918 research outputs found

    New ammonia masers towards NGC6334I

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    We report the detection of new ammonia masers in the non-metastable (8,6) and (11,9) transitions towards the massive star forming region NGC6334I. Observations were made with the ATCA interferometer and the emitting region appears unresolved in the 2.7" x 0.8" beam, with deconvolved sizes less than an arcsecond. We estimate peak brightness temperatures of 7.8 x 10^5 and 1.2 x 10^5 K for the (8,6) and (11,9) transitions, respectively. The masers appear coincident both spatially and in velocity with a previously detected ammonia (6,6) maser. We also suggest that emission in the (10,9), (9,9) and (7,6) transitions may also be masers, based on their narrow line widths and overlapping velocity ranges with the above masers, as observed with the single-dish Mopra radiotelescope

    Job crafting for female contractors in a male-dominated profession

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    In this paper, we explore the job crafting experiences of women who left permanent employment for contracting positions in Information Technology (IT), a sector widely considered male-dominated with limited career opportunities for women. This qualitative study is based on interviews with 24 female IT contractors. Findings show that through the flexibility and autonomy that come with contracting, numerous crafting practices are adopted by female IT contractors enabling them to gain empowerment in a male-dominated environment. The study contributes to in-depth understanding of job crafting theory by showing a reflexive relationship between role and resource crafting for women in alternative forms of employment, especially those with a high degree of autonomy. By engaging directly with the experiences of these female IT contractors, we provide unique insights into what might drive women into IT contracting, and why they often stay with this option owing to the freedom and autonomy offered

    Characterisation of the Mopra Radio Telescope at 16--50 GHz

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    We present the results of a programme of scanning and mapping observations of astronomical masers and Jupiter designed to characterise the performance of the Mopra Radio Telescope at frequencies between 16-50 GHz using the 12-mm and 7-mm receivers. We use these observations to determine the telescope beam size, beam shape and overall telescope beam efficiency as a function of frequency. We find that the beam size is well fit by λ\lambda/DD over the frequency range with a correlation coefficient of ~90%. We determine the telescope main beam efficiencies are between ~48-64% for the 12-mm receiver and reasonably flat at ~50% for the 7-mm receiver. Beam maps of strong H2_2O (22 GHz) and SiO masers (43 GHz) provide a means to examine the radial beam pattern of the telescope. At both frequencies the radial beam pattern reveals the presence of three components, a central `core', which is well fit by a Gaussian and constitutes the telescopes main beam, and inner and outer error beams. At both frequencies the inner and outer error beams extend out to approximately 2 and 3.4 times the full-width half maximum of the main beam respectively. Sources with angular sizes a factor of two or more larger than the telescope main beam will couple to the main and error beams, and therefore the power contributed by the error beams needs to be considered. From measurements of the radial beam power pattern we estimate the amount of power contained in the inner and outer error beams is of order one-fifth at 22 GHz rising slightly to one-third at 43 GHz.Comment: Accepted for publication in PAS

    X-ray and radio observations of central black holes in nearby low-mass early-type galaxies: Preliminary evidence for low Eddington fractions

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    We present new radio and X-ray observations of two nearby (<4< 4 Mpc) low-mass early-type galaxies with dynamically-confirmed central black holes: NGC 5102 and NGC 205. NGC 5102 shows a weak nuclear X-ray source and has no core radio emission. However, for the first time we demonstrate that it shows luminous extended radio continuum emission in low-resolution, low-frequency (<3< 3 GHz) data, consistent with jet lobes on scales 100\gtrsim 100 pc formed from past accretion and jet activity. By contrast, in new, extremely deep, strictly-simultaneous Very Large Array and Chandra observations, no radio or X-ray emission is detected from the black hole in NGC 205. We consider these measurements and upper limits in the context of the few other low-mass early-type galaxies with dynamically-confirmed black holes, and show that the mean ratio of bolometric to Eddington luminosity in this sample is only log(Lbol/LEdd)=6.57±0.50\textrm{log} \, (L_{\rm bol}/L_{\rm Edd}) = -6.57\pm0.50. These Eddington ratios are lower than typical in a comparison sample of more massive early-type galaxies, though this conclusion is quite tentative due to our small sample of low-mass galaxies and potential biases in the comparison sample. This preliminary result is in mild tension with previous work using less sensitive observations of more distant galaxies, which predict higher X-ray luminosities than we observe for low-mass galaxies. If it is confirmed that central black holes in low-mass galaxies typically have low Eddington ratios, this presents a challenge to measuring the occupation fraction of central black holes with standard optical emission line, X-ray, or radio surveys.Comment: 13 pages, 4 figures, 3 tables. Accepted for publication in Ap

    Spitzer-IRAC GLIMPSE of high mass protostellar objects. I Infrared point sources and nebulae

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    The GLIMPSE archive was used to obtain 3.6--8.0micron, point source photometry and images for 381 massive protostellar candidates lying in the Galactic mid-plane. The colours, magnitudes and spectral indicies of sources in each of the 381 target fields were analysed and compared with the predictions of 2D radiative transfer model simulations. Although no discernable embedded clusters were found in any targets, multiple sources or associations of redenned young stellar objects were found in many sources indicating multiplicity at birth. The spectral index (α\alpha) of these point sources in 3.6--8.0mum bands display large values of α\alpha=2--5. A color-magnitude analog plot was used to identify 79 infrared counterparts to the HMPOs. Compact nebulae are found in 75% of the detected sources with morphologies that can be well described by core-halo, cometary, shell-like and bipolar geometries similar to those observed in ultra-compact HII regions. The IRAC band SEDs of the IR counterparts of HMPOs are best described to represent YSOs with a mass range of 8--20\msun in their Class I stages when compared with 2D radiative transfer models. They also suggest that the high α\alpha values represent reprocessed star/star+disk emission that is arising in the dense envelopes. Thus we are witnessing the luminous envelopes around the protostars rather than their photospheres or disks. We argue that the compact infrared nebulae likely reflect the underlying physical structure of the dense cores and are found to imitate the morphologies of known UCHII regions. Our results favour models of continuuing accretion involving both molecular and ionised accretion components to build the most massive stars rather than purely molecular rapid accretion flows.Comment: 13 pages, 7 figures, accepted by A&

    Does the student-led osteopathy clinical learning environment prepare students for practice?

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    BACKGROUND: For many allied health disciplines, pre-professional clinical education takes place in student-led, on-campus clinic environments. In these environments, pre-professional students undertake patient care under the supervision of qualified health professionals. Literature exploring the benefits of the student-led clinical learning environment is limited and little is known about the role student-led clinics play in preparing pre-professional osteopathy students for professional practice. AIM: To explore the perceptions of osteopathy clinical educators about the role of the student-led clinic at Victoria University (VU) in preparing pre-professional students for professional practice. METHODS: A qualitative collective case study methodology was utilised to explore clinical educator perceptions. Individual interviews were conducted with clinical educators employed in the university osteopathy clinic. Interview questions were framed around the Capabilities for Osteopathic Practice which set the Australian osteopathy practice standards. Data were assessed by two of the authors using thematic analysis. RESULTS: Nine clinical educators out of 31 employed at the university clinic (29%) agreed to participate. Qualitative analysis generated three themes: perceptions of the student-led clinic (SLC) as a learning environment; clinical educator perception of their role in the SLC; and, challenges to and of the SLC environment. CONCLUSIONS: Clinical educators perceived that the student-led osteopathy clinical learning environment develops pre-professional learners to meet some, but not all, of the capabilities for professional practice as an osteopath in Australia. The environment may be improved through faculty development, fostering a proactive learning approach, addressing system-based issues, and providing opportunities to interact with other health professions

    Pharmacokinetic profiles for oral and subcutaneous methotrexate in patients with Crohn\u27s disease

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    Background Methotrexate (MTX) is administered subcutaneously to Crohn\u27s Disease (CD) patients. There are very few studies evaluating the use of oral (PO) MTX in CD. A drug and its pharmaceutical alternative are equivalent (bioequivalence) when the bioavailability of the alternative falls within 80-125% of the bioavailability of the standard (US Food and Drug Administration - FDA). Aim To compare the pharmacokinetic (PK) profiles of PO and subcutaneous (SC) MTX in CD patients to determine the bioequivalence of these two routes. Methods Eleven patients received a PO and an SC MTX dose (25 mg) separated by one week over a two-week interval. Blood samples were collected at specified times over a 24-h period for each patient on two separate days. MTX plasma levels were obtained using sensitive mass spectrometry. Areas under the curve (AUC) were compared between the two routes. Results The mean AUC values were 3375 ng/mL × h (PO MTX) and 3985 ng/mL × h (SC MTX). The mean AUC ratio (PO/SC) was 0.86 (0.62-1.08). This correlates with a relative PO bioavailability of 86% in comparison to SC. The 90% confidence interval for the mean AUC (PO/SC) ratio is (0.785, 0.929). There were no adverse events. Conclusions The mean MTX AUC (PO/SC) in these patients falls outside the 90% confidence interval for the bioequivalence limit. SC MTX is more bioavailable than PO MTX; however, the mean relative MTX bioavailability (PO/SC) nearly met the FDA bioequivalence standard and PO MTX could be proposed in responders who would prefer this route. © 2012 Blackwell Publishing Ltd

    Finitely generated free Heyting algebras via Birkhoff duality and coalgebra

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    Algebras axiomatized entirely by rank 1 axioms are algebras for a functor and thus the free algebras can be obtained by a direct limit process. Dually, the final coalgebras can be obtained by an inverse limit process. In order to explore the limits of this method we look at Heyting algebras which have mixed rank 0-1 axiomatizations. We will see that Heyting algebras are special in that they are almost rank 1 axiomatized and can be handled by a slight variant of the rank 1 coalgebraic methods

    Quadratic Forms in Singular Normal Variables

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    16 pages, 1 article*Quadratic Forms in Singular Normal Variables* (Rodhe, C. A.; Urquhart, N. S.; Searle, S. R.) 16 page
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