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Editorial -Special issue on adaptive multimedia computing
In recent years, there is an emerging research area in multimedia computing, with the increasing number of related work in scalable video, adaptive multimedia documents, adaptive multimedia services, to name just a few. This new trend comes about partly due to the increasing use of mobile media devices where media requirements could change among users and devices and at different times of reception or presentation, and partly due to the changing network conditions, where best-effort service is the general practice. Any change in Quality of Services (QoS) could imply a change in the delivery or scheduling of media contents. To complicate the matter, user interruptions or requirement changes during the communication process could also occur; for example, a user may not be satisfied with the current media quality and decide an upgrade in real time. The status quo is that this new research paradigm is beginning to take shape while no effort has been made to draw a roadmap for it. We could see some major research work missing, for example, formal methods or modeling of adaptive multimedi
Growth of graphene on 6H-SiC by molecular dynamics simulation
Classical molecular-dynamics simulations were carried out to study epitaxial
growth of graphene on 6H-SiC(0001) substrate. It was found that there exists a
threshold annealing temperature above which we observe formation of graphitic
structure on the substrate. To check the sensitivity of the simulation results,
we tested two empirical potentials and evaluated their reliability by the
calculated characteristics of graphene, its carbon-carbon bond-length, pair
correlation function, and binding energy.Comment: 7 pages, 5 figure
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Neuroinflammation is a putative target for the prevention and treatment of perioperative neurocognitive disorders.
IntroductionThe demographics of aging of the surgical population has increased the risk for perioperative neurocognitive disorders in which trauma-induced neuroinflammation plays a pivotal role.Sources of dataAfter determining the scope of the review, the authors used PubMed with select phrases encompassing the words in the scope. Both preclinical and clinical reports were considered.Areas of agreementNeuroinflammation is a sine qua non for development of perioperative neurocognitive disorders.Areas of controversyWhat is the best method for ameliorating trauma-induced neuroinflammation while preserving inflammation-based wound healing.Growing pointsThis review considers how to prepare for and manage the vulnerable elderly surgical patient through the entire spectrum, from preoperative assessment to postoperative period.Areas timely for developing researchWhat are the most effective and safest interventions for preventing and/or reversing Perioperative Neurocognitive Disorders
How strong are the Rossby vortices?
The Rossby wave instability, associated with density bumps in differentially
rotating discs, may arise in several different astrophysical contexts, such as
galactic or protoplanetary discs. While the linear phase of the instability has
been well studied, the nonlinear evolution and especially the saturation phase
remain poorly understood. In this paper, we test the non-linear saturation
mechanism analogous to that derived for wave-particle interaction in plasma
physics. To this end we perform global numerical simulations of the evolution
of the instability in a two-dimensional disc. We confirm the physical mechanism
for the instability saturation and show that the maximum amplitude of vorticity
can be estimated as twice the linear growth rate of the instability. We provide
an empirical fitting formula for this growth rate for various parameters of the
density bump. We also investigate the effects of the azimuthal mode number of
the instability and the energy leakage in the spiral density waves. Finally, we
show that our results can be extrapolated to 3D discs.Comment: Accepted for publication in MNRA
Chaotic Dynamics of Stellar Spin in Binaries and the Production of Misaligned Hot Jupiters
Many exoplanetary systems containing hot Jupiters are observed to have highly
misaligned orbital axes relative to the stellar spin axes. Kozai-Lidov
oscillations of orbital eccentricity/inclination induced by a binary companion,
in conjunction with tidal dissipation, is a major channel for the production of
hot Jupiters. We demonstrate that gravitational interaction between the planet
and its oblate host star can lead to chaotic evolution of the stellar spin axis
during Kozai cycles. As parameters such as the planet mass and stellar rotation
period vary, periodic islands can appear in an ocean of chaos, in a manner
reminiscent of other dynamical systems. In the presence of tidal dissipation,
the complex spin evolution can leave an imprint on the final spin-orbit
misalignment angles.Comment: 26 pages, 13 figures. Includes supplementary materials. To be
published in the September 12, 2014 edition of Science Magazine. For
additional information, please visit
http://astro.cornell.edu/~dong/sciencepaper.htm
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