4,690 research outputs found
The envelope of the power spectra of over a thousand \delta Scuti stars. The - scaling relation
CoRoT and Kepler high-precision photometric data allowed the detection and
characterization of the oscillation parameters in stars other than the Sun.
Moreover, thanks to the scaling relations, it is possible to estimate masses
and radii for thousands of solar-type oscillating stars. Recently, a \Delta\nu
- \rho relation has been found for \delta Scuti stars. Now, analyzing several
hundreds of this kind of stars observed with CoRoT and Kepler, we present an
empiric relation between their frequency at maximum power of their oscillation
spectra and their effective temperature. Such a relation can be explained with
the help of the \kappa-mechanism and the observed dispersion of the residuals
is compatible with they being caused by the gravity-darkening effect
Community-focused strategies.
This article introduces the notion of community-focused strategies to refer to the set of actions, activities and policies that firms undertake to establish connections or relational links with one or more target communities of (potential) customers. Drawing on social identity theory and strategy research, this study begins with a proposed taxonomy of different community-focused strategies. Then it illustrates how such strategies contribute to the creation of competitive advantage and explores their boundary conditions. Finally, the authors offer implications for theory development and practice, as well as suggestions for further research.Communities; Competitive advantage; Firm strategies; Identity;
Evidence of amplitude modulation due to Resonant Mode Coupling in the delta Scuti star KIC5892969
A study of the star KIC5892969 observed by the Kepler satellite is presented.
Its three highest amplitude modes present a strong amplitude modulation. The
aim of this work is to investigate amplitude variations in this star and their
possible cause. Using the 4 years-long observations available, we obtained the
frequency content of the full light curve. Then, we studied the amplitude and
phase variations with time using shorter time stamps. The results obtained are
compared with the predicted ones for resonant mode coupling of an unstable mode
with lower frequency stable modes. Our conclusion is that resonant mode
coupling is consistent as an amplitude limitation mechanism in several modes of
KIC5892969 and we discuss to which extent it might play an important role for
other delta Scuti stars
Clues for the existence of two resonances
The axial vector meson was studied within the chiral unitary
approach, where it was shown that it has a two-pole structure. We reanalyze the
high-statistics WA3 experiment at 63 GeV, which
established the existence of both and , and we show that
it clearly favors our two-pole interpretation. We also reanalyze the
traditional K-matrix interpretation of the WA3 data and find that the good fit
of the data obtained there comes from large cancellations of terms of unclear
physical interpretation.Comment: published version in PRD; typos corrected; title changed to "Clues
for the existence of two resonances
Mobility through Heterogeneous Networks in a 4G Environment
Serving and Managing users in a heterogeneous environment. 17th WWRF Meeting in Heidelberg, Germany, 15 - 17 November 2006. [Proceeding presented at WG3 - Co-operative and Ad-hoc Networks]The increase will of ubiquitous access of the users to the requested services points towards the integration of heterogeneous networks. In this sense, a user shall be able to access its services through different access technologies, such as WLAN, Wimax, UMTS and DVB technologies, from the same or different network operators, and to seamless move between different networks with active communications. In this paper we propose a mobility architecture able to support this usersâ ubiquitous access and seamless movement, while simultaneously bringing a large flexibility to access network operators
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