Price competition with consumer confusion

Copyright © 2013, INFORMS. Article posted with permission.This paper proposes a model in which identical sellers of a homogeneous product compete in both prices and price frames (i.e., ways to present price information). Frame choices affect the comparability of price offers and may cause consumer confusion and lower price sensitivity. In equilibrium, firms randomize their frame choices to obfuscate price comparisons and sustain positive profits. The nature of the equilibrium depends on whether frame differentiation or frame complexity is more confusing. Moreover, an increase in the number of competitors induces firms to rely more on frame complexity, and this may boost industry profits and lower consumer surplus

Exploratory studies of contact angle hysteresis, wetting of solidified rare gases and surface properties of mercury Final report

Contact angle hysteresis, wetting of solidified rare gases, and surface properties of mercur

The multi-band nonthermal emission from the supernova remnant RX J1713.7-3946

Nonthermal X-rays and very high-energy (VHE) $\gamma$-rays have been detected from the supernova remnant (SNR) RX J1713.7-3946, and especially the recent observations with the \textit{Suzaku} satellite clearly reveal a spectral cutoff in the X-ray spectrum, which directly relates to the cutoff of the energy spectrum of the parent electrons. However, whether the origin of the VHE $\gamma$-rays from the SNR is hadronic or leptonic is still in debate. We studied the multi-band nonthermal emission from RX J1713.7-3946 based on a semi-analytical approach to the nonlinear shock acceleration process by including the contribution of the accelerated electrons to the nonthermal radiation. The results show that the multi-band observations on RX J1713.7-3946 can be well explained in the model with appropriate parameters and the TeV $\gamma$-rays have hadronic origin, i.e., they are produced via proton-proton (p-p) interactions as the relativistic protons accelerated at the shock collide with the ambient matter.Comment: 6 pages, 5 figures, accepted by MNRA

Diffusion due to the Beam-Beam Interaction and Fluctuating Fields in Hadron Colliders

Random fluctuations in the tune, beam offsets and beam size in the presence of the beam-beam interaction are shown to lead to significant particle diffusion and emittance growth in hadron colliders. We find that far from resonances high frequency noise causes the most diffusion while near resonances low frequency noise is responsible for the large emittance growth observed. Comparison of different fluctuations shows that offset fluctuations between the beams causes the largest diffusion for particles in the beam core.Comment: 5 pages, 3 postscript figure

Time's Barbed Arrow: Irreversibility, Crypticity, and Stored Information

We show why the amount of information communicated between the past and future--the excess entropy--is not in general the amount of information stored in the present--the statistical complexity. This is a puzzle, and a long-standing one, since the latter is what is required for optimal prediction, but the former describes observed behavior. We layout a classification scheme for dynamical systems and stochastic processes that determines when these two quantities are the same or different. We do this by developing closed-form expressions for the excess entropy in terms of optimal causal predictors and retrodictors--the epsilon-machines of computational mechanics. A process's causal irreversibility and crypticity are key determining properties.Comment: 4 pages, 2 figure

Particle Acceleration in Supernova Remnants and the Production of Thermal and Nonthermal Radiation

If highly efficient, cosmic ray production can have a significant effect on the X-ray emission from SNRs as well as their dynamical evolution. Using hydrodynamical simulations including diffusive shock acceleration, we produce spectra for both the thermal and nonthermal forward shock emission. For a given ambient density and explosion energy, we find that the position of the forward shock at a given age is a strong function of the acceleration efficiency, providing a signature of cosmic-ray production. Using an approximate treatment for the ionization state of the plasma, we investigate the effects of slow vs. rapid heating of the postshock electrons on the ratio of thermal to nonthermal X-ray emission at the forward shock. We also investigate the effects of magnetic field strength on the observed spectrum for efficient cosmic-ray acceleration. The primary effect of a large field is a considerable flattening of the nonthermal spectrum in the soft X-ray band. Spectral index measurements from X-ray observations may thus be indicators of the postshock magnetic field strength. The predicted gamma-ray flux from inverse-Compton (IC) scattering and neutral pion decay is strongly affected by the ambient conditions and, for the particular parameters used in our examples, the IC emission at E ~ 1 TeV exceeds that from pion decay, although at both lower and higher energies this trend is reversed for cases of high ambient density. More importantly, high magnetic fields produce a steepening of the electron spectrum over a wide energy range which may make it more difficult to differentiate between IC and pion-decay emission solely by spectral shape.Comment: 30 pages, 12 figures, submitted to ApJ January 200

KECK HIRES Spectroscopy of APM 08279+5255

With an optical R-band magnitude of 15.2, the recently discovered z=3.911 BAL quasar APM 08279+5255 is an exceptionally bright high redshift source. Its brightness has allowed us to acquire a high signal-to-noise ratio (~100), high resolution (~6 km/s) spectrum using the HIRES echelle spectrograph on the 10-m Keck I telescope. Given the quality of the data, these observations provide an unprecedented view of associated and intervening absorption systems. Here we announce the availability of this spectrum to the general astronomical community and present a brief analysis of some of its main features.Comment: 21 pages including 5 figures. Accepted for publication by PAS