12,981 research outputs found
Strategic Buyers, Horizontal Mergers and Synergies: An Experimental Investigation*
This paper reports an experiment designed to evaluate interrelationships between strategic buyers, market power and merger-induced synergies. The experiment consists of 40 posted-offer quadropolies. Treatments include the use of simulated or human buyers, seller consolidations and merger-induced fixed cost and unit cost synergies. In the simulated-buyer markets we observe behavior generally consistent with comparative static predictions: prices rise post-merger, and unit (but not fixed) cost synergies may exert some price-moderating effect. The addition of powerful buyers changes results markedly. Although prices are lower in the human buyer markets, outcomes are more variable and predicted comparative static effects are no longer observed.
Cosmic Origins Spectrograph Observations of Warm Intervening Gas Towards 3C263
We present HST/COS high S/N observations of the z = 0.32566 multi-phase
absorber towards 3C263. The COS data shows absorption from H I, O VI, C III, N
III, Si III and C II. The Ne VIII in this absorber is detected in the FUSE
spectrum. The low and intermediate ions are kinematically aligned with each
other and H I and display narrow line widths of 6 km/s. The O VI lines are
kinematically offset by 12 km/s from the low ions and are a factor of four
broader. All metal ions except O VI and Ne VIII are consistent with an origin
in gas photoionized by the extragalactic background radiation. The bulk of the
observed H I is also traced by this photoionized medium. The carbon abundance
in this gas phase is near-solar. The O VI and Ne VIII favor an origin in
collisionally ionized gas at T = 5.2 x 10^5 K. The H I absorption associated
with this warm absorber is a BLA marginally detected in the COS spectrum. This
warm gas phase has total hydrogen column density of N(H) ~ 3 x 10^19 which is 2
dex higher than what is traced by the photoionized gas. Simultaneous detection
of O VI, Ne VIII and BLAs in an absorber can be a strong diagnostic of gas with
temperature in the range of 10^5 - 10^6 K corresponding to the warm phase of
the WHIM or shock-heated gas in the extended halos of galaxies.Comment: Accepted for publication in the Astrophysical Journa
The Generalised Liar Paradox: A Quantum Model and Interpretation
The formalism of abstracted quantum mechanics is applied in a model of the
generalized Liar Paradox. Here, the Liar Paradox, a consistently testable
configuration of logical truth properties, is considered a dynamic conceptual
entity in the cognitive sphere. Basically, the intrinsic contextuality of the
truth-value of the Liar Paradox is appropriately covered by the abstracted
quantum mechanical approach. The formal details of the model are explicited
here for the generalized case. We prove the possibility of constructing a
quantum model of the m-sentence generalizations of the Liar Paradox. This
includes (i) the truth-falsehood state of the m-Liar Paradox can be represented
by an embedded 2m-dimensional quantum vector in a (2m)^m dimensional complex
Hilbert space, with cognitive interactions corresponding to projections, (ii)
the construction of a continuous 'time' dynamics is possible: typical truth and
falsehood value oscillations are described by Schrodinger evolution, (iii)
Kirchoff and von Neumann axioms are satisfied by introduction of 'truth-value
by inference' projectors, (iv) time invariance of unmeasured state.Comment: 13 pages, to be published in Foundations of Scienc
The Formation of IRIS diagnostics. IV. The Mg II triplet lines as a new diagnostic for lower chromospheric heating
A triplet of subordinate lines of Mg II exists in the region around the h&k
lines. In solar spectra these lines are seen mostly in absorption, but in some
cases can become emission lines. The aim of this work is to study the formation
of this triplet, and investigate any diagnostic value they can bring. Using 3D
radiative magnetohydrodynamic simulations of quiet Sun and flaring flux
emergence, we synthesize spectra and investigate how spectral features respond
to the underlying atmosphere. We find that emission in the lines is rare and is
typically caused by a steep temperature increase in the lower chromosphere
(above 1500 K, with electron densities above 10 m). In both
simulations the lines are sensitive to temperature increases taking place at
column masses >= 5e-4 g cm. Additional information can also be inferred
from the peak-to-wing ratio and shape of the line profiles. Using observations
from NASA's Interface Region Imaging Spectrograph we find both absorption and
emission line profiles with similar shapes to the synthetic spectra, which
suggests that these lines represent a useful diagnostic that complements the
MgII h&k lines.Comment: 8 pages, 7 figures. Accepted for publication in Ap
Cytomegalovirus (CMV) retinitis is an important problem that is being missed in HIV-positive individuals attending routine clinics in Cambodia.
How to play two-players restricted quantum games with 10 cards
We show that it is perfectly possible to play 'restricted' two-players,
two-strategies quantum games proposed originally by Marinatto and Weber having
as the only equipment a pack of 10 cards. The 'quantum board' of such a model
of these quantum games is an extreme simplification of 'macroscopic quantum
machines' proposed by one of the authors in numerous papers that allow to
simulate by macroscopic means various experiments performed on two entangled
quantum objectsComment: 4 pages, 3 figure
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