1,209 research outputs found
Integrating multiple knowledge bases within Google Desktop
Google is clearly the preferred solution when searching for information. However, how does one search for information within proprietary knowledge bases? We believe that we can use the power of Google Desktop (GD) as a repository and search mechanism for local proprietary knowledge. We have constructed a multi-socketed server (using C++) which allows network clients explicit control of textual input to GD. Using the ATL/COM interface, our software registers as a GD plug-in. Our server supports GD API "events", such as note, email, and instant message, and processes events at approximately 10/s. To test the effectiveness of the system, we downloaded 600,000 posts from a popular, public threaded discussion forum and 150,000 posts from a subscription-based forum. Our server partitions these knowledge sets so that they can be independently searched. We found that when compared to forum string search functions, our partitioned GD search tool produced significantly superior results.CableLabs Favorite
Monochloroamine with Grignard Reagents
Certain Grignard reagents react with monochloroamine in dry ether solution to form amines. There is a wide variation in the amount of amine produced. In some cases considerable ammonia is formed. With benzyl magnesium chloride, which thus far has given the best yield of amine, an 80 to 90% yield based on the monochloroamine is obtained
Gravitational Radiation from Nonaxisymmetric Instability in a Rotating Star
We present the first calculations of the gravitational radiation produced by
nonaxisymmetric dynamical instability in a rapidly rotating compact star. The
star deforms into a bar shape, shedding of its mass and
of its angular momentum. The gravitational radiation is calculated in the
quadrupole approximation. For a mass M and radius km, the gravitational waves have frequency kHz and amplitude
at the distance of the Virgo Cluster. They carry off
energy and radiate angular momentum .Comment: 16 pages, LaTeX with REVTEX macros, reprints available - send mailing
address to [email protected]. Published: PRL 72, 1314 (1994
Evaluation of Seasonal Water Budget Components over the Major Drainage Basins of North America Using an Ensemble-Based Land Surface Model Approach
An ensemble of land surface models and forcing data was developed to assess variability in SWE estimation over North America. In this study, the ensemble output was used to assess how SWE uncertainty impacts stream flow estimation. The analysis was conducted by major basins of North America over the 2009-2017 time period
Gravitational Radiation from Rotational Instabilities in Compact Stellar Cores with Stiff Equations of State
We carry out 3-D numerical simulations of the dynamical instability in
rapidly rotating stars initially modeled as polytropes with n = 1.5, 1.0, and
0.5. The calculations are done with a SPH code using Newtonian gravity, and the
gravitational radiation is calculated in the quadrupole limit. All models
develop the global m=2 bar mode, with mass and angular momentum being shed from
the ends of the bar in two trailing spiral arms. The models then undergo
successive episodes of core recontraction and spiral arm ejection, with the
number of these episodes increasing as n decreases: this results in
longer-lived gravitational wave signals for stiffer models. This instability
may operate in a stellar core that has expended its nuclear fuel and is
prevented from further collapse due to centrifugal forces. The actual values of
the gravitational radiation amplitudes and frequencies depend sensitively on
the radius of the star R_{eq} at which the instability develops.Comment: 39 pages, uses Latex 2.09. To be published in the Dec. 15, 1996 issue
of Physical Review D. 21 figures (bitmapped). Originals available in
compressed Postscript format at ftp://zonker.drexel.edu/papers/bars
Heart and en-bloc thymus transplantation in miniature swine
BackgroundDonor-specific tolerance to organ allografts might be induced by cotransplantation of a sufficient amount of vascularized donor thymus. To facilitate donor thymus-induced cardiac allograft tolerance, we have developed a novel technique for heart and en-bloc thymus transplantation in swine.MethodsDonor heart and en-bloc thymus grafts were prepared by a technique that preserves the entire arterial supply and venous drainage of the right thymic lobe. En-bloc grafts (n = 4) were transplanted heterotopically into the abdomens of major histocompatibility complex-matched miniature swine. Recipients received 12 days of cyclosporine intravenously. Grafts were monitored by palpation, electrocardiographic monitoring, and periodic open biopsy. Engraftment of the donor thymus was demonstrated by measuring the proportion of recipient-type thymocytes in the donor thymus with flow cytometry.ResultsAll of the heart and en-bloc thymus grafts had normal cardiac contractility and immediate perfusion of the thymus. All en-bloc grafts were accepted for more than 200 days without significant acute cellular rejection or cardiac allograft vasculopathy. Thymic tissue of en-bloc grafts displayed normal architecture and supported thymopoiesis of recipient-type cells.ConclusionWe have validated a new technique of donor thymus transplantation that could have utility in human heart transplantation
Comparison of advanced gravitational-wave detectors
We compare two advanced designs for gravitational-wave antennas in terms of
their ability to detect two possible gravitational wave sources. Spherical,
resonant mass antennas and interferometers incorporating resonant sideband
extraction (RSE) were modeled using experimentally measurable parameters. The
signal-to-noise ratio of each detector for a binary neutron star system and a
rapidly rotating stellar core were calculated. For a range of plausible
parameters we found that the advanced LIGO interferometer incorporating RSE
gave higher signal-to-noise ratios than a spherical detector resonant at the
same frequency for both sources. Spheres were found to be sensitive to these
sources at distances beyond our galaxy. Interferometers were sensitive to these
sources at far enough distances that several events per year would be expected
Gravitational Waves from the Dynamical Bar Instability in a Rapidly Rotating Star
A rapidly rotating, axisymmetric star can be dynamically unstable to an m=2
"bar" mode that transforms the star from a disk shape to an elongated bar. The
fate of such a bar-shaped star is uncertain. Some previous numerical studies
indicate that the bar is short lived, lasting for only a few bar-rotation
periods, while other studies suggest that the bar is relatively long lived.
This paper contains the results of a numerical simulation of a rapidly rotating
gamma=5/3 fluid star. The simulation shows that the bar shape is long lived:
once the bar is established, the star retains this shape for more than 10
bar-rotation periods, through the end of the simulation. The results are
consistent with the conjecture that a star will retain its bar shape
indefinitely on a dynamical time scale, as long as its rotation rate exceeds
the threshold for secular bar instability. The results are described in terms
of a low density neutron star, but can be scaled to represent, for example, a
burned-out stellar core that is prevented from complete collapse by centrifugal
forces. Estimates for the gravitational-wave signal indicate that a dynamically
unstable neutron star in our galaxy can be detected easily by the first
generation of ground based gravitational-wave detectors. The signal for an
unstable neutron star in the Virgo cluster might be seen by the planned
advanced detectors. The Newtonian/quadrupole approximation is used throughout
this work.Comment: Expanded version to be published in Phys. Rev. D: 13 pages, REVTeX,
13 figures, 9 TeX input file
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