2,129 research outputs found

    Yelling Fire and Hacking: Why the First Amendment Does Not Permit Distributing DVD Decryption Technology?

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    One of the consequences of the black-hole "no-hair" theorem in general relativity (GR) is that gravitational radiation (quasi-normal modes) from a perturbed Kerr black hole is uniquely determined by its mass and spin. Thus, the spectrum of quasi-normal mode frequencies have to be all consistent with the same value of the mass and spin. Similarly, the gravitational radiation from a coalescing binary black hole system is uniquely determined by a small number of parameters (masses and spins of the black holes and orbital parameters). Thus, consistency between different spherical harmonic modes of the radiation is a powerful test that the observed system is a binary black hole predicted by GR. We formulate such a test, develop a Bayesian implementation, demonstrate its performance on simulated data and investigate the possibility of performing such a test using previous and upcoming gravitational wave observations

    An effectual template bank for the detection of gravitational waves from inspiralling compact binaries with generic spins

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    We report the construction of a three-dimensional template bank for the search for gravitational waves from inspiralling binaries consisting of spinning compact objects. The parameter space consists of two dimensions describing the mass parameters and one "reduced-spin" parameter, which describes the secular (non-precessing) spin effects in the waveform. The template placement is based on an efficient stochastic algorithm and makes use of the semi-analytical computation of a metric in the parameter space. We demonstrate that for "low-mass" (m1+m2≲12 M⊙m_1 + m_2 \lesssim 12\,M_\odot) binaries, this template bank achieves effective fitting factors ∼0.92\sim0.92--0.990.99 towards signals from generic spinning binaries in the advanced detector era over the entire parameter space of interest (including binary neutron stars, binary black holes, and black hole-neutron star binaries). This provides a powerful and viable method for searching for gravitational waves from generic spinning low-mass compact binaries. Under the assumption that spin magnitudes of black-holes [neutron-stars] are uniformly distributed between 0--0.98 [0 -- 0.4] and spin angles are isotropically distributed, the expected improvement in the average detection volume (at a fixed signal-to-noise-ratio threshold) of a search using this reduced-spin bank is ∼20−52%\sim20-52\%, as compared to a search using a non-spinning bank.Comment: Minor changes, version appeared in Phys. Rev.

    IN VITRO HEPATOPROTECTIVE ACTIVITY OF YELLOW LEAF EXTRACTS OF THESPESIA POPULNEA AGAINST CARBON TETRACHLORIDE INDUCED TOXICITY

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    Objective: The study was aimed to evaluate in vitro hepatoprotective activity of yellow leaf extracts of Thespesiapopulnea. Methods: Hepatoprotective activity is studied by carbon tetrachloride-induced hepato-toxicity in isolated rat hepatocytes. The biochemical parameters observed in serum were serum glutamate oxaloacetate transaminase (SGOT/AST), serum glutamate pyruvate transaminase (SGPT/ALT) levels. The extracts exhibited a dose-dependent reduction in AST, ALT levels. Results: Methanolic extract was found to exhibit higher hepatoprotection. T. populnea extract was found to be antihepatotoxic at a concentration of 125 mcg with a significant decrease in ALT (P<0.001) and AST (P<0.0001). Conclusion: The results suggest that the methanolic extract has produced significant (p<0.001) hepatoprotection by decreasing the activity of serum enzymes which is comparable to that of standard drug silymarin

    Indian Medicinal Mushrooms as a Source of Antioxidant and Antitumor Agents

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    Medicinal mushrooms occurring in South India namely Ganoderma lucidum, Phellinus rimosus, Pleurotus florida and Pleurotus pulmonaris possessed profound antioxidant and antitumor activities. This indicated that these mushrooms would be valuable sources of antioxidant and antitumor compounds. Investigations also revealed that they had significant antimutagenic and anticarcinogenic activities. Thus, Indian medicinal mushrooms are potential sources of antioxidant and anticancer compounds. However, intensive and extensive investigations are needed to exploit their valuable therapeutic use

    An Efficient Algorithm for Automatic Structure Optimization in X-ray Standing-Wave Experiments

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    X-ray standing-wave photoemission experiments involving multilayered samples are emerging as unique probes of the buried interfaces that are ubiquitous in current device and materials research. Such data require for their analysis a structure optimization process comparing experiment to theory that is not straightforward. In this work, we present a new computer program for optimizing the analysis of standing-wave data, called SWOPT, that automates this trial-and-error optimization process. The program includes an algorithm that has been developed for computationally expensive problems: so-called black-box simulation optimizations. It also includes a more efficient version of the Yang X-ray Optics Program (YXRO) [Yang, S.-H., Gray, A.X., Kaiser, A.M., Mun, B.S., Sell, B.C., Kortright, J.B., Fadley, C.S., J. Appl. Phys. 113, 1 (2013)] which is about an order of magnitude faster than the original version. Human interaction is not required during optimization. We tested our optimization algorithm on real and hypothetical problems and show that it finds better solutions significantly faster than a random search approach. The total optimization time ranges, depending on the sample structure, from minutes to a few hours on a modern laptop computer, and can be up to 100x faster than a corresponding manual optimization. These speeds make the SWOPT program a valuable tool for realtime analyses of data during synchrotron experiments

    EFFECT OF ACTINOMYCETES ON GROWTH OF OCIMUM SANCTUM

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    Objective: The study was aimed to isolate and identify Actinomycetes from rhizosphere soil of Malik deenar college of pharmacy, Kasaragod, Kerala, and to screen the plant growth promoting the activity of isolated actinomycetes on Ocimum sanctum. Methods: The Actinomycetes were isolated from rhizosphere region soil by serial dilution and pour plating method. Then they were identified to a generic level based on morphological characters, and biochemical characters. Plant growth promoting activity was screened by placing 3 sets of Ocimum sanctum seedlings in different pots and the shoot length was measured after 10 d and compared with control. Results: 19 different types of isolates were chosen based on their morphological characteristics and used for assessments of plant growth promoting activity. Among the 19 isolates, 17 isolates were identified as Streptomyces spp. And 2 were belongs to Nocardia spp. The actinomycetes isolates which belong to Streptomyces spp were shown plant growth promoting activity. Conclusion: The result of this study revealed that the rhizosphere soil has different types of actinomycetes, among these Streptomyces spp. are more abundant and common. These Streptomyces spp. have predominant activity on plant growth promotion with respect to Ocimum sanctum

    Complete phenomenological gravitational waveforms from spinning coalescing binaries

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    The quest for gravitational waves from coalescing binaries is customarily performed by the LIGO-Virgo collaboration via matched filtering, which requires a detailed knowledge of the signal. Complete analytical coalescence waveforms are currently available only for the non-precessing binary systems. In this paper we introduce complete phenomenological waveforms for the dominant quadrupolar mode of generically spinning systems. These waveforms are constructed by bridging the gap between the analytically known inspiral phase, described by spin Taylor (T4) approximants in the restricted waveform approximation, and the ring-down phase through a phenomenological intermediate phase, calibrated by comparison with specific, numerically generated waveforms, describing equal mass systems with dimension-less spin magnitudes equal to 0.6. The overlap integral between numerical and phenomenological waveforms ranges between 0.95 and 0.99.Comment: Proceeding for the GWDAW-14 conference. Added reference in v
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