Physical Sciences and Mathematics Commons^™

Connecting Self-Efficacy And Views About Nature Of Science In Undergraduate Research Experiences, Gina Quan, Andrew Elby

Faculty Publications

Undergraduate research can support students’ more central participation in physics. We analyze markers of two coupled shifts in participation: changes in students’ views about the nature of science coupled to shifts in self-efficacy toward physics research. Students in the study worked with faculty and graduate student mentors on research projects while also participating in a seminar where they learned about research and reflected on their experiences. In classroom discussions and in clinical interviews, students described gaining more nuanced views about the nature of science, specifically related to who can participate in research and what participation in research looks like. This …

Inflammatory Properties Of Diet And Glucose-Insulin Homeostasis In A Cohort Of Iranian Adults, Nazanin Moslehi, Behnaz Ehsani, Parvin Mirmiran, Nitin Shivappa, Maryam Tohidi, James R. Hébert, Fereidoun Azizi

Faculty Publications

We aimed to investigate associations of the dietary inflammatory index (DII) with glucose-insulin homeostasis markers, and the risk of glucose intolerance. This cross-sectional study included 2975 adults from the Tehran Lipid and Glucose Study. Fasting plasma glucose (FPG), 2-h post-load glucose (2h-PG), and fasting serum insulin were measured. Homeostatic model assessment of insulin resistance index (HOMA-IR) and β-cell function (HOMA-B), and the quantitative insulin sensitivity check index (QUICKI) were calculated. Glucose tolerance abnormalities included impaired fasting glucose (IFG), impaired glucose tolerance (IGT), and type 2 diabetes (T2DM). DII scores were positively associated with 2h-PG (β = 0.04; p = 0.05). …

Long-Term Warming Alters Carbohydrate Degradation Potential In Temperate Forest Soils, Grace Pold, Andrew F. Billings, Jeff L. Blanchard, Daniel B. Burkhardt, Serita D. Frey, Jerry M. Melillo, Julia Schnabel, Linda T. A. Van Diepen, Kristen M. Deangelis

Faculty Publications

As Earth's climate warms, soil carbon pools and the microbial communities that process them may change, altering the way in which carbon is recycled in soil. In this study, we used a combination of metagenomics and bacterial cultivation to evaluate the hypothesis that experimentally raising soil temperatures by 5°C for 5, 8, or 20 years increased the potential for temperate forest soil microbial communities to degrade carbohydrates. Warming decreased the proportion of carbohydrate-degrading genes in the organic horizon derived from eukaryotes and increased the fraction of genes in the mineral soil associated with Actinobacteria in all studies. Genes associated with …

Soil Microbial Biomass And Function Are Altered By 12 Years Of Crop Rotation, Marshall D. Mcdaniel, A. Stuart Grandy

Faculty Publications

Declines in plant diversity will likely reduce soil microbial biomass, alter microbial functions, and threaten the provisioning of soil ecosystem services. We examined whether increasing temporal plant biodiversity in agroecosystems (by rotating crops) can partially reverse these trends and enhance soil microbial biomass and function. We quantified seasonal patterns in soil microbial biomass, respiration rates, extracellular enzyme activity, and catabolic potential three times over one growing season in a 12-year crop rotation study at the W. K. Kellogg Biological Station LTER. Rotation treatments varied from one to five crops in a 3-year rotation cycle, but all soils were sampled under …

A Discrete Chemo-Dynamical Model Of The Giant Elliptical Galaxy Ngc 5846: Dark Matter Fraction, Internal Rotation, And Velocity Anisotropy Out To Six Effective Radii, Ling Zhu, Aaron Romanowsky, Glenn Van De Ven, R. Long, Laura Watkins, Vincenzo Pota, Nicola Napolitano, Duncan Forbes, Jean Brodie, Caroline Foster

Faculty Publications

We construct a suite of discrete chemo-dynamical models of the giant elliptical galaxy NGC 5846. These models are a powerful tool to constrain both the mass distribution and internal dynamics of multiple tracer populations. We use Jeans models to simultaneously fit stellar kinematics within the effective radius Re, planetary nebula (PN) radial velocities out to 3 Re, and globular cluster (GC) radial velocities and colours out to 6 Re. The best-fitting model is a cored dark matter halo which contributes ∼10 per cent of the total mass within 1 Re, and 67 per cent ± 10 per cent within 6 …

Formal Performance Guarantees For Behavior-Based Localization Missions, Damian Lyons, Ron Arkin, Shu Jiang, Matt O'Brien, Feng Tang, Peng Tang

Faculty Publications

Abstract— Localization and mapping algorithms can allow a robot to navigate well in an unknown environment. However, whether such algorithms enhance any specific robot mission is currently a matter for empirical validation. In this paper we apply our MissionLab/VIPARS mission design and verification approach to an autonomous robot mission that uses probabilistic localization software.

Two approaches to modeling probabilistic localization for verification are presented: a high-level approach, and a sample-based approach which allows run-time code to be embedded in verification. Verification and experimental validation results are presented for two different missions, each using each method, demonstrating the accuracy …

High Pressure Line Shapes Of The Rb D1 And D2 Lines For 4He And 3He Collisions, Wooddy S. Miller, Christopher A. Rice, Gordon D. Hager, Matthew D. Rotondaro, Hamid Berriche, Glen P. Perram

Faculty Publications

Line shapes for the Rb D₁ (5²S_1/2 ↔ 5²P_1/2) and D₂ (5²S_1/2 ↔ 5²P_3/2) transitions with ⁴He and ³He collisions at pressures of 500–15,000 Torr and temperatures of 333–533 K have been experimentally observed and compared to predictions from the Anderson–Talman theory. The ground X²Σ⁺_1/2 and excited A²Π_1/2, A²Π_3/2, and B²Σ⁺_1/2 potential energy surfaces required for the line shape predictions have been calculated using a one-electron …

A General Elliptic Nonlinear System Of Multiple Functions With Application, Timothy Robertson, Joon Hyuk Kang

Faculty Publications

The purpose of this paper is to give a sufficient condition for the existence, nonexistence and uniqueness of positive solutions to a rather general type of elliptic system of the Dirichlet problem on a bounded domain Ω in Rn . We also investigate the effects of perturbation on the positive solutions to the system. The techniques used in this paper are upper-lower solutions, eigenvalues of operators, the maximum principles and spectrum estimates. The arguments also rely on some detailed properties for the solution of logistic equations. This result yields an algebraically computable criterion for the positive coexistence of competing species …

Wind Power: Frustrating Yet Inevitable, Garth Woodruff

Faculty Publications

No abstract provided.

Confidence Investigation Of Discovering Organizational Network Structures Using Transfer Entropy, Joshua V. Rodewald, John M. Colombi, Kyle F. Oyama, Alan W. Johnson

Faculty Publications

Transfer entropy has long been used to discover network structures and relationships based on the behavior of nodes in the system, especially for complex adaptive systems. Using the fact that organizations often behave as complex adaptive systems, transfer entropy can be applied to discover the relationships and structure within an organizational network. The organizational structures are built using a model developed by Dodd, Watts, et al, and a simulation method for complex adaptive supply networks is used to create node behavior data. The false positive rate and true positive rates are established for various organizational structures and compared to a …

A Method For Revealing And Addressing Security Vulnerabilities In Cyber-Physical Systems By Modeling Malicious Agent Interactions With Formal Verification, Dean C. Wardell, Robert F. Mills, Gilbert L. Peterson, Mark E. Oxley

Faculty Publications

Several cyber-attacks on the cyber-physical systems (CPS) that monitor and control critical infrastructure were publically announced over the last few years. Almost without exception, the proposed security solutions focus on preventing unauthorized access to the industrial control systems (ICS) at various levels – the defense in depth approach. While useful, it does not address the problem of making the systems more capable of responding to the malicious actions of an attacker once they have gained access to the system. The first step in making an ICS more resilient to an attacker is identifying the cyber security vulnerabilities the attacker can …

Block Ionomer Complexes Consisting Of Sirna And ARaft-Synthesized Hydrophilic-Block-Cationic Copolymers Ii: The Influence Of Cationic Block Charge Density On Gene Suppression, Keith Hampton Parsons, Andrew Christopher Holley, Gabrielle A. Munn, Alex S. Flynt, Charles L. Mccormick

Faculty Publications

Block ionomer complex (BIC)–siRNA interactions and effectiveness in cell transfection are reported. Aqueous RAFT polymerization was used to prepare a series of hydrophilic-block-cationic copolymers in which the cationic block statistically incorporates increasing amounts of neutral, hydrophilic monomer such that the number of cationic groups remains unchanged but the cationic charge density is diluted along the polymer backbone. Reduced charge density decreases the electrostatic binding strength between copolymers and siRNA with the goal of improving siRNA release after targeted cellular delivery. However, lower binding strength resulted in decreased transfection and RNA interference pathway activation, leading to reduced gene knockdown. Enzymatic siRNA …

Ultraluminous X-Ray Bursts In Two Ultracompact Companions To Nearby Elliptical Galaxies, Jimmy Irwin, W. Maksym, Gregory Sivakoff, Aaron Romanowsky, Dacheng Lin, Tyler Speegle, Ian Prado, David Mildebrath, Jay Strader, Jifeng Liu, Jon Miller

Faculty Publications

A search of archival X-ray data for 70 nearby galaxies has yielded two flaring sources in globular clusters or ultracompact dwarf companions of parent elliptical galaxies. One source flared once, and the other five times. When not flaring, these sources appear to be normal accreting neutron-star or black-hole X-ray binaries. Unlike magnetars and other bodies that produce repetitive flares of similar luminosity, they are located in old stellar populations.

Sources, Distributions, And Dynamics Of Dissolved Organic Matter In The Canada And Makarov Basins, Yuan Shen, Ronald Benner, Lisa Robbins, Jonathan Wynn

Faculty Publications

A comprehensive survey of dissolved organic carbon (DOC) and chromophoric dissolved organic matter (CDOM) was conducted in the Canada and Makarov Basins and adjacent seas during 2010–2012 to investigate the dynamics of dissolved organic matter (DOM) in the Arctic Ocean. Sources and distributions of DOM in polar surface waters were very heterogeneous and closely linked to hydrological conditions. Canada Basin surface waters had relatively low DOC concentrations (69 ± 6 μmol L−1), CDOM absorption (a325: 0.32 ± 0.07 m−1) and CDOM-derived lignin phenols (3 ± 0.4 nmol L−1), and high spectral slope values (S275–295: 31.7 ± …

Sources, Distributions And Dynamics Of Dissolved Organic Matter In The Canada And Makarov Basins, Yuan Shen, Ronald Benner, Lisa L. Robbins, Jonathan G. Wynn

Faculty Publications

A comprehensive survey of dissolved organic carbon (DOC) and chromophoric dissolved organic matter (CDOM) was conducted in the Canada and Makarov Basins and adjacent seas during 2010–2012 to investigate the dynamics of dissolved organic matter (DOM) in the Arctic Ocean. Sources and distributions of DOM in polar surface waters were very heterogeneous and closely linked to hydrological conditions. Canada Basin surface waters had relatively low DOC concentrations (69 ± 6 μmol L−1), CDOM absorption (a325: 0.32 ± 0.07 m−1) and CDOM-derived lignin phenols (3 ± 0.4 nmol L−1), and high spectral slope values (S275–295: 31.7 ± …

Coastal Wetland Response To Sea-Level Rise In A Fluvial Estuarine System, Karim Alizad, Scott C. Hagen, James T. Morris, Stephen C. Medeiros, Matthew V. Bilskie, John F. Weishampel

Faculty Publications

Coastal wetlands are likely to lose productivity under increasing rates of sea-level rise (SLR). This study assessed a fluvial estuarine salt marsh system using the Hydro-MEM model under four SLR scenarios. The Hydro-MEM model was developed to apply the dynamics of SLR as well as capture the effects associated with the rate of SLR in the simulation. Additionally, the model uses constants derived from a 2-year bioassay in the Apalachicola marsh system. In order to increase accuracy, the lidar-based marsh platform topography was adjusted using Real Time Kinematic survey data. A river inflow boundary condition was also imposed to simulate …

Using Survival Analysis To Identify Risk Factors For Treatment Interruption Among New And Retreatment Tuberculosis Patients In Kenya, Enos O. Masini, Omar Mansour, Clare E. Speer, Vittorio Addona, Christy L. Hanson, Joseph K. Sitienei, Hillary K. Kipruto, Martin Muhingo Githiomi, Brenda Nyambura Mungai

Faculty Publications

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Despite high tuberculosis (TB) treatment success rate, treatment adherence is one of the major obstacles to tuberculosis control in Kenya. Our objective was to identify patient-related factors that were associated with time to TB treatment interruption and the geographic distribution of the risk of treatment interruption by county. Data of new and retreatment patients registered in TIBU, a Kenyan national case-based electronic data recording system, between 2013 and 2014 was obtained. Kaplan-Meier curves and log rank tests were used to assess the adherence patterns. Mixed-effects Cox proportional hazards modeling was used for multivariate analysis. Records from 90,170 patients were …

Alongcoast Structure And Interannual Variability Of Seasonal Midshelf Water Properties And Velocity In The Northern California Current System, B. Hickey, S. Geier, N. Kachel, S. Ramp, P. Kosro, Thomas Connolly

Faculty Publications

Moored sensors were maintained for ∼5 years on the northern California Current System (CCS) midshelf. The alongcoast sensor array spanned the area of influence of the plume from the Columbia River, several submarine canyons, as well as a coastal promontory where the equatorward coastal jet frequently separates from the shelf. Upwelling-favorable wind stress magnitude decreases poleward by more than a factor of three over the latitudinal range and shelf width varies by a factor of two. In spite of the alongcoast structure in setting, both seasonal and interannual patterns in subsurface layer water properties were remarkably similar at all sites. …

Dealloying Behavior Of Nico And Nicocu Thin Films, Benjamin Peecher, Jennifer R. Hampton

Faculty Publications

Porous metals and alloys, such as those fabricated via electrochemical dealloying, are of interest for a variety of energy applications, ranging from their potential for enhanced catalytic behavior to their use as high surface area supports for pseudocapacitor materials. Here, the electrochemical dealloying process was explored for electrodeposited binary NiCo and ternary NiCoCu thin films. For each of the four different metal ratios, films were dealloyed using linear sweep voltammetry to various potentials in order to gain insight into the evolution of the film over the course of the linear sweep. Electrochemical capacitance, scanning electron microscopy, and energy dispersive X-ray …

Solving Fredholm Integral Equations Via A Piecewise Linear Maximum Entropy Method, Congming Jin, Jiu Ding

Faculty Publications

We propose a piecewise linear approximation method, based on the maximum entropy principle, to approximate a nonnegative solution of a Fredholm integral equation numerically. The theoretical analysis and numerical examples show that our method has a convergence rate of order 2, and it can get more accurate approximations with more moments used without ill-condition of the classic maximum entropy approach. The method can also be applied to solve Fredholm integral equations with singular kernels.

Large-Scaleoff-Target Identificationusing Fast And Accurate Dual Regularized Oneclass Collaborative Filtering And Its Application To Drug Repurposing, Hansaim Lim, Alexsandar Poleksic, Yuan Yao, Hanghang Tong, Di He, Luke Zhuang, Patrick Meng, Lei Xie

Faculty Publications

Target-based screening is one of the major approaches in drug discovery. Besides the intended target, unexpected drug off-target interactions often occur, and many of them have not been recognized and characterized. The off-target interactions can be responsible for either therapeutic or side effects. Thus, identifying the genome-wide off-targets of lead compounds or existing drugs will be critical for designing effective and safe drugs, and providing new opportunities for drug repurposing. Although many computational methods have been developed to predict drug-target interactions, they are either less accurate than the one that we are proposing here or computationally too intensive, thereby limiting …

A General Elliptic Nonlinear System Of Two Functions With Application, Timothy Robertson, Joon Hyuk Kang

Faculty Publications

The purpose of this paper is to give a sufficient condition for the existence and nonexistence of positive solutions to a rather general type of elliptic system of the Dirichlet problem on the bounded domain Ω in Rn. Also considered are the effects of perturbations on the coexistence state and uniqueness. The techniques used in this paper are upper-lower solutions, eigenvalues of operators, maximum principles and spectrum estimates. The arguments also rely on some detailed properties for the solution of logistic equations. These results yield an algebraically computable criterion for the positive coexistence of competing species of animals in many …

Sn Vacancies In Photorefractive Sn2P2S6 Crystals: An Electron Paramagnetic Resonance Study Of An Optically Active Hole Trap, Eric M. Golden, Sergey A. Basun, D. R. Evans, A. A. Grabar, I. M. Stoika, Nancy C. Giles, Larry E. Halliburton

Faculty Publications

Electron paramagnetic resonance (EPR) is used to identify the singly ionized charge state of the Sn vacancy (V⁻_Sn) in single crystals of Sn₂P₂S₆ (often referred to as SPS). These vacancies, acting as a hole trap, are expected to be important participants in the photorefractive effect observed in undoped SPS crystals. In as-grown crystals, the Sn vacancies are doubly ionized (V²⁻_Sn) with no unpaired spins. They are then converted to a stable EPR-active state when an electron is removed (i.e., a hole is trapped) during an illumination below 100 K …

Investigation Of Shadowing Effects In Typical Propagation Scenarios For High Speed Railway At 2350 Mhz, Liu Liu, Cheng Tao, David W. Matolak, Tao Zhou, Houjin Chen

Faculty Publications

Based on realistic measurements in China, shadowing characteristics at the frequency of 2350 MHz were investigated in typical High-Speed Railway environments. After confirming that the measured shadowing satisfies wide-sense stationarity (assessed via the reverse arrangement test method), we quantify the shadowing correlation. Three types of correlation models are compared for the shadowing characterization, and the Normalized Mean Square Error is used to determine the best matching model: a single decaying exponential function. Decorrelation distances were found to be 11.9 m, 17.7 m, and 8.3 m in our three HSR scenarios, respectively. The results should be useful for the evaluation and …

The Changshu Declaration On Wetlands, R. Eugene Turner, Jos T. A. Verhoeven, Ania Grobicki, Jenny Davis, Shuqing An

Faculty Publications

No abstract provided.

Inversion Of Diffraction Data For Amorphous Materials, Anup Pandey, Parthapratim Biswas, D.A. Drabold

Faculty Publications

The general and practical inversion of diffraction data–producing a computer model correctly representing the material explored–is an important unsolved problem for disordered materials. Such modeling should proceed by using our full knowledge base, both from experiment and theory. In this paper, we describe a robust method to jointly exploit the power of ab initio atomistic simulation along with the information carried by diffraction data. The method is applied to two very different systems: amorphous silicon and two compositions of a solid electrolyte memory material silver-doped GeSe₃. The technique is easy to implement, is faster and yields results much …

Landmark Detection With Surprise Saliency Using Convolutional Neural Networks, Feng Tang, Damian Lyons, Daniel Leeds

Faculty Publications

Abstract—Landmarks can be used as reference to enable people or robots to localize themselves or to navigate in their environment. Automatic definition and extraction of appropriate landmarks from the environment has proven to be a challenging task when pre-defined landmarks are not present. We propose a novel computational model of automatic landmark detection from a single image without any pre-defined landmark database. The hypothesis is that if an object looks abnormal due to its atypical scene context (what we call surprise saliency), it then may be considered as a good landmark because it is unique and easy to spot by …

A New Class Of Allosteric Hiv-1 Integrase Inhibitors Identified By Crstallographic Fragment Screening Of The Catalytic Core Domain, Disha Patel, Janet Antwi, Pratibha C. Koneru, Erik Serrao, Stefano Forli, Jacques J. Kessl, Lei Feng, Nanjie Deng, Ronald M. Levy, James R. Fuchs, Arthur J. Olson, Alan N. Engelman, Joseph D. Bauman, Mamuka Kvaratskhelia, Eddy Arnold

Faculty Publications

HIV-1 integrase (IN) is essential for virus replication and represents an important multifunctional therapeutic target. Recently discovered quinoline-based allosteric IN inhibitors (ALLINIs) potently impair HIV-1 replication and are currently in clinical trials. ALLINIs exhibit a multimodal mechanism of action by inducing aberrant IN multimerization during virion morphogenesis and by competing with IN for binding to its cognate cellular cofactor LEDGF/p75 during early steps of HIV-1 infection. However, quinoline-based ALLINIs impose a low genetic barrier for the evolution of resistant phenotypes, which highlights a need for discovery of second-generation inhibitors. Using crystallographic screening of a library of 971 fragments against the …

Observation Of Spatial Charge And Spin Correlations In The 2d Fermi-Hubbard Model, Lawrence Cheuk, Matthew Nichols, Katherine Lawrence, Melih Okan, Hao Zhang, Ehsan Khatami, Nandini Trivedi, Thereza Paiva, Marcos Rigol, Martin Zwierlein

Faculty Publications

Strong electron correlations lie at the origin of high-temperature superconductivity. Its essence is believed to be captured by the Fermi-Hubbard model of repulsively interacting fermions on a lattice. Here we report on the site-resolved observation of charge and spin correlations in the two-dimensional (2D) Fermi-Hubbard model realized with ultracold atoms. Antiferromagnetic spin correlations are maximal at half-filling and weaken monotonically upon doping. At large doping, nearest-neighbor correlations between singly charged sites are negative, revealing the formation of a correlation hole, the suppressed probability of finding two fermions near each other. As the doping is reduced, the correlations become positive, signaling …

Recurrence Relations For Orthogonal Polynomials For Pdes In Polar And Cylindrical Geometrics, Megan Richardson, James V. Lambers

Faculty Publications

This paper introduces two families of orthogonal polynomials on the interval (−1,1), with weight function w(x)=1. The first family satisfies the boundary condition p(1)=0, and the second one satisfies the boundary conditions p(-1)=p(1)=0. These boundary conditions arise naturally from PDEs defined on a disk with Dirichlet boundary conditions and the requirement of regularity in Cartesian coordinates. The families of orthogonal polynomials are obtained by orthogonalizing short linear combinations of Legendre polynomials that satisfy the same boundary conditions. Then, the three-term recurrence relations are derived. Finally, it is shown that from these recurrence relations, one can …