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We have observed the G23 field of the Galaxy AndMass Assembly (GAMA) survey using the Australian Square Kilometre Array Pathfinder (ASKAP) in its commissioning phase to validate the performance of the telescope and to characterise the detected galaxy populations. This observation covers ~48 deg2 with synthesised beam of 32.7 arcsec by 17.8 arcsec at 936MHz, and ~39 deg2 with synthesised beam of 15.8 arcsec by 12.0 arcsec at 1320MHz. At both frequencies, the root-mean-square (r.m.s.) noise is ~0.1 mJy/beam. We combine these radio observations with the GAMA galaxy data, which includes spectroscopy of galaxies that are i-band selected with a magnitude limit of 19.2. Wide-field Infrared Survey Explorer (WISE) infrared (IR) photometry is used to determine which galaxies host an active galactic nucleus (AGN). In properties including source counts, mass distributions, and IR versus radio luminosity relation, the ASKAP-detected radio sources behave as expected. Radio galaxies have higher stellar mass and luminosity in IR, optical, and UV than other galaxies. We apply optical and IR AGN diagnostics and find that they disagree for ~30% of the galaxies in our sample. We suggest possible causes for the disagreement. Some cases can be explained by optical extinction of the AGN, but for more than half of the cases we do not find a clear explanation. Radio sources aremore likely (~6%) to have an AGN than radio quiet galaxies (~1%), but the majority of AGN are not detected in radio at this sensitivity.
The discovery of the first electromagnetic counterpart to a gravitational wave signal has generated follow-up observations by over 50 facilities world-wide, ushering in the new era of multi-messenger astronomy. In this paper, we present follow-up observations of the gravitational wave event GW170817 and its electromagnetic counterpart SSS17a/DLT17ck (IAU label AT2017gfo) by 14 Australian telescopes and partner observatories as part of Australian-based and Australian-led research programs. We report early- to late-time multi-wavelength observations, including optical imaging and spectroscopy, mid-infrared imaging, radio imaging, and searches for fast radio bursts. Our optical spectra reveal that the transient source emission cooled from approximately 6 400 K to 2 100 K over a 7-d period and produced no significant optical emission lines. The spectral profiles, cooling rate, and photometric light curves are consistent with the expected outburst and subsequent processes of a binary neutron star merger. Star formation in the host galaxy probably ceased at least a Gyr ago, although there is evidence for a galaxy merger. Binary pulsars with short (100 Myr) decay times are therefore unlikely progenitors, but pulsars like PSR B1534+12 with its 2.7 Gyr coalescence time could produce such a merger. The displacement (~2.2 kpc) of the binary star system from the centre of the main galaxy is not unusual for stars in the host galaxy or stars originating in the merging galaxy, and therefore any constraints on the kick velocity imparted to the progenitor are poor.
Housed pigs are exposed chronically to aerial pollutants, principally dust and ammonia, at concentrations that may affect performance, possibly by raising the incidence and prevalence of multi-factorial respiratory diseases. Tolerable limits for aerial pollutants are unknown. The aim of this experiment was to test the hypothesis that chronic exposure of weaner pigs to controlled concentrations of aerial dust and ammonia lead to slower growth and lower feed intake compared with controls kept in ‘fresh air’.
The Taipan galaxy survey (hereafter simply ‘Taipan’) is a multi-object spectroscopic survey starting in 2017 that will cover 2π steradians over the southern sky (δ ≲ 10°, |b| ≳ 10°), and obtain optical spectra for about two million galaxies out to z < 0.4. Taipan will use the newly refurbished 1.2-m UK Schmidt Telescope at Siding Spring Observatory with the new TAIPAN instrument, which includes an innovative ‘Starbugs’ positioning system capable of rapidly and simultaneously deploying up to 150 spectroscopic fibres (and up to 300 with a proposed upgrade) over the 6° diameter focal plane, and a purpose-built spectrograph operating in the range from 370 to 870 nm with resolving power R ≳ 2000. The main scientific goals of Taipan are (i) to measure the distance scale of the Universe (primarily governed by the local expansion rate, H0) to 1% precision, and the growth rate of structure to 5%; (ii) to make the most extensive map yet constructed of the total mass distribution and motions in the local Universe, using peculiar velocities based on improved Fundamental Plane distances, which will enable sensitive tests of gravitational physics; and (iii) to deliver a legacy sample of low-redshift galaxies as a unique laboratory for studying galaxy evolution as a function of dark matter halo and stellar mass and environment. The final survey, which will be completed within 5 yrs, will consist of a complete magnitude-limited sample (i ⩽ 17) of about 1.2 × 106 galaxies supplemented by an extension to higher redshifts and fainter magnitudes (i ⩽ 18.1) of a luminous red galaxy sample of about 0.8 × 106 galaxies. Observations and data processing will be carried out remotely and in a fully automated way, using a purpose-built automated ‘virtual observer’ software and an automated data reduction pipeline. The Taipan survey is deliberately designed to maximise its legacy value by complementing and enhancing current and planned surveys of the southern sky at wavelengths from the optical to the radio; it will become the primary redshift and optical spectroscopic reference catalogue for the local extragalactic Universe in the southern sky for the coming decade.
Longitudinal maternal mental health data are needed from high HIV prevalence settings. The Siyakhula Cohort (SC) is a population-based cohort of HIV-positive and negative mothers (n=1506) with HIV-negative children (n=1536) from rural South Africa. SC includes 767 HIV-negative mothers; 465 HIV-positive in pregnancy; 272 HIV-positive since pregnancy (n=2 missing HIV status). A subgroup (n=890) participated in a non-randomized breastfeeding intervention [Vertical Transmission Study (VTS)]; the remaining (n=616) were resident in the same area and received antenatal care at the time of the VTS, but were not part of the VTS, instead receiving the standard of care Prevention of Mother-to-Child Transmission (PMTCT) Programme. In secondary analysis we investigated the prevalence of, and factors associated with, psychological morbidity amongst mothers who were still the primary caregiver of the child (1265 out of 1506) at follow-up (7–11 years post-birth). We measured maternal depression (Patient Health Questionnaire-9), anxiety (General Anxiety Disorder Scale-7) and parenting stress (Parenting Stress Index-36), using standardized cut-offs and algorithms. In total, 75 (5.9%) mothers met criteria for depression, 37 (2.9%) anxiety and 134 (10.6%) parenting stress. Using complete case logistic regression (n=1206 out of 1265 mothers) as compared to being HIV-negative, testing HIV-positive in pregnancy doubled odds of depression [adjusted odd ratios (aOR)=1.96 [1.0–3.7] P=0.039]. Parenting stress was positively associated with acquisition of HIV after pregnancy (aOR=3.11 [1.9–5.2] P<0.001) and exposure to household crime (aOR=2.02 [1.3–3.2] P=0.003); negatively associated with higher maternal education (aOR=0.29 [0.1–0.8] P=0.014), maternal employment (aOR=0.55 [0.3–0.9] P=0.024). Compared with the standard of care PMTCT, VTS mothers had reduced odds of parenting stress (aOR=0.61 [0.4–0.9] P=0.016). Integrating parental support into mostly bio-medical treatment programmes, during and beyond pregnancy, is important.
The ABS surveys of 1981 and 1988 show that within the total population of handicapped persons a number of families with dependents have one or both parents who are handicapped. Also included within this group are lone handicapped parents and families who have in addition some other non-dependent handicapped person living with them. Besides the usual socio-economic problems surrounding disabling conditions this group are also faced with the difficulties associated with the everyday tasks of parenting. Yet, judging by the professional and research literature, they have received scant attention here in Australia or elsewhere.
This paper reports the results of a small qualitative pilot study of 19 families in which one of the parents had some physical handicap and which examined the everyday parenting tasks faced by them. It reports on some of the difficulties they experienced and also the affirmative action they took to overcome those difficulties.
Receiving an education is essential for children living in poverty to fulfil their potential. Success in the early years of schooling is important as children who repeat grade one are particularly at risk for future dropout. We examined early life factors associated with grade repetition through logistic regression and explored reasons for repeating a grade through parent report. In 2012–2014 we re-enrolled children aged 7–11 years in rural KwaZulu-Natal who had been part of an early life intervention. Of the 894 children included, 43.1% had repeated a grade, of which 62.9% were boys. Higher maternal education (aOR 0.44; 95% CI 0.2–0.9) and being further along in the birth order (aOR 0.46; 95% CI 0.3–0.9) reduced the odds of grade repetition. In addition, maternal HIV status had the strongest effect on grade repetition for girls (aOR 2.17; 95% CI 1.3–3.8), whereas for boys, it was a fridge in the household (aOR 0.59; 95% CI 0.4–1.0). Issues with school readiness was the most common reason for repeating a grade according to parental report (126/385, 32.7%), while school disruptions was an important reason among HIV-exposed boys. Further research is needed to elucidate the pathways through which HIV affects girls’ educational outcomes and potentially impacts on disrupted schooling for boys. Our results also highlight the importance of preparation for schooling in the early years of life; future research could focus on gaining a better understanding of mechanisms by which to improve early school success, including increased quality of reception year and investigating the protective effect of older siblings.
A gas-filled cylindrical liner z-pinch configuration has been used to drive convergent radiative shock waves into different gases at velocities of 20–50 km s−1. On application of the 1.4 MA, 240 ns rise-time current pulse produced by the Magpie generator at Imperial College London, a series of cylindrically convergent shock waves are sequentially launched into the gas-fill from the inner wall of the liner. This occurs without any bulk motion of the liner wall itself. The timing and trajectories of the shocks are used as a diagnostic tool for understanding the response of the liner z-pinch wall to a large pulsed current. This analysis provides useful data on the liner resistivity, and a means to test equation of state (EOS) and material strength models within MHD simulation codes. In addition to providing information on liner response, the convergent shocks are interesting to study in their own right. The shocks are strong enough for radiation transport to influence the shock wave structure. In particular, we see evidence for both radiative preheating of material ahead of the shockwaves and radiative cooling instabilities in the shocked gas. Some preliminary results from initial gas-filled liner experiments with an applied axial magnetic field are also discussed.
PILOT (the Pathfinder for an International Large Optical Telescope) is a proposed 2.5-m optical/infrared telescope to be located at Dome C on the Antarctic plateau. The atmospheric conditions at Dome C deliver a high sensitivity, high photometric precision, wide-field, high spatial resolution, and high-cadence imaging capability to the PILOT telescope. These capabilities enable a unique scientific potential for PILOT, which is addressed in this series of papers. The current paper presents a series of projects dealing with the nearby Universe that have been identified as key science drivers for the PILOT facility. Several projects are proposed that examine stellar populations in nearby galaxies and stellar clusters in order to gain insight into the formation and evolution processes of galaxies and stars. A series of projects will investigate the molecular phase of the Galaxy and explore the ecology of star formation, and investigate the formation processes of stellar and planetary systems. Three projects in the field of exoplanet science are proposed: a search for free-floating low-mass planets and dwarfs, a program of follow-up observations of gravitational microlensing events, and a study of infrared light-curves for previously discovered exoplanets. Three projects are also proposed in the field of planetary and space science: optical and near-infrared studies aimed at characterising planetary atmospheres, a study of coronal mass ejections from the Sun, and a monitoring program searching for small-scale Low Earth Orbit satellite debris items.
PILOT (the Pathfinder for an International Large Optical Telescope) is a proposed 2.5-m optical/infrared telescope to be located at Dome C on the Antarctic plateau. Conditions at Dome C are known to be exceptional for astronomy. The seeing (above ∼30 m height), coherence time, and isoplanatic angle are all twice as good as at typical mid-latitude sites, while the water-vapour column, and the atmosphere and telescope thermal emission are all an order of magnitude better. These conditions enable a unique scientific capability for PILOT, which is addressed in this series of papers. The current paper presents an overview of the optical and instrumentation suite for PILOT and its expected performance, a summary of the key science goals and observational approach for the facility, a discussion of the synergies between the science goals for PILOT and other telescopes, and a discussion of the future of Antarctic astronomy. Paper II and Paper III present details of the science projects divided, respectively, between the distant Universe (i.e. studies of first light, and the assembly and evolution of structure) and the nearby Universe (i.e. studies of Local Group galaxies, the Milky Way, and the Solar System).
The cold, dry, and stable air above the summits of the Antarctic plateau provides the best ground-based observing conditions from optical to sub-millimetre wavelengths to be found on the Earth. Pathfinder for an International Large Optical Telescope (PILOT) is a proposed 2 m telescope, to be built at Dome C in Antarctica, able to exploit these conditions for conducting astronomy at optical and infrared wavelengths. While PILOT is intended as a pathfinder towards the construction of future grand-design facilities, it will also be able to undertake a range of fundamental science investigations in its own right. This paper provides the performance specifications for PILOT, including its instrumentation. It then describes the kinds of projects that it could best conduct. These range from planetary science to the search for other solar systems, from star formation within the Galaxy to the star formation history of the Universe, and from gravitational lensing caused by exo-planets to that produced by the cosmic web of dark matter. PILOT would be particularly powerful for wide-field imaging at infrared wavelengths, achieving near diffraction-limited performance with simple tip–tilt wavefront correction. PILOT would also be capable of near diffraction-limited performance in the optical wavebands, as well be able to open new wavebands for regular ground-based observation, in the mid-IR from 17 to 40 μm and in the sub-millimetre at 200 μm.
Properties of radiatively cooled supersonic plasma jets formed by ablation of thin Al
foils driven by 1.4 MA, 250 ns current pulse are presented. The jets are highly collimated
with half-opening angles of ~2°. Measurements of the flow velocity (~60
km/s) and plasma temperature (~15 eV) in the jet with Thomson scattering diagnostic
give internal Mach number of M ~ 3, suggesting additional collimation of the jet by
toroidal magnetic fields.
The formation of supersonic, radiatively cooled plasma jets with applications to
laboratory astrophysics has been an active area of research on the MAGPIE generator. One
of the ways of producing astrophysically-relevant jets in the laboratory is by using the
ablation of plasma from a radial foil Z-pinch. In this configuration a ~1.4 MA, 250
ns current pulse is introduced into an aluminium disk with a thickness of 15
μm. The ablated plasma from the foil converges on the axis, producing a
steady and collimated jet with a typical axial velocity of ~100 km/s. The setup
allows for the addition of argon above the foil for jet-ambient interaction studies. The
interaction is characterised by the formation of several shock features, which are
presented and discussed from experimental data and numerical simulations.
A survey of the Milky Way disk and the Magellanic System at the wavelengths of the 21-cm atomic hydrogen (H i) line and three 18-cm lines of the OH molecule will be carried out with the Australian Square Kilometre Array Pathfinder telescope. The survey will study the distribution of H i emission and absorption with unprecedented angular and velocity resolution, as well as molecular line thermal emission, absorption, and maser lines. The area to be covered includes the Galactic plane (|b| < 10°) at all declinations south of δ = +40°, spanning longitudes 167° through 360°to 79° at b = 0°, plus the entire area of the Magellanic Stream and Clouds, a total of 13 020 deg2. The brightness temperature sensitivity will be very good, typically σT≃ 1 K at resolution 30 arcsec and 1 km s−1. The survey has a wide spectrum of scientific goals, from studies of galaxy evolution to star formation, with particular contributions to understanding stellar wind kinematics, the thermal phases of the interstellar medium, the interaction between gas in the disk and halo, and the dynamical and thermal states of gas at various positions along the Magellanic Stream.
A widely held view is that a “mini halo” with much less than 108M⊙ in dark matter is unlikely to retain any baryons because even a single SN event is expected to sweep out all of the gas. But we show that a clumpy medium is much less susceptible to SN sweeping (particularly if it is off-centred) because the coupling efficiency of the explosive energy is much lower than for a diffuse interstellar medium. With the aid of the sophisticated 3D hydro code Fyris, we show that baryons are retained and stars are formed in dark matter haloes down to 3 × 106M⊙. The gas survives the SN explosion and is enriched with specific abundance yields of the discrete events. The smallest galaxies may not contribute a large fraction of baryons and dark matter to the formation of galaxies. But they are likely to carry important chemical signatures that were laid down in the earliest epochs of star formation, as we show. We discuss the results in light of the newly discovered, very metal poor, damped Lyα systems and ultra-faint dwarf galaxies.
We have recently carried out MOCVD experiments that showed for the first time the doping of AlN thin films with manganese. Films of AlN that were doped with less than 0.1% of manganese showed emission bands at 427 nm, 488 nm and 600 nm in accordance with previous published excitation and emission spectra of manganese incorporated in bulk A1N. A film with a higher percentage of manganese (1.7%) grown on top of a pure A1N layer (underlayer) showed weak emission at 601 nm. A portion of the underlayer not covered during growth of the overlayer has a very strong emission band at 408 nm and a weaker band at 605 nm. SIMS and EDX analyses of this film revealed both carbon and oxygen contamination as well as diffusion of manganese into the A1N underlayer. The band at 408 nm is associated with direct gap emission from oxygen contaminated A1N and the band at 605 nm is from manganese incorporated by diffusion into the A1N underlayer.
Many semiconductor processes, Organometallic Vapor Phase Epitaxy (OMVPE) in this case, require the use of concentrated hydride sources. The toxicity of many of these compounds (e.g. arsine, diborane) and the pyrophoric nature of others (phosphine and silane) demand that the facility provide both environmental protection and a safe work place. A facility is described which meets stringent environmental emission standards from NY State's Department of Environmental Conservation. The outlined approach also sets new standards for hydride storage and containment, laboratory alarm systems, exhaust gas treatment and dilution, and process integration into the facility. Under normal operation, we demonstrate hydride emissions of less than 10−5 ppb at the exhaust stack.
Collaborative care is an effective intervention for depression which includes both organizational and patient-level intervention components. The effect in the UK is unknown, as is whether cluster- or patient-randomization would be the most appropriate design for a Phase III clinical trial.
We undertook a Phase II patient-level randomized controlled trial in primary care, nested within a cluster-randomized trial. Depressed participants were randomized to ‘collaborative care’ – case manager-coordinated medication support and brief psychological treatment, enhanced specialist and GP communication – or a usual care control. The primary outcome was symptoms of depression (PHQ-9).
We recruited 114 participants, 41 to the intervention group, 38 to the patient randomized control group and 35 to the cluster-randomized control group. For the intervention compared to the cluster control the PHQ-9 effect size was 0.63 (95% CI 0.18–1.07). There was evidence of substantial contamination between intervention and patient-randomized control participants with less difference between the intervention group and patient-randomized control group (−2.99, 95% CI −7.56 to 1.58, p=0.186) than between the intervention and cluster-randomized control group (−4.64, 95% CI −7.93 to −1.35, p=0.008). The intra-class correlation coefficient for our primary outcome was 0.06 (95% CI 0.00–0.32).
Collaborative care is a potentially powerful organizational intervention for improving depression treatment in UK primary care, the effect of which is probably partly mediated through the organizational aspects of the intervention. A large Phase III cluster-randomized trial is required to provide the most methodologically accurate test of these initial encouraging findings.