Digital Commons Network^™

Optimal Estimation Inversion Of Ionospheric Electron Density From Gnss-Pod Limb Measurements: Part I-Algorithm And Morphology, Dong L. Wu, Nimalan Swarnalingam, Cornelius C. J. H. Salinas, Daniel J. Emmons, Tyler C. Summers, Robert Gardiner-Garden

Faculty Publications

GNSS-LEO radio links from Precise Orbital Determination (POD) and Radio Occultation (RO) antennas have been used increasingly in characterizing the global 3D distribution and variability of ionospheric electron density (Ne). In this study, we developed an optimal estimation (OE) method to retrieve Ne profiles from the slant total electron content (hTEC) measurements acquired by the GNSS-POD links at negative elevation angles (ε < 0°). Although both OE and onion-peeling (OP) methods use the Abel weighting function in the Ne inversion, they are significantly different in terms of performance in the lower ionosphere. The new OE results can overcome the large Ne oscillations, sometimes negative values, seen in the OP retrievals in the E-region ionosphere. In the companion paper in this Special Issue, the HmF2 and NmF2 from the OE retrieval are validated against ground-based ionosondes and radar observations, showing generally good agreements in NmF2 from all sites. Nighttime hmF2 measurements tend to agree better than the daytime when the ionosonde heights tend to be slightly lower. The OE algorithm has been applied to all GNSS-POD data acquired from the COSMIC-1 (2006–2019), COSMIC-2 (2019–present), and Spire (2019–present) constellations, showing a consistent ionospheric Ne morphology. The unprecedented spatiotemporal sampling of the ionosphere from these constellations now allows a detailed analysis of the frequency–wavenumber spectra for the Ne variability at different heights. In the lower ionosphere (~150 km), we found significant spectral power in DE1, DW6, DW4, SW5, and SE4 wave components, in addition to well-known DW1, SW2, and DE3 waves. In the upper ionosphere (~450 km), additional wave components are still present, including DE4, DW4, DW6, SE4, and SW4. The co-existence of eastward- and westward-propagating wave4 components implies the presence of a stationary wave4 (SPW4), as suggested by other earlier studies. Further improvements to the OE method are proposed, including a tomographic inversion technique that leverages the asymmetric sampling about the tangent point associated with GNSS-LEO links.

The Determinants Of Sustained Adherence To Covid-19 Preventive Measures Among Older Syrian Refugees In Lebanon, Nisreen Salti, Stephen J. Mccall, Berthe Abi Zeid, Noura El Salibi, Marwan Alawieh, Zeinab Ramadan, Hala Ghattas Ph.D, Sawsan Abdulrahim

Faculty Publications

Introduction Lebanon has battled the COVID-19 pandemic in the midst of an economic crisis. The evolution of the pandemic and a fragile health system have meant that public health policy has had to rely heavily on non-pharmaceutical interventions for disease control. However, changes in disease dynamics, an unraveling economy, and pandemic fatigue have meant that disease control policies need to be updated. Methods Using recent and timely data on older (50 years and above) Syrian refugees in Lebanon, this paper uses multivariate linear probability models to explore the determinants of adherence to two non-pharmaceutical COVID-19 prevention measures (wearing a mask …

Structural And Intermediary Social Determinants Of Health And The Emotional And Behavioral Health Of Us Children, Ngozi V. Enelamah, Margaret Lombe, Mansoo Yu, Melissa L. Villodas, Andrew Foell, Chrisann Newransky, Lisa C. Smith, Von Nebbitt

Faculty Publications

Children grow up in homes where varying environmental and socioeconomic contexts have a bearing on their emotional and behavioral health (EBH). This study used data from a representative sample of the child supplement of the US National Health Information Survey (NHIS) and applied the social determinants of health (SDoH) framework to explore factors associated with child EBH. We conducted a path analysis of the child’s EBH measured by the strengths and difficulties questionnaire (SDQ) from their macro and socioeconomic contexts, e.g., policy, household, and other health system risk factors. For children in the sample, aged 4 to 17 years old …

Climate, Controversy, And Courts, Todd S. Aagaard

Faculty Publications

The Supreme Court’s 2022 decision in West Virginia v. EPA, along with other recent cases in which federal courts have grappled with the ongoing climate crisis, offers an opportunity to assess the role of the judiciary in helping the United States adopt effective responses to monumental threats such as the climate crisis. Courts reviewing legislative and executive actions must find ways to enforce constitutional limits without preventing the political branches from implementing effective policy responses to potentially catastrophic problems. Three relatively recent climate cases—West Virginia v. EPA, Utility Air Regulatory Group v. EPA, and Juliana v. United States—illustrate the need …

Advancing Flame Retardant Prediction: A Self-Enforcing Machine Learning Approach For Small Datasets, Cheng Yan, Xiang Lin, Xiaming Feng, Hongyu Yang, Patrick Mensah, Guoqiang Li

Faculty Publications

Improving the fireproof performance of polymers is crucial for ensuring human safety and enabling future space colonization. However, the complexity of the mechanisms for flame retardant and the need for customized material design pose significant challenges. To address these issues, we propose a machine learning (ML) framework based on substructure fingerprinting and self-enforcing deep neural networks (SDNN) to predict the fireproof performance of flame-retardant epoxy resins. Our model is based on a comprehensive understanding of the physical mechanisms of materials and can predict fireproof performance and eliminate the needs for properties descriptors, making it more convenient than previous ML models. …

Intrinsically Stretchable Three Primary Light-Emitting Films Enabled By Elastomer Blend For Polymer Light-Emitting Diodes, Min Woo Jeong, Jin Hyun Ma, Jae Sung Shin, Jun Su Kim, Guorong Ma, Tae Uk Nam, Xiaodan Gu, Seong Jun Kang, Jin Young Oh

Faculty Publications

Intrinsically stretchable light-emitting materials are crucial for skin-like wearable displays; however, their color range has been limited to green-like yellow lights owing to the restricted stretchable light-emitting materials (super yellow series materials). To develop skin-like full-color displays, three intrinsically stretchable primary light-emitting materials [red, green, and blue (RGB)] are essential. In this study, we report three highly stretchable primary light-emitting films made from a polymer blend of conventional RGB light-emitting polymers and a nonpolar elastomer. The blend films consist of multidimensional nanodomains of light-emitting polymers that are interconnected in an elastomer matrix for efficient light-emitting under strain. The RGB blend …

Determining Ion Activity Coefficients In Ion-Exchange Membranes With Machine Learning And Molecular Dynamics Simulations, Hishara Keshani Gallage Dona, Teslim Olayiwola, Luis A. Briceno-Mena, Christopher G. Arges, Revati Kumar, Jose A. Romagnoli

Faculty Publications

The activity coefficients of ions in polymeric ion-exchange membranes (IEMs) dictate the equilibrium partitioning coefficient of the ions between the membrane and the liquid. It also affects ion transport processes, such as conductivity, in ion-exchange membranes. Accurately predicting the ion activity coefficient without experimental data has been elusive as most models are empirical or semi-empirical. This work employs an embedding process that maps microscopic and macroscopic properties for modeling of ion activity coefficients in IEMs with molecular dynamics (MD) and machine learning (ML). This strategy is effective for accurately predicting activity coefficients in various IEM materials, including random copolymer and …

Numerical Simulation Of The Korteweg–De Vries Equation With Machine Learning, Kristina O. F. Williams, Benjamin F. Akers

Faculty Publications

A machine learning procedure is proposed to create numerical schemes for solutions of nonlinear wave equations on coarse grids. This method trains stencil weights of a discretization of the equation, with the truncation error of the scheme as the objective function for training. The method uses centered finite differences to initialize the optimization routine and a second-order implicit-explicit time solver as a framework. Symmetry conditions are enforced on the learned operator to ensure a stable method. The procedure is applied to the Korteweg–de Vries equation. It is observed to be more accurate than finite difference or spectral methods on coarse …

Effects Of Size At Birth On Health, Growth And Developmental Outcomes In Children Up To Age 18: An Umbrella Review, Zeina Jamaluddine, Eman Sharara, Vanessa Helou, Nadine El Rashidi, Gloria Safadi, Nehmat El-Helou, Hala Ghattas Ph.D, Miho Sato, Hannah Blencowe, Oona M.R. Campbell

Faculty Publications

Background Size at birth, an indicator of intrauterine growth, has been studied extensively in relation to subsequent health, growth and developmental outcomes. Our umbrella review synthesises evidence from systematic reviews and meta-analyses on the effects of size at birth on subsequent health, growth and development in children and adolescents up to age 18, and identifies gaps.

Methods We searched five databases from inception to mid-July 2021 to identify eligible systematic reviews and meta-analyses. For each meta-analysis, we extracted data on the exposures and outcomes measured and the strength of the association.

Findings We screened 16 641 articles and identified 302 …

Opinion: How Fear Of Nuclear Winter Has Helped Save The World, So Far, Alan Robock, Lili Xia, Cheryl S. Harrison, Joshua Coupe, Owen B. Toon, Charles G. Bardeen

Faculty Publications

The direct effects of nuclear war would be horrific, with blasts, fires, and radiation killing and injuring many people. But in 1983, United States and Soviet Union scientists showed that a nuclear war could also produce a nuclear winter, with catastrophic consequences for global food supplies for people far removed from the conflict. Smoke from fires ignited by nuclear weapons exploded on cities and industrial targets would block out sunlight, causing dark, cold, and dry surface conditions, producing a nuclear winter, with surface temperatures below freezing even in summer for years. Nuclear winter theory helped to end the nuclear arms …

Marine Anoxia Initiates Giant Sulfur-Bacteria Mat Proliferation And Associated Changes In Benthic Nitrogen, Sulfur, And Iron Cycling In The Santa Barbara Basin, California Borderland, David J. Yousavich, De'marcus Robinson, Xuefeng Peng, Sebastian J.E. Krause, Frank Wenzhoefer, Felix Janßen, Na Liu, Jonathan Tarn, Frank Kinnaman, David L. Valentine, Tina Treude

Faculty Publications

The Santa Barbara Basin naturally experiences transient deoxygenation due to its unique geological setting in the southern California Borderland and seasonal changes in ocean currents. Long-term measurements of the basin showed that anoxic events and subsequent nitrate exhaustion in the bottom waters have been occurring more frequently and lasting longer over the past decade. One characteristic of the Santa Barbara Basin is the seasonal development of extensive mats of benthic nitrate-reducing sulfur-oxidizing bacteria, which are found at the sediment–water interface when the basin's bottom waters reach anoxia but still provide some nitrate. To assess the mat's impact on the benthic …

Effects Of Fucoidan Supplementation On Inflammatory And Immune Response After High-Intensity Exercise, Bridget A. Mcfadden, Caroline S. Vincenty, Akexa J. Chandler, Harry P. Cintineo, Blaine S. Lints, Gianna F. Mastrofini, Shawn M. Arent Ph.D., Cscs*D, Fissn, Facsm, Fnak

Faculty Publications

Introduction: High-intensity exercise (HIE) can damage the musculotendon complex and impact the immune response, resulting in post-exercise inflammation. Sufficient rest and recovery will improve muscular resilience against future damaging bouts; however, HIE with minimal durations of rest is common in athletic competitions that facilitate persistent inflammation and immune dysregulation. Fucoidans are fucose-rich sulfated polysaccharides with demonstrated anti-inflammatory and pro-immune responses. Fucoidans may improve inflammation and immune responses, which may prove beneficial for individuals who regularly engage in repeated HIE. The research purpose was to investigate the safety and efficacy of fucoidans on inflammatory and immune markers following HIE. Methods: Eight …

Algorithm 1035: A Gradient-Based Implementation Of The Polyhedral Active Set Algorithm, William W. Hager, Hongchao Zhang

Faculty Publications

The Polyhedral Active Set Algorithm (PASA) is designed to optimize a general nonlinear function over a polyhedron. Phase one of the algorithm is a nonmonotone gradient projection algorithm, while phase two is an active set algorithm that explores faces of the constraint polyhedron. A gradient-based implementation is presented, where a projected version of the conjugate gradient algorithm is employed in phase two. Asymptotically, only phase two is performed. Comparisons are given with IPOPT using polyhedral-constrained problems from CUTEst and the Maros/Meszaros quadratic programming test set.

Analysis Of Globally Propagating Spherical Shockwaves From Great Volcano Eruptions Using Barometric Pressure Data, Chunyan Li

Faculty Publications

Here, we present a protocol for the analysis of barometric pressure data from multiple stations for the globally propagating spherical shockwaves generated by catastrophic explosions. We demonstrate the analytical procedure using the Tonga underwater volcano eruption of January 2022. We also present a protocol to make a data recorder using off-the-shelf electronic components for barometric pressure measurements at ∼1 Hz. The data recorder and the analysis protocol can be used to study similar future catastrophic events. For complete details on the use and execution of this protocol, please refer to Li (2022).¹

Food Insecurity Among Households With Children During The Early Months Of The Covid-19 Pandemic, Bailey Houghtaling, Megan M. Patton-López, Lindsey Haynes-Maslow, Nila Pradhananga, Lauri Andress, T. Elaine Prewitt, Annie Hardison-Moody, Justin D. Shanks, Michelle Grocke-Dewey, Eliza Webber, Denise Holston, Carmen Byker Shanks

Faculty Publications

Understanding impacts of the COVID-19 pandemic among households with children is necessary to design appropriate public health responses that protect food and nutrition security. The objecttive of this research was to understand predictors of food insecurity during the COVID-19 pandemic among households with at least one child (<18 >years), including whether foods reported as out-ofstock were associated with the likelihood of food insecurity. An online survey using validated measures and open-ended questions was distributed to a convenience sample in five states— Louisiana, Montana, North Carolina, Oregon, and West Virginia—during the early months of the COVID-19 pandemic (April through September of …

New Records Of Southern Pine Beetle (Dendroctonus Frontalis Zimmermann; Coleoptera: Curculionidae) In New York, New Hampshire, And Maine, Usa Indicate Northward Range Expansion, Caroline R. Kanaskie, Thomas C. Schmeelk, Jessica A. Cancelliere, Jeff R. Garnas

Faculty Publications

No abstract provided.

Effects Of Carao (Cassia Grandis L.) On Physico-Chemical, Microbiological And Rheological Characteristics Of Yogurt, Luis Medina, Ricardo S. Aleman, Roberto Cedillos, Kayanush Aryana, Douglas W. Olson, Jhunior Marcia, Charles Boeneke

Faculty Publications

Yogurt fortification with functional ingredients can increase health benefits. Carao fruit has bioactive compounds which could exert antidiabetic potential. Objective was to study the influence of carao powder on physicochemical, microbiological, and rheological properties of yogurt. Carao powder was added at 0, 1.3, 2.65, and 5.3 g/L to milk to produce yogurt, which was stored for 42 days. The pH, titratable acidity (TA), syneresis, color, Streptococcus thermophilus (ST) and Lactobacillus delbrueckii spp. bulgaricus (LB) counts, viscosity, steady shear flow, thixotropic analysis, and frequency sweep measurements were evaluated over yogurt shelf life. The protease activity of yogurt starter culture bacteria and …

Investigation Of Iron(Iii) Tetraphenylporphyrin As A Redox Flow Battery Anolyte: Unexpected Side Reactivity With The Electrolyte, Nathan H. Mitchell, Noémie Elgrishi

Faculty Publications

Redox flow batteries (RFBs) present an opportunity to bridge the gap between the intermittent availability of green energy sources and the need for on-demand grid level energy storage. While aqueous vanadium-based redox flow batteries have been commercialized, they are limited by the constraints of using water as an electrochemical solvent. Nonaqueous redox flow battery systems can be used to produce high voltage batteries due to the larger electrochemical window in nonaqueous solvents and the ability to tune the redox properties of active materials through functionalization. Iron porphyrins, a class of organometallic macrocycles, have been the subject of many studies for …

Tectonic Advection Of Contacts Enhances Landscape Transience, Nate Mitchell, Adam M. Forte

Faculty Publications

Contrasts in bedrock erodibility have been shown to drive landscape transience, but it is unclear whether horizontal tectonic displacements would enhance such effects. Furthermore, one might expect these factors to coexist, as tectonic convergence helps to create rock strength contrasts in settings like the Himalayas. How do landscapes respond when contacts separating units are raised vertically and shifted horizontally by tectonics? To evaluate such questions, we use landscape evolution models to simulate the exposure of a weak unit in a landscape equilibrated to a strong unit. We explore different simulations varying factors like weak unit erodibility, diffusivity, contact dip, and …

Cr-Containing Diamond-Like Carbon Coatings Deposited On 316 Stainless Steel Substrates: Characterization And Interfacial Fracture Toughness Measurements, N. J. Anderson, Bin Zhang, A. C. Meng, Xiaoman Zhang, K. P. Lijesh, M. M. Khonsari, W. J. Meng

Faculty Publications

A series of Cr-containing hydrogenated amorphous carbon (a-C:H:Cr) coatings were deposited onto 316 stainless steel (316SS) substrates using inductively coupled plasma assisted reactive sputter deposition. Elemental Cr interlayers with different thicknesses of 100, 200, and 300 nm were deposited between a-C:H:Cr and 316SS. Detailed composition, structure, and mechanical behavior characterization of deposited a-C:H:Cr/Cr/316SS specimens were performed. Fracture toughness values of the a-C:H:Cr layer, the Cr layer, and the a-C:H:Cr/Cr/316SS interfacial regions were measured by bending of microcantilever beams with focused ion beam milled pre-notches in-situ a scanning electron microscope. Measured fracture toughness of a-C:H:Cr/Cr/316SS interfacial regions exhibits an approximately linear …

Nutrition Interventions Addressing Structural Racism: A Scoping Review, Matthew Greene, Bailey Houghtaling, Claire Sadeghzadeh, Molly De Marco, De'jerra Bryant, Randa Morgan, Denise Holston

Faculty Publications

African Americans experience high rates of obesity and food insecurity in part due to structural racism, or overlapping discriminatory systems and practices in housing, education, employment, health care and other settings. Nutrition education and nutrition-focused policy, systems and environmental changes may be able to address structural racism in the food environment. This scoping review aimed to summarise the available literature regarding nutrition interventions for African Americans that address structural racism in the food environment and compare them with the 'Getting to Equity in Obesity Prevention' framework of suggested interventions. An electronic literature search was conducted with the assistance of a …

In The Ceo We Trust: Negative Effects Of Trust Between The Board And The Ceo, Kee-Hong Bae, Sadok El Ghoul, Zhaoran (Jason) Gong, Omrane Guedhami

Faculty Publications

In this study, we investigate whether and how trust between board members and the CEO (board–CEO trust) affects the performance of mergers and acquisitions. Contrary to conventional wisdom, we find that firms with higher levels of board–CEO trust exhibit poor M&A performance. High trust is associated with low acquisition announcement returns, long-term stock return performance, and post-deal operating performance. This negative effect of board–CEO trust is more pronounced among acquiring companies prone to agency problems. Our results suggest that, in the institutional setting of corporate boards, high trust can be too much of a good thing.

The New Ali Restatement And The Doctrine Of Non-Self-Executing Treaties, David Sloss

Faculty Publications

No abstract provided.

Validating The Spatial Variability In The Semidiurnal Internal Tide In A Realistic Global Ocean Simulation With Argo And Mooring Data, Gaspard Geoffroy, Jonas Nycander, Maarten C. Buijsman, Jay F. Shriver, Brian K. Arbic

Faculty Publications

The autocovariance of the semidiurnal internal tide (IT) is examined in a 32 d segment of a global run of the HYbrid Coordinate Ocean Model (HYCOM). This numerical simulation, with 41 vertical layers and 1/25° horizontal resolution, includes tidal and atmospheric forcing, allowing for the generation and propagation of ITs to take place within a realistic eddying general circulation. The HYCOM data are in turn compared with global observations of the IT around 1000 dbar, from Argo float park-phase data and mooring records. HYCOM is found to be globally biased low in terms of the IT variance and decay of …

Relative Genetic Homogeneity Within A Phenotypically Diverse Group; A Case Of The Lake Tana Labeobarbus (Cyprinidae) Species Flock, Ethiopia, Kebede Beshera

Faculty Publications

The Lake Tana Labeobarbus species flock represents one of the world’s most famous examples of lacustrine species radiations. Previous studies of this group have resulted in the description of at least 15 species based on their differences in functional morphology and definition of two clades (lacustrine and riverine spawning clades) based on life history traits. A total of 166 fish representing 14 Labeobarbus species were genotyped using 10 lineage-specific hexaploid microsatellite loci. Six of these loci were developed for this study based on DNA sequence contigs derived from a microsatellite-enriched genomic library of Labeobarbus intermedius from Lake Tana; the remaining …

Active Colloids As Models, Materials, And Machines, Kyle J.M. Bishop, Sibani Lisa Biswal, Bhuvnesh Bharti

Faculty Publications

Active colloids use energy input at the particle level to propel persistent motion and direct dynamic assemblies. We consider three types of colloids animated by chemical reactions, time-varying magnetic fields, and electric currents. For each type, we review the basic propulsion mechanisms at the particle level and discuss their consequences for collective behaviors in particle ensembles. These microscopic systems provide useful experimental models of nonequilibrium many-body physics in which dissipative currents break time-reversal symmetry. Freed from the constraints of thermodynamic equilibrium, active colloids assemble to form materials that move, reconfigure, heal, and adapt. Colloidal machines based on engineered particles and …

Imparting Systems Engineering Experience Via Interactive Fiction Serious Games, Thomas C. Ford, David Long, Echo Ford

Faculty Publications

Serious games for education are becoming increasing popular. Interactive fiction games are some of the most popular in app stores and are also beginning to be heavily used in education to teach analysis and decision-making. Noting that it is difficult for systems engineers to experience all necessary situations which prepare them for the role of a chief engineer, in this paper, we explore the use of interactive fiction serious games to impart systems engineering experience and to teach systems engineering principles. The results of a cognitive viability, qualitative viability, and replayability analysis of 14 systems engineering serious games developed in …

Zeolite Supported Pt For Depolymerization Of Polyethylene By Induction Heating, Bernard Whajah, Joseph N. Heil, Cameron L. Roman, James A. Dorman, Kerry M. Dooley

Faculty Publications

We demonstrate that for polyethylene depolymerization with induction heating (IH), using a bifunctional (Pt- or Pt− Sn-containing zeolite) hydrocracking catalyst, we can obtain high hydrocarbon product yields (up to 95 wt % in 2 h) at a relatively low surface temperature (375 °C) and with a tunable product distribution ranging from light gas products to gasoline- to diesel-range hydrocarbons. Four zeolite types [MFI, LTL, CHA(SSZ-13), and TON] were chosen as the supports due to their varying pore sizes and structures. These depolymerization results are obtained at atmospheric pressure and without the use of H2 and result in an alkane/alkene mixture …

Bringing The Analysis Of Electrodeposition Signals In Voltammetry Out Of The Shadows, Devin Rappleye, Ranon G. Fuller

Faculty Publications

Voltammetry studies of electrodeposition are growing rapidly. Yet, relations for the analysis of electrodeposition reactions in voltammetry remain relatively obscure in the literature. The existing cyclic and square wave voltammetry relations for electrodeposition and their limitations are discussed to increase awareness. A retrospective analysis is performed to demonstrate the impact of model selection in improving the analysis of electrodeposition behavior with voltammetric data. A repository for voltammetry models of electrodeposition is proposed to further increase familiarity and application of the most appropriate models, which would support a rapidly growing area of research and technological development.

Incorporating Resilience When Assessing Pandemic Risk In The Arctic: A Case Study Of Alaska, Sweta Tiwari, Andrey Petrov, Nino Mateshvili, Michele Devlin, Nikolay Golosov, Marya Rozanova-Smith, Mark Welford, John Degroote, Tatiana Degai, Stanislav Ksenofontov

Faculty Publications

The discourse on vulnerability to COVID-19 or any other pandemic is about the susceptibility to the effects of disease outbreaks. Over time, vulnerability has been assessed through various indices calculated using a confluence of societal factors. However, categorising Arctic communities, without considering their socioeconomic, cultural and demographic uniqueness, into the high and low continuum of vulnerability using universal indicators will undoubtedly result in the underestimation of the communities' capacity to withstand and recover from pandemic exposure. By recognising vulnerability and resilience as two separate but interrelated dimensions, this study reviews the Arctic communities' ability to cope with pandemic risks. In …