16,793 research outputs found
Remote sensing X-ray spectrometer
Spectrometer measures chemical composition of lunar rocks by remote sensing from orbit and senses lunar X-rays produced by interaction of solar X-rays and elements on the lunar surface. Instrument features high sensitivity, data handling system that accumulates and prepares data for telemetry, and automatic calibration
Black Extended Objects, Naked Singularities and P-Branes
We treat the horizons of charged, dilaton black extended objects as quantum
mechanical objects. We show that the S matrix for such an object can be written
in terms of a p-brane-like action. The requirements of unitarity of the S
matrix and positivity of the p-brane tension equivalent severely restrict the
number of space-time dimensions and the allowed values of the dilaton parameter
a. Generally, black objects transform at the extremal limit into p-branes.Comment: 9 pages, REVTE
Comment about pion electro-production and the axial form factors
The claim by Haberzettl (Phys.Rev.Lett.85 (2000) 3576) that the axial form
factor of the nucleon cannot be accessed through threshold pion
electroproduction is unfounded
Seasonal Emergence Patterns of Black Flies (Diptera: Simuliidae) in Northwestern Pennsylvania
A two-year emergence trap study of black flies at four sites in northwestern Pennsylvania yielded 1%3 individuals of nine species. The collections included Prosimulium mixtum, P. jU5cum, Stegapterna mutata, Simulium aureum, S. excisum (recorded for the first time from Pennsylvania), S. gauldingi, S. sp. nr. innacens, S. vittatum, and S. tuberasum. Species richness for all sites peaked during May. Emergence collections below a sewage plant effluent outfall represented fewer individuals and species than collections above the effluent outfall. Chromosomal analysis of supplementary larval collections revealed the IIIL-l and IS-7 sibling species of S. vittatum and the FG sibling of S. tuberasum
An Energy-Minimization Finite-Element Approach for the Frank-Oseen Model of Nematic Liquid Crystals: Continuum and Discrete Analysis
This paper outlines an energy-minimization finite-element approach to the
computational modeling of equilibrium configurations for nematic liquid
crystals under free elastic effects. The method targets minimization of the
system free energy based on the Frank-Oseen free-energy model. Solutions to the
intermediate discretized free elastic linearizations are shown to exist
generally and are unique under certain assumptions. This requires proving
continuity, coercivity, and weak coercivity for the accompanying appropriate
bilinear forms within a mixed finite-element framework. Error analysis
demonstrates that the method constitutes a convergent scheme. Numerical
experiments are performed for problems with a range of physical parameters as
well as simple and patterned boundary conditions. The resulting algorithm
accurately handles heterogeneous constant coefficients and effectively resolves
configurations resulting from complicated boundary conditions relevant in
ongoing research.Comment: 31 pages, 3 figures, 3 table
High Temperature Expansion Study of the Nishimori multicritical Point in Two and Four Dimensions
We study the two and four dimensional Nishimori multicritical point via high
temperature expansions for the distribution, random-bond, Ising model.
In we estimate the the critical exponents along the Nishimori line to be
, . These, and earlier estimates
, are remarkably close to the critical
exponents for percolation, which are known to be , in
and and in . However, the
estimated Nishimori exponents , , are
quite distinct from the percolation results ,
.Comment: 5 pages, RevTex, 3 postscript files; To appear in Physical Review
Symmetry Breaking for Matter Coupled to Linearized Supergravity From the Perspective of the Current Supermultiplet
We consider a generic supersymmetric matter theory coupled to linearized
supergravity, and analyze scenarios for spontaneous symmetry breaking in terms
of vacuum expectation values of components of the current supermultiplet. When
the vacuum expectation of the energy momentum tensor is zero, but the scalar
current or pseudoscalar current gets an expectation, evaluation of the
gravitino self energy using the supersymmetry current algebra shows that there
is an induced gravitino mass term. The structure of this term generalizes the
supergravity action with cosmological constant to theories with CP violation.
When the vacuum expectation of the energy momentum tensor is nonzero,
supersymmetry is broken; requiring cancellation of the cosmological constant
gives the corresponding generalized gravitino mass formula.Comment: 11 page
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