1,686 research outputs found

    Deep Near-Infrared Observations of L1014: Revealing the nature of the core and its embedded source

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    Recently, the Spitzer Space Telescope discovered L1014-IRS, a mid-infrared source with protostellar colors, toward the heretofore "starless" core L1014. We present deep near-infrared observations that show a scattered light nebula extending from L1014-IRS. This nebula resembles those typically associated with protostars and young stellar objects, tracing envelope cavities presumably evacuated by an outflow. The northern lobe of the nebula has an opening angle of ~100 degrees, while the southern lobe is barely detected. Its morphology suggests that the bipolar cavity and inferred protostellar disk is not inclined more than 30 degrees from an edge-on orientation. The nebula extends at least 8" from the source at Ks, strongly suggesting that L1014-IRS is embedded within L1014 at a distance of 200 pc rather than in a more distant cloud associated with the Perseus arm at 2.6 kpc. In this case, the apparently low luminosity of L1014-IRS, 0.090 Lsun, is consistent with it having a substellar mass. However, if L1014-IRS is obscured by a circumstellar disk, its luminosity and inferred mass may be greater. Using near-infrared colors of background stars, we investigate characteristics of the L1014 molecular cloud core. We determine a mass of 3.6 Msun for regions of the core with Av > 2 magnitudes. A comparison of the radial extinction profile of L1014 with other cores suggests that L1014 may be among the most centrally condensed cores known, perhaps indicative of the earliest stages of brown dwarf or star formation processes.Comment: Replacement includes revision to mass of core. 22 pages, 6 figures. Accepted by Ap

    Endemic invasive amoebiasis in northern Australia

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    In October 2000, a 10-year-old Aboriginal boy from the Darwin region of the Northern Territory was referred to hospital with a 24-hour history of abdominal pain, initially generalised, but then localising to the right iliac fossa. The pain was accompanied by occasional vomiting, but no fever or diarrhoea was noted. At laparotomy, a gangrenous, unruptured appendix was removed. Postoperatively, the patient made a good recovery. Neither he nor any family members had travelled outside the Northern Territory.Histological sections of the surgical specimen showed changes typical of acute suppurative appendicitis. Closer examination, however, revealed numerous round-to-oval structures resembling trophozoites (see Box). When the possibility of invasive amoebiasis was raised, staining of the section with Entamoeba histolytica-specific sera confirmed the diagnosis. E. histolytica serology was negative

    Orbit image analysis machine learning software can be used for the histological quantification of acute ischemic stroke blood clots

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    Our aim was to assess the utility of a novel machine learning software (Orbit Image Analysis) in the histological quantification of acute ischemic stroke (AIS) clots. We analyzed 50 AIS blood clots retrieved using mechanical thrombectomy procedures. Following HandE staining, quantification of clot components was performed by two different methods: a pathologist using a reference standard method (Adobe Photoshop CC) and an experienced researcher using Orbit Image Analysis. Following quantification, the clots were categorized into 3 types: RBC dominant (\u3e/=60% RBCs), Mixed and Fibrin dominant ( \u3e /=60% Fibrin). Correlations between clot composition and Hounsfield Units density on Computed Tomography (CT) were assessed. There was a significant correlation between the components of clots as quantified by the Orbit Image Analysis algorithm and the reference standard approach (rho = 0.944**, p \u3c 0.001, n = 150). A significant relationship was found between clot composition (RBC-Rich, Mixed, Fibrin-Rich) and the presence of a Hyperdense artery sign using the algorithmic method (X2(2) = 6.712, p = 0.035*) but not using the reference standard method (X2(2) = 3.924, p = 0.141). Orbit Image Analysis machine learning software can be used for the histological quantification of AIS clots, reproducibly generating composition analyses similar to current reference standard methods

    A Prospective Longitudinal Study of the Clinical Outcomes from Cryptococcal Meningitis following Treatment Induction with 800 mg Oral Fluconazole in Blantyre, Malawi

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    Introduction: Cryptococcal meningitis is the most common neurological infection in HIV infected patients in Sub Saharan Africa, where gold standard treatment with intravenous amphotericin B and 5 flucytosine is often unavailable or difficult to administer. Fluconazole monotherapy is frequently recommended in national guidelines but is a fungistatic drug compromised by uncertainty over optimal dosing and a paucity of clinical end-point outcome data. Methods: From July 2010 until March 2011, HIV infected adults with a first episode of cryptococcal meningitis were recruited at Queen Elizabeth Central Hospital, Blantyre, Malawi. Patients were treated with oral fluconazole monotherapy 800 mg daily, as per national guidelines. ART was started at 4 weeks. Outcomes and factors associated with treatment failure were assessed 4, 10 and 52 weeks after fluconazole initiation. Results: Sixty patients were recruited. 26/60 (43%) died by 4 weeks. 35/60 (58.0%) and 43/56 (77%) died or failed treatment by 10 or 52 weeks respectively. Reduced consciousness (Glasgow Coma Score ,14 of 15), moderate/severe neurological disability (modified Rankin Score .3 of 5) and confusion (Abbreviated Mental Test Score ,8 of 10) were all common at baseline and associated with death or treatment failure. ART prior to recruitment was not associated with better outcomes. Conclusions: Mortality and treatment failure from cryptococcal meningitis following initiation of treatment with 800 mg oral fluconazole is unacceptably high. To improve outcomes, there is an urgent need for better therapeutic strategies and point-of-care diagnostics, allowing earlier diagnosis before development of neurological deficit

    Evolution in the Disks and Bulges of Group Galaxies since z=0.4

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    We present quantitative morphology measurements of a sample of optically selected group galaxies at 0.3 < z < 0.55 using the Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS) and the GIM2D surface brightness--fitting software package. The group sample is derived from the Canadian Network for Observational Cosmology Field Redshift survey (CNOC2) and follow-up Magellan spectroscopy. We compare these measurements to a similarly selected group sample from the Millennium Galaxy Catalogue (MGC) at 0.05 < z < 0.12. We find that, at both epochs, the group and field fractional bulge luminosity (B/T) distributions differ significantly, with the dominant difference being a deficit of disk--dominated (B/T < 0.2) galaxies in the group samples. At fixed luminosity, z=0.4 groups have ~ 5.5 +/- 2 % fewer disk--dominated galaxies than the field, while by z=0.1 this difference has increased to ~ 19 +/- 6 %. Despite the morphological evolution we see no evidence that the group environment is actively perturbing or otherwise affecting the entire existing disk population. At both redshifts, the disks of group galaxies have similar scaling relations and show similar median asymmetries as the disks of field galaxies. We do find evidence that the fraction of highly asymmetric, bulge--dominated galaxies is 6 +/- 3 % higher in groups than in the field, suggesting there may be enhanced merging in group environments. We replicate our group samples at z=0.4 and z=0 using the semi-analytic galaxy catalogues of Bower et al (2006). This model accurately reproduces the B/T distributions of the group and field at z=0.1. However, the model does not reproduce our finding that the deficit of disks in groups has increased significantly since z=0.4.Comment: Accepted for publication in MNRAS. 20 pages, 17 figure

    Large‐Amplitude Mountain Waves in the Mesosphere Observed on 21 June 2014 During DEEPWAVE: 1.Wave Development, Scales, Momentum Fluxes, and Environmental Sensitivity

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    A remarkable, large‐amplitude, mountain wave (MW) breaking event was observed on the night of 21 June 2014 by ground‐based optical instruments operated on the New Zealand South Island during the Deep Propagating Gravity Wave Experiment (DEEPWAVE). Concurrent measurements of the MW structures, amplitudes, and background environment were made using an Advanced Mesospheric Temperature Mapper, a Rayleigh Lidar, an All‐Sky Imager, and a Fabry‐Perot Interferometer. The MW event was observed primarily in the OH airglow emission layer at an altitude of ~82 km, over an ~2‐hr interval (~10:30–12:30 UT), during strong eastward winds at the OH altitude and above, which weakened with time. The MWs displayed dominant horizontal wavelengths ranging from ~40 to 70 km and temperature perturbation amplitudes as large as ~35 K. The waves were characterized by an unusual, “saw‐tooth” pattern in the larger‐scale temperature field exhibiting narrow cold phases separating much broader warm phases with increasing temperatures toward the east, indicative of strong overturning and instability development. Estimates of the momentum fluxes during this event revealed a distinct periodicity (~25 min) with three well‐defined peaks ranging from ~600 to 800 m2/s2, among the largest ever inferred at these altitudes. These results suggest that MW forcing at small horizontal scales (km) can play large roles in the momentum budget of the mesopause region when forcing and propagation conditions allow them to reach mesospheric altitudes with large amplitudes. A detailed analysis of the instability dynamics accompanying this breaking MW event is presented in a companion paper, Fritts et al. (2019, https://doi.org/10.1029/2019jd030899)

    Sloan Digital Sky Survey Imaging of Low Galactic Latitude Fields: Technical Summary and Data Release

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    The Sloan Digital Sky Survey (SDSS) mosaic camera and telescope have obtained five-band optical-wavelength imaging near the Galactic plane outside of the nominal survey boundaries. These additional data were obtained during commissioning and subsequent testing of the SDSS observing system, and they provide unique wide-area imaging data in regions of high obscuration and star formation, including numerous young stellar objects, Herbig-Haro objects and young star clusters. Because these data are outside the Survey regions in the Galactic caps, they are not part of the standard SDSS data releases. This paper presents imaging data for 832 square degrees of sky (including repeats), in the star-forming regions of Orion, Taurus, and Cygnus. About 470 square degrees are now released to the public, with the remainder to follow at the time of SDSS Data Release 4. The public data in Orion include the star-forming region NGC 2068/NGC 2071/HH24 and a large part of Barnard's loop.Comment: 31 pages, 9 figures (3 missing to save space), accepted by AJ, in press, see http://photo.astro.princeton.edu/oriondatarelease for data and paper with all figure

    Garden and landscape-scale correlates of moths of differing conservation status: significant effects of urbanization and habitat diversity

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    Moths are abundant and ubiquitous in vegetated terrestrial environments and are pollinators, important herbivores of wild plants, and food for birds, bats and rodents. In recent years, many once abundant and widespread species have shown sharp declines that have been cited by some as indicative of a widespread insect biodiversity crisis. Likely causes of these declines include agricultural intensification, light pollution, climate change, and urbanization; however, the real underlying cause(s) is still open to conjecture. We used data collected from the citizen science Garden Moth Scheme (GMS) to explore the spatial association between the abundance of 195 widespread British species of moth, and garden habitat and landscape features, to see if spatial habitat and landscape associations varied for species of differing conservation status. We found that associations with habitat and landscape composition were species-specific, but that there were consistent trends in species richness and total moth abundance. Gardens with more diverse and extensive microhabitats were associated with higher species richness and moth abundance; gardens near to the coast were associated with higher richness and moth abundance; and gardens in more urbanized locations were associated with lower species richness and moth abundance. The same trends were also found for species classified as increasing, declining and vulnerable under IUCN (World Conservation Union) criteria

    The Fifth Data Release of the Sloan Digital Sky Survey

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    This paper describes the Fifth Data Release (DR5) of the Sloan Digital Sky Survey (SDSS). DR5 includes all survey quality data taken through June 2005 and represents the completion of the SDSS-I project (whose successor, SDSS-II will continue through mid-2008). It includes five-band photometric data for 217 million objects selected over 8000 square degrees, and 1,048,960 spectra of galaxies, quasars, and stars selected from 5713 square degrees of that imaging data. These numbers represent a roughly 20% increment over those of the Fourth Data Release; all the data from previous data releases are included in the present release. In addition to "standard" SDSS observations, DR5 includes repeat scans of the southern equatorial stripe, imaging scans across M31 and the core of the Perseus cluster of galaxies, and the first spectroscopic data from SEGUE, a survey to explore the kinematics and chemical evolution of the Galaxy. The catalog database incorporates several new features, including photometric redshifts of galaxies, tables of matched objects in overlap regions of the imaging survey, and tools that allow precise computations of survey geometry for statistical investigations.Comment: ApJ Supp, in press, October 2007. This paper describes DR5. The SDSS Sixth Data Release (DR6) is now public, available from http://www.sdss.or
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