142,955 research outputs found
Drinking Bourbon with Cupid
It was Valentine’s Day, and rather than enjoying the suspiciously commercial holiday with a romantic partner, I was alone watching reruns of “How I Met Your Mother,” from a cozy armchair with a cigar in one hand and a glass of bourbon in the other. The show prompted me to examine the nature of relationships; specifically, how the media portrays them vastly different than reality and the implications that arise as a result. Romantic relationships in film and literature appear to be idealized to a ridiculous degree. Unfortunately for us, this means that we create unrealistic expectations for our partners that lead many to remain single while they search for a relationship that adheres to the media’s extravagant standards. [excerpt
Attractors for Damped Semilinear Wave Equations with Singularly Perturbed Acoustic Boundary Conditions
Under consideration is the damped semilinear wave equation in a bounded domain in
subject to an acoustic boundary condition with a singular perturbation, which
we term "massless acoustic perturbation," \ep\delta_{tt}+\delta_t+\delta =
-u_t\quad\text{for}\quad \ep\in[0,1]. By adapting earlier work by S.
Frigeri, we prove the existence of a family of global attractors for each
\ep\in[0,1]. We also establish the optimal regularity for the global
attractors, as well as the existence of an exponential attractor, for each
\ep\in[0,1]. The later result insures the global attractors possess finite
(fractal) dimension, however, we cannot yet guarantee that this dimension is
independent of the perturbation parameter \ep. The family of global
attractors are upper-semicontinuous with respect to the perturbation parameter
\ep, a result which follows by an application of a new abstract result also
contained in this article. Finally, we show that it is possible to obtain the
global attractors using weaker assumptions on the nonlinear term , however,
in that case, the optimal regularity, the finite dimensionality, and the
upper-semicontinuity of the global attractors does not necessarily hold.Comment: To appear in EJDE. arXiv admin note: substantial text overlap with
arXiv:1503.01821 and text overlap with arXiv:1302.426
Global existence of weak solutions for strongly damped wave equations with nonlinear boundary conditions and balanced potentials
We demonstrate the global existence of weak solutions to a class of
semilinear strongly damped wave equations possessing nonlinear hyperbolic
dynamic boundary conditions. Our work assumes
with and where is the Wentzell-Laplacian.
Hence, the associated linear operator admits a compact resolvent. A balance
condition is assumed to hold between the nonlinearity defined on the interior
of the domain and the nonlinearity on the boundary. This allows for arbitrary
(supercritical) polynomial growth on each potential, as well as mixed
dissipative/anti-dissipative behavior. Moreover, the nonlinear function defined
on the interior of the domain is assumed to be only
Infrared Imaging of Planetary Nebulae from the Ground Up
New ground-based telescopes and instruments, the return of the NICMOS
instrument on the Hubble Space Telescope (HST), and the recent launch of the
Spitzer Space Telescope have provided new tools that are being utilized in the
study of planetary nebulae. Multiwavelength, high spatial resolution
ground-based and HST imaging have been used to probe the inner regions of young
PNe to determine their structure and evaluate formation mechanisms.
Spitzer/IRAC and MIPS have been used to image more evolved PNe to determine the
spatial distribution of molecular hydrogen, ionized gas, and dust in the
nebulae and halos.Comment: 8 pages, 3 figures, invited review given at IAU Symp. 234, to appear
in "Planetary Nebulae in Our Galaxy and Beyond", eds. M. J. Barlow & R. H.
Mende
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