19,583 research outputs found
Measuring eccentricity in binary black hole inspirals with gravitational waves
When binary black holes form in the field, it is expected that their orbits
typically circularize before coalescence. In galactic nuclei and globular
clusters, binary black holes can form dynamically. Recent results suggest that
of mergers in globular clusters result from three-body
interactions. These three-body interactions are expected to induce significant
orbital eccentricity when they enter the Advanced LIGO band at a
gravitational-wave frequency of 10 Hz. Measurements of binary black hole
eccentricity therefore provide a means for determining whether or not dynamic
formation is the primary channel for producing binary black hole mergers. We
present a framework for performing Bayesian parameter estimation on
gravitational-wave observations of black hole inspirals. Using this framework,
and employing the non-spinning, inspiral-only EccentricFD waveform approximant,
we determine the minimum detectable eccentricity for an event with masses and
distance similar to GW150914. At design sensitivity, we find that the current
generation of advanced observatories will be sensitive to orbital
eccentricities of at a gravitational-wave frequency of 10 Hz,
demonstrating that existing detectors can use eccentricity to distinguish
between circular field binaries and globular cluster triples. We compare this
result to eccentricity distributions predicted to result from three black hole
binary formation channels, showing that measurements of eccentricity could be
used to infer the population properties of binary black holes.Comment: 12 pages, 7 figures, 2 table
An objective method of measuring swine
This investigation was initiated in order to obtain information relative to the value of photographs as an objective permanent record of swine. The primary emphasis of the study was placed on a comparison of the relative accuracy and repeatability of body measurements made on the live animal and body measurements taken from photographs
Experimental triplet and quadruplet fluctuation densities and spatial distribution function integrals for liquid mixtures
Citation: Ploetz, E. A., & Smith, P. E. (2015). Experimental triplet and quadruplet fluctuation densities and spatial distribution function integrals for liquid mixtures. Journal of Chemical Physics, 142(9), 14. doi:10.1063/1.4913514Kirkwood-Buff or Fluctuation Solution Theory can be used to provide experimental pair fluctuations, and/or integrals over the pair distribution functions, from experimental thermodynamic data on liquid mixtures. Here, this type of approach is used to provide triplet and quadruplet fluctuations, and the corresponding integrals over the triplet and quadruplet distribution functions, in a purely thermodynamic manner that avoids the use of structure factors. The approach is then applied to binary mixtures of water + methanol and benzene + methanol over the full composition range under ambient conditions. The observed correlations between the different species vary significantly with composition. The magnitude of the fluctuations and integrals appears to increase as the number of the most polar molecule involved in the fluctuation or integral also increases. A simple physical picture of the fluctuations is provided to help rationalize some of these variations. (C) 2015 AIP Publishing LLC
Rescuing Democracy
This book proposes a new institution — the ‘People’s Forum’ — to enable democratic governments to effectively address long-running issues like global warming and inequality. It would help citizens decide what strategic problems their government must fix, especially where this requires them to suffer some inconvenience or cost. The People’s Forum is first based on a new diagnosis of government failure in democracies. The book tests its own analyses of government failure by seeing whether these might help us to explain the failures of particular democracies to address (and in some cases, to even recognize) several crucial environmental problems. The essential features of a new design for democracy are described and then compared with those of previous institutional designs that were also intended to improve the quality of democratic government. In that comparison, the People’s Forum turns out to be not only the most effective design for developing and implementing competent policy, but also the easiest to establish and run. The latter advantage is crucial as there has been no success in getting previous designs into actual trial practice. It is hoped that this book may inspire a small group to raise the money to set up and run the People’s Forum. Then, as citizens see it operating and engage with it, they may come to regard the new Forum as essential in helping them to deliberate long-running issues and to get their resulting initiatives implemented by government. Smith also discusses how the People’s Forum must be managed and how groups with different political ideologies may react to it. An Afterword sets out the method by which this design was produced, to help those who might want to devise an institution themselves. The new concepts in environmental science that the book develops to test its diagnosis are applied in an Appendix to outline crucial options for the future of Tasmania. Similar options apply to many countries, states and provinces. As indicated above, those choices are currently beyond the capacity of democratic governments to address and in some cases, even to recognize. But the People’s Forum may lift them out of that morass
Decision-tree early warning score (DTEWS) validates the design of the National Early Warning Score (NEWS)
Patterns in the recording of vital signs and early warning scores: compliance with a clinical escalation protocol
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