Introducing Vireo: an ETD Submittal and Management System for DSpace

4th International Conference on Open RepositoriesThis presentation was part of the session : DSpace User Group PresentationsDate: 2009-05-20 03:30 PM – 05:00 PMThe Texas Digital Library (TDL) is a consortium of public and private institutions from across the state of Texas; a major project in TDL is the development of a state-wide repository for managing the entire life-cycle of electronic theses and dissertations (ETDs). The Texas ETD Repository is a large effort that span multiple independent initiatives, all of which interact to support the overall task of managing ETDs in Texas. This presentation will describe Vireo, the customized submission and workflow management application that TDL developed for DSpace, and it's role within the Texas ETD Repository. We will describe its current implementation as a Manakin aspect and theme, and discuss the future plans for the application, including its release to the repository community under an open source license.Institute for Museum and Library Sciences; Texas Digital Librar

Fraction-Free Computation of Determinants

Here we examine Dodgson\u27s Method, a fraction-free methods for computing determinants. In some cases, this method fails due to division by zero. We propose a workaround for Dodgson\u27s Method that ensures it also can be used to compute the determinant of any integer matrix

Integrated Cooperation within a Grass-Roots Movement’s the Class Emphasis

Under what conditions is it possible for members of different racial groups to cooperate in an integrated sense to build a successful, working class, community based, mutual benefits association -- one with the long-term intent of organizing workplaces where mutual-benefits association members happen to work? Can this inter-racial cooperation occur at all levels of the organization? Given this long term possibility of unionization, an end product not too different from an association-union recently achieved by Caesar Chavez\u27s NFWA-UFVOC , what are the initial organizational prerequisites for successfully bringing together blacks, whites, Chicanos, Puerto Ricans and others within these local associations

Generalizing Dodgson's method: a "double-crossing" approach to computing determinants

Dodgson's method of computing determinants was recently revisited in a paper that appeared in the College Math Journal. The method is attractive, but fails if an interior entry of an intermediate matrix has the value zero. This paper reviews the structure of Dodgson's method and introduces a generalization, called a "double-crossing" method, that provides a workaround to the failure for many interesting cases.Comment: 14 pages, 3 figures; corrected some typo

ULAS J141623.94+134836.3: a Blue T Dwarf Companion to a Blue L Dwarf

We confirm the substellar nature of ULAS J141623.94+134836.3, a common proper motion companion to the blue L dwarf SDSS J141624.08+134826.7 identified by Burningham et al. and Scholz. Low-resolution 0.8-2.4 micron spectroscopy obtained with IRTF/SpeX shows strong H2O and CH4 absorption bands, consistent with a T7.5 spectral type, and we see possible indications of NH3 absorption in the 1.0-1.3 micron region. More importantly, the spectrum of ULAS J1416+1348 shows a broadened Y-band peak and highly suppressed K-band flux, both indicative of high surface gravity and/or subsolar metallicity. These traits are verified through spectral model fits, from which we derive atmospheric parameters Teff = 650+/-60 K, log g = 5.2+/-0.4 cgs, [M/H] <= -0.3 and Kzz = 10^4 cm^2/s, the temperature being significantly warmer than that estimated by Burningham et al. These fits also indicate a model-dependent spectroscopic distance of 10.6(+3.0,-2.8) pc for ULAS J1416+1348, formally consistent with the 7.9+/-1.7 pc astrometric distance for SDSS J1416+1348 from Scholz. The common peculiarities of these two co-spatial, co-moving sources suggest that their unusual blue colors - and those of other blue L and T dwarfs in general - arise from age or metallicity, rather than cloud properties alone.Comment: 21 pages, 3 figures (manuscript format); submitted to ApJ, constructive comments welcom

Pair condensation and bound states in fermionic systems

We study the finite temperature-density phase diagram of an attractive fermionic system that supports two-body (dimer) and three-body (trimer) bound states in free space. Using interactions characteristic for nuclear systems, we obtain the critical temperature T_c2 for the superfluid phase transition and the limiting temperature T_c3 for the extinction of trimers. The phase diagram features a Cooper-pair condensate in the high-density, low-temperature domain which, with decreasing density, crosses over to a Bose condensate of strongly bound dimers. The high-temperature, low-density domain is populated by trimers whose binding energy decreases toward the density-temperature domain occupied by the superfluid and vanishes at a critical temperature T_c3 > T_c2.Comment: 11 pages, 4 figures, uses RevTex; v2: 12 pages, 4 figures, matches published versio

Auxiliary field formalism for dilute fermionic atom gases with tunable interactions

We develop the auxiliary field formalism corresponding to a dilute system of spin-1/2 fermions. This theory represents the Fermi counterpart of the BEC theory developed recently by F. Cooper et al. [Phys. Rev. Lett. 105, 240402 (2010)] to describe a dilute gas of Bose particles. Assuming tunable interactions, this formalism is appropriate for the study of the crossover from the regime of Bardeen-Cooper-Schriffer (BCS) pairing to the regime of Bose-Einstein condensation (BEC) in ultracold fermionic atom gases. We show that when applied to the Fermi case at zero temperature, the leading-order auxiliary field (LOAF) approximation gives the same equations as those obtained in the standard BCS variational picture. At finite temperature, LOAF leads to the theory discussed by by Sa de Melo, Randeria, and Engelbrecht [Phys. Rev. Lett. 71, 3202(1993); Phys. Rev. B 55, 15153(1997)]. As such, LOAF provides a unified framework to study the interacting Fermi gas. The mean-field results discussed here can be systematically improved upon by calculating the one-particle irreducible (1-PI) action corrections, order by order.Comment: 12 pages, 5 figure

The Binary White Dwarf LHS 3236

The white dwarf LHS 3236 (WD1639+153) is shown to be a double-degenerate binary, with each component having a high mass. Astrometry at the U.S. Naval Observatory gives a parallax and distance of 30.86 +/- 0.25 pc and a tangential velocity of 98 km/s, and reveals binary orbital motion. The orbital parameters are determined from astrometry of the photocenter over more than three orbits of the 4.0-year period. High-resolution imaging at the Keck Observatory resolves the pair with a separation of 31 and 124 mas at two epochs. Optical and near-IR photometry give a set of possible binary components. Consistency of all data indicates that the binary is a pair of DA stars with temperatures near 8000 and 7400 K and with masses of 0.93 and 0.91 M_solar; also possible, is a DA primary and a helium DC secondary with temperatures near 8800 and 6000 K and with masses of 0.98 and 0.69 M_solar. In either case, the cooling ages of the stars are ~3 Gyr and the total ages are <4 Gyr. The combined mass of the binary (1.66--1.84 M_solar) is well above the Chandrasekhar limit; however, the timescale for coalescence is long.Comment: Accepted for the Astrophysical Journa

Effects of in vitro Brevetoxin Exposure on Apoptosis and Cellular Metabolism in a Leukemic T Cell Line (Jurkat)

Harmful algal blooms (HABs) of the toxic dinoflagellate, Karenia brevis, produce red tide toxins, or brevetoxins. Significant health effects associated with red tide toxin exposure have been reported in sea life and in humans, with brevetoxins documented within immune cells from many species. The objective of this research was to investigate potential immunotoxic effects of brevetoxins using a leukemic T cell line (Jurkat) as an in vitro model system. Viability, cell proliferation, and apoptosis assays were conducted using brevetoxin congeners PbTx-2, PbTx-3, and PbTx-6. The effects of in vitro brevetoxin exposure on cell viability and cellular metabolism or proliferation were determined using trypan blue and MTT (1-(4,5-dimethylthiazol-2-yl)-3,5-diphenylformazan), respectively. Using MTT, cellular metabolic activity was decreased in Jurkat cells exposed to 5 – 10 μg/ml PbTx-2 or PbTx-6. After 3 h, no significant effects on cell viability were observed with any toxin congener in concentrations up to 10 μg/ml. Viability decreased dramatically after 24 h in cells treated with PbTx-2 or -6. Apoptosis, as measured by caspase-3 activity, was significantly increased in cells exposed to PbTx-2 or PbTx-6. In summary, brevetoxin congeners varied in effects on Jurkat cells, with PbTx-2 and PbTx-6 eliciting greater cellular effects compared to PbTx-3

Study of Supersolidity and Shear Modulus Anomaly of 4He in a Triple Compound Oscillator

The recently discovered shear modulus anomaly in solid 4He bears a strong similarity to the phenomenon of supersolidity in solid 4He and can lead to the period shift and dissipative signals in torsional oscillator experiments that are nearly identical to the classic NCRI signals observed by Kim and Chan. In the experiments described here, we attempt to isolate the effects of these two phenomena on the resonance periods of torsion oscillators. We have constructed a triple compound oscillator with distinct normal modes. We are able to demonstrate that, for this oscillator, the period shifts observed below 200 mK have their primary origin in the temperature dependence of the shear modulus of the solid 4He sample rather than the formation of a supersolid state