Mathematics Newsletter

Welcome to our annual Mathematics Department Newsletter. We had an exciting year with many activities and accomplishments. Our students have received awards, attended conferences, conducted research, and have really contributed to the life of the department. Our faculty have had many accomplishments in teaching and scholarship. We conducted several events such as Alumni Night, hosted a guest speaker for the university community, had our Pi Mu Epsilon induction and awards ceremony, and much more. We have heard from several alumni and are happy to report what they are doing. Our Math Club has been becoming more active. On the curriculum …

From Mirrors To Wallpapers: A Virtual Math Circle Module On Symmetry, Nicole A. Sullivant, Christina L. Duron, Douglas T. Pfeffer

Journal of Math Circles

Symmetry is a natural property that children see in their everyday lives; it also has deep mathematical connections to areas like tiling and objects like wallpaper groups. The Tucson Math Circle (TMC) presents a 7-part module on symmetry that starts with reflective symmetry and culminates in the deconstruction of wallpapers into their ‘generating tiles’. This module utilizes a scaffolded, hands-on approach to cover old and new mathematical topics with various interactive activities; all activities are made available through free web-based platforms. In this paper, we provide lesson plans for the various activities used, and discuss their online implementation with Zoom, …

Understanding The Green Workforce, Gladys Torres Olivarria, Darbi Berry, Leaders 20/20, University Of San Diego

San Diego Regional Quality of Life Dashboard

One initiative to improve environmental conditions is prioritizing the Green Workforce. The Green workforce is an economic approach to combating climate change. The Green Workforce refers to jobs that help us advance towards a more sustainable society and help us transition from the over-dependence on oil towards reducing greenhouse gas emissions. A Green workforce can bring in millions of new jobs and opportunities.

Understanding Urban Heat Islands And Impacts, Darbi Berry, Nicole Fassina, A-Bel Gong

San Diego Regional Climate Collaborative

Urban heat islands play a large role in aggravating climate impacts on water, electricity, and air pollutants, and affect vulnerable communities disproportionately. This blog calls onto historical redlining and disinvestment and urban development as direct contributors of socioeconomic disparities and includes a case study of one of our region’s most vulnerable communities.

Water And Agriculture In The San Diego Region, Olivia Frigyes, Darbi Berry, A-Bel Gong

San Diego Regional Climate Collaborative

The San Diego region is susceptible to drought with little annual precipitation. The rising temperature and changing precipitation is expected to affect the agriculture economy. Classified as having a mediterranean climate, San Diego has hot, dry summers and cooler, wet winters. In this blog, learn about how San Diego's climate shapes its agricultural communities' reliance on water supply.

2022 Annual Report, San Diego Regional Climate Collaborative

San Diego Regional Climate Collaborative

The San Diego Regional Climate Collaborative is a network for public agencies that serves the San Diego region to share expertise, leverage resources and advance comprehensive solutions to facilitate climate change planning. By partnering with academia, nonprofits, and businesses, the SDRCC also works to leverage the profile of regional leadership. This is the 2021 San Diego Regional Climate Collaborative Annual Report.

Mobilizing Regional Action: Insights From The San Diego Region Coastal Resilience Roadmap, Darbi Berry, Civicwell, Sdrcc

San Diego Regional Climate Collaborative

This case study details the process of developing the San Diego Region Coastal Resilience Roadmap with particular attention to how this process can be replicated in other regions throughout California – for coastal resilience, as well as other climate impacts and community priorities.

Understanding Binational Water Scarcity, Avery Aquino, Darbi Berry

San Diego Regional Climate Collaborative

Water scarcity has become a growing concern in many regions around the world, including the San Diego, CA and Tijuana, MX border region Water is a valuable resource that sustains all life on earth, and the San Diego/Tijuana border region is no exception. With increasing population growth, urbanization, and changing climate patterns on both sides of the border, the demand for water resources has significantly outstripped its availability in this region. As a result, it has become essential tounderstand the extent and impacts of water scarcity, and to develop innovative and sustainable solutions that can mitigate its effects.

Leading Climate & Environmental Action In The San Diego Region, Tessa Tinkler, Eo Hanabusa, Emily Young, Darbi Berry, Connelly Meschen

Environment

Leading Climate & Environmental Action in the San Diego Region presents the state of environment-focused nonprofits in the San Diego region and their legacies that position them to continue impactful climate action. Findings in this report are synthesized from quarterly public opinion pollings (San Diego Residents Survey), surveys of 30 local environmental nonprofit leaders (Nonprofit Leaders Survey), the latest nonprofit data from the Internal Revenue Service (IRS), and data on foundation grants awarded to local nonprofits (Candid). The environmental nonprofit sector in the San Diego region is relatively small, but it has worked on the frontlines for many years to …

Models For Decision-Making - Second Edition, Steven Cosares, Fred Rispoli

Open Educational Resources

Decision-Making often refers to a multi-stage process that starts with some form of introspection or reflection about a situation in which a person or group of people find themselves. These ruminations usually lead to series of questions that need to be answered, or to a set of data that needs to be collected and analyzed, or to some calculations that need to be performed before someone can be in a position to make informed decisions and take appropriate actions.

We provide some simple examples of Quantitative Models, which are often found in a decision-making situation. We focus on the use …