839 research outputs found

    Traditional Cultural Districts: An Opportunity for Alaska Tribes to Protect Subsistence Rights and Traditional Lands

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    Alaska tribes have limited control over their traditional lands and waters. Tribes may increase their influence through a Traditional Cultural District designation under Section 106 of the National Historic Preservation Act. This designation does not stop development, but requires federal agencies to consult with tribes regarding potential development that may impact the district. The consultation right applies regardless of whether a tribe owns or has formally designated the district. In Alaska, where no Traditional Cultural Districts exist as of 2014, there is potential for designating large areas of land or water that correspond to the range of traditionally important species

    Effective-one-body multipolar waveforms for eccentric binary black holes with nonprecessing spins

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    We construct an inspiral-merger-ringdown eccentric gravitational-wave (GW) model for binary black holes with non-precessing spins within the effective-one-body formalism. This waveform model, SEOBNRv4EHM, extends the accurate quasi-circular SEOBNRv4HM model to eccentric binaries by including recently computed eccentric corrections up to 2PN order in the gravitational waveform modes, notably the (l,∣m∣)=(2,2),(2,1),(3,3),(4,4),(5,5)(l,|m|)=(2,2),(2,1),(3,3),(4,4),(5,5) multipoles. The waveform model reproduces the zero eccentricity limit with an accuracy comparable to the underlying quasi-circular model, with the unfaithfulness of ≲1%\lesssim1\% against quasi-circular numerical-relativity (NR) simulations. When compared against 28 public eccentric NR simulations from the Simulating eXtreme Spacetimes catalog with initial orbital eccentricities up to e≃0.3e\simeq0.3 and dimensionless spin magnitudes up to +0.7+0.7, the model provides unfaithfulness <1%<1\%, showing that both the (2,∣2∣)(2,|2|)-modes and the higher-order modes are reliably described without calibration to NR datasets in the eccentric sector. The waveform model SEOBNRv4EHM is able to qualitatively reproduce the phenomenology of dynamical captures, and can be extended to include spin-precession effects. It can be employed for upcoming observing runs with the LIGO-Virgo-KAGRA detectors and used to re-analyze existing GW catalogs to infer the eccentricity parameters for binaries with e≲0.3e\lesssim0.3 (at 20 Hz or lower) and spins up to ≲0.9−0.95\lesssim 0.9-0.95. The latter is a promising region of the parameter space where some astrophysical formation scenarios of binaries predict mild eccentricity in the ground-based detectors' bandwidth. Assessing the accuracy and robustness of the eccentric waveform model SEOBNRv4EHM for larger eccentricities and spins will require comparisons with, and, likely, calibration to eccentric NR waveforms in a larger region of the parameter space

    Attosecond Streaking in the Water Window: A New Regime of Attosecond Pulse Characterization

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    We report on the first streaking measurement of water-window attosecond pulses generated via high harmonic generation, driven by sub-2-cycle, CEP-stable, 1850 nm laser pulses. Both the central photon energy and the energy bandwidth far exceed what has been demonstrated thus far, warranting the investigation of the attosecond streaking technique for the soft X-ray regime and the limits of the FROGCRAB retrieval algorithm under such conditions. We also discuss the problem of attochirp compensation and issues regarding much lower photo-ionization cross sections compared with the XUV in addition to the fact that several shells of target gases are accessed simultaneously. Based on our investigation, we caution that the vastly different conditions in the soft X-ray regime warrant a diligent examination of the fidelity of the measurement and the retrieval procedure.Comment: 14 Pages, 12 figure

    El papel del marketing en el deporte

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    La aplicación del marketing se va extendiendo a gran diversidad de campos en los que tradicionalmente no tenía cabida, por ejemplo, el deporte. Dos coordenadas fundamentales explican el desarrollo del marketing deportivo: en primer lugar, el afianzamiento del marketing como disciplina y los avances de sus herramientas y resultados, y en segundo lugar, la creciente importancia del fenómeno deportivo como hecho social y cultural

    Total Directional Variation for Video Denoising

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    In this paper, we propose a variational approach for video denoising, based on a total directional variation (TDV) regulariser proposed in Parisotto et al. (2018), for image denoising and interpolation. In the TDV regulariser, the underlying image structure is encoded by means of weighted derivatives so as to enhance the anisotropic structures in images, e.g. stripes or curves with a dominant local directionality. For the extension of TDV to video denoising, the space-time structure is captured by the volumetric structure tensor guiding the smoothing process. We discuss this and present our whole video denoising work-flow. Our numerical results are compared with some state-of-the-art video denoising methods.SP acknowledges UK EPSRC grant EP/L016516/1 for the CCA DTC. CBS acknowledges support from Leverhulme Trust project on Breaking the non-convexity barrier, EPSRC grant Nr. EP/M00483X/1, the EPSRC Centre EP/N014588/1, the RISE projects CHiPS and NoMADS, the CCIMI and the Alan Turing Institute

    A high-quality video denoising algorithm based on reliable motion estimation

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    11th European Conference on Computer Vision, Heraklion, Crete, Greece, September 5-11, 2010, Proceedings, Part IIIAlthough the recent advances in the sparse representations of images have achieved outstanding denosing results, removing real, structured noise in digital videos remains a challenging problem. We show the utility of reliable motion estimation to establish temporal correspondence across frames in order to achieve high-quality video denoising. In this paper, we propose an adaptive video denosing framework that integrates robust optical flow into a non-local means (NLM) framework with noise level estimation. The spatial regularization in optical flow is the key to ensure temporal coherence in removing structured noise. Furthermore, we introduce approximate K-nearest neighbor matching to significantly reduce the complexity of classical NLM methods. Experimental results show that our system is comparable with the state of the art in removing AWGN, and significantly outperforms the state of the art in removing real, structured noise

    Initial Data and Eccentricity Reduction Toolkit for Binary Black Hole Numerical Relativity Waveforms

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    The production of numerical relativity waveforms that describe quasicircular binary black hole mergers requires high-quality initial data, and an algorithm to iteratively reduce residual eccentricity. To date, these tools remain closed source, or in commercial software that prevents their use in high performance computing platforms. To address these limitations, and to ensure that the broader numerical relativity community has access to these tools, herein we provide all the required elements to produce high-quality numerical relativity simulations in supercomputer platforms, namely: open source parameter files to numerical simulate spinning black hole binaries with asymmetric mass-ratios; open source Python\texttt{Python} tools to produce high-quality initial data for numerical relativity simulations of spinning black hole binaries on quasi-circular orbits; open source Python\texttt{Python} tools for eccentricity reduction, both as stand-alone software and deployed in the Einstein Toolkit\texttt{Einstein Toolkit}'s software infrastructure. This open source toolkit fills in a critical void in the literature at a time when numerical relativity has an ever increasing role in the study and interpretation of gravitational wave sources. As part of our community building efforts, and to streamline and accelerate the use of these resources, we provide tutorials that describe, step by step, how to obtain and use these open source numerical relativity tools

    Time-domain phenomenological model of gravitational-wave subdominant harmonics for quasicircular nonprecessing binary black hole coalescences

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    In this work we present an extension of the time domain phenomenological model IMRPhenomT for gravitational wave signals from binary black hole coalescences to include subdominant harmonics, specifically the (l=2,m=±1)(l=2, m=\pm 1), (l=3,m=±3)(l=3, m=\pm 3), (l=4,m=±4)(l=4, m=\pm 4) and (l=5,m=±5)(l=5, m=\pm 5) spherical harmonics. We also improve our model for the dominant (l=2,m=±2)(l=2, m=\pm 2) mode and discuss mode mixing for the (l=3,m=±2)(l=3, m=\pm 2) mode. The model is calibrated to numerical relativity solutions of the full Einstein equations up to mass ratio 18, and to numerical solutions of the Teukolsky equations for higher mass ratios. This work complements the latest generation of traditional frequency domain phenomenological models (IMRPhenomX), and provides new avenues to develop computationally efficient models for gravitational wave signals from generic compact binaries

    Eccentric binary black holes: Comparing numerical relativity and small mass-ratio perturbation theory

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    The modelling of unequal mass binary black hole systems is of high importanceto detect and estimate parameters from these systems. Numerical relativity (NR)is well suited to study systems with comparable component masses, m_1\simm_2, whereas small mass ratio (SMR) perturbation theory applies to binarieswhere q=m2/m1asafunctionofmassratioforeccentricnon−spinningbinaryblackholes.Weproduceq=m_2/m_1as a function of mass ratio for eccentric non-spinning binary black holes. Weproduce 52NRsimulationswithmassratiosbetween NR simulations with mass ratios between 1:10and and 1:1andinitialeccentricitiesupto andinitial eccentricities up to 0.7$. From these we extract quantities likegravitational wave energy and angular momentum fluxes and periastron advance,and assess their accuracy. To facilitate comparison, we develop tools to mapbetween NR and SMR inspiral evolutions of eccentric binary black holes. Wederive post-Newtonian accurate relations between different definitions ofeccentricity. Based on these analyses, we introduce a new definition ofeccentricity based on the (2,2)-mode of the gravitational radiation, whichreduces to the Newtonian definition of eccentricity in the Newtonian limit.From the comparison between NR simulations and SMR results, we quantify theunknown next-to-leading order SMR contributions to the gravitational energy andangular momentum fluxes, and periastron advance. We show that in the comparablemass regime these contributions are subdominant and higher order SMRcontributions are negligible.<br
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