Physical Sciences and Mathematics Commons^™

Multi-Abstraction Concern Localization, Tien-Duy B. Duy, Shaowei Wang, David Lo

David LO

Concern localization refers to the process of locating code units that match a particular textual description. It takes as input textual documents such as bug reports and feature requests and outputs a list of candidate code units that need to be changed to address the bug reports or feature requests. Many information retrieval (IR) based concern localization techniques have been proposed in the literature. These techniques typically represent code units and textual descriptions as a bag of tokens at one level of abstraction, e.g., each token is a word, or each token is a topic. In this work, we propose …

Theory And Practice, Do They Match? A Case With Spectrum-Based Fault Localization, Tien-Duy B. Le, Ferdian Thung, David Lo

David LO

Spectrum-based fault localization refers to the process of identifying program units that are buggy from two sets of execution traces: normal traces and faulty traces. These approaches use statistical formulas to measure the suspiciousness of program units based on the execution traces. There have been many spectrum-based fault localization approaches proposing various formulas in the literature. Two of the best performing and well-known ones are Tarantula and Ochiai. Recently, Xie et al. find that theoretically, under certain assumptions, two families of spectrum-based fault localization formulas outperform all other formulas including those of Tarantula and Ochiai. In this work, we empirically …

Ba4kfe3o9: A Novel Ferrite Containing Discrete 6-Membered Rings Of Corner-Sharing Feo4 Tetrahedra, Qingbiao Zhao, Saritha Nellutla, Won-Joon Son, Shae Vaughn, Longfei Ye, Mark Smith, Vincent Caignaert, Michael Lufaso, Thomas Pekarek, Alex Smirnov, Myung-Hwan Whangbo, Hans Zur Loye

Michael W. Lufaso

No abstract provided.

Spontaneous Oscillations In Simple Fluid Networks, Nathaniel Karst, Brian Storey, John Geddes

Brian Storey

Nonlinear phenomena including multiple equilibria and spontaneous oscillations are common in fluid networks containing either multiple phases or constituents. In many systems, such behavior might be attributed to the complicated geometry of the network, the complex rheology of the constituent fluids, or, in the case of microvascular blood flow, biological control. In this paper we investigate two examples of a simple three-node fluid network containing two miscible Newtonian fluids of differing viscosities, the first modeling microvascular blood flow and the second modeling stratified laminar flow. We use a combination of analytic and numerical techniques to identify and track saddle-node and …

Spontaneous Oscillations In Simple Fluid Networks, Nathaniel Karst, Brian Storey, John Geddes

John B. Geddes

Nonlinear phenomena including multiple equilibria and spontaneous oscillations are common in fluid networks containing either multiple phases or constituents. In many systems, such behavior might be attributed to the complicated geometry of the network, the complex rheology of the constituent fluids, or, in the case of microvascular blood flow, biological control. In this paper we investigate two examples of a simple three-node fluid network containing two miscible Newtonian fluids of differing viscosities, the first modeling microvascular blood flow and the second modeling stratified laminar flow. We use a combination of analytic and numerical techniques to identify and track saddle-node and …

Effects Of Environmental Factors On Dimethylated Sulfur Compounds And Their Potential Role In The Antioxidant System Of The Coral Holobiont, Elisabeth Deschaseaux, Graham Jones, Myrna Deseo, Kellie Shepherd, R Kiene, H Swan, Peter Harrison, Bradley Eyre

Dr Myrna A Deseo

Biogenic dimethylsulfide (DMS) and its main precursors, dimethylsulfoniopropionate (DMSP) and dimethylsulfoxide (DMSO), are potential scavengers of reactive oxygen species in marine algae, and these dimethylated sulfur compounds (DSC) could take part in the algal antioxidant system. In this study, a link between the DSC production and the antioxidant capacity (AOC) of Acropora aspera reef coral was investigated under a range of environmental factors (temperature, light, salinity, and air exposure) that can lead to oxidative stress in the coral holobiont. Enhanced DMS(P)(O) production occurred under experimental conditions, indicating that DSC are potential biomarkers of stress level in coral tissue. Differences in …

Sustainable Development, John Dernbach

John C. Dernbach

No abstract provided.

The Impact Of Host Rock Geochemistry On Bacterial Community Structure In Oligotrophic Cave Environments, Hazel Barton, Nicholas Taylor, Michael Kreate, Austin Springer, Stuart Oehrle, Janet Bertog

Hazel Barton

Despite extremely starved conditions, caves contain surprisingly diverse microbial communities. Our research is geared toward understanding what ecosystems drivers are responsible for this high diversity. To asses the effect of rock fabric and mineralogy, we carried out a comparative geomicrobiology study within Carlsbad Cavern, New Mexico, USA. Samples were collected from two different geologic locations within the cave: WF1 in the Massive Member of the Capitan Formation and sF88 in the calcareous siltstones of the Yates Formation. We examined the organic content at each location using liquid chromatography mass spectroscopy and analyzed microbial community structure using molecular phylogenetic analyses. In …

The Hyperspherical Four-Fermion Problem, Seth Rittenhouse, J Stecher, J D'Incao, Nirav Mehta, Chris Greene

Nirav P Mehta

The problem of a few interacting fermions in quantum physics has sparked intense interest, particularly in recent years owing to connections with the behaviour of superconductors, fermionic superfluids and finite nuclei. This review addresses recent developments in the theoretical description of four fermions having finite-range interactions, stressing insights that have emerged from a hyperspherical coordinate perspective. The subject is complicated, so we have included many detailed formulae that will hopefully make these methods accessible to others interested in using them. The universality regime, where the dominant length scale in the problem is the two-body scattering length, is particularly stressed, including …

Born-Oppenheimer Study Of Two-Component Few-Particle Systems Under One-Dimensional Confinement, Nirav Mehta

Nirav P Mehta

The energy spectrum, atom-dimer scattering length, and atom-trimer scattering length for systems of three and four ultracold atoms with δ-function interactions in one dimension are presented as a function of the relative mass ratio of the interacting atoms. The Born-Oppenheimer approach is used to treat three-body (“HHL”) systems of one light and two heavy atoms, as well as four-body (“HHHL”) systems of one light and three heavy atoms. Zero-range interactions of arbitrary strength are assumed between different atoms, but the heavy atoms are assumed to be noninteracting among themselves. Fermionic and bosonic heavy atoms with both positive and negative parity …

General Theoretical Description Of N-Body Recombination, Nirav Mehta, Seth Rittenhouse, J D’Incao, J Stecher, Chris Greene

Nirav P Mehta

Formulas for the cross section and event rate constant describing recombination of N particles are derived in terms of general S-matrix elements. Our result immediately yields the generalized Wigner threshold scaling for the recombination of N bosons. A semianalytical formula encapsulates the overall scaling with energy and scattering length, as well as resonant modifications by the presence of N-body states near the threshold collision energy in the entrance channel. We then apply our model to the case of four-boson recombination into an Efimov trimer and a free atom.

Low-Energy Operators In Effective Theories, C Felline, Nirav Mehta, J Piekarewicz, James Shepard

Nirav P Mehta

Modern effective-theory techniques are applied to the nuclear many-body problem. A novel approach is proposed for the renormalization of operators in a manner consistent with the construction of the effective potential. To test this approach, a one-dimensional, yet realistic, nucleon-nucleon potential is introduced. An effective potential is then constructed by tuning its parameters to reproduce the exact effective-range expansion and a variety of bare operators are renormalized in a fashion compatible with this construction. Predictions for the expectation values of these effective operators in the ground state reproduce the results of the exact theory with remarkable accuracy (at the 0.5% …

Green’S Functions And The Adiabatic Hyperspherical Method, Seth Rittenhouse, Nirav Mehta, Chris Greene

Nirav P Mehta

We address the few-body problem using the adiabatic hyperspherical representation. A general form for the hyperangular Green’s function in d dimensions is derived. The resulting Lippmann-Schwinger equation is solved for the case of three particles with s-wave zero-range interactions. Identical particle symmetry is incorporated in a general and intuitive way. Complete semianalytic expressions for the nonadiabatic channel couplings are derived. Finally, a model to describe the atom loss due to three-body recombination for a three-component Fermi gas of Li6 atoms is presented.

Efimov States Embedded In The Three-Body Continuum, Nirav Mehta, Seth Rittenhouse, J D’Incao, Chris Greene

Nirav P Mehta

We present analytical solutions for the three-body problem with multichannel interactions and identify a class of quasibound Efimov states that can be viewed as three-body Fano-Feshbach resonances. Our method employs a multichannel generalization of the Fermi pseudopotential to model low-energy atom-atom interactions near a magnetically tunable Fano-Feshbach resonance. We discuss the conditions under which quasibound Efimov states may be supported and identify the interaction parameters that limit the lifetimes of these states. We speculate that it may be possible to observe these states using spectroscopic methods, perhaps allowing for the measurement of multiple Efimov resonances.

Three-Body Recombination In One Dimension, Nirav Mehta, B Esry, Chris Greene

Nirav P Mehta

We study the three-body problem in one dimension for both zero- and finite-range interactions using the adiabatic hyperspherical approach. Particular emphasis is placed on the threshold laws for recombination, which are derived for all combinations of the parity and exchange symmetries. For bosons, we provide a numerical demonstration of several universal features that appear in the three-body system, and discuss how certain universal features in three dimensions are different in one dimension. We show that the probability for inelastic processes vanishes as the range of the pairwise interaction is taken to zero and demonstrate numerically that the recombination threshold law …

An Injection From Standard Fillings To Parking Functions, Elizabeth Niese

Elizabeth Niese

The Hilbert series of the Garsia-Haiman module can be written as a generating function of standard fillings of Ferrers diagrams. It is conjectured by Haglund and Loehr that the Hilbert series of the diagonal harmonics can be written as a generating function of parking functions. In this paper we present a weight-preserving injection from standard fillings to parking functions for certain cases.

Intertwining Material And Virtual Work, Daniel Robey, Kathy Schwaig, Leigh Jin

Kathy S Schwaig

Virtual work in organizations continues to be promoted despite the absence of a strong conceptual understanding of virtual work and its consequences. In this paper, we draw from and , who treat virtual work as a second, electronically mediated representation of material work. The virtual and material representations co-exist and intertwine, potentially allowing teams and organizations to extend their capabilities. We identify four aspects of intertwining: reinforcement, complementarity, synergy, and reciprocity. In instances where the relationship between virtual and material worlds of work lack one or more of these aspects, ironic and confused outcomes may result. We illustrate these aspects …

Isoquinoline-Derivatized Tris(2-Pyridylmethyl)Amines As Fluorescent Zinc Sensors With Strict Zn2+/Cd2+ Selectivity, Shawn Burdette, Yuji Mikata, Keiko Kawata, Saaya Takeuchi, Kaori Nakanishi, Hideo Konno, Saori Itami, Keiko Yasuda, Satoshi Tamotsu

Shawn C. Burdette

Tris(2-pyridylmethyl)amine-based fluorescent ligands, N,N-bis(1-isoquinolylmethyl)-2-pyridylmethylamine (1-isoBQPA) and N,N-bis(7-methoxy-1-isoquinolylmethyl)-2-pyridylmethylamine (7-MeO-1-isoBQPA), have been prepared and the Zn2+-induced fluorescence enhancement has been investigated. Upon excitation at 324 nm, 1-isoBQPA exhibits a very weak emission (ϕ = [similar]0.010) in DMF–H2O (1 : 1). Upon Zn2+ addition, the 1-isoBQPA fluorescence increases (ϕZn = 0.055) at 357 nm and 464 nm. The fluorescence enhancement at longer wavelengths is Zn2+-specific, whereas Cd2+ induces a small emission increase at 464 nm (ICd/I0 = 1.1, ICd/IZn = 14%). The Zn2+/Cd2+ selectivity of the fluorescent response correlates with the Cd–Nisoquinoline and Zn–Nisoquinoline bond distances measured in the crystal structures. Introduction of …

Estimating Unsaturated Hydraulic Functions For Coarse Sediment From A Field-Scale Infiltration Experiment, Michael Thoma, Warren Barrash, Michael Cardiff, John Bradford, Jodi Mead

Jodi Mead

A field-scale infiltration experiment was conducted in coarse conglomeratic soil with high gravel fraction. Unsaturated flow properties were estimated from modeling of infiltration using the van Genuchten–Mualem model and a Metropolis–Hasting optimization scheme. Results provide optimal unsaturated flow parameters for a soil type that is underrepresented for vadose zone flow. Conglomeratic alluvial sediments (sand–gravel–cobbles) are common in fluvial, periglacial, and tectonically active regions but have received little attention with respect to unsaturated flow, specifically moisture–tension–conductivity relationships, due to difficulty in making measurements in the field or laboratory and lack of agricultural value. We used a field-scale infiltration experiment, a one-dimensional …

Mathematical Reasoning: Writing And Proof, Version 2.0, Ted Sundstrom

Ted Sundstrom, Professor of Mathematics

Quantum Chemical Studies Of Carbonyl Oxide Chemistry In Combustion And In The Lower Atmosphere Peroxides, Keith Kuwata

Keith Kuwata

No abstract provided.

Effects Of Bandgap On Secondary Electron Emission For Graphitic Carbon Semiconductiors, Jodie Gillespie, Jr Dennison

Jodie Corbridge Gillespie

Preliminary data indicates a relationship between bandgap width and magnitude of secondary electron (SE) yield. Our work extends this research to investigate the correlation of small bandgap width to SE yield. These trends are compared with current semiempirical models of two limiting cases, conductors and large bandgap semiconductors. Specifically, five graphitic amorphous carbon (g-C) samples of decreasing bandgap width were produced by vacuum annealing from 0C-1050C. Preliminary data shows a 30of g-C above nanocrystalline graphite. Measurements include SE yields, backscattered yields and electron emission spectra, as well as characterization with SEM, photoyields, AES, resistivity, and Raman spectroscopy. SE yields were …

Computational Treatments Of Peroxy Radicals In Combustion And Atmospheric Reactions, Keith Kuwata

Keith Kuwata

No abstract provided.

Effect Of Trans-Cis Photoisomerization On Phase Equilibria And Phase Transition Of Liquid-Crystalline Azobenzene Chromophore And Its Blends With Reactive Mesogenic Diacrylate, Namil Kim, Quan Li, Thein Kyu

Thein Kyu

Photoisomerization-induced phase transition of neat liquid-crystalline azobenzene chromophore (LCAC) and its effect on phase diagrams of its mixtures with reactive mesogenic diacrylate monomer (RM257) have been investigated experimentally and theoretically. Upon irradiation with ultraviolet light, the nematic phase of LCAC transformed to isotropic, while the crystal phase showed corrugated textures on the surface (i.e., ripples). The phase-transition temperatures and corresponding morphologies of the blends have been investigated by means of differential scanning calorimetry and optical microscopy. A theoretical phase diagram of a binary nematic and crystalline system was constructed by self-consistently solving the combined free energies of Flory-Huggins, Maier-Saupe, and …

Spatio-Temporal Growth Of Nematic Domains In Liquid Crystal Polymer Mixtures, Hao-Wen Chiu, Thein Kyu

Thein Kyu

Dynamics of phase separation and morphology development in mixtures of a low molar mass liquid crystal (LC) and a polymer have been investigated theoretically in comparison with experimental results. In the theoretical model, the combined free-energy densities of Flory-Huggins theory for isotropic mixing and Maier-Saupe theory for nematic ordering have been incorporated into the time-dependent Ginzburg-Landau equation (type C). The temporal evolution of the structure factor and the emergence of phase-separated liquid crystal domains have been simulated on the basis of an explicit central difference method based on a square lattice (128 x 128) with a periodic boundary condition. Of …

Observation Of Novel Liquid-Crystalline Phase Above The Bulk-Melting Temperature, Keshav Gautam, Satyendra Kumar, Didier Wermeille, Doug Robinson, Ali Dhinojwala

Ali Dhinojwala

In this paper, we show that a noncrystalline but ordered smectic-like phase exists above the bulk-melting temperature (T-m) at poly(n-alkyl acrylates)-air interface. The surface ordered phase is one monolayer thick and undergoes a sharp transition from order to disorder 10degreesC above T-m for n=22. The presence of a surface phase that does not exist in the bulk has important implications in the design of thermally responsive adhesives.

Statistical Mechanics Of Wormlike Polymers From A New Generating Function. Ii. The Force-Elongation Relationship, Gustavo Carri

Gustavo A. Carri

No abstract provided.

Acidity Fractions In Acid Sulfate Soils And Sediments: Contributions Of Schwertmannite And Jarosite, Chamindra Vithana, Leigh Sullivan, Richard Bush, Edward Burton

Associate Professor Edward D Burton

In Australia, the assessment of acidity hazard in acid sulfate soils requires the estimation of operationally defined acidity fractions such as actual acidity, potential sulfidic acidity, and retained acidity. Acid–base accounting approaches in Australia use these acidity fractions to estimate the net acidity of acid sulfate soils materials. Retained acidity is the acidity stored in the secondary Fe/Al hydroxy sulfate minerals, such as jarosite, natrojarosite, schwertmannite, and basaluminite. Retained acidity is usually measured as either net acid-soluble sulfur (S_NAS) or residual acid soluble sulfur (S_RAS). In the present study, contributions of schwertmannite and jarosite to the …

Liberation Of Acidity And Arsenic From Schwertmannite: Effect Of Fulvic Acid, Chamindra Vithana, Leigh Sullivan, Edward Burton, Richard Bush

Associate Professor Edward D Burton

Schwertmannite is one of the major components that produces acidity in acid mine drainage (AMD) and acid sulfate soils (ASS) and is also known to be an effective scavenger of Arsenic (As) in such environments. Fulvic acid (FA) is an active component of natural organic matter (NOM) and is known to interact strongly with both schwertmannite and As. Two main environmental hazards related to schwertmannite are acidity liberation and potential re-mobilization of adsorbed or co-precipitated As upon hydrolysis. This study focused on understanding the behaviour of As-substituted schwertmannite with regard to the potential of acidity liberation, the effect of FA …

Effect Of Fulvic Acid On Liberation Of Acidity And Arsenic Form Arsenic Substituted Schwertmannite, Chamindra Vithana, Leigh Sullivan, Richard Bush, Edward Burton

Associate Professor Edward D Burton

INTRODUCTION

Schwertmannite is one of the main secondary iron hydroxy sulfate minerals contributing to acidity in acid sulfate soils (ASS). While it is an important source of acidity in ASS, schwertmannite is also known to be a potential sink for trace metals such as arsenic (As) and chromium (Cr) (Fukushi et al. 2003; Regenspurg and Peiffer. 2005).Trace metal adsorption/substitution is known to stabilize schwertmannite which in turn retards its transformation to goethite which is one of the main processes of acidity generation in ASS. Fulvic Acid (FA) is a subclass of natural organic materials that are ubiquitous in aquatic environments …