387 research outputs found
Alien Registration- Metivier, Roland L. (Brunswick, Cumberland County)
https://digitalmaine.com/alien_docs/31557/thumbnail.jp
Analytical Study of Certain Magnetohydrodynamic-alpha Models
In this paper we present an analytical study of a subgrid scale turbulence
model of the three-dimensional magnetohydrodynamic (MHD) equations, inspired by
the Navier-Stokes-alpha (also known as the viscous Camassa-Holm equations or
the Lagrangian-averaged Navier-Stokes-alpha model). Specifically, we show the
global well-posedness and regularity of solutions of a certain MHD-alpha model
(which is a particular case of the Lagrangian averaged
magnetohydrodynamic-alpha model without enhancing the dissipation for the
magnetic field). We also introduce other subgrid scale turbulence models,
inspired by the Leray-alpha and the modified Leray-alpha models of turbulence.
Finally, we discuss the relation of the MHD-alpha model to the MHD equations by
proving a convergence theorem, that is, as the length scale alpha tends to
zero, a subsequence of solutions of the MHD-alpha equations converges to a
certain solution (a Leray-Hopf solution) of the three-dimensional MHD
equations.Comment: 26 pages, no figures, will appear in Journal of Math Physics;
corrected typos, updated reference
A nonlinear instability for 3Ă3 systems of conservation laws
The phenomenon of nonlinear resonance provides a mechanism for the unbounded amplification of small solutions of systems of conservation laws. We construct spatially 2Ï-periodic solutions u N â C â ([0, t N ] Ă â with t N bounded, satisfyingPeer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46488/1/220_2005_Article_BF02105186.pd
Multifragment production in Au+Au at 35 MeV/u
Multifragment disintegration has been measured with a high efficiency
detection system for the reaction at . From the event
shape analysis and the comparison with the predictions of a many-body
trajectories calculation the data, for central collisions, are compatible with
a fast emission from a unique fragment source.Comment: 9 pages, LaTex file, 4 postscript figures available upon request from
[email protected]. - to appear in Phys. Lett.
Hydrological Behaviour of Tritium on the Former Semipalatinsk Nuclear Test Site (Kazakhstan) Determined using Stable Isotope Measurements
Tritium and stable isotope (deuterium 2H and 18O) concentrations have been determined in natural waters
collected from shallow lakes, wells, streams and rivers inside and in the vicinity of the former Semipalatinsk
Nuclear Test Site (NE Kazakhstan). The Semipalatinsk Test Site (STS) was one of the main proving grounds
for the testing of nuclear weapons by the former Soviet Union. Tritium activity concentrations have been
determined by liquid scintillation counting, while hydrogen isotopic composition have been determined
using a GV-Isoprime mass spectrometer coupled to an elemental analyzer. Tritium activity concentrations
recorded in lake waters (in most cases >10 Bq L-1) were significantly higher than those in well, stream and
the Irtysh River waters. In lake waters, enrichments in deuterium and 18O (ÎŽD and ÎŽ18O varying between â5
and â64 â° V-SMOW and â8.4 and +5.5 â° V-SMOW, respectively), and high salt concentrations, strongly
suggest that significant evaporation has occurred. In contrast, deuterium and tritium signatures of âcommonâ
surface and underground waters at the STS were mostly typical of present-day isotope backgrounds of natural waters in NE Kazakhstan. In STS, come salt lakes like Bajansor and Tumatsor with elevated tritium activity from 12 to 15 Bq L-1 lie close to the Global Meteoric Water Line. The potential tritium source for these lakes is residual concentration of tritium after former nuclear test in STS. The study provides evidence to show that export of tritium from underground nuclear test areas and tritium enrichment produced by evaporation are both important determinants of tritium concentrations in standing waters on the Semipalatinsk test site
Dynamics of nuclear receptor target gene regulation
Ligand-regulated nuclear receptors, such as estrogen receptors, glucocorticoid receptor, vitamin D receptor, and peroxisome proliferator-activated receptors, belong to the most widely studied and best understood transcription factors. Therefore, the dynamic nature of transcriptional regulation was observed first with different members of the nuclear receptor superfamily, but is now also extended to other transcription factors, such as nuclear factor ÎșB. Dynamic and in part cyclical processes were observed on the level of translocation into the nucleus, association with genomic binding sites, exchange of co-regulators and chromatin modifiers, occurrence of chromatin marks, and activities of RNA polymerase II resulting in mRNA synthesis. In this review, we summarize recent findings on the dynamic regulation of nuclear receptor target genes in the chromatin context
Stochastic Reaction-diffusion Equations Driven by Jump Processes
We establish the existence of weak martingale solutions to a class of second
order parabolic stochastic partial differential equations. The equations are
driven by multiplicative jump type noise, with a non-Lipschitz multiplicative
functional. The drift in the equations contains a dissipative nonlinearity of
polynomial growth.Comment: See journal reference for teh final published versio
Large Deviations for the Stochastic Shell Model of Turbulence
In this work we first prove the existence and uniqueness of a strong solution
to stochastic GOY model of turbulence with a small multiplicative noise. Then
using the weak convergence approach, Laplace principle for so- lutions of the
stochastic GOY model is established in certain Polish space. Thus a
Wentzell-Freidlin type large deviation principle is established utilizing
certain results by Varadhan and Bryc.Comment: 21 pages, submitted for publicatio
Dimer formation and conformational flexibility ensure cytoplasmic stability and nuclear accumulation of Elk-1
The ETS (E26) protein Elk-1 serves as a paradigm for mitogen-responsive transcription factors. It is multiply phosphorylated by mitogen-activated protein kinases (MAPKs), which it recruits into pre-initiation complexes on target gene promoters. However, events preparatory to Elk-1 phosphorylation are less well understood. Here, we identify two novel, functional elements in Elk-1 that determine its stability and nuclear accumulation. One element corresponds to a dimerization interface in the ETS domain and the second is a cryptic degron adjacent to the serum response factor (SRF)-interaction domain that marks dimerization-defective Elk-1 for rapid degradation by the ubiquitinâproteasome system. Dimerization appears to be crucial for Elk-1 stability only in the cytoplasm, as latent Elk-1 accumulates in the nucleus and interacts dynamically with DNA as a monomer. These findings define a novel role for the ETS domain of Elk-1 and demonstrate that nuclear accumulation of Elk-1 involves conformational flexibility prior to its phosphorylation by MAPKs
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