Physical Sciences and Mathematics Commons^™

Directional Limits On Persistent Gravitational Waves Using Ligo S5 Science Data, J. Abadie, B. P. Abbott, R. Abbott, M. Abernathy, T. Accadia, F. Acernese, C. Adams, R. Adhikari, P. Ajith, B. Allen, G. S. Allen, E. Amador Ceron, R. S. Amin, S. B. Anderson, W. G. Anderson, F. Antonucci, M. A. Arain, M. C. Araya, M. Aronsson, K. G. Arun, Y. Aso, S. M. Aston, P. Astone, D. Atkinson, P. Aufmuth, C. Aulbert, S. Babak, P. Baker, G. Ballardin, S. Ballmer, D. Barker, Tiffany Z. Summerscales

Faculty Publications

The gravitational-wave (GW) sky may include nearby pointlike sources as well as stochastic backgrounds. We perform two directional searches for persistent GWs using data from the LIGO S5 science run: one optimized for pointlike sources and one for arbitrary extended sources. Finding no evidence to support the detection of GWs, we present 90% confidence level (C.L.) upper-limit maps of GW strain power with typical values between 2-20×10-50strain2Hz-1 and 5-35×10 -49strain2Hz-1sr-1 for pointlike and extended sources, respectively. The latter result is the first of its kind. We also set 90% C.L. limits on the narrow-band root-mean-square GW strain from interesting targets …

Learning The Structure Of Gene Regulatory Networks From Time Series Gene Expression Data, Haoni Li, Nan Wang, Ping Gong, Edward J. Perkins, Chaoyang Zhang

Faculty Publications

Background: Dynamic Bayesian Network (DBN) is an approach widely used for reconstruction of gene regulatory networks from time-series microarray data. Its performance in network reconstruction depends on a structure learning algorithm. REVEAL (REVerse Engineering ALgorithm) is one of the algorithms implemented for learning DBN structure and used to reconstruct gene regulatory networks (GRN). However, the two-stage temporal Bayes network (2TBN) structure of DBN that specifies correlation between time slices cannot be obtained by score metrics used in REVEAL.

Methods: In this paper, we study a more sophisticated score function for DBN first proposed by Nir Friedman for stationary …

Ordered Phases In Ruthenium Binary Alloys From High-Throughput First-Principles Calculations, Gus L. W. Hart, Lance J. Nelson, Michal Jahnátek, Ohad Levy, Roman V. Chepulskii, J. Xue, Stephano Curtarolo

Faculty Publications

Despite the increasing importance of ruthenium in numerous technological applications, e.g., catalysis and electronic devices, experimental and computational data on its binary alloys are sparse. In particular, data are scant on those binary systems believed to be phase-separating. We performed a comprehensive study of ruthenium binary systems with the 28 transition metals, using high-throughput first-principles calculations. These computations predict novel unsuspected compounds in 7 of the 16 binary systems previously believed to be phase-separating and in two of the three systems reported with only a high-temperature σ phase. They also predict a few unreported compounds in five additional systems and …

A Speculative Approach To Parallelization In Particle Swarm Optimization, Matthew Gardner, Andrew Mcnabb, Kevin Seppi

Faculty Publications

Particle swarm optimization (PSO) has previously been parallelized primarily by distributing the computation corresponding to particles across multiple processors. In these approaches, the only benefit of additional processors is an increased swarm size. However, in many cases this is not efficient when scaled to very large swarm sizes (on very large clusters). Current methods cannot answer well the question: “How can 1000 processors be fully utilized when 50 or 100 particles is the most efficient swarm size?” In this paper we attempt to answer that question with a speculative approach to the parallelization of PSO that we refer to as …

Thermodynamics And Phase Transitions For The Heisenberg Model On The Pinwheel Distorted Kagome Lattice, Ehsan Khatami, Rajiv Singh, Marcos Rigol

Faculty Publications

We study the Heisenberg model on the pinwheel distorted kagome lattice as observed in the material Rb2Cu3SnF12. Experimentally relevant thermodynamic properties at finite temperatures are computed utilizing numerical linked-cluster expansions. We also develop a Lanczos-based, zero-temperature, numerical linked-cluster expansion to study the approach of the pinwheel distorted lattice to the uniform kagome-lattice Heisenberg model. We find strong evidence for a phase transition before the uniform limit is reached, implying that the ground state of the kagome-lattice Heisenberg model is likely not pinwheel dimerized and is stable to finite pinwheel-dimerizing perturbations.

Quantum Many-Body Calculation Of Mixed-Parity Pairing In The Sr2ruo4 Superconductor Induced By Spin-Orbit Coupling, J. J. Deisz, Tim Kidd

Faculty Publications

The unusual superconducting state in Sr₂RuO₄ has long been viewed as being analogous to a superfluid state in liquid ³He. Nevertheless, calculations based on this odd-parity state are presently unable to completely reconcile the properties of Sr₂RuO₄. Using a self-consistent quantum many-body scheme that employs realistic parameters, we are able to model several signature properties of the normal and superconducting states of Sr₂RuO₄. We find that the dominant component of the model superconducting state is of even parity and closely related to superconducting state for the high-T_{c …}

Density Functional Theory Study On The Electronic Structure Of N- And P-Type Doped Srtio3 At Anodic Solid Oxide Fuel Cell Conditions, Suwit Suthirakun, Salai Cheettu Ammal, Guoliang Xiao, Fanglin Chen, Andreas Heyden, Hans-Conrad Zur Loye

Faculty Publications

The electronic conductivity and thermodynamic stability of mixed n-type and p-type doped SrTiO₃ have been investigated at anodic solid oxide fuel cell (SOFC) conditions using density functional theory (DFT) calculations. In particular, constrained ab initio thermodynamic calculations have been performed to evaluate the phase stability and reducibility of various Nb- and Ga-doped SrTiO₃ at synthesized and anodic SOFC conditions. The density of states (DOS) of these materials was analyzed to study the effects of n- and p-doping on the electronic conductivity. In agreement with experimental observations, we find that the transformation from 20% Nb-doped Sr-deficient SrTiO …

Thermodynamics Of Strongly Interacting Fermions In Two-Dimensional Optical Lattices, Ehsan Khatami, Marcos Rigol

Faculty Publications

We study finite-temperature properties of strongly correlated fermions in two-dimensional optical lattices by means of numerical linked cluster expansions, a computational technique that allows one to obtain exact results in the thermodynamic limit. We focus our analysis on the strongly interacting regime, where the on-site repulsion is of the order of or greater than the band width. We compute the equation of state, double occupancy, entropy, uniform susceptibility, and spin correlations for temperatures that are similar to or below the ones achieved in current optical lattice experiments. We provide a quantitative analysis of adiabatic cooling of trapped fermions in two …

Dynamic Behavior Sequencing For Hybrid Robot Architectures, Gilbert L. Peterson, Jeffrey P. Duffy, Daylond J. Hooper

Faculty Publications

Hybrid robot control architectures separate planning, coordination, and sensing and acting into separate processing layers to provide autonomous robots both deliberative and reactive functionality. This approach results in systems that perform well in goal-oriented and dynamic environments. Often, the interfaces and intents of each functional layer are tightly coupled and hand coded so any system change requires several changes in the other layers. This work presents the dynamic behavior hierarchy generation (DBHG) algorithm, which uses an abstract behavior representation to automatically build a behavior hierarchy for meeting a task goal. The generation of the behavior hierarchy occurs without knowledge of …

Windows Driver Memory Analysis: A Reverse Engineering Methodology, James S. Okolica, Gilbert L. Peterson

Faculty Publications

In a digital forensics examination, the capture and analysis of volatile data provides significant information on the state of the computer at the time of seizure. Memory analysis is a premier method of discovering volatile digital forensic information. While much work has been done in extracting forensic artifacts from Windows kernel structures, less focus has been paid to extracting information from Windows drivers. There are two reasons for this: (1) source code for one version of the Windows kernel (but not associated drivers) is available for educational use and (2) drivers are generally called asynchronously and contain no exported functions. …

Preparation Of Novel Hydrolyzing Urethane Modified Thiol-Ene Networks, Nicole M. Mackey, Bridget S. Confait, James Wynne, J. Paige Buchanan

Faculty Publications

Novel tetra-functional hydrolyzing monomers were prepared from the reaction of TEOS and select alkene-containing alcohols, ethylene glycol vinyl ether or 2-allyloxy ethanol, and combined with trimethylolpropane tris(3-mercaptopropionate) (tri-thiol) in a thiol-ene “click” polymerization reaction to produce clear, colorless thiol-ene networks using both radiation and thermal-cure techniques. These networks were characterized for various mechanical characteristics, and found to posses T_g’s (DSC), hardness, tack, and thermal stability (TGA) consistent with their molecular structures. A new ene-modified urethane oligomer was prepared based on the aliphatic polyisocyanate Desmodur^® N 3600 and added to the thiol-ene hydrolyzable network series in increasing amounts, …

Hubble Space Telescope Imaging Of Post-Starburst Quasars, S. Cales, M. Brotherton, Zhaohui Shang, Vardha Bennert, Gabriela Canalizo, R. Stoll, R. Ganguly, D. Berk, Cassandra Paul, A. Diamond-Stanic

Faculty Publications

We present images of 29 post-starburst quasars (PSQs) from a Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS) Wide Field Channel Snapshot program. These broadlined active galactic nuclei (AGNs) possess the spectral signatures of massive (Mburst ∼ 1010 M⊙), moderate-aged stellar populations (hundreds of Myr). Thus, their composite nature provides insight into the AGN–starburst connection. We measure quasar-to-host galaxy light contributions via semi-automated two-dimensional light profile fits of point-spread-function-subtracted images. We examine the host morphologies and model the separate bulge and disk components. The HST/ACS-F606W images reveal an equal number of spiral (13/29) and early-type (13/29) hosts, with the …

Vibrational And Electronic Spectra Of 9, 10-Dihydrobenzo (A) Pyren-7 (8h)-One And 7, 8, 9, 10-Tetrahydrobenzo (A) Pyrene: An Experimental And Computational Study [Abstract], Kefa Karimu Onchoke, Prabir K. Dutta, Matthew Parks, Mireya Martinez

Faculty Publications

No abstract provided.

Study Of Tau-Pair Production At Hera, Aharon Levy, H. Abramowicz, L. Adamczyk, M. Adamus, R. Aggarwal, S. Antonelli, P. Antonioli, A. Antonov, M. Arneodo, V. Aushev, Y. Aushev, O. Bachynska, A. Bamberger, A. N. Barakbaev, G. Barbagli, G. Bari, F. Barreiro, N. Bartosik, D. Bartsch, M. Basile, O. Behnke, J. Behr, U. Behrens, L. Bellagamba, A. Bertolin, S. Bhadra, M. Bindi, C. Blohm, V. Bokhonov, T. Bold, O. Bolilyi, Margarita C. K. Mattingly

Faculty Publications

A study of events containing two tau leptons with high transverse momentum has been performed with the ZEUS detector at HERA, using a data sample corresponding to an integrated luminosity of 0.33 fb-1. The tau candidates were identified from their decays into electrons, muons or hadronic jets. The number of tau-pair candidates has been compared with the prediction from the Standard Model, where the largest contribution is expected from Bethe-Heitler processes. The total visible cross section was extracted. Standard Model expectations agree well with the measured distributions, also at high invariant mass of the tau pair.

A Modified Stokes-Einstein Equation For A Beta Aggregation, Srisairam Achuthan, Bong Jae Chung, Preetam Ghosh, Vijayaraghavan Rangachari, Ashwin Vaidya

Faculty Publications

Background: In all amyloid diseases, protein aggregates have been implicated fully or partly, in the etiology of the disease. Due to their significance in human pathologies, there have been unprecedented efforts towards physiochemical understanding of aggregation and amyloid formation over the last two decades. An important relation from which hydrodynamic radii of the aggregate is routinely measured is the classic Stokes-Einstein equation. Here, we report a modification in the classical Stokes-Einstein equation using a mixture theory approach, in order to accommodate the changes in viscosity of the solvent due to the changes in solute size and shape, to implement a …

Consequences Of Neutrino Lorentz Violation For Leptonic Meson Decays, Brett David Altschul

Faculty Publications

If the observation by OPERA of apparently superluminal neutrinos is correct, the Lagrangian for second-generation leptons must break Lorentz invariance. We calculate the effects of an energy-independent change in the neutrino speed on another observable, the charged pion decay rate. The rate decreases by an factor [1 - 3/(1 - (m_mu)^2 / (m_pi) ^ 2) (< v_(nu) > - 1)], where < v_(nu) > is the (directionally averaged) neutrino speed in the pion's rest frame. This provides a completely independent experimental observable that is sensitive to the same forms of Lorentz violation as a neutrino time of flight measurement.

A Once And Future Gulf Of Mexico Ecosystem: Restoration Recommendations Of An Expert Working Group, Charles H. Peterson, Felicia C. Coleman, Jeremy B. C. Jackson, R. Eugene Turner, Gilbert T. Rowe, Richard T. Barber, Karen A. Bjorndal, Robert S. Carney, Robert K. Cowen, Jonathan M. Hoekstra, James T. Hollibaugh, Shirley B. Laska, Richard A. Luettich, Jr., Craig W. Osenberg, Stephen E. Roady, Stanley Senner, John M. Teal, Ping Wong

Faculty Publications

The Deepwater Horizon (DWH) well blowout released more petroleum hydrocarbons into the marine environment than any previous U.S. oil spill (4.9 million barrels), fouling marine life, damaging deep sea and shoreline habitats and causing closures of economically valuable fisheries in the Gulf of Mexico. A suite of pollutants—liquid and gaseous petroleum compounds plus chemical dispersants—poured into ecosystems that had already been stressed by overfishing, development and global climate change. Beyond the direct effects that were captured in dramatic photographs of oiled birds in the media, it is likely that there are subtle, delayed, indirect and potentially synergistic impacts of these …

The Regulation Of Skeletal Muscle Protein Turnover During The Progression Of Cancer Cachexia In The ApcMin/+ Mouse, James P. White, John W. Baynes, Stephen L. Welle, Matthew C. Kostek, Lydia E. Matesic, Shuichi Sato, James A. Carson

Faculty Publications

Muscle wasting that occurs with cancer cachexia is caused by an imbalance in the rates of muscle protein synthesis and degradation. The Apc(Min/+) mouse is a model of colorectal cancer that develops cachexia that is dependent on circulating IL-6. However, the IL-6 regulation of muscle protein turnover during the initiation and progression of cachexia in the Apc(Min/+) mouse is not known. Cachexia progression was studied in Apc(Min/+) mice that were either weight stable (WS) or had initial (≤5%), intermediate (6-19%), or extreme (≥20%) body weight loss. The initiation of cachexia reduced %MPS 19% and a further ∼50% with additional weight …

Measurement Of The Elastic Tensor Of Smsco3 And Ndsc03 Using Resonant Ultrasound Spectroscopy With Ab Initio Calculations, K. A. Pestka Ii, E. S. Scott, Y. Le Page

Faculty Publications

The complete elastic tensors of SmScO₃ and NdScO₃ were measured using resonant ultrasound spectroscopy (RUS) in combination with ab-initio calculations. Measurement of the elastic tensor of these recently synthesized single crystal RE scandates is essential for understanding dynamic lattice applications including phonon confinement, strain induced thin film growth and superlattice construction. On average, the experimental elastic constants differed by less than 5% of the theoretical values, further validating the accuracy of modern ab-initio calculations as a means of estimating the initial elastic constants used in RUS measurements.

Hydrogen Donors And Ti3+ Ions In Reduced Tio2 Crystals, A. T. Brant, Shan Yang (杨山), Nancy C. Giles, Larry E. Halliburton

Faculty Publications

Electron paramagnetic resonance (EPR) and electron-nuclear double resonance (ENDOR) are used to identify and characterize the neutral hydrogen donor in TiO₂ crystals having the rutile structure. These spectra are best observed near 5 K. The neutral donors are present without photoexcitation in crystals that have been slightly reduced at high temperature in a nitrogen atmosphere. The same defects can be photoinduced at low temperature in oxidized crystals. The neutral hydrogen donor in this lattice consists of a substitutional Ti³⁺ ion adjacent to a substitutional OH^– molecular ion. The axis of the OH^– molecule lies in the …

Improving Occupancy Grid Fastslam By Integrating Navigation Sensors, Christopher Weyers, Gilbert L. Peterson

Faculty Publications

When an autonomous vehicle operates in an unknown environment, it must remember the locations of environmental objects and use those object to maintain an accurate location of itself. This vehicle is faced with Simultaneous Localization and Mapping (SLAM), a circularly defined robotics problem of map building with no prior knowledge. The SLAM problem is a difficult but critical component of autonomous vehicle exploration with applications to search and rescue missions. This paper presents the first SLAM solution combining stereo cameras, inertial measurements, and vehicle odometry into a Multiple Integrated Navigation Sensor (MINS) path. The FastSLAM algorithm, modified to make use …

The F5 Criterion Revised, Alberto Arri, John E. Perry

Faculty Publications

The purpose of this work is to generalize part of the theory behind Faugere's "F5" algorithm. This is one of the fastest known algorithms to compute a Gröbner basis of a polynomial ideal I generated by polynomials f₁,…,f_m. A major reason for this is what Faugere called the algorithm's "new" criterion, and we call "the F5 criterion": it provides a sufficient condition for a set of polynomialsGto be a Gröbner basis. However. the F5 algorithm is difficult to grasp, and there are unresolved questions regarding its termination. This paper introduces some new concepts that place the …

The Method Of Approximate Particular Solutions For Solving Elliptic Problems With Variable Coefficients, C.S. Chen, Chia-Ming Fan, Pihua Wen

Faculty Publications

A new version of the method of approximate particular solutions (MAPSs) using radial basis functions (RBFs) has been proposed for solving a general class of elliptic partial differential equations. In the solution process, the Laplacian is kept on the left-hand side as a main differential operator. The other terms are moved to the right-hand side and treated as part of the forcing term. In this way, the close-form particular solution is easy to obtain using various RBFs. The numerical scheme of the new MAPSs is simple to implement and yet very accurate. Three numerical examples are given and the results …

Time Reversal Invariance Violating And Parity Conserving Effects In Neutron-Deuteron Scattering, Young-Ho Song, Rimantas Lazauskas, Vladimir Gudkov

Faculty Publications

Time reversal invariance violating and parity conserving effects for low-energy elastic neutron-deuteronscattering are calculated for meson exchange and effective field theory type potentials in a distorted wave-bornapproximation using realistic hadronic wave functions, obtained by solving three-body Faddeev equations inconfiguration space.

Guiding The Experimental Discovery Of Magnesium Alloys, Richard H. Taylor, Gus L. W. Hart, Stefano Curtarolo

Faculty Publications

Magnesium alloys are among the lightest structural materials known and are of considerable technological interest. To develop superior magnesium alloys, experimentalists must have a thorough understanding of the concentration-dependent precipitates that form in a given system, and hence, the thermodynamic stability of crystal phases must be determined. This information is often lacking but can be supplied by first-principles methods. Within the high-throughput framework, AFLOW, T = 0 K ground-state predictions are made by scanning a large set of known candidate structures for thermodynamic (formation energy) minima. The following 34 systems are investigated: AlMg, AuMg, CaMg, CdMg, CuMg, FeMg , GeMg, …

Dynamics Of Spin Relaxation In Finite-Size Two-Dimensional Systems: An Exact Solution, Valeriy A. Slipko, Yuriy V. Pershin

Faculty Publications

We find an exact solution for the problem of electron spin relaxation in a two-dimensional (2D) circle with Rashba spin-orbit interaction. Our analysis shows that the spin relaxation in finite-size regions involves three stages and is described by multiple spin relaxation times. It is important that the longest spin relaxation time increases with the decrease in system radius but always remains finite. Therefore, at long times, the spin polarization in small 2D systems decays exponentially with a size-dependent rate. This prediction is supported by results of Monte Carlo simulations.

Bounding Lorentz Violation At Particle Colliders By Tracking The Motion Of Charged Particles, Brett David Altschul

Faculty Publications

In the presence of Lorentz violation, the motion of a charged particle in a magnetic field is distorted. By measuring the eccentricities of particles’ elliptical orbits and studying how those eccentricities vary with the absolute orientation of the laboratory, it is possible to constrain the Lorentz-violating cJK parameters. For each observed species, this method can provide constraints on four linear combinations of coefficients for which, in some species, there are presently no two-sided bounds.

Extracting The Windows Clipboard From Physical Memory, James S. Okolica, Gilbert L. Peterson

Faculty Publications

When attempting to reconstruct the events leading up to a cyber security incident, one potentially important piece of information is the clipboard (Prosise et al., 2003). The clipboard has been present in Windows since Windows 3.1 and is the mechanism for transferring information from one application to another through copy and pasting actions. Being able to retrieve the last file copied or the last password used may provide investigators with invaluable information during a forensic investigation. This paper describes the Windows clipboard structure and the process of retrieving copy/paste information from Windows XP, Vista, and Windows 7 (both 32 bit …

Experimental And Theoretical Study Of Vibrational Spectra Of 3-Nitrofluoranthene [Abstract], Kefa Karimu Onchoke, Matthew Parks

Faculty Publications

No abstract provided.

No-Net-Loss Not Met For Nutrient Function In Freshwater Marshes: Recommendations For Wetland Mitigation Policies, Katie Hossler, Virginie Bouchard, M. Siobhan Fennessy, Serita D. Frey, Evelyn Anemaet, Ellen Herbert

Faculty Publications

Wetlands provide many important services throughout the world, with an estimated economic value that, in comparison to other ecosystems, far exceeds their relatively small global extent. In recognition of their importance, both national and international regulations exist to protect the world's remaining wetlands. Of growing interest is the “no-net-loss” policy which permits unavoidable destruction of wetlands if compensated by restoration of degraded wetlands or creation of new wetlands. The fundamental assumption of no-net-loss is that wetlands can be created which function equivalently to natural wetlands. One integral function that wetlands perform is cycling of carbon, nitrogen and phosphorus. Here we …