Physical Sciences and Mathematics Commons^™

Rapid Single- And Multiple-Scattering Exafs Debye-Waller Factor Calculations On Active Sites Of Metalloproteins, Nicholas Dimakis, M-Ali Al-Akhras, Grant Bunker

Physics & Astronomy Faculty Publications

This paper describes recent results using our approach to calculating self-consistently single (SS) and multiple-scattering (MS) Debye- Waller factors (DWF) on active sites of metalloproteins. The calculation of MS DWF, together with the Feff7 program allows us to simulate ab-initio EXAFS spectra for a given temperature systems with no adjustable parameters. In our latest report (Dimakis N., and Bunker G., 1998) we calculate, using density functional and semiempirical approaches, the SS and MS DWF for small molecules and compared them to Raman, infrared and EXAFS spectra. In this report calculation of DWFs is done for tetrahedral Zn imidazole, a complex …

On Different Integrable Systems Sharing The Same Nondynamical R-Matrix, Zhijun Qiao, Walter Strampp

School of Mathematical & Statistical Sciences Faculty Publications

In a recent paper @Zhijun Qiao and Ruguang Zhou, Phys. Lett. A 235, 35 ~1997!#, the amazing fact was reported that a discrete and a continuous integrable system share the same r-matrix with the interesting property of being nondynamical. Now, we present three further pairs of different continuous integrable systems sharing the same r-matrix again being nondynamical. The first pair is the finite-dimensional constrained system ~FDCS! of the famous AKNS hierarchy and the Dirac hierarchy; the second pair is the FDCS of the well-known geodesic flows on the ellipsoid and the Heisenberg spin chain hierarchy; and the third pair is …

Radio Pulse Properties Of The Millisecond Pulsar Psr J0437-4715. I. Observations At 20 Centimeters, F. A. Jenet, S. B. Anderson, V. M. Kaspi, T. A. Prince, S. C. Unwin

Physics & Astronomy Faculty Publications

We present a total of 48 minutes of observations of the nearby, bright millisecond pulsar PSR J0437-4715 taken at the Parkes Observatory in Australia. The data were obtained at a central radio frequency of 1380 MHz using a high-speed tape recorder that permitted coherent Nyquist sampling of 50 MHz of bandwidth in each of two polarizations. Using the high time resolution available from this voltage recording technique, we have studied a variety of single-pulse properties, many for the first time in a millisecond pulsar. We show that individual pulses are broad band, have pulse widths ranging from ∼ 10 (∼ …

Searching For Periodic Sources With Ligo, Patrick R. Brady, Teviet Creighton, Curt Cutler, Bernard F. Schutz

Physics & Astronomy Faculty Publications

We investigate the computational requirements for all-sky, all-frequency searches for gravitational waves from spinning neutron stars, using archived data from interferometric gravitational wave detectors such as LIGO. These sources are expected to be weak, so the optimal strategy involves coherent accumulaton of signal-to-noise using Fourier transforms of long stretches of data (months to years). Earth-motion-induced Doppler shifts, and intrinsic pulsar spindown, will reduce the narrow-band signal-to-noise by spreading power across many frequency bins; therefore, it is necessary to correct for these effects before performing the Fourier transform. The corrections can be implemented by a parametrized model, in which one does …

Ab Initio Single- And Multiple-Scattering Exafs Debye-Waller Factors: Raman And Infrared Data, Nicholas Dimakis, Grant Bunker

Physics & Astronomy Faculty Publications

The extended x-ray-absorption fine structure (EXAFS) Debye-Waller factor is an essential term appearing in the EXAFS equation that accounts for the molecular structural and thermal disorder of a sample. Single- and multiple-scattering Debye-Waller factors must be known accurately to obtain quantitative agreement between theory and experiment. Since the total number of fitting parameters that can be varied is limited in general, data cannot support fitting of all relevant multiple-scattering Debye-Waller factors. Calculation of the Debye-Waller factors is typically done using the correlated Debye approximation, where a single parameter (Debye temperature) is varied. However, this procedure cannot account in general for …

Three Types Of Gamma-Ray Bursts, Soma Mukherjee, Eric D. Feigelson, Gutti Jogesh Babu, Flonn Murtagh, Chris Fralev, Adrian Raftery

Physics & Astronomy Faculty Publications

A multivariate analysis of gamma-ray burst (GRB) bulk properties is presented to discriminate between distinct classes of GRBs. Several variables representing burst duration, fluence, and spectral hardness are considered. Two multivariate clustering procedures are used on a sample of 797 bursts from the Third BATSE Catalog, a nonparametric average linkage hierarchical agglomerative clustering procedure validated with Wilks' Λ* and other multivariate analysis of variance tests and a parametric maximum likelihood model-based clustering procedure assuming multinormal populations calculated with the Expectation-Maximization algorithm and validated with the Bayesian Information Criterion. The two methods yield very similar results. The BATSE GRB population consists …

Hierarchical Search Strategy For The Detection Of Gravitational Waves From Coalescing Binaries: Extension To Post-Newtonian Waveforms, Soumya Mohanty

Physics & Astronomy Faculty Publications

The detection of gravitational waves from coalescing compact binaries would be a computationally intensive process if a single bank of template wave forms (one step search) is used. In an earlier paper we presented a detection strategy, called a two step search, that utilizes a hierarchy of template banks. It was shown that in the simple case of a family of Newtonian signals, an on-line two step search was ≃8 times faster than an on-line one step search (for the initial LIGO). In this paper we extend the two step search to the more realistic case of …

Critical Casimir Forces Between Spherical Particles In Fluids, Andreas Hanke, F. Schlesener, E. Eisenriegler, S. Dietrich

Physics & Astronomy Faculty Publications

Long-ranged correlations in a fluid close to its critical point Tc cause distinct forces between immersed colloidal particles and the container walls. We calculate such a force and its temperature dependence for the generic case of a spherical particle located at a distance D from a planar wall and find that the force attains a maximum at a temperature Tmax(D) above Tc, which facilitates quantitative experimental tests. The corresponding effective pair interaction between the colloidal particles themselves, potentially leading to aggregation, is also discussed.

A Data Analysis Approach For Detecting Gravitational Waves From Psr 0437-4715, Soumya Mohanty, I. S. Heng, David Blair, S. Dhurandhar, M. Tovar, E. Ivanov

Physics & Astronomy Faculty Publications

A search for gravitational waves from the millisecond pulsar PSR 0437-4715 has been initiated using the bar detector NIOBE which is located at the University of Western Australia. We present a detailed report on the data analysis algorithm, called phase plane rotation, which will be used in this search. A discussion of the actual implementation of the algorithm is presented. The data analysis algorithm mentioned above has the advantage that it requires minimal changes to the already-existing data acquisition facility of NIOBE but, at the same time, it is as efficient as optimal filtering in detecting a signal. This …

Large-Amplitude Solitary Waves In Finite Temperature Dusty Plasma, R. Roychoudhury, S. Mukherjee

Physics & Astronomy Faculty Publications

Large-amplitude solitary waves in dusty plasma are investigated, taking into account the dusty particle temperature. It is shown that finite dusty temperature restricts the region for the existence of solitary waves.

Magnetic Field Decay In Single Radio Pulsars: A Statistical Study, Soma Mukherjee, Ajit Kembhavi

Physics & Astronomy Faculty Publications

We report on an extensive statistical study of single radio pulsar properties, which we undertook to estimate the decay timescale of pulsar magnetic fields. We synthesized a population of pulsars using assumed theoretical distributions of age, initial magnetic field, period of rotation, position, luminosity, and dispersion measure, taking into account the new distance model for pulsars as well as new velocity estimates. We also took into account the selection effects that characterize pulsar observations. We compared the simulated population with the observed single pulsar population using one- and two-dimensional Kolmogorov-Smirnov tests to obtain a lower bound of ∼160 Myr on …

Macrophage-Mediated 15-Lipoxygenase Expression Protects Against Atherosclerosis Development, Jianhe Shen, Ed Herderick, J. Fredrick Cornhill, Eva Zsigmond, Han Seob Kim, Hartmut Kühn, Natalia V. Guevara, Lawrence Chan

Physics & Astronomy Faculty Publications

Oxidative modification of LDL increases its atherogenicity, and 15- lipoxygenase (15-LO) has been implicated in the process. To address this issue, we generated transgenic rabbits that expressed 15-LO in a macrophage- specific manner and studied their susceptibility to atherosclerosis development when they were fed a high-fat, high-cholesterol (HFHC) diet (Teklad 0533 rabbit diet 7009 with 10% corn oil and 0.25% cholesterol) for 13.5 wk. Transgenic and nontransgenic rabbits developed similar degrees of hypercholesterolemia and had similar levels of triglyceride, VLDL, LDL, and HDL. Quantitative morphometric analysis of the aortic atherosclerosis indicated that the transgenic animals (n = 19) had significantly …

Effective Characteristic Polynomials And Two-Point Pade Approximants As Summation Techniques For The Strongly Divergent Perturbation Expansions Of The Ground State Energies Of Anharmonic Oscillators, Jiri Cizek, Ernst Joachim Weniger, Paul Bracken, Vladimir Spirko

School of Mathematical & Statistical Sciences Faculty Publications

Pade approximants are able to sum effectively the Rayleigh-Schrodinger perturbation series for the ground state energy of the quartic anharmonic oscillator, as well as the corresponding renormalized perturbation expansion [E.J. Weniger, J. Cizek, and F. Vinette, J. Math. Phys. 34, 571 (1993)]. In the sextic case, Pade approximants are still able to sum these perturbation series, but convergence is so slow that they are computationally useless. In the octic case, Pade approximants are not powerful enough and fail. On the other hand, the inclusion of only a few additional data from the strong coupling domain [E.J. Weniger, Ann. Phys. (N.Y.) …

A Survey For Millisecond Pulsars, P. S. Ray, S. E. Thorsett, F. A. Jenet, M. H. Van Kerkwuk, S. R. Kulkarni, T. A. Prince, J. S. Sandhu, D. J. Nice

Physics & Astronomy Faculty Publications

We have searched 960 square degrees of sky for radio pulsars, using the 305 m telescope at Arecibo, Puerto Rico. The 430 MHz survey reached a limiting sensitivity for slow pulsars of 0.7 mJy using a dual-polarization, 32 channel filter bank over 8 MHz of bandwidth. We have detected one new millisecond pulsar, 11 new slow pulsars, one previously known millisecond pulsar, and eight previously known slow pulsars. The new millisecond pulsar, PSR J2033 + 17, with a period of 5.9 ms, has been found to be in a binary system. The Keplerian circular orbital solution has a period of …

Polymers Interacting With Spherical And Rodlike Particles, E. Eisenriegler, Andreas Hanke, S. Dietrich

Physics & Astronomy Faculty Publications

The interaction of a long flexible polymer chain with mesoscopic particles of spherical or elongated cylindrical shape is investigated by field-theoretic methods using the polymer-magnet analogy. In the case that these particles are immersed in a dilute polymer solution and exhibit purely repulsive surfaces we study density profiles for monomers and chain ends near such a particle, the change of configurational entropy by immersing a particle into the solution, and the depletion interaction between a particle and a distant planar wall. Both ideal chains and chains with an excluded-volume interaction are considered. We also analyze particle surfaces with a short-ranged …

Hierarchical Search Strategy For The Detection Of Gravitational Waves From Coalescing Binaries, Soumya Mohanty, S. Dhurandhar

Physics & Astronomy Faculty Publications

The detection of gravitational waves from coalescing compact binaries would be a computationally intensive process if a single bank of template wave forms (i.e., a one-step search) is used. We present, in this paper, a method which leads to a large reduction in the computational power required as compared to a one-step search. This method is a hierarchical search strategy involving two template banks. We show that the computational power required by such a two-step search, for an on-line detection of the one-parameter family of Newtonian signals, is 18 of that required when an on-line one-step search is used. This …

A Completely Integrable System And Parametric Representation Of Solutions Of The Wadati-Konno-Ichikawa Hierarchy, Zhijun Qiao

School of Mathematical & Statistical Sciences Faculty Publications

A finite-dimensional involutive system is presented, and the Wadati-Konno- Ichikawa (WKI) hierarchy of nonlinear evolution equations and their commutator representations are discussed in this article. By this finite-dimensional involutive system, it is proven that under the so-called Bargmann constraint between the potentials and the eigenfunctions, the eigenvalue problem (called the WKI eigenvalue problem) studied by Wadati, Konno, and Ichikawa [J. Phys. Sot. Jpn. 47, 1698 (1979)] is nonlinearized as a completely integrable Hamiltonian system in the Liouville sense. Moreover, the parametric representation of the solution of each equation in the WKI hierarchy is obtained by making use of the solution …

Density Of States Of A Damped Quantum Oscillator, Andreas Hanke, W. Zwerger

Physics & Astronomy Faculty Publications

We calculate the density of states of a damped quantum-mechanical harmonic oscillator which is described by a Caldeira-Leggett type model with Ohmic dissipation and a Drude-like cutoff. From the exact expression for the associated partition function, we derive the asymptotic behavior of the density of states using Tauberian theorems. An effective algorithm to evaluate the density of states is presented and examples are given. It is pointed out that the calculated density of states is an experimentally accessible quantity.

A Hierarchy Of Nonlinear Evolution Equations And Finite-Dimensional Involutive Systems, Zhijun Qiao

School of Mathematical & Statistical Sciences Faculty Publications

A spectral problem and an associated hierarchy of nonlinear evolution equations are presented in this article. In particular, the reductions of the two representative equations in this hierarchy are given: one is the nonlinear evolution equation rl= - ar,- 2icu/3] r2] r which looks like the nonlinear Schrijdinger equation, the other is the generalized derivative nonlinear Schrijdinger equation rt= $ar,,- ialr12r- a/3(lr12r),- a j3I r I 2r,-2iap21r14r which is just a combination of the nonlinear Schrijdinger equation and two different derivative nonlinear Schrodinger equations [D. J. Kaup and A. C. Newell, J. Math. Phys. 19, 789 (1978); M. J. Ablowitz, …

Supplemental Carbon Dioxide And Light Improved Tomato And Pepper Seedling Growth And Yield, Alejandro Fierro, Nicolas Tremblay, André Gosselin

School of Earth, Environmental, & Marine Sciences Faculty Publications

The experiment was conducted to determine the effects of CO, enrichment (900 μl·liter-1, 8 hours/day) in combination with supplementary lighting of 100 μmol·s-1·m-2 (16- h photoperiod) on tomato (Lycopersicon esculentum Mill.) and sweet pepper (Capsicum annuum L.) seedling growth in the greenhouse and subsequent yield in the field. Enrichment with CO2 and supplementary lighting for » 3 weeks before transplanting increased accumulation of dry matter in shoots by » 50% compared with the control, while root dry weight increased 49% for tomato and 6270 for pepper. Early yields increased by =1570 and 11% for tomato and pepper, respectively.

An Involutive System And Integrable C. Neumann System Associated With The Modified Korteweg-De Vries Hierarchy, Zhijun Qiao

School of Mathematical & Statistical Sciences Faculty Publications

In this article, a system of finite-dimensional involutive functions is presented and proven to be integrable in the Liouville sense. By using the nonlinearization method, the C. Neumann system associated with the modified Korteweg-de Vries (mKdV) hierarchy is obtained. Thus, the C. Neumann system is shown to be completely integrable via a gauge transformation between it and an integrable Hamiltonian system. Finally, the solution of a stationary mKdV equation and the involutive solutions of the mKdV hierarchy are secured. As two examples, the involutive solutions are given for the mKdV equation: u,+ ;uXXX- $u2u,=0 and the 5th mKdV equation v,- …

Dilaton Black Holes With Electric Charge, Malik Rakhmanov

Physics & Astronomy Faculty Publications

New static spherically symmetric solutions of the Einstein-Maxwell gravity with the dilaton field are found. The solutions correspond to black holes and naked singularities. In addition to mass and electric charge these solutions are labeled by a new parameter, the dilaton charge of the black hole. Depending on the values of electric and dilaton charges there are different types of solutions. The solutions exhibit a new type of a symmetry. Namely one solution transforms into another when the mass and the dilaton charge are interchanged. We also found that there is a finite interval of values of electric charge for …

A New Completely Integrable Liouville's System Produced By The Kaup-Newell Elgenvalue Problem, Zhijun Qiao

School of Mathematical & Statistical Sciences Faculty Publications

Under the constraint between the potentials and eigenfunctions, the Kaup–Newell eigenvalue problem is nonlinearized as a new completely integrable Hamiltonian system (R2N,dpΛdq,H): H=i〈Λ2p,q〉+1/2〈Λq,q〉〈Λp,p〉. Furthermore, the involutive solution of the high‐order Kaup–Newell equation is obtained. Specifically, the involutive solution of the well‐known derivative Schrödinger equation ut=1/2iuxx+1/2(u‖u‖2)x is developed.

Site Assessment / Initial Remedial Action, Phillips Properties (Mcallen, Tx), Valley Scientific Remediation (Palmview, Tx)

Contaminación Collection

"This report presents the data, analyses, results, and recommendations from the Initial Remedial Actions and Phase II Environmental Site Assessment. This report has been performed by Valley Scientific Remediation, Inc. (VSR) in the last quarter of 1991 and the first quarter of 1992, on behalf of Phillips Properties, Inc. at the Phillips Properties# 1 McAllen facility, located at 2215 West Business Hwy 83, near the southeast corner of Business Highway 83 and 23rd st., McAllen, Texas."

Second-Order Parametrized-Post-Newtonian Lagrangian, Matthew J. Benacquista

Physics & Astronomy Faculty Publications

A many-body Lagrangian to second post-Newtonian order using an extension of the parametrized-post-Newtonian (PPN) formalism is introduced and the properties of new parameters are explored. A parametrized gauge transformation is developed to permit comparison with theories of gravity in a variety of different coordinate systems. A procedure to impose Lorentz invariance on a general second-order post-Newtonian Lagrangian is developed. The Lagrangian is then constrained to possess Lorentz invariance and a "Lorentz-invariant" gauge is introduced. The constrained Lagrangian is found to be described by ten new second-order PPN parameters. When the Lagrangian is further constrained to describe theories of gravity for …

Organochlorine Pesticide Residue, Physico-Chemical, And Bacteriological Profile Of The Lower Rio Grande River Of Texas, Juan H. Gonzalez

Theses and Dissertations - UTB/UTPA

An investigation was conducted to determine if the widespread and abundant use of organochlorine pesticides in the Lower Rio Grande Valley of Texas has had any effect on the microbial flora in the water and in the bottom sediments of the Lower Rio Grande River of Texas.

Rio Grande River water and bottom sediments were cultured for microbial flora, were analyzed for pesticide residues, and the physicochemical properties of the water were determined. Samples were taken at four different sites during a ten month sampling period in 1974.

Traces of organochlorine residues were found in the water, and higher concentrations …

Coastal Vegetational Communities Of The Two Texas Barrier Islands, Boca Chica And Brazos, Baltazar Cisneros

Theses and Dissertations - UTB/UTPA

Two Texas barrier islands, Boca Chica and Brazos, have unique coastal vegetational communities that may be Influenced by several environmental factors. These environmental factors include temperature, precipitation, wind speed, sunshine exposure, day length, and dune height. The purpose of this investigation was to determine the total number of coastal plant species per station, season, and year and to consider environmental factors that may significantly affect the number and pattern of coastal species. Coverage comparison between aerial and land sampling and aerial vegetational zonation was also considered.

Results indicated the presence of 21 angiosperm families and a total of 54 species. …

Plan Of Development For Valley Gravity Project, Julius A. Krug, Michael W. Straus, Wesley R. Nelson

Lower Rio Grande Valley Curated Material

"The Valley Gravity Project Plan has been formulated to furnish an adequate and dependable irrigation water supply for fertile and productive area in the Lower Rio Grande Valley, Texas, It would also provide drainage works, which would remove the threat of destruction of the economy of the area due to effects of a high water table and salt accumulations. The project works would permit generation of the maximum practicable amount of electrical energy which otherwise would be required to operate irrigation pumping plants. Other incidental benefits include fish and wildlife conservation, recreation and flood control."

Project report no. 5-0619-0