9,351 research outputs found
The ACIGA Data Analysis programme
The Data Analysis programme of the Australian Consortium for Interferometric
Gravitational Astronomy (ACIGA) was set up in 1998 by the first author to
complement the then existing ACIGA programmes working on suspension systems,
lasers and optics, and detector configurations. The ACIGA Data Analysis
programme continues to contribute significantly in the field; we present an
overview of our activities.Comment: 10 pages, 0 figures, accepted, Classical and Quantum Gravity,
(Proceedings of the 5th Edoardo Amaldi Conference on Gravitational Waves,
Tirrenia, Pisa, Italy, 6-11 July 2003
Developments in GRworkbench
The software tool GRworkbench is an ongoing project in visual, numerical
General Relativity at The Australian National University. Recently, GRworkbench
has been significantly extended to facilitate numerical experimentation in
analytically-defined space-times. The numerical differential geometric engine
has been rewritten using functional programming techniques, enabling objects
which are normally defined as functions in the formalism of differential
geometry and General Relativity to be directly represented as function
variables in the C++ code of GRworkbench. The new functional differential
geometric engine allows for more accurate and efficient visualisation of
objects in space-times and makes new, efficient computational techniques
available. Motivated by the desire to investigate a recent scientific claim
using GRworkbench, new tools for numerical experimentation have been
implemented, allowing for the simulation of complex physical situations.Comment: 14 pages. To appear A. Moylan, S.M. Scott and A.C. Searle,
Developments in GRworkbench. Proceedings of the Tenth Marcel Grossmann
Meeting on General Relativity, editors M. Novello, S. Perez-Bergliaffa and R.
Ruffini. Singapore: World Scientific 200
Network sensitivity to geographical configuration
Gravitational wave astronomy will require the coordinated analysis of data
from the global network of gravitational wave observatories. Questions of how
to optimally configure the global network arise in this context. We have
elsewhere proposed a formalism which is employed here to compare different
configurations of the network, using both the coincident network analysis
method and the coherent network analysis method. We have constructed a network
model to compute a figure-of-merit based on the detection rate for a population
of standard-candle binary inspirals. We find that this measure of network
quality is very sensitive to the geographic location of component detectors
under a coincident network analysis, but comparatively insensitive under a
coherent network analysis.Comment: 7 pages, 4 figures, accepted for proceedings of the 4th Edoardo
Amaldi conference, incorporated referees' suggestions and corrected diagra
Functional programming framework for GRworkbench
The software tool GRworkbench is an ongoing project in visual, numerical
General Relativity at The Australian National University. Recently, the
numerical differential geometric engine of GRworkbench has been rewritten using
functional programming techniques. By allowing functions to be directly
represented as program variables in C++ code, the functional framework enables
the mathematical formalism of Differential Geometry to be more closely
reflected in GRworkbench . The powerful technique of `automatic
differentiation' has replaced numerical differentiation of the metric
components, resulting in more accurate derivatives and an order-of-magnitude
performance increase for operations relying on differentiation
Issues Arising In The International Missionary Council Study On The Christian Enterprise In China
https://place.asburyseminary.edu/firstfruitspapers/1105/thumbnail.jp
Pericentromeric organization at the fusion point of mouse Robertsonian translocation chromosomes
In mammals, Robertsonian (Rb) translocation (the joining of two telo/acrocentric chromosomes at their centromere to form a metacentric) is the most effective process in chromosomal evolution leading to speciation; its occurrence also affects human health (through the induction of trisomies) and the fertility of farm animals. To understand the mechanism of Rb translocation, we used the house mouse as a model system and studied the organization of pericentromeric satellite DNAs (satDNA) of telocentrics and Rb chromosomes, both minor and major satDNA. The chromosome-orientation fluorescence in situ hybridization (CO-FISH) technique was used to analyze the major satDNA. To detect the very small amount of minor satDNA, a procedure was developed that combines CO-FISH with primed in situ labeling and conventional FISH and is five times more sensitive than the CO-FISH procedure alone. It was found that both the major and the minor satDNA tandem repeats are oriented head-to-tail in telocentric and Rb chromosomes, and their polarity is always the same relative to the centromere. We suggest that all tandemly repetitive satDNAs in a species probably are locked into such a symmetry constraint as a universal consequence of chromosomal evolution. Rb translocation breakpoints were found localized within the minor satDNA of telocentrics, and these sequences contributed symmetrically to the formation of the centromeric region of the Rb chromosomes. These results are important for an understanding of the geometry of Rb translocations and suggest the study of DNA orientation as a new tool for investigating these rearrangements
Numerical wave optics and the lensing of gravitational waves by globular clusters
We consider the possible effects of gravitational lensing by globular
clusters on gravitational waves from asymmetric neutron stars in our galaxy. In
the lensing of gravitational waves, the long wavelength, compared with the
usual case of optical lensing, can lead to the geometrical optics approximation
being invalid, in which case a wave optical solution is necessary. In general,
wave optical solutions can only be obtained numerically. We describe a
computational method that is particularly well suited to numerical wave optics.
This method enables us to compare the properties of several lens models for
globular clusters without ever calling upon the geometrical optics
approximation, though that approximation would sometimes have been valid.
Finally, we estimate the probability that lensing by a globular cluster will
significantly affect the detection, by ground-based laser interferometer
detectors such as LIGO, of gravitational waves from an asymmetric neutron star
in our galaxy, finding that the probability is insignificantly small.Comment: To appear in: Proceedings of the Eleventh Marcel Grossmann Meetin
An Artistic Contemplative Inquiry: What arrives in co-contemplating assessment and evaluation
Contemporary arts-based inquiry invites us to linger in moments, to reflect upon our lives, our encounters, our relationships within the grander context of the worlds within which we dwell and those that we co-create. Here, we explore the landscape of the arts in relation to assessment and evaluation. Through a collaborative artistic contemplative inquiry, an emergent dialogue exploring assessment and evaluation is recorded and presented as a found poem, “What Arrives.” Our hope, when we embarked upon this artistic contemplation, was that we would evoke, provoke, and interrupt each other for the purpose of creating possibilities of alliance and (re)cognition when thinking about the arts, assessment, and evaluation
Robust Bayesian detection of unmodelled bursts
A Bayesian treatment of the problem of detecting an unmodelled gravitational
wave burst with a global network of gravitational wave observatories reveals
that several previously proposed statistics have implicit biases that render
them sub-optimal for realistic signal populations.Comment: 9 pages, 1 figure, submitted to CQG Amaldi proceedings special issu
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