23,363 research outputs found
Clients\u27 Internal Representations of Their Therapists
Thirteen adults in long-term individual psychotherapy were interviewed regarding their internal representations (defined as bringing to awareness the internalized image ) of their therapists. Results indicated that in the context of a good therapeutic relationship, clients\u27 internal representations combined auditory, visual, and kinesthetic (i.e., felt presence) modalities; were triggered when clients thought about past or future sessions, or when distressed; occurred in diverse locations; and varied in frequency, duration, and intensity. Clients felt positively about their representations and used them to introspect or influence therapy within sessions, beyond sessions, or both. The frequency of, comfort with, and use of clients\u27 internal representations increased over the course of therapy, and the representations benefited the therapy and therapeutic relationship. Therapists tended not to take a deliberate role in creating clients\u27 internal representations, and few clients discussed their internal representations with their therapists
Evidence of Skyrmion excitations about in n-Modulation Doped Single Quantum Wells by Inter-band Optical Transmission
We observe a dramatic reduction in the degree of spin-polarization of a
two-dimensional electron gas in a magnetic field when the Fermi energy moves
off the mid-point of the spin-gap of the lowest Landau level, . This
rapid decay of spin alignment to an unpolarized state occurs over small changes
to both higher and lower magnetic field. The degree of electron spin
polarization as a function of is measured through the magneto-absorption
spectra which distinguish the occupancy of the two electron spin states. The
data provide experimental evidence for the presence of Skyrmion excitations
where exchange energy dominates Zeeman energy in the integer quantum Hall
regime at
The Inverse Shapley Value Problem
For a weighted voting scheme used by voters to choose between two
candidates, the \emph{Shapley-Shubik Indices} (or {\em Shapley values}) of
provide a measure of how much control each voter can exert over the overall
outcome of the vote. Shapley-Shubik indices were introduced by Lloyd Shapley
and Martin Shubik in 1954 \cite{SS54} and are widely studied in social choice
theory as a measure of the "influence" of voters. The \emph{Inverse Shapley
Value Problem} is the problem of designing a weighted voting scheme which
(approximately) achieves a desired input vector of values for the
Shapley-Shubik indices. Despite much interest in this problem no provably
correct and efficient algorithm was known prior to our work.
We give the first efficient algorithm with provable performance guarantees
for the Inverse Shapley Value Problem. For any constant \eps > 0 our
algorithm runs in fixed poly time (the degree of the polynomial is
independent of \eps) and has the following performance guarantee: given as
input a vector of desired Shapley values, if any "reasonable" weighted voting
scheme (roughly, one in which the threshold is not too skewed) approximately
matches the desired vector of values to within some small error, then our
algorithm explicitly outputs a weighted voting scheme that achieves this vector
of Shapley values to within error \eps. If there is a "reasonable" voting
scheme in which all voting weights are integers at most \poly(n) that
approximately achieves the desired Shapley values, then our algorithm runs in
time \poly(n) and outputs a weighted voting scheme that achieves the target
vector of Shapley values to within error $\eps=n^{-1/8}.
Microlensing and the Search for Extraterrestrial Life
Are microlensing searches likely to discover planets that harbor life? Given
our present state of knowledge, this is a difficult question to answer. We
therefore begin by asking a more narrowly focused question: are conditions on
planets discovered via microlensing likely to be similar to those we experience
on Earth? In this paper I link the microlensing observations to the well-known
"Goldilocks Problem" (conditions on the Earth-like planets need to be "just
right"), to find that Earth-like planets discovered via microlensing are likely
to be orbiting stars more luminous than the sun. This means that light from the
planetary system's central star may contribute a significant fraction of the
baseline flux relative to the star that is lensed. Such blending of light from
the lens with light from the lensed source can, in principle, limit our ability
to detect these events. This turns out not to be a significant problem,
however. A second consequence of blending is the opportunity to determine the
spectral type of the lensed spectral type of the lensed star. This
circumstance, plus the possibility that finite-source-size effects are
important, implies that some meaningful follow-up observations are likely to be
possible for a subset Earth-like planets discovered via microlensing. In
addition, calculations indicate that reasonable requirements on the planet's
density and surface gravity imply that the mass of Earth-like planets is likely
to be within a factor of of an Earth mass.Comment: 15 pages, 2 figures. To be published in the Astrophysical Journa
Introduction
This volume of the Economic Policy Review, "Special issue on the economic effects of September 11," explores some of the key economic consequences of the attacks of September 11. The six articles that make up the volume address several important questions: how great were the losses in New York City on September 11 and in the difficult months thereafter? How much will the nation spend to prevent future attacks? Did the destruction of information and infrastructure impair the functioning of the payments and securities settlement systems, and what steps minimize further damage? Will these events hurt New York's future vitality and cause businesses and workers to retreat from the city? ; The six articles fall into three broad groups: 1) detailed accountings of economic costs--those incurred as a direct consequence of the September 11 attacks and those arising from efforts to prevent future attacks, 2) studies of the attacks' disruptive effects on the payments and securities settlement systems, and 3) analyses of New York City's prospects after September 11.Disaster relief ; Terrorism ; War - Economic aspects ; Economic conditions - New York (N.Y.) ; Federal Reserve District, 2nd
Dynamics of electromagnetic waves in Kerr geometry
Here we are interested to study the spin-1 particle i.e., electro-magnetic
wave in curved space-time, say around black hole. After separating the
equations into radial and angular parts, writing them according to the black
hole geometry, say, Kerr black hole we solve them analytically. Finally we
produce complete solution of the spin-1 particles around a rotating black hole
namely in Kerr geometry. Obviously there is coupling between spin of the
electro-magnetic wave and that of black hole when particles propagate in that
space-time. So the solution will be depending on that coupling strength. This
solution may be useful to study different other problems where the analytical
results are needed. Also the results may be useful in some astrophysical
contexts.Comment: 15 Latex pages, 4 Figures; Accepted for publication in Classical and
Quantum Gravit
Gravitational Flexion by Elliptical Dark Matter Haloes
We present equations for the gravitational lensing flexion expected for an
elliptical lens mass distribution. These can be reduced to one-dimensional
finite integrals, thus saving significant computing time over a full
two-dimensional calculation. We estimate constraints on galaxy halo
ellipticities for a range of potential future surveys, finding that the
constraints from the two different types of flexion are comparable and are up
to two orders of magnitude tighter than those from shear. Flexion therefore
appears to be a very promising potential tool for constraining the shapes of
galaxy haloes from future surveys.Comment: 7 pages, 5 figures, submitted to MNRA
Gravitational waves from binary systems in circular orbits: Convergence of a dressed multipole truncation
The gravitational radiation originating from a compact binary system in
circular orbit is usually expressed as an infinite sum over radiative multipole
moments. In a slow-motion approximation, each multipole moment is then
expressed as a post-Newtonian expansion in powers of v/c, the ratio of the
orbital velocity to the speed of light. The bare multipole truncation of the
radiation consists in keeping only the leading-order term in the post-Newtonian
expansion of each moment, but summing over all the multipole moments. In the
case of binary systems with small mass ratios, the bare multipole series was
shown in a previous paper to converge for all values v/c < 2/e, where e is the
base of natural logarithms. In this paper, we extend the analysis to a dressed
multipole truncation of the radiation, in which the leading-order moments are
corrected with terms of relative order (v/c)^2 and (v/c)^3. We find that the
dressed multipole series converges also for all values v/c < 2/e, and that it
coincides (within 1%) with the numerically ``exact'' results for v/c < 0.2.Comment: 9 pages, ReVTeX, 1 postscript figur
End of the cosmic neutrino energy spectrum
There may be a high-energy cutoff of neutrino events in IceCube data. In
particular, IceCube does not observe either continuum events above 2 PeV, or
the Standard Model Glashow-resonance events expected at 6.3 PeV. There are also
no higher energy neutrino signatures in the ANITA and Auger experiments. This
absence of high-energy neutrino events motivates a fundamental restriction on
neutrino energies above a few PeV. We postulate a simple scenario to terminate
the neutrino spectrum that is Lorentz-invariance violating, but with a limiting
neutrino velocity that is always smaller than the speed of light. If the
limiting velocity of the neutrino applies also to its associated charged
lepton, then a significant consequence is that the two-body decay modes of the
charged pion are forbidden above two times the maximum neutrino energy, while
the radiative decay modes are suppressed at higher energies. Such stabilized
pions may serve as cosmic ray primaries.Comment: 6 pages. Version to appear in PL
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Fracture-controlled gas hydrate systems in the northern Gulf of Mexico
High-angle, open mode fractures control the presence of natural gas hydrate in water-saturated clays at the Keathley Canyon 151 site in the northern Gulf of Mexico, which was investigated for gas hydrates as part of the Chevron Joint Industry Project drilling in 2005. We analyze logging-while-drilling resistivity images and infer that gas hydrate accumulated in situ in two modes: filling fractures and saturating permeable beds. High-angle hydrate-filled fractures are the most common mode for gas hydrate occurrence at this site, with most of these fractures dipping at angles of more than 40° and occurring between 220 and 300 m below seafloor. These fractures all strike approximately N–S, which agrees with the 165°SE–345°NW maximum horizontal stress direction determined from borehole breakouts and which aligns with local bathymetric contours. In one interval of hydrate-filled fractures, porosity increases with increasing hydrate saturation. We suggest that high pore pressure may have dilated sediments during fracture formation, causing this increase in porosity. Furthermore, the formation of gas hydrate may have heaved fractures apart, also increasing the formation porosity in this interval
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