85,157 research outputs found
Differences between European Regional Innovation Systems in Terms of Technological and Economic Characteristics
innovation, networks
Advertising and Word-of-Mouth Effects on Pre-launch Consumer Interest and Initial Sales of Experience Products
This study examines how consumers' interest in a new experience product develops as a result of advertising and word-of-mouth activities during the pre-launch period. The empirical settings are the U.S. motion picture and video game industries. The focal variables include weekly ad spend, blog volume, online search volume during pre-launch periods, opening-week sales, and product characteristics. We treat pre-launch search volume of keywords as a measure of pre-launch consumer interest in the related product. To identify probable persistent effects among the pre-launch time-series variables, we apply a vector autoregressive modeling approach. We find that blog postings have permanent, trend-setting effects on pre-launch consumer interest in a new product, while advertising has only temporary effects. In the U.S. motion picture industry, the four-week cumulative elasticity of pre-launch consumer interest is 0.187 to advertising and 0.635 to blog postings. In the U.S. video game industry, the elasticities are 0.093 and 1.306, respectively. We also find long-run co-evolution between blog and search volume, which suggests that consumers' interest in the upcoming product cannot grow without bounds for a given level of blog volume
Near field pressure fluctuations in a circular jet
The vortical structures in shear layers govern many dynamic aspects of the jet, including entrainment of mass, transfer of momentum and noise generation. These structures develop from instability waves and undergo a merging process. Vortex merging reduces the time scale and increases the length scale of the shear layer. At the same time pressure fluctuations are induced by the unsteady motion. These pressure perturbations can exert high level dynamic loading on nearby structures, and radiate to the far field as noise. In this study, the generation mechanism of the pressure fluctuations and the radiation process are examined
Noncommutative D-Brane in Non-Constant NS-NS B Field Background
We show that when the field strength H of the NS-NS B field does not vanish,
the coordinates X and momenta P of an open string endpoints satisfy a set of
mixed commutation relations among themselves. Identifying X and P with the
coordinates and derivatives of the D-brane world volume, we find a new type of
noncommutative spaces which is very different from those associated with a
constant B field background.Comment: 11 pages, Latex, minor modification
Supersymmetric reduced models with a symmetry based on Filippov algebra
Generalizations of the reduced model of super Yang-Mills theory obtained by
replacing the Lie algebra structure to Filippov -algebra structures are
studied. Conditions for the reduced model actions to be supersymmetric are
examined. These models are related with what we call \{cal N}_{min}=2 super
-brane actions.Comment: v3: In the previous versions we overlooked that Eq.(3.9) holds more
generally, and missed some supersymmetric actions. Those are now included and
modifications including a slight change in the title were made accordingly.
1+18 page
Charged lepton mixing and oscillations from neutrino mixing in the early Universe
Charged lepton mixing as a consequence of neutrino mixing is studied for two
generations in the temperature regime in the
early Universe. We state the general criteria for charged lepton mixing,
critically reexamine aspects of neutrino equilibration and provide arguments to
suggest that neutrinos may equilibrate as mass eigenstates in the temperature
regime \emph{prior} to flavor equalization. We assume this to be the case, and
that neutrino mass eigenstates are in equilibrium with different chemical
potentials. Charged lepton self-energies are obtained to leading order in the
electromagnetic and weak interactions. The upper bounds on the neutrino
asymmetry parameters from CMB and BBN without oscillations, combined with the
fit to the solar and KamLAND data for the neutrino mixing angle, suggest that
for the two generation case there is resonant \emph{charged lepton} mixing in
the temperature range . In this range the charged lepton
oscillation frequency is of the same order as the electromagnetic damping rate.Comment: 17 pages, 2 figs, same results with more discussions on quantum Zeno
effect. To appear in Astroparticle Physic
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