2,234 research outputs found
STICAP: A linear circuit analysis program with stiff systems capability. Volume 3: Systems
For abstract, see N76-13798
CONSTITUTIONAL STANDOFF: AN EXAMPLE OF PRACTICAL DIFFICULTY IN MISSISSIPPI VENUE RULES
Mississippi’s legislature and judiciary have been locked in a constitutional standoff over procedural rulemaking power for decades. In an article describing the history of the conflict, author William H. Page has predicted that the situation will inevitably lead to “practical difficulties” down the road. Years later, given ongoing conflicts among various aspects of civil procedure in Mississippi, that prediction is beginning to appear prescient. A prime example has developed in Mississippi’s venue rules.
This Comment has three goals. First, it seeks to resurface Page’s discussion of the “constitutional standoff.”3 Second, it describes how Page was likely correct in predicting that practical difficulties would arise down the road and provides an example in the form of present conflicts between Mississippi venue rules. Finally, it discusses potential solutions to the narrow issue of venue, ultimately concluding that a more cooperative process between the legislature and the judiciary is needed to prevent similar problems from arising in the future.
Part II of this article provides (1) a brief recitation of how the constitutional standoff between the two branches came about, (2) a short history of Mississippi’s venue rules, (3) an explanation of how the standoff has potentially led to a practical difficulty in satisfying venue requirements, and (4) an explanation of the foundational concepts and federal model of venue to provide context for the analysis. Part III describes how Mississippi’s venue rules present practical difficulties; this includes the narrow issue of venue, the broad issue of the constitutional standoff, and potential answers to these problems. Part IV will conclude with final thoughts and a proposed solution to this longstanding problem
Twenty Years of Searching for (and Finding) Globular Cluster Pulsars
Globular clusters produce orders of magnitude more millisecond pulsars per
unit mass than the Galactic disk. Since the first cluster pulsar was uncovered
twenty years ago, at least 138 have been identified - most of which are binary
millisecond pulsars. Because of their origins involving stellar encounters,
many of these systems are exotic objects that would never be observed in the
Galactic disk. Examples include pulsar-main sequence binaries, extremely rapid
rotators (including the current record holder), and millisecond pulsars in
highly eccentric orbits. These systems are allowing new probes of the
interstellar medium, the equation of state of material at supra-nuclear
density, the mass distribution of neutron stars, and the dynamics of globular
clusters.Comment: 9 pages, 6 figures. Submitted review for the "40 Years of Pulsars"
conference in Montreal, Aug 2007. To be published by the AI
The Timing of Nine Globular Cluster Pulsars
We have used the Robert C. Byrd Green Bank Telescope to time nine previously
known pulsars without published timing solutions in the globular clusters M62,
NGC 6544, and NGC 6624. We have full timing solutions that measure the spin,
astrometric, and (where applicable) binary parameters for six of these pulsars.
The remaining three pulsars (reported here for the first time) were not
detected enough to establish solutions. We also report our timing solutions for
five pulsars with previously published solutions, and find good agreement with
past authors, except for PSR J1701-3006B in M62. Gas in this system is probably
responsible for the discrepancy in orbital parameters, and we have been able to
measure a change in the orbital period over the course of our observations.
Among the pulsars with new solutions we find several binary pulsars with very
low mass companions (members of the so-called "black widow" class) and we are
able to place constraints on the mass-to-light ratio in two clusters. We
confirm that one of the pulsars in NGC 6624 is indeed a member of the rare
class of non-recycled pulsars found in globular clusters. We also have measured
the orbital precession and Shapiro delay for a relativistic binary in NGC 6544.
If we assume that the orbital precession can be described entirely by general
relativity, which is likely, we are able to measure the total system mass
(2.57190(73) M_sun) and companion mass (1.2064(20) M_sun), from which we derive
the orbital inclination [sin(i) = 0.9956(14)] and the pulsar mass (1.3655(21)
M_sun), the most precise such measurement ever obtained for a millisecond
pulsar. The companion is the most massive known around a fully recycled pulsar.Comment: Published in ApJ; 33 pages, 5 figures, 7 table
The Eccentric Binary Millisecond Pulsar in NGC 1851
PSR J0514-4002A is a 5-ms pulsar is located in the globular cluster NGC 1851;
it belongs to a highly eccentric (e = 0.888) binary system. It is one of the
earliest known examples of a numerous and fast-growing class of eccentric
binary MSPs recently discovered in globular clusters. Using the GBT, we have
obtained a phase-coherent timing solution for the pulsar, which includes a
measurement of the rate of advance of periastron: 0.01289(4) degrees per year,
which if due completely to general relativity, implies a total system mass of
2.453(14) solar masses. We also derive m_p 0.96
solar masses. The companion is likely to be a massive white dwarf star.Comment: 3 pages, including 2 figures. To appear in the proceedings of "40
Years of Pulsars: Millisecond Pulsars, Magnetars, and More", August 12-17,
2007, McGill University, Montreal, Canad
GMRT Discovery of A Millisecond Pulsar in a Very Eccentric Binary System
We report the discovery of the binary millisecond pulsar J0514-4002A, which
is the first known pulsar in the globular cluster NGC 1851 and the first pulsar
discovered using the Giant Metrewave Radio Telescope (GMRT). The pulsar has a
rotational period of 4.99 ms, an orbital period of 18.8 days, and the most
eccentric pulsar orbit yet measured (e = 0.89). The companion has a minimum
mass of 0.9 M_sun and its nature is presently unclear. After accreting matter
from a low-mass companion star which spun it up to a (few) millisecond spin
period, the pulsar eventually exchanged the low-mass star for its more massive
present companion. This is exactly the same process that could form a system
containing a millisecond pulsar and a black hole; the discovery of NGC 1851A
demonstrates that such systems might exist in the Universe, provided that
stellar mass black holes exist in globular clusters.Comment: 12 pages (referee format), 3 figures, accepted for publication in
Astrophysical Journal Letter
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