5,131 research outputs found
Experiments on the effectiveness of marketing communications tactics to support ‘unappealing’ animals
This study was designed for investigating how effective different marketing communications
tactics are at influencing donations to animal conservation campaigns featuring ‘unappealing’
(non-flagship) species. Experiments were executed to evaluate the effectiveness of celebrity
endorsements, anthropomorphism, message framing, and personal incentives in fictitious
animal conservation adverts. Results showed that urgent message tone was not successful at
gaining support for non-flagship campaigns but combining anthropomorphism with positive
message did increase support for nonflagship causes. Celebrity endorsements were shown to
be successful at influencing willingness to donate, provided that the celebrity is highly
credible in the world of animal conservation. Offering personal incentives to influence
donations achieved its purpose when used in campaigns featuring ‘popular’ animals, but it
was not a successful marketing tactic when used to promote ‘undesirable’ animals.
Interestingly, the results revealed that participants were strongly influenced to donate to a
non-flagship campaign when they believed that it would result in wider environmental
benefits that would also be beneficial to humans. Overall, a participant’s prior knowledge or
preference for a specific species had a great influence over donation choice. However, this
study has revealed that through effective marketing participants can be swayed to support
‘undesirable’ animals instead of typically ‘preferred’ specie
Quantitative Photo-acoustic Tomography with Partial Data
Photo-acoustic tomography is a newly developed hybrid imaging modality that
combines a high-resolution modality with a high-contrast modality. We analyze
the reconstruction of diffusion and absorption parameters in an elliptic
equation and improve an earlier result of Bal and Uhlmann to the partial date
case. We show that the reconstruction can be uniquely determined by the
knowledge of 4 internal data based on well-chosen partial boundary conditions.
Stability of this reconstruction is ensured if a convexity condition is
satisfied. Similar stability result is obtained without this geometric
constraint if 4n well-chosen partial boundary conditions are available, where
is the spatial dimension. The set of well-chosen boundary measurements is
characterized by some complex geometric optics (CGO) solutions vanishing on a
part of the boundary.Comment: arXiv admin note: text overlap with arXiv:0910.250
Simulating the collapse transition of a two-dimensional semiflexible lattice polymer
It has been revealed by mean-field theories and computer simulations that the
nature of the collapse transition of a polymer is influenced by its bending
stiffness . In two dimensions, a recent analytical work
demonstrated that the collapse transition of a partially directed lattice
polymer is always first-order as long as is positive
[H. Zhou {\em et al.}, Phys. Rev. Lett. {\bf 97}, 158302 (2006)]. Here we
employ Monte Carlo simulation to investigate systematically the effect of
bending stiffness on the static properties of a 2D lattice polymer. The
system's phase-diagram at zero force is obtained. Depending on and the temperature , the polymer can be in one of three phases:
crystal, disordered globule, or swollen coil. The crystal-globule transition is
discontinuous, the globule-coil transition is continuous. At moderate or high
values of the intermediate globular phase disappears and the
polymer has only a discontinuous crystal-coil transition. When an external
force is applied, the force-induced collapse transition will either be
continuous or discontinuous, depending on whether the polymer is originally in
the globular or the crystal phase at zero force. The simulation results also
demonstrate an interesting scaling behavior of the polymer at the force-induced
globule-coil transition.Comment: 16 page
Quantum Chaos of Bogoliubov Waves for a Bose-Einstein Condensate in Stadium Billiards
We investigate the possibility of quantum (or wave) chaos for the Bogoliubov
excitations of a Bose-Einstein condensate in billiards. Because of the mean
field interaction in the condensate, the Bogoliubov excitations are very
different from the single particle excitations in a non-interacting system.
Nevertheless, we predict that the statistical distribution of level spacings is
unchanged by mapping the non-Hermitian Bogoliubov operator to a real symmetric
matrix. We numerically test our prediction by using a phase shift method for
calculating the excitation energies.Comment: minor change, 4 pages, 4 figures, to appear in Phys. Rev. Let
Controlled Generation of Dark Solitons with Phase Imprinting
The generation of dark solitons in Bose-Einstein condensates with phase
imprinting is studied by mapping it into the classic problem of a damped driven
pendulum. We provide simple but powerful schemes of designing the phase imprint
for various desired outcomes. We derive a formula for the number of dark
solitons generated by a given phase step, and also obtain results which explain
experimental observations.Comment: 4pages, 4 figure
Transition to Instability in a Kicked Bose-Einstein Condensate
A periodically kicked ring of a Bose-Einstein condensate is considered as a
nonlinear generalization of the quantum kicked rotor. For weak interactions
between atoms, periodic motion (anti-resonance) becomes quasiperiodic (quantum
beating) but remains stable. There exists a critical strength of interactions
beyond which quasiperiodic motion becomes chaotic, resulting in an instability
of the condensate manifested by exponential growth in the number of
noncondensed atoms. Similar behavior is observed for dynamically localized
states (essentially quasiperiodic motions), where stability remains for weak
interactions but is destroyed by strong interactions.Comment: 4 pages, 6 figs. A new affiliation is added. Accepted by Phys. Rev.
Let
Energy-momentum for Randall-Sundrum models
We investigate the conservation law of energy-momentum for Randall-Sundrum
models by the general displacement transform. The energy-momentum current has a
superpotential and are therefore identically conserved. It is shown that for
Randall-Sundrum solution, the momentum vanishes and most of the bulk energy is
localized near the Planck brane. The energy density is .Comment: 13 pages, no figures, v4: introduction and new conclusion added, v5:
11 pages, title changed and references added, accepted by Mod. Phys. Lett.
Reconstruction of Gas Temperature and Density Profiles of the Galaxy Cluster RX J1347.5-1145
We use observations of Sunyaev-Zel'dovich effect and X-ray surface brightness
to reconstruct the radial profiles of gas temperature and density under the
assumption of a spherically symmetric distribution of the gas. The method of
reconstruction, first raised by Silk & White, depends directly on the
observations of the Sunyaev-Zel'dovich effect and the X-ray surface brightness,
without involving additional assumptions such as the equation of state of the
gas or the conditions of hydrostatic equilibrium. We applied this method to the
cluster RX J1347.5-1145, which has both the Sunyaev-Zel'dovich effect and X-ray
observations with relative high precision. It is shown that it will be an
effective method to obtain the gas distribution in galaxy clusters. Statistical
errors of the derived temperature and density profiles of gas were estimated
according to the observational uncertainties.Comment: 6 pages, 1 figure. The published version, 2008, Chin. J. Astron.
Astrophys., 8, 67
Vesicles in solutions of hard rods
The surface free energy of ideal hard rods near curved hard surfaces is
determined to second order in curvature for surfaces of general shape. In
accordance with previous results for spherical and cylindrical surfaces it is
found that this quantity is non-analytical when one of the principal curvatures
changes signs. This prohibits writing it in the common Helfrich form. It is
shown that the non-analytical terms are the same for any aspect ratio of the
rods. These results are used to find the equilibrium shape of vesicles immersed
in solutions of rod-like (colloidal) particles. The presence of the particles
induces a change in the equilibrium shape and to a shift of the prolate-oblate
transition in the vesicle phase diagram, which are calculated within the
framework of the spontaneous curvature model. As a consequence of the special
form of the energy contribution due to the rods these changes cannot be
accounted for by a simple rescaling of the elastic constants of the vesicle as
for solutions of spherical colloids or polymers.Comment: 11 pages, 7 figures, submitted to Phys. Rev.
Comments on Noncommutative ADHM Construction
We extend the method of matrix partition to obtain explicitly the gauge field
for noncommutative ADHM construction in some general cases. As an application
of this method we apply it to the U(2) 2-instanton and get explicit result for
the gauge fields in the coincident instanton limit. We also easily apply it to
the noncommutative 't Hooft instantons in the appendix.Comment: 17 pages, LaTeX; an appendix added, typos corrected, refs adde
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