5,414 research outputs found
Molecular Hydrogen Optical Depth Templates for FUSE Data Analysis
The calculation and use of molecular hydrogen optical depth templates to
quickly identify and model molecular hydrogen absorption features longward of
the Lyman edge at 912 Angstroms are described. Such features are commonly
encountered in spectra obtained by the Far Ultraviolet Spectroscopic Explorer
and also in spectra obtained by the Space Telescope Imaging Spectrograph,
albeit less commonly. Individual templates are calculated containing all the
Lyman and Werner transitions originating from a single rotational state (J'')
of the 0th vibrational level (v'') of the ground electronic state. Templates
are provided with 0.01 Angstrom sampling for doppler parameters ranging from 2
<= b <= 20 km s^-1 and rotational states 0 <= J'' <= 15. Optical depth
templates for excited vibrational states are also available for select doppler
parameters. Each template is calculated for a fiducial column density of
log[N(cm^-2)] = 21 and may be scaled to any column less than this value without
loss of accuracy. These templates will facilitate the determination of the
distribution of molecular hydrogen column density as a function of rotational
level. The use of these templates will free the user from the computationally
intensive task of calculating profiles for a large number of lines and allow
concentration on line profile or curve-of-growth fitting to determine column
densities and doppler parameters. The templates may be downloaded freely from
http://www.pha.jhu.edu/~stephan/h2ools2.htmlComment: 20 pages, 2 tables, 6 figures, submitted to PASP 02-04-2003 Accepted
for publication on 03-05-2003 with revisions, including modified fg1, modifed
fg6 to become fg2 to support improved error discussion. To appear in the June
2003 issue of the PAS
Oceanic tide maps and spherical harmonic coefficients from Geosat altimetry
Maps and tables for the global ocean tides, 69 degree N to 68 degree S, derived from two years of Geosat altimetry are presented. Global maps of local and Greenwich admittance of the (altimetric) ocean tide, and maps of amplitude and Greenwich phase lag of the ocean tide are shown for M(sub 2), S(sub 2), N(sub 2), O(sub 1), and K(sub 1). Larger scale maps of amplitude and phases are also shown for regional areas of special interest. Spherical harmonic coefficients of the ocean tide through degree and order 8 are tabulated for the six major constituents
Global Diffusion in a Realistic Three-Dimensional Time-Dependent Nonturbulent Fluid Flow
We introduce and study the first model of an experimentally realizable
three-dimensional time-dependent nonturbulent fluid flow to display the
phenomenon of global diffusion of passive-scalar particles at arbitrarily small
values of the nonintegrable perturbation. This type of chaotic advection,
termed {\it resonance-induced diffusion\/}, is generic for a large class of
flows.Comment: 4 pages, uuencoded compressed postscript file, to appear in Phys.
Rev. Lett. Also available on the WWW from http://formentor.uib.es/~julyan/,
or on paper by reques
Workplace harassment - a health issue: Anti-discrimination cases and work compensation claims
This article describes the adverse health-related effects of racial and sexual harassment elicited from files held by the Western Australian Equal Opportunity Commission where the complainant has nominated sexual or racial harassment as a ground of discrimination. Those results are compared with publicly available data on work-related stress claims obtained from the Compendium of Workers' Compensation Statistics Australia 2004-06, arising from allegations of harassment. Information gleaned from a survey of unreported court decisions (from publicly available legal data bases, such as www.austlii.edu.au and www.ohs.alert.com) is also reviewed. The purpose of examining this data is to consider the links between various forms of unlawful harassment, workplace stress and the evidence of adverse effect upon worker health. The results of this triangulation of data are consistent with that body of research which shows that workplace harassment can give rise to a range of adverse health outcomes. This paper explores how the inter-relationship of anti-discrimination and workers compensation laws may affect claimant behaviours
Information-theoretic significance of the Wigner distribution
A coarse grained Wigner distribution p_{W}(x,u) obeying positivity derives
out of information-theoretic considerations. Let p(x,u) be the unknown joint
PDF (probability density function) on position- and momentum fluctuations x,u
for a pure state particle. Suppose that the phase part Psi(x,z) of its Fourier
transform F.T.[p(x,u)]=|Z(x,z)|exp[iPsi(x,z)] is constructed as a hologram.
(Such a hologram is often used in heterodyne interferometry.) Consider a
particle randomly illuminating this phase hologram. Let its two position
coordinates be measured. Require that the measurements contain an extreme
amount of Fisher information about true position, through variation of the
phase function Psi(x,z). The extremum solution gives an output PDF p(x,u) that
is the convolution of the Wigner p_{W}(x,u) with an instrument function
defining uncertainty in either position x or momentum u. The convolution arises
naturally out of the approach, and is one-dimensional, in comparison with the
two-dimensional convolutions usually proposed for coarse graining purposes. The
output obeys positivity, as required of a PDF, if the one-dimensional
instrument function is sufficiently wide. The result holds for a large class of
systems: those whose amplitudes a(x) are the same at their boundaries
(Examples: states a(x) with positive parity; with periodic boundary conditions;
free particle trapped in a box).Comment: pdf version has 16 pages. No figures. Accepted for publ. in PR
Robust Magnetic Polarons in Type-II (Zn,Mn)Te Quantum Dots
We present evidence of magnetic ordering in type-II (Zn, Mn) Te quantum dots.
This ordering is attributed to the formation of bound magnetic polarons caused
by the exchange interaction between the strongly localized holes and Mn within
the dots. In our photoluminescence studies, the magnetic polarons are detected
at temperatures up to ~ 200 K, with a binding energy of ~ 40 meV. In addition,
these dots display an unusually small Zeeman shift with applied field (2 meV at
10 T). This behavior is explained by a small and weakly temperature-dependent
magnetic susceptibility due to anti-ferromagnetic coupling of the Mn spins
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