6,595 research outputs found

    VLA Observations of the Infrared Dark Cloud G19.30+0.07

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    We present Very Large Array observations of ammonia (NH3) (1,1), (2,2), and CCS (2_1-1_0) emission toward the Infrared Dark Cloud (IRDC) G19.30+0.07 at ~22GHz. The NH3 emission closely follows the 8 micron extinction. The NH3 (1,1) and (2,2) lines provide diagnostics of the temperature and density structure within the IRDC, with typical rotation temperatures of ~10 to 20K and NH3 column densities of ~10^15 cm^-2. The estimated total mass of G19.30+0.07 is ~1130 Msun. The cloud comprises four compact NH3 clumps of mass ~30 to 160 Msun. Two coincide with 24 micron emission, indicating heating by protostars, and show evidence of outflow in the NH3 emission. We report a water maser associated with a third clump; the fourth clump is apparently starless. A non-detection of 8.4GHz emission suggests that the IRDC contains no bright HII regions, and places a limit on the spectral type of an embedded ZAMS star to early-B or later. From the NH3 emission we find G19.30+0.07 is composed of three distinct velocity components, or "subclouds." One velocity component contains the two 24 micron sources and the starless clump, another contains the clump with the water maser, while the third velocity component is diffuse, with no significant high-density peaks. The spatial distribution of NH3 and CCS emission from G19.30+0.07 is highly anti-correlated, with the NH3 predominantly in the high-density clumps, and the CCS tracing lower-density envelopes around those clumps. This spatial distribution is consistent with theories of evolution for chemically young low-mass cores, in which CCS has not yet been processed to other species and/or depleted in high-density regions.Comment: 29 pages, 9 figures, accepted for publication by ApJ. Please contact the authors for higher resolution versions of the figure

    First Results from a 1.3 cm EVLA Survey of Massive Protostellar Objects: G35.03+0.35

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    We have performed a 1.3 centimeter survey of 24 massive young stellar objects (MYSOs) using the Expanded Very Large Array (EVLA). The sources in the sample exhibit a broad range of massive star formation signposts including Infrared Dark Clouds (IRDCs), UCHII regions, and extended 4.5 micron emission in the form of Extended Green Objects (EGOs). In this work, we present results for G35.03+0.35 which exhibits all of these phenomena. We simultaneously image the 1.3 cm ammonia (1,1) through (6,6) inversion lines, four methanol transitions, two H recombination lines, plus continuum at 0.05 pc resolution. We find three areas of thermal ammonia emission, two within the EGO (designated the NE and SW cores) and one toward an adjacent IRDC. The NE core contains an UCHII region (CM1) and a candidate HCHII region (CM2). A region of non-thermal, likely masing ammonia (3,3) and (6,6) emission is coincident with an arc of 44 GHz methanol masers. We also detect two new 25 GHz Class I methanol masers. A complementary Submillimeter Array 1.3 mm continuum image shows that the distribution of dust emission is similar to the lower-lying ammonia lines, all peaking to the NW of CM2, indicating the likely presence of an additional MYSO in this protocluster. By modeling the ammonia and 1.3 mm continuum data, we obtain gas temperatures of 20-220 K and masses of 20-130 solar. The diversity of continuum emission properties and gas temperatures suggest that objects in a range of evolutionary states exist concurrently in this protocluster.Comment: To appear in Astrophysical Journal Letters Special Issue on the EVLA. 16 pages, 3 figures. Includes the complete version of Figure 3, which was unable to fit into the journal article due to the number of panel

    Archaeological Salvage Research at 41BX901, a Prehistoric Quarry in Bexar County, Texas

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    During the months of October and November, 1990, staff members and volunteers of the Center of Archaeological Research (CAR), The University of Texas at San Antonio (UTSA), conducted surface survey, mapping, subsurface testing and private collection research at 41 BX 901 and surrounding areas. 41 BX 901 is an extensive prehistoric chert stone quarry in northeastern Bexar county, Texas. The site had been selected for construction of a new middle school by the Northeast Independent School District (NEISD). Survey and testing research was performed in order to evaluate 41 BX 901 and to locate any additional archaeological remains which might be affected by school construction and operation. Extensive prehistoric archaeological remains were encountered at 41 BX 901. Surface and subsurface testing at the site produced abundant lithic remains which indicate lithic procurement and the initial stages of tool fabrication took place here during prehistoric times. However, time-diagnostic artifacts were not recovered from 41 BX 901. Chronological placement of the site depends upon neighboring, more securely dated sites which, it is proposed in this report, had a functional relationship with 41 BX 901. Although 41 BX 901 is one of the most impressive quarries yet documented in this region, the site has been largely destroyed by school construction. 41 BX 905, recorded as part of this project and likely a continuation of 41 BX 901 on neighboring property, is well preserved and will be proposed for national register status. No further archaeological research is recommended for 41 BX 901 due to the destruction of the site. Two neighboring sites, 41 BX 903 and 41 BX 905, merit national register status and protection from development and looting

    Pedagogical possibilities for unruly bodies

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    Project Reβ€’Vision uses disability arts to disrupt stereotypical understandings of disability and difference that create barriers to healthcare. In this paper, we examine how digital stories produced through Reβ€’Vision disrupt biopedagogies by working as body-becoming pedagogies to create nondidactic possibilities for living in/with difference. We engage in meaning making about eight stories made by women and trans people living with disabilities and differences, with our interpretations guided by the following considerations: what these stories β€˜teach’ about new ways of living with disability; how these stories resist neoliberalism through their production of new possibilities for living; how digital stories wrestle with representing disability in a culture in which disabled bodies are on display or hidden away; how vulnerability and receptivity become β€˜conditions of possibility’ for the embodiments represented in digital stories; and how curatorial practice allows disability-identified artists to explore possibilities of β€˜looking back’ at ableist gazes

    A Search for Dense Molecular Gas in High Redshift Infrared-Luminous Galaxies

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    We present a search for HCN emission from four high redshift far infrared (IR) luminous galaxies. Current data and models suggest that these high zz IR luminous galaxies represent a major starburst phase in the formation of spheroidal galaxies, although many of the sources also host luminous active galactic nuclei (AGN), such that a contribution to the dust heating by the AGN cannot be precluded. HCN emission is a star formation indicator, tracing dense molecular hydrogen gas within star-forming molecular clouds (n(H2_2) ∼105\sim 10^5 cmβˆ’3^{-3}). HCN luminosity is linearly correlated with IR luminosity for low redshift galaxies, unlike CO emission which can also trace gas at much lower density. We report a marginal detection of HCN (1-0) emission from the z=2.5832z=2.5832 QSO J1409+5628, with a velocity integrated line luminosity of LHCNβ€²=6.7Β±2.2Γ—109L_{\rm HCN}'=6.7\pm2.2 \times10^{9} K km sβˆ’1^{-1} pc2^2, while we obtain 3Οƒ\sigma upper limits to the HCN luminosity of the z=3.200z=3.200 QSO J0751+2716 of LHCNβ€²=1.0Γ—109L_{\rm HCN}'=1.0\times10^{9} K km sβˆ’1^{-1} pc2^2, LHCNβ€²=1.6Γ—109L_{\rm HCN}'=1.6\times10^{9} K km sβˆ’1^{-1} pc2^2 for the z=2.565z= 2.565 starburst galaxy J1401+0252, and LHCNβ€²=1.0Γ—1010L_{\rm HCN}'=1.0\times10^{10} K km sβˆ’1^{-1} pc2^2 for the z=6.42z = 6.42 QSO J1148+5251. We compare the HCN data on these sources, plus three other high-zz IR luminous galaxies, to observations of lower redshift star-forming galaxies. The values of the HCN/far-IR luminosity ratios (or limits) for all the high zz sources are within the scatter of the relationship between HCN and far-IR emission for low zz star-forming galaxies (truncated).Comment: aastex format, 4 figures. to appear in the Astrophysical Journal; Revised lens magnification estimate for 1401+025

    A strong immune response in young adult honeybees masks their increased susceptibility to infection compared to older bees

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    Honeybees, Apis mellifera, show age-related division of labor in which young adults perform maintenance ("housekeeping") tasks inside the colony before switching to outside foraging at approximately 23 days old. Disease resistance is an important feature of honeybee biology, but little is known about the interaction of pathogens and age-related division of labor. We tested a hypothesis that older forager bees and younger "house" bees differ in susceptibility to infection. We coupled an infection bioassay with a functional analysis of gene expression in individual bees using a whole genome microarray. Forager bees treated with the entomopathogenic fungus Metarhizium anisopliae s.l. survived for significantly longer than house bees. This was concomitant with substantial differences in gene expression including genes associated with immune function. In house bees, infection was associated with differential expression of 35 candidate immune genes contrasted with differential expression of only two candidate immune genes in forager bees. For control bees (i.e. not treated with M. anisopliae) the development from the house to the forager stage was associated with differential expression of 49 candidate immune genes, including up-regulation of the antimicrobial peptide gene abaecin, plus major components of the Toll pathway, serine proteases, and serpins. We infer that reduced pathogen susceptibility in forager bees was associated with age-related activation of specific immune system pathways. Our findings contrast with the view that the immunocompetence in social insects declines with the onset of foraging as a result of a trade-off in the allocation of resources for foraging. The up-regulation of immune-related genes in young adult bees in response to M. anisopliae infection was an indicator of disease susceptibility; this also challenges previous research in social insects, in which an elevated immune status has been used as a marker of increased disease resistance and fitness without considering the effects of age-related development

    "Even if the test result is negative, they should be able to tell us what is wrong with us": a qualitative study of patient expectations of rapid diagnostic tests for malaria.

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    BACKGROUND: The debate on rapid diagnostic tests (RDTs) for malaria has begun to shift from whether RDTs should be used, to how and under what circumstances their use can be optimized. This has increased the need for a better understanding of the complexities surrounding the role of RDTs in appropriate treatment of fever. Studies have focused on clinician practices, but few have sought to understand patient perspectives, beyond notions of acceptability. METHODS: This qualitative study aimed to explore patient and caregiver perceptions and experiences of RDTs following a trial to assess the introduction of the tests into routine clinical care at four health facilities in one district in Ghana. Six focus group discussions and one in-depth interview were carried out with those who had received an RDT with a negative test result. RESULTS: Patients had high expectations of RDTs. They welcomed the tests as aiding clinical diagnoses and as tools that could communicate their problem better than they could, verbally. However, respondents also believed the tests could identify any cause of illness, beyond malaria. Experiences of patients suggested that RDTs were adopted into an existing system where patients are both physically and intellectually removed from diagnostic processes and where clinicians retain authority that supersedes tests and their results. In this situation, patients did not feel able to articulate a demand for test-driven diagnosis. CONCLUSIONS: Improvements in communication between the health worker and patient, particularly to explain the capabilities of the test and management of RDT negative cases, may both manage patient expectations and promote patient demand for test-driven diagnoses

    Scanning Electron Microscopy of Microcorrosion Casts: Applications in Ophthalmologic Research

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    In light of the complicated nature of the ocular vasculature, it has been difficult to define the normal ocular anatomy by reference to two-dimensional tissue sections. Since it provides three-dimensional replicas, scanning electron microscopy (SEM) of vascular corrosion casts has therefore been an invaluable addition to the study of ocular vasculature. This technique also often permits identification of a normal vessel\u27s arterial, venous, or capillary nature by its surface features. In addition, this technique is finding increased use in defining anatomical features of human vascular disease and is especially well suited for the study of experimental neovascularization as it relates to the eye. This paper reviews the application of SEM of microscopic casts to the study of normal and diseased ocular vessels, as well as the contribution of this method to studies of experimental ocular neovascularization
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