1,729 research outputs found

    Advanced LIGO's ability to detect apparent violations of the cosmic censorship conjecture and the no-hair theorem through compact binary coalescence detections

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    We study the ability of the advanced Laser Interferometer Gravitational-wave Observatory (aLIGO) to detect apparent violations of the cosmic censorship conjecture and the no-hair theorem. The cosmic censorship conjecture, which is believed to be true in the theory of general relativity, limits the spin-to-mass-squared ratio of a Kerr black hole. The no-hair theorem, which is also believed to be true in the theory of general relativity, suggests a particular value for the tidal Love number of a non-rotating black hole. Using the Fisher matrix formalism, we examine the measurability of the spin and tidal deformability of compact binary systems involving at least one putative black hole. Using parameter measurement errors and correlations obtained from the Fisher matrix, we determine the smallest detectable violation of bounds implied by the cosmic censorship conjecture and the no-hair theorem. We examine the effect of excluding unphysical areas of parameter space when determining the smallest detectable apparent violations, and we examine the effect of different post-Newtonian corrections to the amplitude of the compact binary coalescence gravitational waveform. In addition, we perform a brief study of how the recently calculated 3.0 pN and 3.5 pN spin-orbit corrections to the phase affect spin and mass parameter measurability. We find that physical priors on the symmetric mass ratio and higher harmonics in the gravitational waveform could significantly affect the ability of aLIGO to investigate cosmic censorship and the no-hair theorem for certain systems.Comment: 21 pages, 7 figures, 6 table

    Towards beating the curse of dimensionality for gravitational waves using Reduced Basis

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    Using the Reduced Basis approach, we efficiently compress and accurately represent the space of waveforms for non-precessing binary black hole inspirals, which constitutes a four dimensional parameter space (two masses, two spin magnitudes). Compared to the non-spinning case, we find that only a {\it marginal} increase in the (already relatively small) number of reduced basis elements is required to represent any non-precessing waveform to nearly numerical round-off precision. Most parameters selected by the algorithm are near the boundary of the parameter space, leaving the bulk of its volume sparse. Our results suggest that the full eight dimensional space (two masses, two spin magnitudes, four spin orientation angles on the unit sphere) may be highly compressible and represented with very high accuracy by a remarkably small number of waveforms, thus providing some hope that the number of numerical relativity simulations of binary black hole coalescences needed to represent the entire space of configurations is not intractable. Finally, we find that the {\it distribution} of selected parameters is robust to different choices of seed values starting the algorithm, a property which should be useful for indicating parameters for numerical relativity simulations of binary black holes. In particular, we find that the mass ratios m1/m2m_1/m_2 of non-spinning binaries selected by the algorithm are mostly in the interval [1,3][1,3] and that the median of the distribution follows a power-law behavior (m1/m2)5.25\sim (m_1/m_2)^{-5.25}

    DEFENSE BUDGETING DYNAMICS: THE RELATIONSHIPS AMONG LATE BUDGETS AND LATE APPROPRIATIONS AND THE CONTENT OF CONTINUING RESOLUTIONS

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    To better prepare the Department of Defense (DOD) against the negative effects of late appropriations and their resultant continuing resolutions (CRs), our research covers three primary areas: 50 years of Presidential Budget (PB) submissions, Congressional Budget Resolutions (BR), and DOD Authorization and Appropriation Act data. First, our research conducts a historical trend analysis intended to highlight positive, negative, and neutral tendencies. Second, our research aims to determine which federal budgetary deliverable has the strongest correlation to appropriation timeliness. Finally, our research examines how CRs have evolved over time across six basic characteristics: frequency of CRs, CR anomalies, supplemental appropriations and anomalies, CR duration, CR page length, and funding rates. Our research indicated significant evidence to support that budgetary deliverable timeliness is getting worse, that political variables are both strongly correlated and highly influential throughout the data, and that CRs have dynamically shifted in funding structure, length, and frequency throughout the years covered by this research.Captain, United States ArmyLieutenant Commander, United States NavyApproved for public release. Distribution is unlimited

    Citation Analysis with Microsoft Academic

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    We explore if and how Microsoft Academic (MA) could be used for bibliometric analyses. First, we examine the Academic Knowledge API (AK API), an interface to access MA data, and compare it to Google Scholar (GS). Second, we perform a comparative citation analysis of researchers by normalizing data from MA and Scopus. We find that MA offers structured and rich metadata, which facilitates data retrieval, handling and processing. In addition, the AK API allows retrieving frequency distributions of citations. We consider these features to be a major advantage of MA over GS. However, we identify four main limitations regarding the available metadata. First, MA does not provide the document type of a publication. Second, the 'fields of study' are dynamic, too specific and field hierarchies are incoherent. Third, some publications are assigned to incorrect years. Fourth, the metadata of some publications did not include all authors. Nevertheless, we show that an average-based indicator (i.e. the journal normalized citation score; JNCS) as well as a distribution-based indicator (i.e. percentile rank classes; PR classes) can be calculated with relative ease using MA. Hence, normalization of citation counts is feasible with MA. The citation analyses in MA and Scopus yield uniform results. The JNCS and the PR classes are similar in both databases, and, as a consequence, the evaluation of the researchers' publication impact is congruent in MA and Scopus. Given the fast development in the last year, we postulate that MA has the potential to be used for full-fledged bibliometric analyses.Comment: preprin

    Four types of research in the humanities: Setting the stage for research quality criteria in the humanities

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    This study presents humanities scholars' conceptions of research and subjective notions of quality in the three disciplines German literature studies, English literature studies, and art history, captured using 21 Repertory Grid interviews. We identified three dimensions that structure the scholars' conceptions of research: quality, time, and success. Further, the results revealed four types of research in the humanities: positively connoted ‘traditional' research (characterized as individual, discipline-oriented, and ground-breaking research), positively connoted ‘modern' research (cooperative, interdisciplinary, and socially relevant), negatively connoted ‘traditional' research (isolated, reproductive, and conservative), and negatively connoted ‘modern' research (career oriented, epigonal, calculated). In addition, 15 quality criteria for research in the three disciplines German literature studies, English literature studies, and art history were derived from the Repertory Grid interview

    Antimicrobial Treatment of Orthopedic Implant-related Infections with Rifampin Combinations

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    The purpose of this prospective clinical study is to evaluate the role of combination chemotherapy with rifampin in the treatment of orthopedic device—related infections in which the implant could not be removed. Eleven patients with orthopedic implant-related infections due to staphylococci or streptococci were treated with the implant in situ. Each antimicrobial regimen included rifampin in combination with a β-lactam antibiotic or ciprofloxacin. The median duration of treatment with rifampin was 86 days (range, 15-336 days) with a median follow-up of >;24 months after cessation of therapy. Treatment was successful for 82% of patients. Failures were associated with documented inappropriate treatment. These preliminary clinical data are supported by data from in vitro studies and animal experiments. Combination therapy with rifampin, in particular rifampin and a quinolone, should be considered for patients with orthopedic implant-related infections if the implant cannot be remove

    Investigating the effect of precession on searches for neutron-star-black-hole binaries with Advanced LIGO

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    The first direct detection of neutron-star-black-hole binaries will likely be made with gravitational-wave observatories. Advanced LIGO and Advanced Virgo will be able to observe neutron-star-black-hole mergers at a maximum distance of 900Mpc. To acheive this sensitivity, gravitational-wave searches will rely on using a bank of filter waveforms that accurately model the expected gravitational-wave signal. The angular momentum of the black hole is expected to be comparable to the orbital angular momentum. This angular momentum will affect the dynamics of the inspiralling system and alter the phase evolution of the emitted gravitational-wave signal. In addition, if the black hole's angular momentum is not aligned with the orbital angular momentum it will cause the orbital plane of the system to precess. In this work we demonstrate that if the effect of the black hole's angular momentum is neglected in the waveform models used in gravitational-wave searches, the detection rate of (10+1.4)M(10+1.4)M_{\odot} neutron-star--black-hole systems would be reduced by 333733 - 37%. The error in this measurement is due to uncertainty in the Post-Newtonian approximations that are used to model the gravitational-wave signal of neutron-star-black-hole inspiralling binaries. We describe a new method for creating a bank of filter waveforms where the black hole has non-zero angular momentum, but is aligned with the orbital angular momentum. With this bank we find that the detection rate of (10+1.4)M(10+1.4)M_{\odot} neutron-star-black-hole systems would be reduced by 263326-33%. Systems that will not be detected are ones where the precession of the orbital plane causes the gravitational-wave signal to match poorly with non-precessing filter waveforms. We identify the regions of parameter space where such systems occur and suggest methods for searching for highly precessing neutron-star-black-hole binaries
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