The effects of reinforcement interval on the acquisition of paired-associate responses

Effects of reinforcement interval on acquisition of paired-associate response

Evaluation of Contamination and Remediation Manvel Saltwater Disposal Site Brazoria County, Texas

The Manvel Saltwater Disposal (SWD) site (RRC Site No. 92-03-00003), which lies within the city limits of Manvel, Texas, in Brazoria County, was investigated by the Bureau of Economic Geology during a 5-month study from July through November 2015. The study included hydrogeological investigation, waste characterization, assessment of environmental impact, and evaluation of remediation options. Saltwater, drilling waste, and crude oil have been disposed of at the site. There have been several instances of pit overflow, levee rupture, or both, resulting in contamination of the surrounding area by saltwater and crude oil. There have been several public complaints to regulatory agencies, centered on the perceived threat to groundwater quality. The site lies in the outcrop of the Beaumont Formation, where the formation is sufficiently thick to be a local aquifer, containing freshwater with chlorinities of less than 100 mg/L. The Beaumont lies above and is hydrologically distinct from the main water-yielding part of the Chicot aquifer.Bureau of Economic Geolog

Evidence for deuterium astration in the planetary nebula Sh2-216?

We present FUSE observations of the line of sight to WD0439+466 (LS V +46 21), the central star of the old planetary nebula Sh2-216. The FUSE data shows absorption by many interstellar and stellar lines, in particular D I, H2 (J = 0 - 9), HD (J = 0 - 1), and CO. Many other stellar and ISM lines are detected in the STIS E140M HST spectra of this sightline, which we use to determine N(HI). We derive, for the neutral gas, D/H=(0.76 +0.12 -0.11)E-5, O/H = (0.89 +0.15 -0.11)E-4 and N/H = (3.24 +0.61-0.55)E-5. We argue that most of the gas along this sightline is associated with the planetary nebula. The low D/H ratio is likely the result of this gas being processed through the star (astrated) but not mixed with the ISM. This would be the first time that the D/H ratio has been measured in predominantly astrated gas. The O/H and N/H ratios derived here are lower than typical values measured in other planetary nebulae likely due to unaccounted for ionization corrections.Comment: Accepted for publication is ApJ

suggestions for spraying commercial grape vineyards, 1967

Information for commerical grape vineyards, including spray programs, quantities of sprays to apply, when to spray, and general pest information. Written for application in Missouri in 1967.W.R. Enns, B.G. Tweedy and H.G. Swartwout (Departments of Horticulture and Entomology

Suggestions for spraying commercial apple orchards, 1967

"1, 67/1500"Suggested spray program -- Special pest discussion -- Comments on spray materials and combinations -- A lead arsenate program -- spray residues.B.G. Tweedy, W.R. Enns and H.G. Swartwout (Departments of Horticulture and Entomology

Hydrogeologic Analysis of Contamination and Evaluation of Remediation Alternatives - Fox Vacuum Site, Jasper County, Texas

The Bureau of Economic Geology (BEG) investigated the Fox Vacuum site (RRC Site No. 93-03-0019) in Jasper County, Texas, during a 4-month study from July through October 1995. Historical aerial photos indicate the site was developed between 1958 and 1976. Contamination identified at the start of this study included a sulfuric-acid contamination plume (soil pH of 1 to 4) that had affected the quality of soil water and killed grass across approximately a one-half-acre (2,023-m²) area of an adjacent pasture. The site also was believed to have seven earthen pits, probably containing spent drilling mud. The depth of the acid contamination was unknown. The scope of the BEG study was to determine the source, present extent, and probable fate of the sulfuric acid contamination and to ascertain the volume and contents of the earthen pits. This report presents the results of that study, along with an environmental impact assessment, risk-based evaluation of cost-effective remediation alternatives, and recommendations for RRC action.Bureau of Economic Geolog

The Orbital Period of the Pre-Cataclysmic Binary RE 2013+400 and a Study of the Atmosphere of the DAO White Dwarf Primary

Several pre-cataclysmic binaries, comprising a hot white dwarf with a red dwarf companion, have been discovered as a result of the optical identification of EUV sources from the ROSAT all-sky survey. The optical spectra have the steep blue continuum and Balmer absorption typical of a hot white dwarf, but there are bright, narrow emission lines of H I (and sometimes He I and Ca II) superimposed. An intense campaign of follow-up observations has been devoted to these binary systems. So far, only RE 2013+400 has exhibited any measurable changes in the radial velocities of the emission components, from which it is possible to estimate that the binary period is 0.71 d. A clear He II 4886-Å absorption feature is detected, which indicates that, like most PCBs with white dwarfs hotter than 40 000 K, the white dwarf is a hydrogen-helium hybrid star (DAO). A combined analysis of the optical, UV and EUV/X-ray data suggests that the atmospheric He abundance is higher in the optical line-forming region of the white dwarf photosphere than in the region where the EUV/X-ray flux is formed. This is an interesting result, in the light of the recent optical study of a sample of DAO white dwarfs by Bergeron et al., if representative of DAO white dwarfs in general

High-resolution FUSE and HST ultraviolet spectroscopy of the white dwarf central star of Sh 2-216

LS V +4621 is the DAO-type central star of the planetary nebula Sh 2-216. We perform a comprehensive spectral analysis of high-resolution, high-S/N ultraviolet observations obtained with FUSE and STIS aboard the HST as well as the optical spectrum of LS V +4621 by means of state-of-the-art NLTE model-atmosphere techniques in order to compare its photospheric properties to theoretical predictions from stellar evolution theory as well as from diffusion calculations. From the N IV - NV, O IV - O VI, Si IV - Si V, and Fe V - Fe VII ionization equilibria, we determined an effective temperature of 95 +/- 2 kK with high precision. The surface gravity is log g = 6.9 +/- 0.2. An unexplained discrepancy appears between the spectroscopic distance d = 224 +46/-58 pc and the parallax distance d = 129 +6/-5 pc of LS V +4621. For the first time, we have identified Mg IV and Ar VI absorption lines in the spectrum of a hydrogen-rich central star and determined the Mg and Ar abundances as well as the individual abundances of iron-group elements (Cr, Mn, Fe, Co, and Ni). With the realistic treatment of metal opacities up to the iron group in the model-atmosphere calculations, the so-called Balmer-line problem (found in models that neglect metal-line blanketing) vanishes. Spectral analysis by means of NLTE model atmospheres has presently arrived at a high level of sophistication, which is now hampered largely by the lack of reliable atomic data and accurate line-broadening tables. Strong efforts should be made to improve upon this situation.Comment: 13 pages, 20 figure

Serendipity and the SDSS: Discovery of the Largest Known Planetary Nebula on the Sky

Investigation of spectra from the Sloan Digital Sky Survey reveals the presence of a region of ionized gas of >2 degrees diameter centered approximately at alpha = 10^h 37^m delta = -00^o 18' (J2000) (Galactic coordinates l=248, b=+48). [OIII] 4959,5007 emission is particularly strong and emission from H-alpha and [NII] 6548,6583 is also detectable over a substantial area on the sky. The combination of emission line ratios, the close to zero heliocentric radial velocity and the morphology of the structure are consistent with an identification as a very nearby planetary nebula. The proximity of the hot, DO white dwarf PG1034+001 further strengthens this interpretation. The object is: i) the largest planetary nebula on the sky, ii) certainly closer than any planetary nebula other than Sh 2--216, iii) the first to be unambiguously associated with a DO white dwarf. A parallax distance for PG1034+001 would establish whether the structure is in fact the closest, and one of the physically largest, planetary nebula known.Comment: 12 pages including 4 figures. ApJ Letters in pres

Persistent and polarised global actin flow is essential for directionality during cell migration

Cell migration is hypothesized to involve a cycle of behaviours beginning with leading edge extension. However, recent evidence suggests that the leading edge may be dispensable for migration, raising the question of what actually controls cell directionality. Here, we exploit the embryonic migration of Drosophila macrophages to bridge the different temporal scales of the behaviours controlling motility. This approach reveals that edge fluctuations during random motility are not persistent and are weakly correlated with motion. In contrast, flow of the actin network behind the leading edge is highly persistent. Quantification of actin flow structure during migration reveals a stable organization and asymmetry in the cell-wide flowfield that strongly correlates with cell directionality. This organization is regulated by a gradient of actin network compression and destruction, which is controlled by myosin contraction and cofilin-mediated disassembly. It is this stable actin-flow polarity, which integrates rapid fluctuations of the leading edge, that controls inherent cellular persistence