6,376 research outputs found
Dynamic Normalization for Compact Binary Coalescence Searches in Non-Stationary Noise
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
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 ACTAâs 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 âwarâ on file-sharers, users of generic medicines, and manufacturers, sellers, and buyers of imitative goods and services â in sum, a large portion of the worldâs 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
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
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
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 âhind- castâ, 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
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CO and CI maps of the starburst galaxy M82
The first map of an external galaxy in the 3Pâ - 3P0 fine-structure line of atomic carbon (CI) is presented towards the nucleus of the starbuster M82, and compared with the distinction of the CO J = 4 - 3 molecular emission. The CI traces features that are seen in lower transition CO maps, and shows that CI and the CO are well mixed and have similar spatial distributions. There are small differences between the CO J = 4 - 3 line and lower transition CO data towards the NE part of the molecular ring, where the emission is less prominent. The abundance ratio [CI]/[CO] across M82 is very high, with an average value ~ 0.5 across most of the nucleus, a factor at least 5 times that which is typical of dense molecular cloud cores seen in our own Galaxy. This means that on average, CI is overabundant towards M82. This result can be explained using models which provide enhancements to the CI abundance above normal Interstellar Medium values, a result of a greater cosmic ray flux in M82, or where there is substantial mixing of the gas
Magnetic Helicity in Sphaleron Debris
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
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: Sm/Sm and
Lu/Lu. These ratios unambiguously determine the spectrum index
and core temperature. The effective neutron absorption cross section of
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 Sm even more . Then, these limits were
converted to the limits for the change of the fine structure constant .
We found that for the rate of change the inequality is fulfilled, which is of the next
higher order than our previous limit.Comment: 16 pages, 7 figure
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