1,859 research outputs found
On the Structure of a Class of Archimedean Lattice-Ordered Algebras
By a Φ-algebra A, we mean an Archimedean lattice-ordered algebra over the real field R which has an identity element 1 that is a weak order unit. The Φ-algebras constitute the class of the title. It is shown that every ф-algebra is isomorphic to an algebra of continuous functions on a compact space X into the two-point compactification of the real line R, each of which is real-valued on an (open) everywhere dense subset of X. Under more restrictive assumptions on A, ropresentations of this sort have long been known. An (incomplete) history of them is given briefly in Section 2
An investigation of the effects of urban expansion on the taxation of real property in west central Missouri
Digitized 2007 AES MoU.Includes bibliographical references (pages 55-56)
G protein beta gamma subunits synthesized in Sf9 cells. Functional characterization and the significance of prenylation of gamma
Heterotrimeric guanine nucleotide-binding regulatory proteins (G proteins) consist of a nucleotide-binding alpha subunit and a high- affinity complex of beta and gamma subunits. There is molecular heterogeneity of beta and gamma, but the significance of this diversity is poorly understood. Different G protein beta and gamma subunits have been expressed both singly and in combinations in Sf9 cells. Although expression of individual subunits is achieved in all cases, beta gamma subunit activity (support of pertussis toxin-catalyzed ADP-ribosylation of rGi alpha 1) is detected only when beta and gamma are expressed concurrently. Of the six combinations of beta gamma tested (beta 1 or beta 2 with gamma 1, gamma 2, or gamma 3), only one, beta 2 gamma 1, failed to generate a functional complex. Each of the other five complexes has been purified by subunit exchange chromatography using Go alpha-agarose as the chromatographic matrix. We have detected differences in the abilities of the purified proteins to support ADP- ribosylation of Gi alpha 1; these differences are attributable to the gamma component of the complex. When assayed for their ability to inhibit calmodulin-stimulated type-I adenylylcyclase activity or to potentiate Gs alpha-stimulated type-II adenylylcyclase, recombinant beta 1 gamma 1 and transducin beta gamma are approximately 10 and 20 times less potent, respectively, than the other complexes examined. Prenylation and/or further carboxyl-terminal processing of gamma are not required for assembly of the beta gamma subunit complex but are indispensable for high affinity interactions of beta gamma with either G protein alpha subunits or adenylylcyclases
Gravitating Fluxbranes
We consider the effect that gravity has when one tries to set up a constant
background form field. We find that in analogy with the Melvin solution, where
magnetic field lines self-gravitate to form a flux-tube, the self-gravity of
the form field creates fluxbranes. Several exact solutions are found
corresponding to different transverse spaces and world-volumes, a dilaton
coupling is also considered.Comment: 14 pages, 5 figure
Higher Order Terms in the Melvin-Morton Expansion of the Colored Jones Polynomial
We formulate a conjecture about the structure of `upper lines' in the
expansion of the colored Jones polynomial of a knot in powers of (q-1). The
Melvin-Morton conjecture states that the bottom line in this expansion is equal
to the inverse Alexander polynomial of the knot. We conjecture that the upper
lines are rational functions whose denominators are powers of the Alexander
polynomial. We prove this conjecture for torus knots and give experimental
evidence that it is also true for other types of knots.Comment: 21 pages, 1 figure, LaTe
Disks around massive young stellar objects: are they common?
We present K-band polarimetric images of several massive young stellar
objects at resolutions 0.1-0.5 arcsec. The polarization vectors around
these sources are nearly centro-symmetric, indicating they are dominating the
illumination of each field. Three out of the four sources show elongated
low-polarization structures passing through the centers, suggesting the
presence of polarization disks. These structures and their surrounding
reflection nebulae make up bipolar outflow/disk systems, supporting the
collapse/accretion scenario as their low-mass siblings. In particular, S140
IRS1 show well defined outflow cavity walls and a polarization disk which
matches the direction of previously observed equatorial disk wind, thus
confirming the polarization disk is actually the circumstellar disk. To date, a
dozen massive protostellar objects show evidence for the existence of disks;
our work add additional samples around MYSOs equivalent to early B-type stars.Comment: 9 pages, including 2 figures, 1 table, to appear on ApJ
Pair creation of black holes joined by cosmic strings
We argue that production of charged black hole pairs joined by a cosmic
string in the presence of a magnetic field can be analyzed using the Ernst
metric. The effect of the cosmic string is to pull the black holes towards each
other, opposing to the background field. An estimation of the production rate
using the Euclidean action shows that the process is suppressed as compared to
the formation of black holes without strings.Comment: 7 pages, LaTeX. Minor typos corrected
Suicide prevention and mood disorders: Self-exclusion agreements for firearms as a suicide prevention strategy
Suicide involves a complex set of behaviors and emotions that lead up to actions that may be based on planning and forethought or the result of impulse. While there are a host of antecedent circumstances the presence of a mood disorder, primarily depression, is the most common factor in suicide. While management of depression is recognized as important prevention strategy in depression, the means by which suicide occurs must be a critical element of prevention. Policies that lower access to the means for suicide will decrease the fatality. Guns are associated with half of suicides and the case fatality rate of gun associated suicide is over 90% compared to 7% for all other means. This emphasizes the importance of offering strategies that limit access to guns to those at higher risk for suicide. A declaration of formal self-exclusion for access to firearms (guns and ammunition) offers the individual at greater risk for suicide to place themselves on an official list that would prevent them from purchasing lethal weapons. A person with depression, when well, might wish to enroll voluntarily to prevent themselves, when ill, from procuring a weapon to harm themselves or others. This recognizes the autonomy of the person and protects both the individual, the family, and society
Radiationless Travelling Waves In Saturable Nonlinear Schr\"odinger Lattices
The longstanding problem of moving discrete solitary waves in nonlinear
Schr{\"o}dinger lattices is revisited. The context is photorefractive crystal
lattices with saturable nonlinearity whose grand-canonical energy barrier
vanishes for isolated coupling strength values. {\em Genuinely localised
travelling waves} are computed as a function of the system parameters {\it for
the first time}. The relevant solutions exist only for finite velocities.Comment: 5 pages, 4 figure
An equatorial wind from the massive young stellar object S140 IRS 1
The discovery of the second equatorial ionized stellar wind from a massive
young stellar object is reported. High resolution radio continuum maps of S140
IRS 1 reveal a highly elongated source that is perpendicular to the larger
scale bipolar molecular outflow. This picture is confirmed by location of a
small scale monopolar near-IR reflection nebula at the base of the blueshifted
lobe. A second epoch of observations over a five year baseline show little
ordered outward proper motion of clumps as would have been expected for a jet.
A third epoch, taken only 50 days after the second, did show significant
changes in the radio morphology. These radio properties can all be understood
in the context of an equatorial wind driven by radiation pressure from the
central star and inner disc acting on the gas in the surface layers of the disc
as proposed by Drew et al. (1998). This equatorial wind system is briefly
compared with the one in S106IR, and contrasted with other massive young
stellar objects that drive ionized jets.Comment: 19 pages, 5 figures, accepted by ApJ, minor changes in light of
referees repor
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