6,494 research outputs found

    Dynamic Normalization for Compact Binary Coalescence Searches in Non-Stationary Noise

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    The output of gravitational-wave interferometers, such as LIGO and Virgo, can be highly non-stationary. Broadband detector noise can affect the detector sensitivity on the order of tens of seconds. Gravitational-wave transient searches, such as those for colliding black holes, estimate this noise in order to identify gravitational-wave events. During times of non-stationarity we see a higher rate of false events being reported. To accurately separate signal from noise, it is imperative to incorporate the changing detector state into gravitational-wave searches. We develop a new statistic which estimates the variation of the interferometric detector noise. We use this statistic to re-rank candidate events identified during LIGO-Virgo's second observing run by the PyCBC search pipeline. This results in a 7% improvement in the sensitivity volume for low mass binaries, particularly binary neutron stars mergers

    Flouting the Elmo Necessity and Denying the Local Roots of Interpretation: Anthropology\u27s Quarrel with ACTA and Authoritarian IP Regimes

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    This paper uses an anthropological definition of culture to examine the intensification of intellectual property policing, coupled with an expansion of its definition. These are ACTA’s aims. I argue that acts of sharing lie at the root of communication; humans must share in order to learn. Furthermore, symbols change their meaning as they circulate in different cultural contexts. Therefore, in denying the fundamental importance of sharing and local interpretation, ACTA will not only fail spectacularly as a policy document. It will also fuel a “war” on file-sharers, users of generic medicines, and manufacturers, sellers, and buyers of imitative goods and services – in sum, a large portion of the world’s population. This avoidable war will be costly, and it will be detrimental to public interests and global health

    Probing the Gravitational Wave Signature from Cosmic Phase Transitions at Different Scales

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    We present a new signature by which to one could potentially discriminate between a spectrum of gravitational radiation generated by a self-ordering scalar field vs that of inflation, specifically a comparison of the magnitude of a flat spectrum at frequencies probed by future direct detection experiments to the magnitude of a possible polarization signal in the Cosmic Microwave Background (CMB) radiation. In the process we clarify several issues related to the proper calculation of such modes, focusing on the effect of post-horizon-crossing evolution.Comment: 4 pages, Phys. Rev D version (revised in response to referee's comments

    Further Results on the Probability Theory of Capacity Value of Additional Generation

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    New theoretical results regarding the capacity value of additional generation are presented, the motivation being explanation of results from applied renewables integration studies. Of particular note are the dependence of calculated values on underlying risk level for any capacity of additional generation, the upper limit on capacity value where there is a given probability of near-zero available capacity, and a closed form result for the case where the distribution of available existing capacity may be approximated as an exponential function. Examples of how these main results may be applied are presented

    Estimation of Joint Distribution of Demand and Available Renewables for Generation Adequacy Assessment

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    In recent years there has been a resurgence of interest in generation adequacy risk assessment, due to the need to include variable generation renewables within such calculations. This paper will describe new statistical approaches to estimating the joint distribution of demand and available VG capacity; this is required for the LOLE calculations used in many statutory adequacy studies, for example those of GB and PJM. The most popular estimation technique in the VG-integration literature is ‘hind- cast’, in which the historic joint distribution of demand and available VG is used as a predictive distribution. Through the use of bootstrap statistical analysis, this paper will show that due to extreme sparsity of data on times of high demand and low VG, hindcast results can suffer from sampling uncertainty to the extent that they have little practical meaning. An alternative estimation approach, in which a marginal distribution of available VG is rescaled according to demand level, is thus proposed. This reduces sampling uncertainty at the expense of the additional model structure assumption, and further provides a means of assessing the sensitivity of model out- puts to the VG-demand relationship by varying the function of demand by which the marginal VG distribution is rescaled

    Magnetic Helicity in Sphaleron Debris

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    We develop an analytical technique to evaluate the magnetic helicity in the debris from sphaleron decay. We show that baryon number production leads to left-handed magnetic fields, and that the magnetic helicity is conserved at late times. Our analysis explicitly demonstrates the connection between sphaleron-mediated cosmic baryogenesis and cosmic magnetogenesis.Comment: 9 pages, 1 figure. v2: Minor revisions; matches published version in Physical Review

    Investigation of the fundamental constants stability based on the reactor Oklo burn-up analysis

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    The burn-up for SC56-1472 sample of the natural Oklo reactor zone 3 was calculated using the modern Monte Carlo codes. We reconstructed the neutron spectrum in the core by means of the isotope ratios: 147^{147}Sm/148^{148}Sm and 176^{176}Lu/175^{175}Lu. These ratios unambiguously determine the spectrum index and core temperature. The effective neutron absorption cross section of 149^{149}Sm calculated using this spectrum was compared with experimental one. The disagreement between these two values allows to limit a possible shift of the low laying resonance of 149^{149}Sm even more . Then, these limits were converted to the limits for the change of the fine structure constant α\alpha. We found that for the rate of α\alpha change the inequality âˆŁÎŽÎ±Ë™/Î±âˆŁâ‰€5⋅10−18|\delta \dot{\alpha}/\alpha| \le 5\cdot 10^{-18} is fulfilled, which is of the next higher order than our previous limit.Comment: 16 pages, 7 figure
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