Physical Sciences and Mathematics Commons^™

Winterberg’S Conjectured Breaking Of The Superluminal Quantum Correlations Over Large Distances, Eleftherios Gkioulekas

School of Mathematical & Statistical Sciences Faculty Publications

We elaborate further on a hypothesis by Winterberg that turbulent fluctuations of the zero point field may lead to a breakdown of the superluminal quantum correlations over very large distances. A phenomenological model that was proposed by Winterberg to estimate the transition scale of the conjectured breakdown, does not lead to a distance that is large enough to be agreeable with recent experiments. We consider, but rule out, the possibility of a steeper slope in the energy spectrum of the turbulent fluctuations, due to compressibility, as a possible mechanism that may lead to an increased lower-bound for the transition scale. …

Rapid Evolution In Introduced Species, ‘Invasive Traits’ And Recipient Communities: Challenges For Predicting Invasive Potential, Kenneth D. Whitney, Christopher A. Gabler

School of Earth, Environmental, & Marine Sciences Faculty Publications

The damaging effects of invasive organisms have triggered the development of Invasive Species Predictive Schemes (ISPS). These schemes evaluate biological and historical characteristics of species and prioritize those that should be the focus of exclusion, quarantine, and/or control. However, it is not clear how commonly these schemes take microevolutionary considerations into account. We review the recent literature and find that rapid evolutionary changes are common during invasions. These evolutionary changes include rapid adaptation of invaders to new environments, effects of hybridization, and evolution in recipient communities. Strikingly, we document 38 species in which the specific traits commonly associated with invasive …

Comparison Of Polymerase Chain Reaction And Bacterial Culture For Salmonella Detection In The Muscovy Duck In Trinidad And Tobago, Joanne Rampersad-Ammons, Jenelle Johnson, Gabriel Brown, Michael S. Samlal, David R. Ammons

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Chemistry)

Objectives: The purpose of this study was to investigate the presence and serovar identity of Salmonella, at the national level, in farmed Muscovy ducks (Cairina moschata) in Trinidad and Tobago, and to compare the relative benefits of bacterial culture to those of polymerase chain reaction (PCR) for use in the routine detection and surveillance of Salmonella in these ducks.

Methods: From March-September 2003, 110 fecal samples were collected from 82 farms across the islands of Trinidad and Tobago. Salmonella was isolated from fresh and frozen samples and the serotype of each was determined through bacterial culture. An in-house, nested PCR …

Arecibo H I Absorption Measurements Of Pulsars And The Electron Density At Intermediate Longitudes In The First Galactic Quadrant, J. M. Weisberg, S. Stanimirović, K. Xilouris, A. Hedden, A. De La Fuente, S. B. Anderson, F. A. Jenet

Physics & Astronomy Faculty Publications

We have used the Arecibo telescope to measure the H I absorption spectra of eight pulsars. We show how kinematic distance measurements depend on the values of the Galactic constants R0 and Θ0, and we select our preferred current values from the literature. We then derive kinematic distances for the low-latitude pulsars in our sample and electron densities along their lines of sight. We combine these measurements with all others in the inner Galactic plane visible from Arecibo to study the electron density in this region. The electron density in the interarm range 48° < l < 70° is 0.017-0.007+0.012(68% c.1.) cm-3. This is 0.75-0.22+0.49(68% c.1.) of the value calculated by the Galactic electron density model of Cordes & Lazio. The model agrees more closely with electron density measurements toward Arecibo pulsars lying closer to the Galactic center, at 30° < l < 48°. Our analysis leads to the best current estimate of the distance of the relativistic binary pulsar B1913+16: d = 9.0 ± 3 kpc We use the high-latitude pulsars to search for small-scale structure in the interstellar hydrogen observed in absorption over multiple epochs. PSR B0301+19 exhibited significant changes in its absorption spectrum over 22 yr, indicating H I structure on a ∼500 AU scale. © 2008. The American Astronomical Society. All rights reserved.

Psr J1856+0245: Arecibo Discovery Of A Young Energetic Pulsar Coincident With The Tev G-Ray Source Hess J1857+026, J. W.T. Hessels, D. J. Nice, B. M. Gaensler, V. M. Kaspi, D. R. Lorimer, D. J. Champion, A. G. Lyne, M. Kramer, J. M. Cordes, P. C.C. Freire, Fredrick A. Jenet

Physics & Astronomy Faculty Publications

We present the discovery of the Vela-like radio pulsar J1856+0245 in the Arecibo PALFA survey. PSR J1856+0245 has a spin period of 81 ms, a characteristic age of 21 kyr, and a spin-down luminosity Ä– p 4.6 x 10 36 ergs s-1. It is positionally coincident with the TeV γ-ray source HESS J1857+026, which has no other known counterparts. Young, energetic pulsars create wind nebulae, and more than a dozen pulsar wind nebulae have been associated with very high energy (100 GeV-100 TeV) γ-ray sources discovered with the HESS telescope. The γ-ray emission seen from HESS J1857+026 is potentially produced …

A Fragment On Euler's Constant In Ramanujan's Lost Notebook, Bruce C. Berndt, Timothy Huber

School of Mathematical & Statistical Sciences Faculty Publications

A formula for Euler’s constant found in Ramanujan’s lost notebook and also in a problem he submitted to the Journal of the Indian Mathematical Society is proved and discussed.

An Action For A Classical String, The Equation Of Motion And Group Invariant Classical Solutions, Paul Bracken

School of Mathematical & Statistical Sciences Faculty Publications

A string action which is essentially a Willmore functional is presented and studied. This action determines the physics of a surface in Euclidean three space which can be used to model classical string configurations. By varying this action an equation of motion for the mean curvature of the surface is obtained which is shown to govern certain classical string configurations. Several classes of classical solutions for this equation are discussed from the symmetry group point of view and an application is presented.

Physiological Aging Of Potato Tubers Produced During Fall And Spring Growing Seasons And Stored Under Different Temperatures, Dilson A. Bisognin, Sergio T. De Freitas, Auri Brackmann, Jeronimo Luiz Andriolo, Engil Isadora Pujol Pereira, Douglas Renator Muller, Mauricio Guerra Bandinelli

School of Earth, Environmental, & Marine Sciences Faculty Publications

Adequate tuber storage is necessary to maintain a good availability of potato tubers in the market and to get seeds with adequate physiological age at planting. The objective of this work was to determine the effect of different storage temperatures on tuber physiological aging of three potato clones produced during fall and spring growing seasons. The experiment was carried out as factorial of three clones (Asterix, SMIJ461-1 and SMINIA793101-3) by four storage temperatures (4, 8, 12 and 25 ºC) and two growing seasons (fall and spring) in a random design with four replications. At 30-day intervals, tubers were evaluated from …

Rapid Evolution In Introduced Species, ‘Invasive Traits’ And Recipient Communities: Challenges For Predicting Invasive Potential, Kenneth D. Whitney, Christopher A. Gabler

School of Earth, Environmental, & Marine Sciences Faculty Publications

The damaging effects of invasive organisms have triggered the development of Invasive Species Predictive Schemes (ISPS). These schemes evaluate biological and historical characteristics of species and prioritize those that should be the focus of exclusion, quarantine, and/or control. However, it is not clear how commonly these schemes take microevolutionary considerations into account. We review the recent literature and find that rapid evolutionary changes are common during invasions. These evolutionary changes include rapid adaptation of invaders to new environments, effects of hybridization, and evolution in recipient communities. Strikingly, we document 38 species in which the specific traits commonly associated with invasive …

An Analysis Of Demographic Disparities Associated With The Proposed U.S.-Mexico Border Fence In Cameron County, Texas, J. Gaines Wilson, Jude A. Benavides, E. Anthony Reisinger, Joseph Lemen, Zachary Hurwitz, Jessica Spangler, Karen Engle

School of Earth, Environmental, & Marine Sciences Faculty Publications

Introduction: The United States Department of Homeland Security (DHS) plans to install a fence along the U.S.-Mexico border by late December 2008. While much attention has been drawn to the environmental, social and political issues surrounding the fence, analysis of demographic data on the populations that will be directly affected has been limited. This paper utilizes geographic information systems (GIS) and U.S. Census Bureau data with the objective of understanding the underlying demographics in areas along the proposed Rio Grande Valley section of the border fence located in Cameron County, Texas.

Data and Methods: Demographic measures of income, education, …

Splitting Np-Complete Sets, Christian Glaßer, A. Pavan, Alan L. Selman, Liyu Zhang

Computer Science Faculty Publications

We show that a set is m-autoreducible if and only if it is m-mitotic. This solves a long-standing open question in a surprising way. As a consequence of this unconditional result and recent work by Glaßer et al., complete sets for all of the following complexity classes are m-mitotic: NP, coNP, ⊕P, PSPACE, and NEXP, as well as all levels of PH, MODPH, and the Boolean hierarchy over NP. In the cases of NP, PSPACE, NEXP, and PH, this at once answers several well-studied open questions. These results tell us that complete sets share a redundancy that was not known …

Kinetics And Thermodynamics Of Salt-Dependent T7 Gene 2.5 Protein Binding To Single- And Double-Stranded Dna., Leila Shokri, Boriana Marintcheva, Mootaz Eldib, Andreas Hanke, Ioulia Rouzina, Mark C. Williams

Physics & Astronomy Faculty Publications

Bacteriophage T7 gene 2.5 protein (gp2.5) is a single-stranded DNA (ssDNA)-binding protein that has essential roles in DNA replication, recombination and repair. However, it differs from other ssDNA-binding proteins by its weaker binding to ssDNA and lack of cooperative ssDNA binding. By studying the rate-dependent DNA melting force in the presence of gp2.5 and its deletion mutant lacking 26 C-terminal residues, we probe the kinetics and thermodynamics of gp2.5 binding to ssDNA and double-stranded DNA (dsDNA). These force measurements allow us to determine the binding rate of both proteins to ssDNA, as well as their equilibrium association constants to dsDNA. …

Beating The Spin-Down Limit On Gravitational Wave Emission From The Crab Pulsar, B. P. Abbott, R. Abbott, R. Adhikari, Mario C. Diaz, Roberto Grosso, Kazuhiro Hayama, Soumya Mohanty, Soma Mukherjee, Joseph D. Romano, Robert Stone

Physics & Astronomy Faculty Publications

We present direct upper limits on gravitational wave emission from the Crab pulsar using data from the first 9 months of the fifth science run of the Laser Interferometer Gravitational-wave Observatory (LIGO). These limits are based on two searches. In the first we assume that the gravitational wave emission follows the observed radio timing, giving an upper limit on gravitational wave emission that beats indirect limits inferred from the spin-down and braking index of the pulsar and the energetics of the nebula. In the second we allow for a small mismatch between the gravitational and radio signal frequencies and interpret …

Search Of S3 Ligo Data For Gravitational Wave Signals From Spinning Black Hole And Neutron Star Binary Inspirals, B. P. Abbott, R. Grosso, Mario C. Diaz, Soumya Mohanty, Soma Mukherjee, Cristina V. Torres

Physics & Astronomy Faculty Publications

We report on the methods and results of the first dedicated search for gravitational waves emitted during the inspiral of compact binaries with spinning component bodies. We analyze 788 hours of data collected during the third science run (S3) of the LIGO detectors. We searched for binary systems using a detection template family specially designed to capture the effects of the spin-induced precession of the orbital plane. We present details of the techniques developed to enable this search for spin-modulated gravitational waves, highlighting the differences between this and other recent searches for binaries with nonspinning components. The template bank we …

Denaturation Transition Of Stretched Dna, Andreas Hanke, Martha G. Ochoa, Ralf Metzler

Physics & Astronomy Faculty Publications

We generalize the Poland-Scheraga model to consider DNA denaturation in the presence of an external stretching force. We demonstrate the existence of a force-induced DNA denaturation transition and obtain the temperature-force phase diagram. The transition is determined by the loop exponent c, for which we find the new value c=4ν−1/2 such that the transition is second order with c=1.85DNA, corresponding to a lower melting temperature T(F), in agreement with single-molecule DNA stretching experiments.

Search For Gravitational Waves Associated With 39 Gamma-Ray Bursts Using Data From The Second, Third, And Fourth Ligo Runs, B. P. Abbott, R. Abbott, Mario C. Diaz, R. Grosso, Wm. R. Johnston, Soumya Mohanty, Soma Mukherjee, Cristina V. Torres

Physics & Astronomy Faculty Publications

We present the results of a search for short-duration gravitational-wave bursts associated with 39 gamma-ray bursts (GRBs) detected by gamma-ray satellite experiments during LIGO’s S2, S3, and S4 science runs. The search involves calculating the crosscorrelation between two interferometer data streams surrounding the GRB trigger time. We search for associated gravitational radiation from single GRBs, and also apply statistical tests to search for a gravitational-wave signature associated with the whole sample. For the sample examined, we find no evidence for the association of gravitational radiation with GRBs, either on a single-GRB basis or on a statistical basis. Simulating gravitational-wave bursts …

All-Sky Search For Periodic Gravitational Waves In Ligo S4 Data, B. P. Abbott, R. Abbott, Mario C. Diaz, R. Grosso, Soumya Mohanty, Soma Mukherjee, Cristina V. Torres

Physics & Astronomy Faculty Publications

We report on an all-sky search with the LIGO detectors for periodic gravitational waves in the frequency range 50–1000 Hz and with the frequency’s time derivative in the range −1×10−8  Hz s−1 to zero. Data from the fourth LIGO science run (S4) have been used in this search. Three different semicoherent methods of transforming and summing strain power from short Fourier transforms (SFTs) of the calibrated data have been used. The first, known as StackSlide, averages normalized power from each SFT. A “weighted Hough” scheme is also developed and used, which also allows for a multi-interferometer search. The third method, …

Search For Gravitational Waves From Binary Inspirals In S3 And S4 Ligo Data, B. P. Abbott, R. Abbott, Mario C. Diaz, R. Grosso, Soumya Mohanty, Soma Mukherjee, Cristina V. Torres

Physics & Astronomy Faculty Publications

We report on a search for gravitational waves from the coalescence of compact binaries during the third and fourth LIGO science runs. The search focused on gravitational waves generated during the inspiral phase of the binary evolution. In our analysis, we considered three categories of compact binary systems, ordered by mass: (i) primordial black hole binaries with masses in the range 0.35M⊙

Quantum Phases For A Generalized Harmonic Oscillator, Paul Bracken

School of Mathematical & Statistical Sciences Faculty Publications

An effective Hamiltonian for the generalized harmonic oscillator is determined by using squeezed state wavefunctions. The equations of motion over an extended phase space are determined and then solved perturbatively for a specific choice of the oscillator parameters. These results are used to calculate the dynamic and geometric phases for the generalized oscillator with this choice of parameters.

On Mathematical Modeling, Nonlinear Properties And Stability Of Secondary Flow In A Dendrite Layer, Daniel N. Riahi

School of Mathematical & Statistical Sciences Faculty Publications

This paper studies instabilities in the flow of melt within a horizontal dendrite layer with deformed upper boundary and in the presence or absence of rotation during the solidification of a binary alloy. In the presence of rotation, it is assumed that the layer is rotating about a vertical axis at a constant angular velocity. Linear and weakly nonlinear stability analyses provide results about various flow features such as the critical mode of convection, neutral stability curve, preferred flow pattern and the solid fraction distribution within the dendrite layer. The preferred shape of the deformed upper boundary of the layer, …

Zinc Cysteine Active Sites Of Metalloproteins: A Density Functional Theory And X-Ray Absorption Fine Structure Study, Nicholas Dimakis, Mohammed Junaid Farooqi, Emily Sofia Garza, Grant Bunker

Physics & Astronomy Faculty Publications

Density functional theory (DFT) and x-ray absorption fine structure (XAFS) spectroscopy are complementary tools for the biophysical study of active sites in metalloproteins. DFT is used to compute XAFS multiple scattering Debye Waller factors, which are then employed in genetic algorithm-based fitting process to obtain a global fit to the XAFS in the space of fitting parameters. Zn-Cys sites, which serve important functions as transcriptional switches in Zn finger proteins and matrix metalloproteinases, previously have proven intractable by this method; here these limitations are removed. In this work we evaluate optimal DFT nonlocal functionals and basis sets for determining optimal …

Microwave Spectra And Ab Initio Studies Of Ar-Propane And Ne-Propane Complexes: Structure And Dynamics, Karen I. Peterson, David Pullman, Wei Lin, Andrea J. Minei, Stewart E. Novick

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Chemistry)

Microwave spectra in the 7-26 MHz region have been measured for the van der Waals complexes, Ar-C H3 C H2 C H3, Ar- C13 H3 C H2 C H3, Ne20 -C H3 C H2 C H3, and Ne22 -C H3 C H2 C H3. Both a - and c -type transitions are observed for the Ar-propane complex. The c -type transitions are much stronger indicating that the small dipole moment of the propane (0.0848 D) is aligned perpendicular to the van der Waals bond axis. While the 42 transition lines observed for the primary argon complex are well fitted to …

An Overview Of The Genus Nardostachys, Asima Chatterjee, Utpal Dutta, Debasish Bandyopadhyay, Anupam Nayak, Bidyut Basak, Avijit Banerji, Julie Banerji

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Chemistry)

Nardostachys jatamansi, a medicinally important herb of Nepalese origin, has been used for centuries in the Ayurvedic and Unani systems of medicine. In combination with Marsilea minuta it is being used as an antistress and anticonvulsant drug and also finds use in the treatment of epilepsy. Recently, it has been reported that N. jatamansi, which plays an important role in protecting from cerebral ischemia and liver damage, is also used for the treatment of osteoporosis and hypercalcemia. The other member of the genus Nardostachys, N. chinensis, possesses antifungal and antimalarial properties. It is also used in the treatment of skin …

In-House Polymerase Chain Reaction For Affordable And Sustainable Chlamydia Trachomatis Detection In Trinidad And Tobago, Joanne Rampersad, Xiaohui Wang, Helen Gayadeen, Samuel Ramsewak, David Ammons

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Chemistry)

Objectives: To provide a preliminary assessment of in-house polymerase chain reaction (PCR) as an alternative to the more costly commercial test for detection of asymptomatic infection by Chlamydia trachomatis and to provide much needed demographic data on infection indicators within the Trinidad and Tobago public health care system.

Methods: An inexpensive in-house nested-PCR with an Internal Amplification Control was used to detect C. trachomatis and Neisseria gonorrhoeae in urine samples collected from 273 apparently healthy, pregnant women from March-September 2004 in Trinidad, West Indies. Demographic information on participants was collected and subjected to statistical analyses.

Results: C. trachomatis was detected …

Upper Limit Map Of A Background Of Gravitational Waves, B. P. Abbott, R. Abbott, Mario C. Diaz, R. Grosso, Soumya Mohanty, Soma Mukherjee, Cristina V. Torres

Physics & Astronomy Faculty Publications

We searched for an anisotropic background of gravitational waves using data from the LIGO S4 science run and a method that is optimized for point sources. This is appropriate if, for example, the gravitational wave background is dominated by a small number of distinct astrophysical sources. No signal was seen. Upper limit maps were produced assuming two different power laws for the source strain power spectrum. For an f−3 power law and using the 50 Hz to 1.8 kHz band the upper limits on the source strain power spectrum vary between 1.2×10−48  Hz−1 (100  Hz/f)3 and 1.2×10−47  Hz−1 (100  Hz/f)3, …

Fundamental Emission Via Wave Advection From A Collapsing Wave Packet In Electromagnetic Strong Plasma Turbulence, Fredrick A. Jenet, A. Melatos, P. A. Robinson

Physics & Astronomy Faculty Publications

Zakharov simulations of nonlinear wave collapse in continuously driven two-dimensional, electromagnetic strong plasma turbulence with electron thermal speeds v⩾0.01c show that for v≲0.1c, dipole radiation occurs near the plasma frequency, mainly near arrest, but for v≳0.1c, a new mechanism applies in which energy oscillates between trapped Langmuir and transverse modes until collapse is arrested, after which trapped transverse waves are advected into incoherent interpacket turbulence by an expanding annular density well, where they detrap. The multipole structure, Poynting flux, source current, and radiation angular momentum are computed.

Searches For Periodic Gravitational Waves From Unknown Isolated Sources And Scorpius X-1: Results From The Second Ligo Science Run, B. P. Abbott, R. Abbott, Mario C. Diaz, R. Grosso, Wm. R. Johnston, Soumya Mohanty, Soma Mukherjee, Cristina V. Torres

Physics & Astronomy Faculty Publications

We carry out two searches for periodic gravitational waves using the most sensitive few hours of data from the second LIGO science run. Both searches exploit fully coherent matched filtering and cover wide areas of parameter space, an innovation over previous analyses which requires considerable algorithm development and computational power. The first search is targeted at isolated, previously unknown neutron stars, covers the entire sky in the frequency band 160–728.8 Hz, and assumes a frequency derivative of less than 4×10−10  Hz/s. The second search targets the accreting neutron star in the low-mass x-ray binary Scorpius X-1 and covers the frequency …

Is The Subdominant Part Of The Energy Spectrum Due To Downscale Energy Cascade Hidden In Quasi-Geostrophic Turbulence?, Eleftherios Gkioulekas, Ka Kit Tung

School of Mathematical & Statistical Sciences Faculty Publications

In systems governing two-dimensional turbulence, surface quasi-geostrophic turbulence, (more generally $\alpha$-turbulence), two-layer quasi-geostrophic turbulence, etc., there often exist two conservative quadratic quantities, one "energy''-like and one "enstrophy''-like. In a finite inertial range there are in general two spectral fluxes, one associated with each conserved quantity. We derive here an inequality comparing the relative magnitudes of the "energy'' and "enstrophy'' fluxes for finite or infinitesimal dissipations, and for hyper or hypo viscosities. When this inequality is satisfied, as is the case of 2D turbulence,where the energy flux contribution to the energy spectrum is small, the subdominant part will be effectively hidden. …

Stellar Population Models And Individual Element Abundances. I. Sensitivity Of Stellar Evolution Models, Aaron Dotter, Brian Chaboyer, Jason W. Ferguson, Hyun Chul Lee, Guy Worthey, Darko Jevremović, E. Baron

Physics & Astronomy Faculty Publications

Integrated light from distant galaxies is often compared to stellar population models via the equivalent widths of spectral features-spectral indices-whose strengths rely on the abundances of one or more elements. Such comparisons hinge not only on the overall metal abundance, but also on relative abundances. Studies have examined the influence of individual elements on synthetic spectra but little has been done to address similar issues in the stellar evolution models that underlie most stellar population models. Stellar evolution models will primarily be influenced by changes in opacities. In order to explore this issue in detail, 12 sets of stellar evolution …

Search For Gravitational Wave Radiation Associated With The Pulsating Tail Of The Sgr 1806−20 Hyperflare Of 27 December 2004 Using Ligo, B. P. Abbott, R. Abbott, Mario C. Diaz, R. Grosso, Soumya Mohanty, Soma Mukherjee, Cristina V. Torres

Physics & Astronomy Faculty Publications

We have searched for gravitational waves (GWs) associated with the SGR 1806−20 hyperflare of 27 December 2004. This event, originating from a Galactic neutron star, displayed exceptional energetics. Recent investigations of the x-ray light curve’s pulsating tail revealed the presence of quasiperiodic oscillations (QPOs) in the 30–2000 Hz frequency range, most of which coincides with the bandwidth of the LIGO detectors. These QPOs, with well-characterized frequencies, can plausibly be attributed to seismic modes of the neutron star which could emit GWs. Our search targeted potential quasimonochromatic GWs lasting for tens of seconds and emitted at the QPO frequencies. We have …