Effect of Corn Type and Form of Supplement on Grazing Steers

Eighty stocker steers were grazed on bromegrass from April to the beginning of November and were provided five different feeds while on grass during the summer. Treatments evaluated included (1) mineral only; (2) free-choice supplementation in the form of liquid feed (MIX30) or (3) block format (Mintrate 40 Red); and hand-fed supplements of 60% corn:40% dried distillers grains at 0.5% of body weight on a dry matter basis offered daily where the corn was either an (4) isoline corn (ISO; parent genetic line) or (5) Enogen feed corn (ENO; includes alpha-amylase gene). Steers were weighed every 28 days while on grass and were carcass quality measured by ultrasound prior to placement in the feedlot. Hand-fed steers had greater gain than self-fed supplemented steers and these steers also had more backfat and tended to have more muscle depth coming off grass than other supplemented steers. Steers that received free-choice mineral or self-fed supplements also had lower gains than steers being hand-fed supplement. Within the first 28 days of the study, the hand-fed steers began weighing more and weighed 125 pounds more than the free-choice supplemented and control steers. On average hand-fed steers had a 0.6 lb/d greater ADG than control steers and those consuming free-choice supplement. Cost of gain was the highest with hand-fed steers at $0.27/pound, but even so profit was greatest with the hand-fed cattle

Magnetic Confinement, MHD Waves, and Smooth Line Profiles in AGN

In this paper, we show that if the broad line region clouds are in approximate energy equipartition between the magnetic field and gravity, as hypothesized by Rees, there will be a significant effect on the shape and smoothness of broad emission line profiles in active galactic nuclei. Line widths of contributing clouds or flow elements are much wider than their thermal widths, due to the presence of non-dissipative MHD waves, and their collective contribution produce emission line profiles broader and smoother than would be expected if a magnetic field were not present. As an illustration, a simple model of isotropically emitting clouds, normally distributed in velocity, is used to show that smoothness can be achieved for less than 80,000 clouds and may even be as low as a few hundred. We conclude that magnetic confinement has far reaching consequences for observing and modeling active galactic nuclei.Comment: to appear in MNRA

Complex X-ray Absorption and the Fe Kalpha Profile in NGC 3516

We present data from simultaneous Chandra, XMM-Newton and BeppoSAX observations of the Seyfert 1 galaxy NGC 3516, taken during 2001 April and Nov. We have investigated the nature of the very flat observed X-ray spectrum. Chandra grating data show the presence of X-ray absorption lines, revealing two distinct components of the absorbing gas, one which is consistent with our previous model of the UV/X-ray absorber while the other, which is outflowing at a velocity of ~1100 km/s has a larger column density and is much more highly ionized. The broad-band spectral characteristics of the X-ray continuum observed with XMM during 2001 April, reveal the presence of a third layer of absorption consisting of a very large column (~2.5 x 10E23 cm^-2) of highly ionized gas with a covering fraction ~50%. This low covering fraction suggests that the absorber lies within a few lt-days of the X-ray source and/or is filamentary in structure. Interestingly, these absorbers are not in thermal equilibrium with one another. The two new components are too highly ionized to be radiatively accelerated, which we suggest is evidence for a hydromagnetic origin for the outflow. Applying our model to the Nov dataset, we can account for the spectral variability primarily by a drop in the ionization states of the absorbers, as expected by the change in the continuum flux. When this complex absorption is accounted for we find the underlying continuum to be typical of Seyfert 1 galaxies. The spectral curvature attributed to the high column absorber, in turn, reduces estimates of the flux and extent of any broad Fe emission line from the accretion disk.Comment: 33 pages, 9 figures, accepted for publication in Ap

Evaluation of Implants, Clover, and Fescue Variety on Stocker Steers – Year 2

Sixty-four growing steers were used in a split-plot experiment, where the whole plot was pasture, and the split-plot was the implant level. Whole plot treatment was a 4 × 2 factorial with four levels of fescue (High Endophyte, Low Endophyte, Novel, or Endophyte Free) and two levels of legume (Legumes or No Legumes). The split-plot included four implant levels (No Implant, Synovex One Grass, Revalor-G, or Ralgro). Data collected were weights, hair coat scores, hair length, rectal temperature (every 28 days), and ultrasound carcass characteristics when steers were coming off grass. Steers on High Endophyte had the lowest average daily gain (ADG) and final weight and smallest loin muscle as compared to steers on all other fescue types. The gain differentiation was observed beginning at day 56 through the end of the study. Overall, ADG was not impacted by the addition of legume. Steers that were implanted with Synovex One Grass had a greater gain, final weight, and lower hair score as compared to non-implanted steers. For many of the other measures, steers implanted with Ralgro or Revalor-G resulted in changes between non-implanted steers and those receiving Synovex One Grass. Steers on high endophyte fescue had greater final weight and ADG than non-implanted steers or those receiving Ralgro, with Synovex One Grass being intermediate. Gains for steers on endophyte free pastures were also impacted by the type of implant where Synovex One Grass steers had greater gains than non-implanted and Revalor-G steers, with Ralgro being intermediate. In this second year of research, the use of low to no endophyte fescue and the addition of implants increased gains

Multi-dimensional modelling of X-ray spectra for AGN accretion-disk outflows III: application to a hydrodynamical simulation

We perform multi-dimensional radiative transfer simulations to compute spectra for a hydrodynamical simulation of a line-driven accretion disk wind from an active galactic nucleus. The synthetic spectra confirm expectations from parameterized models that a disk wind can imprint a wide variety of spectroscopic signatures including narrow absorption lines, broad emission lines and a Compton hump. The formation of these features is complex with contributions originating from many of the different structures present in the hydrodynamical simulation. In particular, spectral features are shaped both by gas in a successfully launched outflow and in complex flows where material is lifted out of the disk plane but ultimately falls back. We also confirm that the strong Fe Kalpha line can develop a weak, red-skewed line wing as a result of Compton scattering in the outflow. In addition, we demonstrate that X-ray radiation scattered and reprocessed in the flow has a pivotal part in both the spectrum formation and determining the ionization conditions in the wind. We find that scattered radiation is rather effective in ionizing gas which is shielded from direct irradiation from the central source. This effect likely makes the successful launching of a massive disk wind somewhat more challenging and should be considered in future wind simulations.Comment: 14 pages, 8 figures. Accepted for publication by MNRA

Dynamics of Warm-Absorbing Gas in Seyfert Galaxies: NGC 5548

A hydromagnetic (MHD) wind from a clumpy molecular accretion disk is invoked to explain observations of warm absorbing (WA) gas in UVX from Sy galaxies. This paper focuses on two issues: (1) compatibility of kinematics and dynamics of MHD wind with the observed properties of WAs; and (2) relationship between the UVX absorptions. We provide an in-depth comparison between the MHD model and the Sy 1 galaxy NGC 5548, which at high spectral resolution exhibits a number of discrete UV absorption components. We find that: (1) the total column densities of Ovii, Oviii and H, are reproduced by constraining the UV ion column densities of Civ and Nv in each component to lie within a factor of 2 of their observed values and optimizing over the possible sets of component ionization states and Civ column densities; (2) the WA exists in the outer part of the wind and is not a continuation of the flow in the BLR; and (3) the WA extends in radial and polar directions and is ionization-stratified. X-ray absorption is found to be heavily biased towards smaller r, and UV absorption originates at larger distances from the central continuum source. We show that the discrete absorption components along the line-of-sight are intrinsically clumpy. Density differences between kinematic components result in a range of ionization and recombination timescales. We further test the applicability of the MHD wind to WAs in general, by constructing a quasi-continuous flow model, and extending it to arbitrary aspect angles. We estimate the fraction of Sy 1s having detectable WAs with larger Ovii column density than Oviii, and the range of total H column densities. We also find that the ratio of Ovii to Oviii optical depths can serve as a new diagnostic of AGN aspect angle.Comment: Latex, 8 postscript figures. Astrophysical Journal, 536, June 10, in pres

X-Ray/Ultraviolet Observing Campaign of the Markarian 279 Active Galactic Nucleus Outflow: a close look at the absorbing/emitting gas with Chandra-LETGS

We present a Chandra-LETGS observation of the Seyfert 1 galaxy Mrk 279. This observation was carried out simultaneously with HST-STIS and FUSE, in the context of a multiwavelength study of this source. The Chandra pointings were spread over ten days for a total exposure time of ~360 ks. The spectrum of Mrk279 shows evidence of broad emission features, especially at the wavelength of the OVII triplet. We quantitatively explore the possibility that this emission is produced in the broad line region (BLR). We modeled the broad UV emission lines seen in the FUSE and HST-STIS spectra following the ``locally optimally emitting cloud" approach. We find that the X-ray lines luminosity derived from the best fit BLR model can match the X-ray features, suggesting that the gas producing the UV lines is sufficient to account also for the X-ray emission. The spectrum is absorbed by ionized gas whose total column density is ~5x10^{20} cm^{-2}. The absorption spectrum can be modeled by two distinct gas components (log xi ~ 0.47 and 2.49, respectively) both showing a significant outflow velocity. However, the data allow also the presence of intermediate ionization components. The distribution of the column densities of such extra components as a function of the ionization parameter is not consistent with a continuous, power law-like, absorber, suggesting a complex structure for the gas outflow for Mrk 279 (abridged).Comment: 16 pages, 12 figures. To appear in A&

High-resolution X-ray spectroscopy of the low and high states of the Seyfert 1 galaxy NGC 4051 with Chandra LETGS

Methods. We analyse two observations taken with the Low Energy Transmission Grating Spectrometer of Chandra. We investigated the spectral response to a sudden flux decrease by a factor of 5, which occurred during the second observation. Results. We detect a highly ionised absorption component with an outflow velocity of -4670 km/s, one of the highest outflow velocity components observed in a Seyfert 1 galaxy. The spectra contain a relativistic O VIII Ly alpha line, and four absorption components spanning a range in ionisation parameter xi between 0.07 and 3.19. An emission component producing radiative recombination continua of C VI and C V appears during the low state. The black body temperature decreases with the drop in flux observed in the second observation. Conclusions. For all absorber components we exclude that the ionisation parameter linearly responded to the decrease in flux by a factor of 5. The variability of the absorber suggest that at least three out of four detected components are located in the range 0.02-1 pc. ABRIDGEDComment: Accepted by A&A, 14 pages, 9 figure

Young women's responses to smoking and breast cancer risk information

Current evidence confirms that young women who smoke or who have regular long-term exposure to secondhand smoke (SHS) have an increased risk of developing premenopausal breast cancer. The aim of this research was to examine the responses of young women to health information about the links between active smoking and SHS exposure and breast cancer and obtain their advice about messaging approaches. Data were collected in focus groups with 46 women, divided in three age cohorts: 15–17, 18–19 and 20–24 and organized according to smoking status (smoking, non-smoking and mixed smoking status groups). The discussion questions were preceded by information about passive and active smoking and its associated breast cancer risk. The study findings show young women's interest in this risk factor for breast cancer. Three themes were drawn from the analysis: making sense of the information on smoking and breast cancer, personal susceptibility and tobacco exposure and suggestions for increasing awareness about tobacco exposure and breast cancer. There was general consensus on framing public awareness messages about this risk factor on ‘protecting others’ from breast cancer to catch smokers’ attention, providing young women with the facts and personal stories of breast cancer to help establish a personal connection with this information and overcome desensitization related to tobacco messages, and targeting all smokers who may place young women at risk. Cautions were also raised about the potential for stigmatization. Implications for raising awareness about this modifiable risk factor for breast cancer are discussed