5,904 research outputs found
On the Existence of Radiation Gauges in Petrov type II spacetimes
The radiation gauges used by Chrzanowski (his IRG/ORG) for metric
reconstruction in the Kerr spacetime seem to be over-specified. Their
specification consists of five conditions: four, which we treat here as valid
gauge conditions, plus an additional condition on the trace of the metric
perturbation. In this work, we utilize a newly developed form of the perturbed
Einstein equations to establish a condition -- on a particular tetrad component
of the stress-energy tensor -- under which the full IRG/ORG can be imposed.
Using gauge freedom, we are able to impose the full IRG for Petrov type II and
type D backgrounds, using a different tetrad for each case. As a specific
example, we work through the process of imposing the IRG in a Schwarzschild
background, using a more traditional approach. Implications for metric
reconstruction using the Teukolsky curvature perturbations in type D spacetimes
are briefly discussed.Comment: 21 pages, uses iop style files. v2: proved a stronger result for type
II backgrounds, added a subsection on remaining gauge freedom in the full IRG
and improved calrity and readability throughout due to insightful referee
comments; published as Class. Quantum Grav. 24 (2007) 2367-238
Application of a Bayesian Method to Absorption Spectral-Line Finding in Simulated ASKAP Data
The large spectral bandwidth and wide field of view of the Australian SKA
Pathfinder radio telescope will open up a completely new parameter space for
large extragalactic HI surveys. Here we focus on identifying and parametrising
HI absorption lines which occur in the line of sight towards strong radio
continuum sources. We have developed a method for simultaneously finding and
fitting HI absorption lines in radio data by using multi-nested sampling, a
Bayesian Monte Carlo algorithm. The method is tested on a simulated ASKAP data
cube, and is shown to be reliable at detecting absorption lines in low
signal-to-noise data without the need to smooth or alter the data. Estimation
of the local Bayesian evidence statistic provides a quantitative criterion for
assigning significance to a detection and selecting between competing
analytical line-profile models.Comment: 8 pages, 5 figures and 1 table; accepted for publication in PAS
The Characterised Noise Hi source finder: Detecting Hi galaxies using a novel implementation of matched filtering
The spectral line datacubes obtained from the Square Kilometre Array (SKA)
and its precursors, such as the Australian SKA Pathfinder (ASKAP), will be
sufficiently large to necessitate automated detection and parametrisation of
sources. Matched filtering is widely acknowledged as the best possible method
for the automated detection of sources. This paper presents the Characterised
Noise Hi (CNHI) source finder, which employs a novel implementation of matched
filtering. This implementation is optimised for the 3-D nature of the planned
Wide-field ASKAP Legacy L-band All- sky Blind surveY's (WALLABY) Hi spectral
line observations. The CNHI source finder also employs a novel sparse
representation of 3-D objects, with a high compression rate, to implement Lutz
one-pass algorithm on datacubes that are too large to process in a single pass.
WALLABY will use ASKAP's phenomenal 30 square degree field of view to image
\sim 70% of the sky. It is expected that WALLABY will find 500 000 Hi galaxies
out to z \sim 0.2.Comment: Part of the 2012 PASA Source Finding Special Issue, 10 figure
Alien Registration- Whiting, William R. (Portland, Cumberland County)
https://digitalmaine.com/alien_docs/21994/thumbnail.jp
An Exploratory Study of Funding for Agricultural Communications Offices
The Department of Information and Publications at the University of Maryland serves the Maryland Cooperative Extension Service, the Maryland Agricultural Experiment Station, and the College of Agriculture
MORTGAGES - SUBROGATION OF A VOLUNTEER
After the marriage of the plaintiff to Victor Scheutz the latter\u27s mother conveyed certain property to Victor and his sister, Viola, subject to an outstanding mortgage which the grantees assumed. Immediately after the completion of this transaction Victor and Viola, with plaintiff joining to release her dower, executed deeds of reconveyance to their mother. Thereafter Victor, Viola, and their mother, and plaintiff used the premises as a summer cottage until 1939, when plaintiff was granted a divorce. In 1932 upon request by the mortgagee for part payment of the mortgage debt plaintiff paid it in full. In this action, instituted subsequent to the divorce, plaintiff seeks to be subrogated to the lien of the mortgagee. Held, plaintiff was a volunteer and may not invoke the relief sought. Schuetz v. Schuetz, 237 Wis. 1, 296 N. W. 70 (1941)
WILLS - CONSTRUCTION - LIMITATION OF DEFEASANCE CLAUSE
Testatrix died leaving as her only heirs at law and next of kin a son, Thomas, and a grandaughter, Malinda, to whom she devised her estate in approximately equal shares. At the time she executed her will Thomas was twenty-two years of age and unmarried and Malinda was eleven. The principal case turns on the construction of a clause in her will, devising a parcel of land to Malinda, which reads as follows: I give and bequeath ... the same to the said Malinda McK. Young and her children but if the said Malinda McK. Young shall die before she attains the full age of twenty-one years without having been married, but if she marries and dies without leaving child or children then in such a case I give the same to my said son, Thomas H. Young. Malinda married at the age of twenty-four and had issue, but both her husband and the child predeceased her. Devisees of the testatrix\u27 son, Thomas, claimed an executory interest in the property on Malinda\u27s death without surviving issue. Held, the fee vested in Malinda subject to defeasance on one event only, namely, if Malinda died without having married and borne a child before her twenty-first birthday. Young v. Munsey Trust Co., (App. D. C. 1940) III F. (2d) 514
SLANDER OF TITLE - NATURE OF THE ACTION - STATUTE OF LIMITATIONS
Plaintiff brought an action to recover damages occasioned by certain letters, alleged to be false and malicious, written by the defendant of and concerning the title to plaintiff\u27s property. Since the letters were written more than one year prior to the commencement of the action, defendant argued that the action was barred by a clause in the local statute of limitations providing that actions for libel and slander shall be commenced within one year after the cause of action shall have accrued. On the other hand the plaintiff asserted that the case came under the statute\u27s two-year limitation of actions for injury to the . . . rights of another, not arising on contract, and not herein especially enumerated . . . . Held, that the limitation as to commencement of actions for libel and slander applies whether the slander involves property or person. Woodard v. Pacific Fruit & Produce Co., (Ore. 1940) 106 P. (2d) 1043
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