794 research outputs found
Fluctuating Multicomponent Lattice Boltzmann Model
Current implementations of fluctuating lattice Boltzmann equations (FLBE)
describe single component fluids. In this paper, a model based on the continuum
kinetic Boltzmann equation for describing multicomponent fluids is extended to
incorporate the effects of thermal fluctuations. The thus obtained fluctuating
Boltzmann equation is first linearized to apply the theory of linear
fluctuations, and expressions for the noise covariances are determined by
invoking the fluctuation-dissipation theorem (FDT) directly at the kinetic
level. Crucial for our analysis is the projection of the Boltzmann equation
onto the ortho-normal Hermite basis. By integrating in space and time the
fluctuating Boltzmann equation with a discrete number of velocities, the FLBE
is obtained for both ideal and non-ideal multicomponent fluids. Numerical
simulations are specialized to the case where mean-field interactions are
introduced on the lattice, indicating a proper thermalization of the system.Comment: 30 pages, 6 figure
A numerical study of the RG equation for the deformed nonlinear sigma model
The Renormalization Group equation describing the evolution of the metric of
the nonlinear sigma model poses some nice mathematical problems involving
functional analysis, differential geometry and numerical analysis. In this
article we briefly report some results obtained from the numerical study of the
solutions in the case of a two dimensional target space (deformation of the
sigma model). In particular, our analysis shows that the so-called
sausages define an attracting manifold in the -symmetric case, at
one-loop level. Moreover, data from two-loop evolution are used to test the
association put forward in Nucl. Phys., B406 (1993) 521 between the so-called
field theory and a certain -symmetric, factorized scattering
theory (FST).Comment: LaTex (RevTex style), 16 pages, 6 uuencoded figures. Minor technical
changes
Active role of elongation factor G in maintaining the mRNA reading frame during translation.
During translation, the ribosome moves along the mRNA one codon at a time with the help of elongation factor G (EF-G). Spontaneous changes in the translational reading frame are extremely rare, yet how the precise triplet-wise step is maintained is not clear. Here, we show that the ribosome is prone to spontaneous frameshifting on mRNA slippery sequences, whereas EF-G restricts frameshifting. EF-G helps to maintain the mRNA reading frame by guiding the A-site transfer RNA during translocation due to specific interactions with the tip of EF-G domain 4. Furthermore, EF-G accelerates ribosome rearrangements that restore the ribosome's control over the codon-anticodon interaction at the end of the movement. Our data explain how the mRNA reading frame is maintained during translation
Creep and locking of a low-angle normal fault: Insights from the Altotiberina fault in the Northern Apennines (Italy)
While low-angle normal faults have been recognized worldwide from geological studies, whether these structures are active or capable of generating big earthquakes is still debated. We provide new constraints on the role and modes of the Altotiberina fault (ATF) in accommodating extension in the Northern Apennines. We model GPS velocities to study block kinematics, faults slip rates and interseismic coupling of the ATF, which is active and accounts, with its antithetic fault, for a large part of the observed chain normal 3 mm/yr tectonic extension. A wide portion of the ATF creeps at the long-term slip rate (1.7 \ub1 0.3 mm/yr), but the shallow locked portions are compatible with M > 6.5 earthquakes. We suggest that positive stress accumulation due to ATF creep is most likely released by more favorable oriented splay faults, whose rupture may propagate downdip along low-angle normal fault surface and reduce the probability of occurrence of a seismic rupture of the shallower locked portion
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Mechanisms of ranolazine's dual protection against atrial and ventricular fibrillation
Coronary artery disease and heart failure carry concurrent risk for atrial fibrillation and life-threatening ventricular arrhythmias. We review evidence indicating that at therapeutic concentrations, ranolazine has potential for dual suppression of these arrhythmias. Mechanisms and clinical implications are discussed
Careggi Smart Hospital: A mobile app for patients, citizens and healthcare staff
This paper presents a mobile app called âCareggi Smart Hospitalâ which has been developed for the Careggi Polyclinic in Florence. The application is designed for Android smartphones and tablets and it is freely downloadable from the Google Play Store. It provides various useful tools to the hospital's users such as personnel and structures finding, way-finding and the possibility to access personal medical records collected on regional electronic health record
Climacostol reduces tumour progression in a mouse model of melanoma via the p53-dependent intrinsic apoptotic programme
Climacostol, a compound produced by the ciliated protozoan Climacostomum virens, displayed cytotoxic properties in vitro. This study demonstrates that it has anti-tumour potential. Climacostol caused a reduction of viability/proliferation of B16-F10 mouse melanoma cells, a rapidly occurring DNA damage, and induced the intrinsic apoptotic pathway characterised by the dissipation of the mitochondrial membrane potential, the translocation of Bax to the mitochondria, the release of Cytochrome c from the mitochondria, and the activation of Caspase 9-dependent cleavage of Caspase 3. The apoptotic mechanism of climacostol was found to rely on the up-regulation of p53 and its targets Noxa and Puma. In vivo analysis of B16-F10 allografts revealed a persistent inhibition of tumour growth rate when melanomas were treated with intra-tumoural injections of climacostol. In addition, it significantly improved the survival of transplanted mice, decreased tumour weight, induced a remarkable reduction of viable cells inside the tumour, activated apoptosis and up-regulated the p53 signalling network. Importantly, climacostol toxicity was more selective against tumour than non-tumour cells. The anti-tumour properties of climacostol and the molecular events associated with its action indicate that it is a powerful agent that may be considered for the design of pro-apoptotic drugs for melanoma therapy
Aseismic deformation associated with an earthquake swarm in the northern Apennines (Italy)
Analyzing the displacement time series from continuous GPS (cGPS) with an Independent Component Analysis, we detect a transient deformation signal that correlates both in space and time with a seismic swarm activity (maximum M_w=3.69 ± 0.09) occurred in the hanging wall of the Altotiberina normal fault (Northern Apennines, Italy) in 2013â2014. The geodetic transient lasted âŒ6 months and produced a NW-SE trending extension of âŒ5.3 mm, consistent with the regional tectonic regime. The seismicity and the geodetic signal are consistent with slip on two splay faults in the Altotiberina fault (ATF) hanging wall. Comparing the seismic moment associated with the geodetic transient and the seismic events, we observe that seismicity accounts for only a fraction of the measured geodetic deformation. The combined seismic and aseismic slip decreased the Coulomb stress on the locked shallow portion of the ATF, while the transition region to the creeping section has been loaded
Thermal fluctuations of an interface near a contact line
The effect of thermal fluctuations near a contact line of a liquid interface
partially wetting an impenetrable substrate is studied analytically and
numerically. Promoting both the interface profile and the contact line position
to random variables, we explore the equilibrium properties of the corresponding
fluctuating contact line problem based on an interfacial Hamiltonian involving
a "contact" binding potential. To facilitate an analytical treatment we
consider the case of a one-dimensional interface. The effective boundary
condition at the contact line is determined by a dimensionless parameter that
encodes the relative importance of thermal energy and substrate energy at the
microscopic scale. We find that this parameter controls the transition from a
partially wetting to a pseudo-partial wetting state, the latter being
characterized by a thin prewetting film of fixed thickness. In the partial
wetting regime, instead, the profile typically approaches the substrate via an
exponentially thinning prewetting film. We show that, independently of the
physics at the microscopic scale, Young's angle is recovered sufficiently far
from the substrate. The fluctuations of the interface and of the contact line
give rise to an effective disjoining pressure, exponentially decreasing with
height. Fluctuations therefore provide a regularization of the singular contact
forces occurring in the corresponding deterministic problem.Comment: 40 Pages, 12 Figure
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