5,711 research outputs found

    VLBA Imaging of the OH Maser in IIIZw35

    Get PDF
    We present a parsec-scale image of the OH maser in the nucleus of the active galaxy IIIZw35, made using the Very Long Baseline Array at a wavelength of 18 cm. We detected two distinct components, with a projected separation of 50 pc (for D=110 Mpc) and a separation in Doppler velocity of 70 km/s, which contain 50% of the total maser flux. Velocity gradients within these components could indicate rotation of clouds with binding mass densities of ~7000 solar masses per cubic parsec, or total masses of more than 500,000 solar masses. Emission in the 1665-MHz OH line is roughly coincident in position with that in the 1667-MHz line, although the lines peak at different Doppler velocities. We detected no 18 cm continuum emission; our upper limit implies a peak apparent optical depth greater than 3.4, assuming the maser is an unsaturated amplifier of continuum radiation.Comment: 10 pages, 3 figure

    Effects of Harmful Algal Blooms on Fish and Shellfish Species: A Case Study of New Zealand in a Changing Environment

    Get PDF
    Harmful algal blooms (HABs) have wide-ranging environmental impacts, including on aquatic species of social and commercial importance. In New Zealand (NZ), strategic growth of the aquaculture industry could be adversely affected by the occurrence of HABs. This review examines HAB species which are known to bloom both globally and in NZ and their effects on commercially important shellfish and fish species. Blooms of Karenia spp. have frequently been associated with mortalities of both fish and shellfish in NZ and the sub-lethal effects of other genera, notably Alexandrium spp., on shellfish (which includes paralysis, a lack of byssus production, and reduced growth) are also of concern. Climate change and anthropogenic impacts may alter HAB population structure and dynamics, as well as the physiological responses of fish and shellfish, potentially further compromising aquatic species. Those HAB species which have been detected in NZ and have the potential to bloom and harm marine life in the future are also discussed. The use of environmental DNA (eDNA) and relevant bioassays are practical tools which enable early detection of novel, problem HAB species and rapid toxin/HAB screening, and new data from HAB monitoring of aquaculture production sites using eDNA are presented. As aquaculture grows to supply a sizable proportion of the world’s protein, the effects of HABs in reducing productivity is of increasing significance. Research into the multiple stressor effects of climate change and HABs on cultured species and using local, recent, HAB strains is needed to accurately assess effects and inform stock management strategies

    GBT Discovery of Two Binary Millisecond Pulsars in the Globular Cluster M30

    Full text link
    We report the discovery of two binary millisecond pulsars in the core-collapsed globular cluster M30 using the Green Bank Telescope (GBT) at 20 cm. PSR J2140-2310A (M30A) is an eclipsing 11-ms pulsar in a 4-hr circular orbit and PSR J2140-23B (M30B) is a 13-ms pulsar in an as yet undetermined but most likely highly eccentric (e>0.5) and relativistic orbit. Timing observations of M30A with a 20-month baseline have provided precise determinations of the pulsar's position (within 4" of the optical centroid of the cluster), and spin and orbital parameters, which constrain the mass of the companion star to be m_2 >~ 0.1Msun. The position of M30A is coincident with a possible thermal X-ray point source found in archival Chandra data which is most likely due to emission from hot polar caps on the neutron star. In addition, there is a faint (V_555 ~ 23.8) star visible in archival HST F555W data that may be the companion to the pulsar. Eclipses of the pulsed radio emission from M30A by the ionized wind from the compact companion star show a frequency dependent duration (\propto\nu^{-\alpha} with \alpha ~ 0.4-0.5) and delay the pulse arrival times near eclipse ingress and egress by up to 2-3 ms. Future observations of M30 may allow both the measurement of post-Keplerian orbital parameters from M30B and the detection of new pulsars due to the effects of strong diffractive scintillation.Comment: 10 pages, 6 figures, Submitted to ApJ. This version includes many recommended modifications, an improved structure, a new author, and a completely redone optical analysi

    The stigmatisation of people with chronic back pain

    Get PDF
    This study responded to the need for better theoretical understanding of experiences that shape the beliefs, attitudes and needs of chronic back patients attending pain clinics. The aim was explore and conceptualise the experiences of people of working age who seek help from pain clinics for chronic back pain. Methods. This was a qualitative study, based on an interpretative phenomenological approach (IPA). During in-depth interviews in their homes, participants were invited to 'tell their story' from the time their pain began. Participants were twelve male and six female patients, aged between 28 and 62 years, diagnosed as having chronic benign back pain. All had recently attended one of two pain clinics as new referrals. The interview transcripts were analysed thematically. Findings. Stigmatisation emerged as a key theme from the narrative accounts of participants. The findings expose subtle as well as overt stigmatising responses by family, friends, health professionals and the general public which appeared to have a profound effect on the perceptions, self esteem and behaviours of those interviewed. Conclusions. The findings suggest that patients with chronic back pain feel stigmatised by the time they attend pain clinics and this may affect their attitudes and behaviours towards those offering professional help. Theories of chronic pain need to accommodate these responses, while pain management programmes need to address the realities and practicalities of dealing with stigma in everyday life

    The self-force on a static scalar test-charge outside a Schwarzschild black hole

    Get PDF
    The finite part of the self-force on a static scalar test-charge outside a Schwarzschild black hole is zero. By direct construction of Hadamard's elementary solution, we obtain a closed-form expression for the minimally coupled scalar field produced by a test-charge held fixed in Schwarzschild spacetime. Using the closed-form expression, we compute the necessary external force required to hold the charge stationary. Although the energy associated with the scalar field contributes to the renormalized mass of the particle (and thereby its weight), we find there is no additional self-force acting on the charge. This result is unlike the analogous electrostatic result, where, after a similar mass renormalization, there remains a finite repulsive self-force acting on a static electric test-charge outside a Schwarzschild black hole. We confirm our force calculation using Carter's mass-variation theorem for black holes. The primary motivation for this calculation is to develop techniques and formalism for computing all forces - dissipative and non-dissipative - acting on charges and masses moving in a black-hole spacetime. In the Appendix we recap the derivation of the closed-form electrostatic potential. We also show how the closed-form expressions for the fields are related to the infinite series solutions.Comment: RevTeX, To Appear in Phys. Rev.

    An interpretative phenomenological analysis of posttraumatic growth in adults bereaved by suicide

    Get PDF
    This study explored experiences of posttraumatic growth in adults bereaved by suicide. Six participants were interviewed using a semi-structured interview schedule. Transcribed interviews were analyzed from an interpretative phenomenological framework. Two superordinate themes, with three ordinate themes in each, were identified: (a) positive growth (“life view,” “knowledge of self,” and “relation to others”) and (b) social context (“gaze of others,” “public guise,” and “solace of other survivors”). Suicide survivors gain extra insights due to their experiences, but are reluctant to acknowledge that they do. This requires consideration in theoretical and clinical setting

    Beyond the Insider—Outsider Perspective: The Study of Religion as a Study of Discourse Construction

    Get PDF
    This essay reflects on contemporary theorizing of religion which embodies an explicit critique of the imperial project, seeing that by most common consent the scholarly disciplinary field of religious studies (history of religion, phenomenology of religion, Religionswissenschaft) is a late nineteenth century invention that coincides with the emergence of anthropology and ethnography as epiphenomena of the colonial project (whether as Orientalism or as exoticism the Other is rendered manageable subjects). The scholarly study of religion is, therefore, simultaneously a study of the history of theory and concept formation, and the social, cultural, and political work performed by such study and theorizing. The metatheory of the study of religion is a main focus of the essay. Alongside that, the essay focuses more pointedly on the concept of discourse, and considers the extraordinary situation where the same methodological vocabulary that functions in religious studies also functions in critical theological studies, which relativizes the division of ‘insider’ and ‘outsider’ perspectives. Yet both are conventionally practised either in isolation from each other as distinct theoretical and disciplinary bounded/defined study fields, or—the other and almost direct opposite—religious studies being performed in the context of theological study, situated in and offered by theological faculties. An overview of recent debates in the field of religious studies serves to highlight the continued struggle to demarcate the boundaries between the study of religion and the study of theology—in some of the recent, very strident debates mainstream religious studies is labelled as nothing more than theology. This contribution, then, aims at a kind of metatheoretical reflection on the study of religion and theology both as discourses that serve mythmaking, identity formation, culturally strategic purposes. That is, from the discourse perspective that is proposed here, it is possible to move beyond the definitional divide between religious studies and theology—even beyond ‘religion’ itself—to focus on the mundanely material practices that constitute that which is called religion. In the way in which the terms are used it is clear that the terminologies themselves bear the imprint of historical social discourses that occasioned the rise of their use. This essay, then, is something of a metacritique of the language of the study of religion—beyond religion, and beyond the study of religion and theology

    Observation of the Dalitz Decay Ds∗+→Ds+e+e−D_{s}^{*+} \to D_{s}^{+} e^{+} e^{-}

    Full text link
    Using 586 pb−1\textrm{pb}^{-1} of e+e−e^{+}e^{-} collision data acquired at s=4.170\sqrt{s}=4.170 GeV with the CLEO-c detector at the Cornell Electron Storage Ring, we report the first observation of Ds∗+→Ds+e+e−D_{s}^{*+} \to D_{s}^{+} e^{+} e^{-} with a significance of 5.3σ5.3 \sigma. The ratio of branching fractions \calB(D_{s}^{*+} \to D_{s}^{+} e^{+} e^{-}) / \calB(D_{s}^{*+} \to D_{s}^{+} \gamma) is measured to be [0.72−0.13+0.15(stat)±0.10(syst)][ 0.72^{+0.15}_{-0.13} (\textrm{stat}) \pm 0.10 (\textrm{syst})]%, which is consistent with theoretical expectations
    • 

    corecore