4,433 research outputs found

    Virtual Advocacy: Lived Experience Takes Center Stage During and After Pandemic

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    COVID-19 forced a significant change for participants of the Disability Policy Seminar (DPS) typically held annually in Washington, D.C. The DPS is a policy event that both informs its participants about current policy and supports attendees visiting Capitol Hill to meet with legislators. In 2020, the DPS event, which took place during the early phase of the pandemic, was shifted from “on the Hill” to “across the screen”. Through the various lenses of an autistic self-advocate, a mother of a child with a developmental disability, and faculty of a LEND (Leadership Education in Neurodevelopmental and related Disabilities) program, this paper describes the ways in which the nature of our collaborative advocacy effort, from Hill visits to co-authorship, was shaped by changes instituted in response to COVID-19. The authors collectively explored the experience, benefit, and lasting impact of engaging in virtual advocacy from an emancipatory perspective, which highlights the voices of self-advocates and family members of people with developmental disabilities. Benefits of virtual include: 1) minimizing the physical challenges involved for persons with disabilities (particularly those with mobility issues, those who utilize durable medical equipment, and those whose disabilities make transportation challenging); 2) increasing visibility by allowing elected representatives a view into constituents’ homes; and 3) enhancing engagement for participants with different learning styles and those who communicate with support. We conclude with lessons learned within the context of a global public health emergency about how to support authentic collaboration between various stakeholders

    The ACIGA Data Analysis programme

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    The Data Analysis programme of the Australian Consortium for Interferometric Gravitational Astronomy (ACIGA) was set up in 1998 by the first author to complement the then existing ACIGA programmes working on suspension systems, lasers and optics, and detector configurations. The ACIGA Data Analysis programme continues to contribute significantly in the field; we present an overview of our activities.Comment: 10 pages, 0 figures, accepted, Classical and Quantum Gravity, (Proceedings of the 5th Edoardo Amaldi Conference on Gravitational Waves, Tirrenia, Pisa, Italy, 6-11 July 2003

    The Imprint of Gravitational Waves in Models Dominated by a Dynamical Cosmic Scalar Field

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    An alternative to the standard cold dark matter model has been recently proposed in which a significant fraction of the energy density of the universe is due to a dynamical scalar field (QQ) whose effective equation-of-state differs from that of matter, radiation or cosmological constant (Λ\Lambda). In this paper, we determine how the Q-component modifies the primordial inflation gravitational wave (tensor metric) contribution to the cosmic microwave background anisotropy and, thereby, one of the key tests of inflation.Comment: 15 pages, 14 figures, revtex, submitted to Phys. Rev.

    SUSY-QCD decoupling properties in H+ -> t \bar b decay

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    The SUSY-QCD radiative corrections to the \Gamma (H+ -> t \bar b) partial decay width are analyzed within the Minimal Supersymmetric Standard Model at the one-loop level, {\mathcal O}(\alpha_s), and in the decoupling limit. We present the analytical expressions of these corrections in the large SUSY masses limit and study the decoupling behaviour of these corrections in various limiting cases. We find that if the SUSY mass parameters are large and of the same order, the one loop SUSY-QCD corrections {\it do not decouple}. The non-decoupling contribution is enhanced by \tan \beta and therefore large corrections are expected in the large \tan \beta limit. In contrast, we also find that the SUSY-QCD corrections decouple if the masses of either the squarks or the gluinos are separately taken large.Comment: LaTeX, 33 pages, 7 figure included. Uses cite.st

    Classical integrability and quantum aspects of the AdS(3) x S(3) x S(3) x S(1) superstring

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    In this paper we continue the investigation of aspects of integrability of the type IIA AdS(3) x S(3) x S(3) x S(1) and AdS(3) x S(3) x T(4) superstrings. By constructing a one parameter family of flat connections we prove that the Green-Schwarz string is classically integrable, at least to quadratic order in fermions, without fixing the kappa-symmetry. We then compare the quantum dispersion relation, fixed by integrability up to an unknown interpolating function h(lambda), to explicit one-loop calculations on the string worldsheet. For AdS(3) x S(3) x S(3) x S(1) the spectrum contains heavy, as well as light and massless modes, and we find that the one-loop contribution differs depending on how we treat these modes showing that similar regularization ambiguities as appeared in AdS(4)/CFT(3) occur also here.Comment: 29 pages; v2: updated references and acknowledgmen

    An instability of higher-dimensional rotating black holes

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    We present the first example of a linearized gravitational instability of an asymptotically flat vacuum black hole. We study perturbations of a Myers-Perry black hole with equal angular momenta in an odd number of dimensions. We find no evidence of any instability in five or seven dimensions, but in nine dimensions, for sufficiently rapid rotation, we find perturbations that grow exponentially in time. The onset of instability is associated with the appearance of time-independent perturbations which generically break all but one of the rotational symmetries. This is interpreted as evidence for the existence of a new 70-parameter family of black hole solutions with only a single rotational symmetry. We also present results for the Gregory-Laflamme instability of rotating black strings, demonstrating that rotation makes black strings more unstable.Comment: 38 pages, 13 figure

    First low-frequency Einstein@Home all-sky search for continuous gravitational waves in Advanced LIGO data

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    We report results of a deep all-sky search for periodic gravitational waves from isolated neutron stars in data from the first Advanced LIGO observing run. This search investigates the low frequency range of Advanced LIGO data, between 20 and 100 Hz, much of which was not explored in initial LIGO. The search was made possible by the computing power provided by the volunteers of the Einstein@Home project. We find no significant signal candidate and set the most stringent upper limits to date on the amplitude of gravitational wave signals from the target population, corresponding to a sensitivity depth of 48.7[1/√Hz]. At the frequency of best strain sensitivity, near 100 Hz, we set 90% confidence upper limits of 1.8 x 10^(-25). At the low end of our frequency range, 20 Hz, we achieve upper limits of 3.9 x10^(-24). At 55 Hz we can exclude sources with ellipticities greater than 10^(-5) within 100 pc of Earth with fiducial value of the principal moment of inertia of 10^(38) kgm^2

    Black holes and gravitational waves in string cosmology

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    Pre--big bang models of inflation based on string cosmology produce a stochastic gravitational wave background whose spectrum grows with decreasing wavelength, and which may be detectable using interferometers such as LIGO. We point out that the gravitational wave spectrum is closely tied to the density perturbation spectrum, and that the condition for producing observable gravitational waves is very similar to that for producing an observable density of primordial black holes. Detection of both would provide strong support to the string cosmology scenario.Comment: 6 pages RevTeX fil

    All-sky search for periodic gravitational waves in the O1 LIGO data

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    We report on an all-sky search for periodic gravitational waves in the frequency band 20-475 Hz and with a frequency time derivative in the range of [-1.0, +0.1]e-8 Hz/s. Such a signal could be produced by a nearby spinning and slightly non-axisymmetric isolated neutron star in our galaxy. This search uses the data from Advanced LIGO's first observational run, O1. No periodic gravitational wave signals were observed, and upper limits were placed on their strengths. The lowest upper limits on worst-case (linearly polarized) strain amplitude h0 are 4e-25 near 170 Hz. For a circularly polarized source (most favorable orientation), the smallest upper limits obtained are 1.5e-25. These upper limits refer to all sky locations and the entire range of frequency derivative values. For a population-averaged ensemble of sky locations and stellar orientations, the lowest upper limits obtained for the strain amplitude are 2.5e-25.The authors gratefully acknowledge the support of the United States National Science Foundation (NSF) for the construction and operation of the LIGO Laboratory and Advanced LIGO as well as the Science and Technology Facilities Council (STFC) of the United Kingdom, the Max-Planck-Society (MPS), and the State of Niedersachsen/Germany for support of the construction of Advanced LIGO and construction and operation of the GEO600 detector. Additional support for Advanced LIGO was provided by the Australian Research Council. The authors gratefully acknowledge the Italian Istituto Nazionale di Fisica Nucleare (INFN), the French Centre National de la Recherche Scientifique (CNRS) and the Foundation for Fundamental Research on Matter supported by the Netherlands Organisation for Scientific Research, for the construction and operation of the Virgo detector and the creation and support of the EGO consortium. The authors also gratefully acknowledge research support from these agencies as well as by the Council of Scientific and Industrial Research of India; Department of Science and Technology, India; Science & Engineering Research Board (SERB), India; Ministry of Human Resource Development, India; the Spanish Ministerio de Economía y Competitividad; the Vicepresidùncia i Conselleria d’Innovació; Recerca i Turisme and the Conselleria d’Educació i Universitat del Govern de les Illes Balears; the National Science Centre of Poland; the European Commission; the Royal Society; the Scottish Funding Council; the Scottish Universities Physics Alliance; the Hungarian Scientific Research Fund (OTKA); the Lyon Institute of Origins (LIO); the National Research Foundation of Korea; Industry Canada and the Province of Ontario through the Ministry of Economic Development and Innovation; the Natural Science and Engineering Research Council Canada; Canadian Institute for Advanced Research; the Brazilian Ministry of Science, Technology, and Innovation; International Center for Theoretical Physics South American Institute for Fundamental Research (ICTP-SAIFR); Russian Foundation for Basic Research; the Leverhulme Trust; the Research Corporation,; Ministry of Science and Technology (MOST), Taiwan and the Kavli Foundation. The authors gratefully acknowledge the support of the NSF, STFC, MPS, INFN, CNRS, PL-Grid and the State of Niedersachsen/Germany for provision of computational resources. This document has been assigned LIGO Laboratory document No. LIGO-P1700052-v18
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