7,466 research outputs found

    The Infra‐Red Spectrum of C2H6

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    The infra‐red spectrum of C2H6 gas has been studied in the region between 1.6 and 13ÎŒ with a spectrometer of high resolving power. From measurements on four resolved ∄ bands the value IB0 = (42.234±0.011)×10−40 g cm2 has been obtained for the large moment of inertia in the ground state. From measurements on the three fundamental ⊄ bands the best value at present available for the small moment of inertia is IA = 10.81×10−40 g cm2. Because of uncertainties concerning the perturbations of degenerate state Îœ8, of which a semi‐quantitative explanation which is apparently basically correct has been obtained, this value is provisional but appears to be fairly reliable. With these values of IB0 and IA, if one assumes C☒C = 1.55A, one obtains C☒H = 1.098A and ≰HCC = 109° 3â€Č. From the considerations of the perturbations of state Îœ8 and of the frequencies and line spacings of the combination ⊄ bands, spectroscopic evidence indicating that the configuration of C2H6 is staggered (point group D3d) has for the first time been obtained. Also from these considerations the reliable value Îœ8 = 1472.2 cm−1 and the values Îœ4 = 290 cm−1 for the torsion frequency and Îœ12 = 1190 cm−1 for the ``uncertain'' frequency have been obtained. The latter two values are perhaps somewhat more reliable and not inconsistent with values obtained previously by other methods. These and other results are summarized in Figs. 1 and 14 and in Tables XII—XV.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70901/2/JCPSA6-17-2-139-1.pd

    A Binary Millisecond Pulsar in Globular Cluster NGC6544

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    We report the detection of a new 3.06 ms binary pulsar in the globular cluster NGC6544 using a Fourier-domain ``acceleration'' search. With an implied companion mass of ~0.01 solar masses and an orbital period of only P_b~1.7 hours, it displays very similar orbital properties to many pulsars which are eclipsed by their companion winds. The orbital period is the second shortest of known binary pulsars after 47 Tuc R. The measured flux density of 1.3 +/- 0.4 mJy at 1332 MHz indicates that the pulsar is almost certainly the known steep-spectrum point source near the core of NGC6544.Comment: Accepted by ApJ Letters on 11 October 2000, 5 page

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

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    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 origin of life: chemical evolution of a metabolic system in a mineral honeycomb?

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    For the RNA-world hypothesis to be ecologically feasible, selection mechanisms acting on replicator communities need to be invoked and the corresponding scenarios of molecular evolution specified. Complementing our previous models of chemical evolution on mineral surfaces, in which selection was the consequence of the limited mobility of macromolecules attached to the surface, here we offer an alternative realization of prebiotic group-level selection: the physical encapsulation of local replicator communities into the pores of the mineral substrate. Based on cellular automaton simulations we argue that the effect of group selection in a mineral honeycomb could have been efficient enough to keep prebiotic ribozymes of different specificities and replication rates coexistent, and their metabolic cooperation protected from extensive molecular parasitism. We suggest that mutants of the mild parasites persistent in the metabolic system can acquire useful functions such as replicase activity or the production of membrane components, thus opening the way for the evolution of the first autonomous protocells on Earth

    Discovery of Water Maser Emission in Five AGN and a Possible Correlation Between Water Maser and Nuclear 2-10 keV Luminosities

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    We report the discovery of water maser emission in five active galactic nuclei (AGN) with the 100-m Green Bank Telescope (GBT). The positions of the newly discovered masers, measured with the VLA, are consistent with the optical positions of the host nuclei to within 1 sigma (0.3 arcsec radio and 1.3 arcsec optical) and most likely mark the locations of the embedded central engines. The spectra of three sources, 2MASX J08362280+3327383, NGC 6264, and UGC 09618 NED02, display the characteristic spectral signature of emission from an edge-on accretion disk with maximum orbital velocity of ~700, ~800, and ~1300 km s^-1, respectively. We also present a GBT spectrum of a previously known source MRK 0034 and interpret the narrow Doppler components reported here as indirect evidence that the emission originates in an edge-on accretion disk with orbital velocity of ~500 km s^-1. We obtained a detection rate of 12 percent (5 out of 41) among Seyfert 2 and LINER systems with 10000 km s^-1 < v_sys < 15000 km s^-1. For the 30 nuclear water masers with available hard X-ray data, we report a possible relationship between unabsorbed X-ray luminosity (2-10 keV) and total isotropic water maser luminosity, L_{2-10} proportional to L_{H2O}^{0.5+-0.1}, consistent with the model proposed by Neufeld and Maloney in which X-ray irradiation and heating of molecular accretion disk gas by the central engine excites the maser emission.Comment: 16 pages, 5 tables, 3 figures, to appear in the November 10, 2006, v651n2 issue of the Astrophysical Journa

    ‘Trying to pin down jelly’ - exploring intuitive processes in quality assessment for meta-ethnography

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    Background: Studies that systematically search for and synthesise qualitative research are becoming more evident in health care, and they can make an important contribution to patient care. However, there is still no agreement as to whether, or how we should appraise studies for inclusion. We aimed to explore the intuitive processes that determined the ‘quality’ of qualitative research for inclusion in qualitative research syntheses. We were particularly interested to explore the way that knowledge was constructed. Methods: We used qualitative methods to explore the process of quality appraisal within a team of seven qualitative researchers funded to undertake a meta-ethnography of chronic non-malignant musculoskeletal pain. Team discussions took place monthly between October 2010 and June 2012 and were recorded and transcribed. Data was coded and organised using constant comparative method. The development of our conceptual analysis was both iterative and collaborative. The strength of this team approach to quality came from open and honest discussion, where team members felt free to agree, disagree, or change their position within the safety of the group. Results: We suggest two core facets of quality for inclusion in meta-ethnography - (1) Conceptual clarity; how clearly has the author articulated a concept that facilitates theoretical insight. (2) Interpretive rigour; fundamentally, can the interpretation ‘be trusted?’ Our findings showed that three important categories help the reader to judge interpretive rigour: (ii) What is the context of the interpretation? (ii) How inductive is the interpretation? (iii) Has the researcher challenged their interpretation? Conclusions: We highlight that methods alone do not determine the quality of research for inclusion into a meta-ethnography. The strength of a concept and its capacity to facilitate theoretical insight is integral to meta-ethnography, and arguably to the quality of research. However, we suggest that to be judged ‘good enough’ there also needs to be some assurance that qualitative findings are more than simply anecdotal. Although our conceptual model was developed specifically for meta-ethnography, it may be transferable to other research methodologies

    The stigmatisation of people with chronic back pain

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    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

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

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    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

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

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    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.

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

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    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
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