Texas Forestry Paper No. 28

Plants following timber harvest: importance to songbirdshttps://scholarworks.sfasu.edu/texas_forestry_papers/1016/thumbnail.jp

LOCATION OF A MIXALCO PRODUCTION FACILITY WITH RESPECT TO ECONOMIC VIABILITY

Monte-Carlo simulation modeling is used to perform a feasibility study of alternative locations for a MixAlco production facility. Net present value distributions will be ranked within feasible risk aversion boundaries. If MixAlco is a profitable investment, it would have a major impact on the fuel oxygenate and gasoline markets.Resource /Energy Economics and Policy,

A trio of month long flares in the nova-like variable V704 And

We present the discovery of an unusual set of flares in the nova-like variable V704 And. Using data from AAVSO, ASAS-SN, and ZTF, of the nova-like variable V704 And, we have discovered a trio of brightening events that occurred during the high state. These events elevate the optical brightness of the source from $\sim13.5$ magnitude to $\sim12.5$ magnitude. The events last for roughly a month, and exhibit the unusual shape of a slow rise and faster decay. Just after the third event we obtained data from regular monitoring with Swift, although by this time the flares had ceased and the source returned to its pre-flare level of activity in the high-state. The Swift observations confirm that during the high-state the source is detectable in the X-rays, and provide simultaneous UV and optical fluxes. As the source is already in the high-state prior to the flares, and thus the disc is expected to already be in the high-viscosity state, we conclude that the driver of the variations must be changes in the mass transfer rate from the companion star and we discuss possible mechanisms for such short-timescale mass transfer variations to occur.Comment: 5 pages + appendix. Accepted for publication in A&A Letter

The influence of prior relationship on perceptions of stalking: A comparison of laypersons, non-specialist police officers and specialist police officers

The current research examined the influence of prior relationship on perceptions of stalking, and compared the perceptions of laypersons, nonspecialist police officers, and specialist police officers. Two studies employed experimental designs where participants were presented with one of three vignettes in which the nature of the prior relationship was manipulated so that the perpetrator and victim were portrayed as strangers, acquaintances, or ex-partners. Participants comprised 101 nonspecialist police officers and 108 laypersons in Study 1, and 49 specialist police officers and 49 nonspecialist police officers in Study 2. Findings indicate that nonspecialist police officers and laypersons shared the common misperception that stranger stalkers present a greater threat to the personal safety of their victims than acquaintance or ex-partner stalkers. Specialist police officers were less susceptible to common misperceptions and believed that intervention was more necessary. Specialist police officers also believed that the perpetrator’s behavior would cause the victim more alarm or personal distress than nonspecialist police officers

Electronic Processes at the Breakdown of the Quantum Hall Effect

Microscopic processes giving the energy gain and loss of a two-dimensional electron system in long-range potential fluctuations are studied theoretically at the breakdown of the quantum Hall effect in the case of even-integer filling factors. The Coulomb scattering within a broadened Landau level is proposed to give the gain, while the phonon scattering to give the loss. The energy balance equation shows that the electron temperature T_e and the diagonal conductivity sigma_{xx} exhibit a bistability above the lower critical electric field E_{c1}. Calculated values of E_{c1} as well as T_e and sigma_{xx} at E_{c1} are in agreement with the observed values in their orders of magnitude.Comment: 4 pages, 2 Postscript figures, submitted to the Journal of the Physical Society of Japa

New magnetic dipole transition of the oxygen molecule: Bʹ³Πg←X ³Σg⁻(0,0)

Through the use of isotopically pure gas at a temperature of 77 K, a weak photoabsorption band of ¹⁶O₂ is found near 1856 Å, underlying the stronger Schumann–Runge (SR) band B³Σ−u←X³Σ−g(8,0). The location, structure, and intensity of this new band are consistent with expectation for the magnetic dipole transitionB′ ³Πg←X³Σ−g(0,0), where the designation B′ is chosen to represent the II ³Πg valence state. This electronic transition contributes to the “excess absorption” underlying the SR bands [B. R. Lewis, S. T. Gibson, and E. H. Roberts, J. Chem. Phys. 115, 245 (2001)]

Upper limits for undetected trace species in the stratosphere of Titan

In this paper we describe a first quantitative search for several molecules in Titan's stratosphere in Cassini CIRS infrared spectra. These are: ammonia (NH3), methanol (CH3OH), formaldehyde (H2CO), and acetonitrile (CH3CN), all of which are predicted by photochemical models but only the last of which observed, and not in the infrared. We find non-detections in all cases, but derive upper limits on the abundances from low-noise observations at 25{\deg}S and 75{\deg}N. Comparing these constraints to model predictions, we conclude that CIRS is highly unlikely to see NH3 or CH3OH emissions. However, CH3CN and H2CO are closer to CIRS detectability, and we suggest ways in which the sensitivity threshold may be lowered towards this goal.Comment: 11 pages plus 6 figure file

Sulphur hexaflouride: low energy (e,2e) experiments and molecular three-body distorted wave theory

Experimental and theoretical triple differential ionisation cross-sections (TDCS’s) are presented for the highest occupied molecular orbital of sulphur hexafluoride. These measurements were performed in the low energy regime, with outgoing electron energies ranging from 5 to 40 eV in a coplanar geometry, and with energies of 10 and 20 eV in a perpendicular geometry. Complementary theoretical predictions of the TDCS were calculated using the molecular three-body distorted wave formalism. Calculations were performed using a proper average over molecular orientations as well as the orientation-averaged molecular orbital approximation. This more sophisticated model was found to be in closer agreement with the experimental data, however neither model accurately predicts the TDCS over all geometries and energies

Intermediate energy cross sections for electron-impact vibrational-excitation of pyrimidine

We report differential cross sections (DCSs) and integral cross sections (ICSs) for electron-impact vibrational-excitation of pyrimidine, at incident electron energies in the range 15–50 eV. The scattered electron angular range for the DCS measurements was 15°–90°. The measurements at the DCS-level are the first to be reported for vibrational-excitation in pyrimidine via electron impact, while for the ICS we extend the results from the only previous condensed-phase study [P. L. Levesque, M. Michaud, and L. Sanche, J. Chem. Phys. 122, 094701 (2005)], for electron energies ⩽12 eV, to higher energies. Interestingly, the trend in the magnitude of the lower energy condensed-phase ICSs is much smaller when compared to the corresponding gas phase results. As there is no evidence for the existence of any shape-resonances, in the available pyrimidine total cross sections [Baek et al., Phys. Rev. A 88, 032702 (2013); Fuss et al., ibid. 88, 042702 (2013)], between 10 and 20 eV, this mismatch in absolute magnitude between the condensed-phase and gas-phase ICSs might be indicative for collective-behaviour effects in the condensed-phase results

Spectroscopy of the Potential Profile in a Ballistic Quantum Constriction

We present a theory for the nonlinear current-voltage characteristics of a ballistic quantum constriction. Nonlinear features first develop because of above-barrier reflection from the potential profile, created by impurities in the vicinity of the constriction. The nonlinearity appears on a small voltage scale and makes it possible to determine distances between impurities as well as the magnitude of the impurity potentials.Comment: 3 pages, 4 figures (availiable upon request), REVTEX, Applied Physics Report 93-5