Long-term stability of fibre-optic transmission for multi-object spectroscopy

We present an analysis of the long-term stability of fibre-optic transmission properties for fibre optics in astronomy. Data from 6 years of operation of the AAOmega multi-object spectrograph at the Anglo-Australian Telescope are presented. We find no evidence for significant degradation in the bulk transmission properties of the 38-m optical fibre train. Significant losses (<20 per cent relative, 4 per cent absolute) are identified and associated with the end termination of the optical fibres in the focal plane. Improved monitoring and maintenance can rectify the majority of this performance degradation

Spatially Resolved PAH Emission Features in Nearby, Low Metallicity, Star-Forming Galaxies

Low-resolution, mid-infrared Spitzer/IRS spectral maps are presented for three nearby, low-metallicity dwarf galaxies (NGC 55, NGC 3109 and IC 5152) for the purpose of examining the spatial distribution and variation of polycyclic aromatic hydrocarbon (PAH) emission. The sample straddles a metallicity of 12+log(O/H)~8.0, a transition point below which PAH intensity empirically drops and the character of the interstellar medium changes. We derive quantitative radiances of PAH features and atomic lines on both global and spatially-resolved scales. The Spitzer spectra, combined with extensive ancillary data from the UV through the mid-infrared, allow us to examine changes in the physical environments and in PAH feature radiances down to a physical scale of 50 pc. We discuss correlations between various PAH emission feature and atomic line radiances. The (6.2 micron)/(11.3 micron), (7.7 micron)/(11.3 micron), (8.6 micron)/(11.3 micron), (7.7 micron)/(6.2 micron), and (8.6 micron)/(6.2 micron) PAH radiance ratios are found to be independent of position across all three galaxies, although the ratios do vary from galaxy to galaxy. As seen in other galaxies, we find no variation in the grain size distribution as a function of local radiation field strength. Absolute PAH feature intensities as measured by a ratio of PAH/(24 micron) radiances are seen to vary both positionally within a given galaxy, and from one galaxy to another when integrated over the full observed extent of each system. We examine direct comparisons of CC mode PAH ratios (7.7 micron)/(6.2 micron) and (8.6 micron)/(6.2 micron) to the mixed (CC/CH) mode PAH ratio (7.7 micron)/(11.3 micron). We find little variation in either mode, and no difference in trends between modes. While the local conditions change markedly over the observed regions of these galaxies, the properties of PAH emission show a remarkable degree of uniformity.Comment: Astrophysical Journal, in pres

The M81 Group Dwarf Irregular Galaxy DDO 165. I. High Velocity Neutral Gas in a Post-Starburst System

We present new multi-configuration VLA HI spectral line observations of the M81 group dIrr post-starburst galaxy DDO 165. The HI morphology is complex, with multiple column density peaks surrounding a large region of very low HI surface density that is offset from the center of the stellar distribution. The bulk of the neutral gas is associated with the southern section of the galaxy; a secondary peak in the north contains ~15% of the total HI mass. These components appear to be kinematically distinct, suggesting that either tidal processes or large-scale blowout have recently shaped the ISM of DDO 165. Using spatially-resolved position-velocity maps, we find multiple localized high-velocity gas features. Cross-correlating with radius-velocity analyses, we identify eight shell/hole structures in the ISM with a range of sizes (~400-900 pc) and expansion velocities (~7-11 km/s). These structures are compared with narrow- and broad-band imaging from KPNO and HST. Using the latter data, recent works have shown that DDO 165's previous "burst" phase was extended temporally (>1 Gyr). We thus interpret the high-velocity gas features, HI holes, and kinematically distinct components of the galaxy in the context of the immediate effects of "feedback" from recent star formation. In addition to creating HI holes and shells, extended star formation events are capable of creating localized high velocity motion of the surrounding interstellar material. A companion paper connects the energetics from the HI and HST data.Comment: The Astrophysical Journal, in press. Full-resolution version available on request from the first autho

Evaluation of irradiation and Termin-8® addition to spray-dried animal plasma, base mix and/or whole diet on growth performance of nursery pigs

Two studies were conducted to evaluate the effects of irradiation of spray-dried animal plasma and Termin-8 treatment to spray-dried animal plasma, base mix (specialty protein products, milk products, ground oat groats, soy flour, flow agent, vitamins, and minerals), or whole diet on nursery pig performance. Overall (d 0 to 14) in Exp. 1, pigs fed diets containing irradiated plasma had increased ADG and pigs fed Termin-8® treated plasma had increased ADG and ADFI compared to pigs fed diets with regular plasma or whole diets (containing either regular or irradiated plasma) treated with Termin-8. No differences in F/G were observed among treatments. In Exp. 2, pigs fed diets that contained either animal plasma or base mix treated with Termin-8 in the SEW diet had increased ADG and F/G from d 0 to 13 compared to no Termin-8 treatment, but no differences were observed overall (d 0 to 40). Therefore, the use of irradiated spray-dried animal plasma and Termin-8 treated spray-dried animal plasma and base mix improves growth performance in nursery pigs during the initial period after weaning

Neutrophil–Lymphocyte and Platelet–Lymphocyte Ratios as Prognostic Factors after Stereotactic Radiation Therapy for Early-Stage Non–Small-Cell Lung Cancer

IntroductionThe hematologic indices of neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) are correlated with clinical outcomes after stereotactic radiation.MethodsWe retrospectively evaluated the pretreatment NLR and PLR in patients treated with stereotactic radiation for early stage non–small-cell lung cancer at our institution. A total of 149 patients treated for non–small-cell lung cancer were identified, and 59 had stage I disease with neutrophil, platelet, and lymphocyte levels within a 3-month period before treatment. Receiver operating characteristic (ROC) analysis was performed to examine cutoff values for survival and nonlocal failure followed by Kaplan–Meier analysis for survival.ResultsWith a median follow-up of 17 months, 28 deaths were observed, and the median overall survival for all patients was 43 months. Based on the ROC analysis, NLR and PLR cutoff values for further survival analysis were determined based on the ROC analysis to be 2.98 and 146. The median overall survival was not reached for patients with low NLR or PLR but the survival was 23 months for patients with high NLR or PLR. There was no correlation between NLR and nonlocal failure, but on multivariate analysis PLR was found to be associated with freedom from nonlocal failure. Nonlocal failure rates were 11% for patients with PLR less than 250 and 58% for PLR greater than 250 (p < 0.001).ConclusionThe pretreatment NLR and PLR represented significant prognostic indicators of survival in patients treated for early-stage non–small-cell lung carcinoma with stereotactic radiation. The PLR may be used as a prognostic indicator for nonlocal failure after stereotactic radiation for early-stage lung cancer

The Formation of Kiloparsec-scale HI Holes in Dwarf Galaxies

The origin of kpc-scale holes in the atomic hydrogen (H i) distributions of some nearby dwarf irregular galaxies presents an intriguing problem. Star formation histories (SFHs) derived from resolved stars give us the unique opportunity to study past star-forming events that may have helped shape the currently visible Hi distribution. Our sample of five nearby dwarf irregular galaxies spans over an order of magnitude in both total Hi mass and absolute B-band magnitude and is at the low-mass end of previously studied systems. We use Very Large Array Hi line data to estimate the energy required to create the centrally dominant hole in each galaxy. We compare this energy estimate to the past energy released by the underlying stellar populations computed from SFHs derived from data taken with the Hubble Space Telescope. The inferred integrated stellar energy released within the characteristic ages exceeds our energy estimates for creating the holes in all cases, assuming expected efficiencies. Therefore, it appears that stellar feedback provides sufficient energy to produce the observed holes. However, we find no obvious signature of single star-forming events responsible for the observed structures when comparing the global SFHs of each galaxy in our sample to each other or to those of dwarf irregular galaxies reported in the literature. We also fail to find evidence of a central star cluster in FUV or Hα imaging. We conclude that large Hi holes are likely formed from multiple generations of star formation and only under suitable interstellar medium conditions