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The Pan American (2007-09-13), Sandra Gonzalez

UTPA Archives - The Pan American Newspaper

58th Year, No. 3

The Collegian (2007-09-10), Isis Lopez

UTB/TSC Archives - The Collegian [Newspaper]

Vol. 60, No. 3

The Collegian (2007-09-03), Isis Lopez

UTB/TSC Archives - The Collegian [Newspaper]

Vol. 60, No. 2

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 …

New Integrable Hierarchy, Its Parametric Solutions, Cuspons, One-Peak Solitons, And M/W-Shape Peak Solitons, Zhijun Qiao

School of Mathematical & Statistical Sciences Faculty Publications

In this paper, we propose a new completely integrable hierarchy. Particularly in the hierarchy we draw two new soliton equations: 1 mt= 1 2 1/m2xxx− 1 2 1/m2 x; 2 mt+mx u2−ux 2+2m2ux=0, m=u−uxx. The first one is the second positive member in the hierarchy while the second one is the second negative member in the hierarchy. Both equations can be derived from the two-dimensional Euler equation by using the approximation procedure. All equations in the hierarchy are proven to have bi-Hamiltonian operators and Lax pairs through solving a crucial matrix equation. Moreover, we develop parametric solutions of the entire …

Autoreducibility, Mitoticity, And Immunity, Christian Glaßer, Mitsunori Ogihara, A. Pavan, Alan L. Selman, Liyu Zhang

Computer Science Faculty Publications

We show the following results regarding complete sets. • NP-complete sets and PSPACE-complete sets are polynomial-time many–one autoreducible.

• Complete sets of any level of PH, MODPH, or the Boolean hierarchy over NP are polynomial-time many–one autoreducible.

• EXP-complete sets are polynomial-time many–one mitotic.

• If there is a tally language in NP ∩ coNP − P , then, for every ϵ > 0 , NP-complete sets are not 2 n ( 1 + ϵ ) -immune.

These results solve several of the open questions raised by Buhrman and Torenvliet in their 1994 survey paper on the structure of complete sets.

Upper Limits On Gravitational Wave Emission From 78 Radio Pulsars, B. P. Abbott, R. Abbott, Mario C. Diaz, Soumya Mohanty, Soma Mukherjee, Cristina V. Torres

Physics & Astronomy Faculty Publications

We present upper limits on the gravitational wave emission from 78 radio pulsars based on data from the third and fourth science runs of the LIGO and GEO 600 gravitational wave detectors. The data from both runs have been combined coherently to maximize sensitivity. For the first time, pulsars within binary (or multiple) systems have been included in the search by taking into account the signal modulation due to their orbits. Our upper limits are therefore the first measured for 56 of these pulsars. For the remaining 22, our results improve on previous upper limits by up to a factor …

On The Age And Metallicity Estimation Of Spiral Galaxies Using Optical And Near-Infrared Photometry, Hyun Chul Lee, Guy Worthey, Scott C. Trager, S. M. Faber

Physics & Astronomy Faculty Publications

In integrated light, some color-color diagrams that use optical and near-infrared photometry show surprisingly orthogonal grids as age and metallicity are varied, and they are coming into common usage for estimating the average age and metallicity of spiral galaxies. In this paper we reconstruct these composite grids using simple stellar population models from several different groups convolved with some plausible functional forms of star formation histories at fixed metallicity. We find that the youngest populations present (t < 2 Gyr) dominate the light, and because of their presence the age-metallicity degeneracy can be partially broken with broadband colors, unlike older populations. The scatter among simple stellar population models by different authors is, however, large at ages t < 2 Gyr. The dominant uncertainties in stellar population models arise from convective core overshoot assumptions and the treatment of the thermally pulsing asymptotic giant branch phase and helium abundance may play a significant role at higher metallicities. Real spiral galaxies are unlikely to have smooth, exponential star formation histories, and burstiness will cause a partial reversion to the single-burst case, which has even larger model-to-model scatter. Finally, it is emphasized that the current composite stellar population models need some implementation of chemical enrichment histories for the proper analysis of the observational data. © 2007. The American Astronomical Society. All rights reserved.

Los Arcos - Spring / Summer 2007, University Of Texas-Pan American

UTPA Archives - Los Arcos Magazine

No abstract provided.

Orange & White - Summer 2007, University Of Texas At Brownsville, Texas Southmost College

UTB/TSC Archives - Orange & White Magazine

No abstract provided.

Orange & White - Summer 2007, University Of Texas At Brownsville, Texas Southmost College

UTB/TSC Archives - Orange & White Magazine

No abstract provided.

Reviving The Dead Greek Guys, William F. Strong, John A. Cook

Communication Faculty Publications

No abstract provided.

Dispersion Measure Variations And Their Effect On Precision Pulsar Timing, X. P. You, G. Hobbs, W. A. Coles, R. N. Manchester, R. Edwards, M. Bailes, J. Sarkissian, J. P.W. Verbiest, Fredrick Jenet

Physics & Astronomy Faculty Publications

We present an analysis of the variations seen in the dispersion measures (DMs) of 20-ms pulsars observed as part of the Parkes Pulsar Timing Array project. We carry out a statistically rigorous structure function analysis for each pulsar and show that the variations seen for most pulsars are consistent with those expected for an interstellar medium characterized by a Kolmogorov turbulence spectrum. The structure functions for PSRs J1045-4509 and J1909-3744 provide the first clear evidence for a large inner scale, possibly due to ion-neutral damping. We also show the effect of the solar wind on the DMs and show that …

The Collegian (2007-04-30), Isis Lopez

UTB/TSC Archives - The Collegian [Newspaper]

Vol. 59, No. 28

The Pan American (2007-04-26), Claudette Gonzalez

UTPA Archives - The Pan American Newspaper

56th Year, No. 28

Searching For A Stochastic Background Of Gravitational Waves With The Laser Interferometer Gravitational-Wave Observatory, B. Abbott, R. Abbott, R. Adhikari, J. Agresti, Mario C. Diaz, Roberto Grosso, Soumya Mohanty, Soma Mukherjee, Cristina V. Torres

Physics & Astronomy Faculty Publications

The Laser Interferometer Gravitational-Wave Observatory (LIGO) has performed the fourth science run, S4, with significantly improved interferometer sensitivities with respect to previous runs. Using data acquired during this science run, we place a limit on the amplitude of a stochastic background of gravitational waves. For a frequency independent spectrum, the new Bayesian 90% upper limit is ΩGW × [H0/(12 km s-1 Mpc-1)]2 < 6.5 × 10-5. This is currently the most sensitive result in the frequency range 51-150 Hz, with a factor of 13 improvement over the previous LIGO result. We discuss the complementarity of the new result with other constraints on a stochastic background of gravitational waves, and we investigate implications of the new result for different models of this background. © 2007. The American Astronumical Society. All rights reserved.

The Collegian (2007-04-16), Isis Lopez

UTB/TSC Archives - The Collegian [Newspaper]

Vol. 59, No. 26

The Collegian (2007-04-09), Isis Lopez

UTB/TSC Archives - The Collegian [Newspaper]

Vol. 59, No. 25

The Collegian (2007-04-02), Isis Lopez

UTB/TSC Archives - The Collegian [Newspaper]

Vol. 59, No. 24

Utb/Tsc Commencement – Spring 2007, University Of Texas At Brownsville, Texas Southmost College

Brownsville Archives - Legacy Commencement Programs

No abstract provided.

Utpa Commencement – Spring 2007, University Of Texas-Pan American

Edinburg Archives - Legacy Commencement Programs

No abstract provided.

The Collegian (2007-03-19), Isis Lopez

UTB/TSC Archives - The Collegian [Newspaper]

Vol. 59, No. 23

The Collegian (2007-03-05), Isis Lopez

UTB/TSC Archives - The Collegian [Newspaper]

Vol. 59, No. 22

Large Merger Recoils And Spin Flips From Generic Black Hole Binaries, Manuela Campanelli, Carlos O. Lousto, Y. Zlochower, David Merritt

Physics & Astronomy Faculty Publications

We report the first results from the evolution of generic black hole binaries, i.e., binaries containing unequal-mass black holes with misaligned spins. Our configuration, which has a mass ratio of 2 : 1, consists of an initially nonspinning hole orbiting a larger, rapidly spinning hole (specific spin a/m = 0.885), with the spin direction oriented -45° with respect to the orbital plane. We track the inspiral and merger for ~2 orbits and find that the remnant receives a substantial kick of 454 km s-1, more than twice as large as the maximum kick from nonspinning binaries. The remnant …

The Collegian (2007-02-26), Isis Lopez

UTB/TSC Archives - The Collegian [Newspaper]

Vol. 59, No. 21

The Collegian (2007-02-19), Isis Lopez

UTB/TSC Archives - The Collegian [Newspaper]

Vol. 59, No. 20

The Pan American (2007-02-15), Claudette Gonzalez

UTPA Archives - The Pan American Newspaper

56th Year, No. 19

On The Elimination Of The Sweeping Interactions From Theories Of Hydrodynamic Turbulence, Eleftherios Gkioulekas

School of Mathematical & Statistical Sciences Faculty Publications

In this paper, we revisit the claim that the Eulerian and quasi-Lagrangian same time correlation tensors are equal. This statement allows us to transform the results of an MSR quasi-Lagrangian statistical theory of hydrodynamic turbulence back to the Eulerian representation. We define a hierarchy of homogeneity symmetries between incremental homogeneity and global homogeneity. It is shown that both the elimination of the sweeping interactions and the derivation of the 4/5-law require a homogeneity assumption stronger than incremental homogeneity but weaker than global homogeneity. The quasi-Lagrangian transformation, on the other hand, requires an even stronger homogeneity assumption which is many-time rather …