899 research outputs found
A systematic review of community participation measures for people with intellectual disabilities
Background: Community participation is considered a fundamental aspect of quality of life and one of the essential goals of services for people with intellectual disabilities (ID), yet there is no agreed way of measuring community participation.
Method: Two systematic searches were performed across eight electronic databases to identify measures of community participation and identify validation studies for each measure. Measures were included if they were developed for adults with ID, measured extent of participation and had published information regarding content and psychometric properties. Each measure was evaluated on the basis of psychometric properties and in relation to coverage of nine domains of community participation from the International Classification of Functioning, Disability and Health (ICF).
Results: Eleven measures were selected with the quality rating scores varying substantially ranging from 2-11 of a possible 16.
Conclusions: The majority of measures were not sufficiently psychometrically tested. Findings suggest a need for the development of a psychometrically robust instrument
Thunder lizard handstands: Manus-only sauropod trackways from the Glen Rose Formation (Lower Cretaceous, Kendall County, Texas)
Three parallel, manus-only sauropod trackways from the Coffee Hollow A-Male tracksite (Glen Rose Formation, Kendall County, Texas) were studied separately by researchers from the Heritage Museum of the Texas Hill Country and the Houston Museum of Natural Sciences. Footprint and trackway measurements generally show good agreement between the two groups’ data sets. Footprints appear to be shallowly impressed true tracks rather than undertracks. One of the Coffee Hollow trackways shows marked asymmetry in the lengths of paces that begin with the left as opposed to the right forefoot, and two of the Coffee Hollow trackways are unusually broad. The Coffee Hollow trackways differ enough from the manus portions of other Glen Rose Formation sauropod trackways to suggest that they were made by a different kind of sauropod. Greater differential pressure exerted on the substrate by the forefeet than the hindfeet probably explains the Coffee Hollow trackways, like other manus-only sauropod trackways, but the possibility that they indicate unusual locomotion cannot at present be ruled out
Reconstruction of the gravitational wave signal during the Virgo science runs and independent validation with a photon calibrator
The Virgo detector is a kilometer-scale interferometer for gravitational wave
detection located near Pisa (Italy). About 13 months of data were accumulated
during four science runs (VSR1, VSR2, VSR3 and VSR4) between May 2007 and
September 2011, with increasing sensitivity.
In this paper, the method used to reconstruct, in the range 10 Hz-10 kHz, the
gravitational wave strain time series from the detector signals is
described. The standard consistency checks of the reconstruction are discussed
and used to estimate the systematic uncertainties of the signal as a
function of frequency. Finally, an independent setup, the photon calibrator, is
described and used to validate the reconstructed signal and the
associated uncertainties.
The uncertainties of the time series are estimated to be 8% in
amplitude. The uncertainty of the phase of is 50 mrad at 10 Hz with a
frequency dependence following a delay of 8 s at high frequency. A bias
lower than and depending on the sky direction of the GW is
also present.Comment: 35 pages, 16 figures. Accepted by CQ
Gravitational Waves From Known Pulsars: Results From The Initial Detector Era
We present the results of searches for gravitational waves from a large selection of pulsars using data from the most recent science runs (S6, VSR2 and VSR4) of the initial generation of interferometric gravitational wave detectors LIGO (Laser Interferometric Gravitational-wave Observatory) and Virgo. We do not see evidence for gravitational wave emission from any of the targeted sources but produce upper limits on the emission amplitude. We highlight the results from seven young pulsars with large spin-down luminosities. We reach within a factor of five of the canonical spin-down limit for all seven of these, whilst for the Crab and Vela pulsars we further surpass their spin-down limits. We present new or updated limits for 172 other pulsars (including both young and millisecond pulsars). Now that the detectors are undergoing major upgrades, and, for completeness, we bring together all of the most up-to-date results from all pulsars searched for during the operations of the first-generation LIGO, Virgo and GEO600 detectors. This gives a total of 195 pulsars including the most recent results described in this paper.United States National Science FoundationScience and Technology Facilities Council of the United KingdomMax-Planck-SocietyState of Niedersachsen/GermanyAustralian Research CouncilInternational Science Linkages program of the Commonwealth of AustraliaCouncil of Scientific and Industrial Research of IndiaIstituto Nazionale di Fisica Nucleare of ItalySpanish Ministerio de Economia y CompetitividadConselleria d'Economia Hisenda i Innovacio of the Govern de les Illes BalearsNetherlands Organisation for Scientific ResearchPolish Ministry of Science and Higher EducationFOCUS Programme of Foundation for Polish ScienceRoyal SocietyScottish Funding CouncilScottish Universities Physics AllianceNational Aeronautics and Space AdministrationOTKA of HungaryLyon Institute of Origins (LIO)National Research Foundation of KoreaIndustry CanadaProvince of Ontario through the Ministry of Economic Development and InnovationNational Science and Engineering Research Council CanadaCarnegie TrustLeverhulme TrustDavid and Lucile Packard FoundationResearch CorporationAlfred P. Sloan FoundationAstronom
First narrow-band search for continuous gravitational waves from known pulsars in advanced detector data
Spinning neutron stars asymmetric with respect to their rotation axis are potential sources of
continuous gravitational waves for ground-based interferometric detectors. In the case of known pulsars a
fully coherent search, based on matched filtering, which uses the position and rotational parameters
obtained from electromagnetic observations, can be carried out. Matched filtering maximizes the signalto-
noise (SNR) ratio, but a large sensitivity loss is expected in case of even a very small mismatch
between the assumed and the true signal parameters. For this reason, narrow-band analysis methods have
been developed, allowing a fully coherent search for gravitational waves from known pulsars over a
fraction of a hertz and several spin-down values. In this paper we describe a narrow-band search of
11 pulsars using data from Advanced LIGO’s first observing run. Although we have found several initial
outliers, further studies show no significant evidence for the presence of a gravitational wave signal.
Finally, we have placed upper limits on the signal strain amplitude lower than the spin-down limit for 5 of
the 11 targets over the bands searched; in the case of J1813-1749 the spin-down limit has been beaten for
the first time. For an additional 3 targets, the median upper limit across the search bands is below the
spin-down limit. This is the most sensitive narrow-band search for continuous gravitational waves carried
out so far
Implementation and testing of the first prompt search for gravitational wave transients with electromagnetic counterparts
Aims. A transient astrophysical event observed in both gravitational wave
(GW) and electromagnetic (EM) channels would yield rich scientific rewards. A
first program initiating EM follow-ups to possible transient GW events has been
developed and exercised by the LIGO and Virgo community in association with
several partners. In this paper, we describe and evaluate the methods used to
promptly identify and localize GW event candidates and to request images of
targeted sky locations.
Methods. During two observing periods (Dec 17 2009 to Jan 8 2010 and Sep 2 to
Oct 20 2010), a low-latency analysis pipeline was used to identify GW event
candidates and to reconstruct maps of possible sky locations. A catalog of
nearby galaxies and Milky Way globular clusters was used to select the most
promising sky positions to be imaged, and this directional information was
delivered to EM observatories with time lags of about thirty minutes. A Monte
Carlo simulation has been used to evaluate the low-latency GW pipeline's
ability to reconstruct source positions correctly.
Results. For signals near the detection threshold, our low-latency algorithms
often localized simulated GW burst signals to tens of square degrees, while
neutron star/neutron star inspirals and neutron star/black hole inspirals were
localized to a few hundred square degrees. Localization precision improves for
moderately stronger signals. The correct sky location of signals well above
threshold and originating from nearby galaxies may be observed with ~50% or
better probability with a few pointings of wide-field telescopes.Comment: 17 pages. This version (v2) includes two tables and 1 section not
included in v1. Accepted for publication in Astronomy & Astrophysic
Astrophysically Triggered Searches for Gravitational Waves: Status and Prospects
In gravitational-wave detection, special emphasis is put onto searches that
focus on cosmic events detected by other types of astrophysical observatories.
The astrophysical triggers, e.g. from gamma-ray and X-ray satellites, optical
telescopes and neutrino observatories, provide a trigger time for analyzing
gravitational wave data coincident with the event. In certain cases the
expected frequency range, source energetics, directional and progenitor
information is also available. Beyond allowing the recognition of gravitational
waveforms with amplitudes closer to the noise floor of the detector, these
triggered searches should also lead to rich science results even before the
onset of Advanced LIGO. In this paper we provide a broad review of LIGO's
astrophysically triggered searches and the sources they target
Search for Gravitational Waves from Low Mass Compact Binary Coalescence in LIGO's Sixth Science Run and Virgo's Science Runs 2 and 3
We report on a search for gravitational waves from coalescing compact
binaries using LIGO and Virgo observations between July 7, 2009 and October 20,
2010. We searched for signals from binaries with total mass between 2 and 25
solar masses; this includes binary neutron stars, binary black holes, and
binaries consisting of a black hole and neutron star. The detectors were
sensitive to systems up to 40 Mpc distant for binary neutron stars, and further
for higher mass systems. No gravitational-wave signals were detected. We report
upper limits on the rate of compact binary coalescence as a function of total
mass, including the results from previous LIGO and Virgo observations. The
cumulative 90%-confidence rate upper limits of the binary coalescence of binary
neutron star, neutron star- black hole and binary black hole systems are 1.3 x
10^{-4}, 3.1 x 10^{-5} and 6.4 x 10^{-6} Mpc^{-3}yr^{-1}, respectively. These
upper limits are up to a factor 1.4 lower than previously derived limits. We
also report on results from a blind injection challenge.Comment: 11 pages, 5 figures. For a repository of data used in the
publication, go to:
. Also see the
announcement for this paper on ligo.org at:
<http://www.ligo.org/science/Publication-S6CBCLowMass/index.php
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