257 research outputs found
Analytic solutions of the Madelung equation
We present analytic self-similar solutions for the one, two and three
dimensional Madelung hydrodynamical equation for a free particle. There is a
direct connection between the zeros of the Madelung fluid density and the
magnitude of the quantum potential.Comment: 10 pages, 3 figure
Analytic solutions of a two-fluid hydrodynamic model
We investigate a one dimensional flow described with the non-compressible
coupled Euler and non-compressible Navier-Stokes equations in Cartesian
coordinate systems. We couple the two fluids through the continuity equation
where different void fractions can be considered. The well-known self-similar
Ansatz was applied and analytic solutions were derived for both velocity and
pressure field as well. The solutions can be expressed with the error
functions.Comment: 11 pages, 4 figure
Lissajous curves with a finite sum of prime number frequencies
The Ulam spiral inspired us to calculate and present Lissajous curves where
the orthogonally added functions are a finite sum of sinus and cosines
functions with consecutive prime number frequencies.Comment: 5 pages and 4 figure
Maximizing nearest neighbour entanglement in finitely correlated qubit--chains
We consider translationally invariant states of an infinite one dimensional
chain of qubits or spin-1/2 particles. We maximize the entanglement shared by
nearest neighbours via a variational approach based on finitely correlated
states. We find an upper bound of nearest neighbour concurrence equal to
C=0.434095 which is 0.09% away from the bound C_W=0.434467 obtained by a
completely different procedure. The obtained state maximizing nearest neighbour
entanglement seems to approximate the maximally entangled mixed states (MEMS).
Further we investigate in detail several other properties of the so obtained
optimal state.Comment: 12 pages, 4 figures, 2nd version minor change
Phosphorylation of phytochrome B inhibits light-induced signaling via accelerated dark reversion in Arabidopsis
The photoreceptor phytochrome B (phyB) interconverts between the biologically active Pfr (lmax = 730 nm) and inactive Pr
(lmax = 660 nm) forms in a red/far-red–dependent fashion and regulates, as molecular switch, many aspects of lightdependent
development in Arabidopsis thaliana. phyB signaling is launched by the biologically active Pfr conformer and
mediated by specific protein–protein interactions between phyB Pfr and its downstream regulatory partners, whereas
conversion of Pfr to Pr terminates signaling. Here, we provide evidence that phyB is phosphorylated in planta at Ser-86
located in the N-terminal domain of the photoreceptor. Analysis of phyB-9 transgenic plants expressing phospho-mimic
and nonphosphorylatable phyB–yellow fluorescent protein (YFP) fusions demonstrated that phosphorylation of Ser-86
negatively regulates all physiological responses tested. The Ser86Asp and Ser86Ala substitutions do not affect stability,
photoconversion, and spectral properties of the photoreceptor, but light-independent relaxation of the phyBSer86Asp Pfr into
Pr, also termed dark reversion, is strongly enhanced both in vivo and in vitro. Faster dark reversion attenuates red light–induced nuclear import and interaction of phyBSer86Asp-YFP Pfr with the negative regulator PHYTOCHROME INTERACTING
FACTOR3 compared with phyB–green fluorescent protein. These data suggest that accelerated inactivation of the
photoreceptor phyB via phosphorylation of Ser-86 represents a new paradigm for modulating phytochrome-controlled
signaling
Strict Forest Reserve Research in the Margin of the Carpathians, the Vár-hegy Case-Study
Sixteen forest reserves are situated in the northern part of Hungary which belongs to the Carpathian region according to EURAC delimitation (Ruffini et al. 2006). These Hungarian forest reserves expand the natural forest remnant/forest reserve net of the Carpathians towards the lower hilly region, representing the deciduous beech and oak forest belts near their lower (xeric) distribution limits. This paper outlines the Hungarian forest reserves belonging to the Carpathian region and the preliminary results of current projects in the Vár-hegy Forest Reserve (Bükk Mts., Hungary) as a case study. The alteration of tree species composition was investigated here based on the reconstruction of forest history in the previous 130 years (management period) and analyses of forest stand inventory. In another project CO2 sequestration changes of these forest stands were modeled since the clear-cutting in the 1880th and carbon stored in the forest ecosystem compartments was estimated. Our results show that the forest reserve stands are presently in a transition state from the managed forest towards a more natural mixed forest with several age-classes
Gravitational waves from spinning eccentric binaries
This paper is to introduce a new software called CBwaves which provides a
fast and accurate computational tool to determine the gravitational waveforms
yielded by generic spinning binaries of neutron stars and/or black holes on
eccentric orbits. This is done within the post-Newtonian (PN) framework by
integrating the equations of motion and the spin precession equations while the
radiation field is determined by a simultaneous evaluation of the analytic
waveforms. In applying CBwaves various physically interesting scenarios have
been investigated. In particular, we have studied the appropriateness of the
adiabatic approximation, and justified that the energy balance relation is
indeed insensitive to the specific form of the applied radiation reaction term.
By studying eccentric binary systems it is demonstrated that circular template
banks are very ineffective in identifying binaries even if they possess tiny
residual orbital eccentricity. In addition, by investigating the validity of
the energy balance relation we show that, on contrary to the general
expectations, the post-Newtonian approximation should not be applied once the
post-Newtonian parameter gets beyond the critical value .
Finally, by studying the early phase of the gravitational waves emitted by
strongly eccentric binary systems---which could be formed e.g. in various
many-body interactions in the galactic halo---we have found that they possess
very specific characteristics which may be used to identify these type of
binary systems.Comment: 37 pages, 18 figures, submitted to Class. Quantum Gra
Phasic, nonsynaptic GABA-A receptor-mediated inhibition entrains thalamocortical oscillations.
GABA-A receptors (GABA-ARs) are typically expressed at synaptic or nonsynaptic sites mediating phasic and tonic inhibition, respectively. These two forms of inhibition conjointly control various network oscillations. To disentangle their roles in thalamocortical rhythms, we focally deleted synaptic, γ2 subunit-containing GABA-ARs in the thalamus using viral intervention in mice. After successful removal of γ2 subunit clusters, spontaneous and evoked GABAergic synaptic currents disappeared in thalamocortical cells when the presynaptic, reticular thalamic (nRT) neurons fired in tonic mode. However, when nRT cells fired in burst mode, slow phasic GABA-AR-mediated events persisted, indicating a dynamic, burst-specific recruitment of nonsynaptic GABA-ARs. In vivo, removal of synaptic GABA-ARs reduced the firing of individual thalamocortical cells but did not abolish slow oscillations or sleep spindles. We conclude that nonsynaptic GABA-ARs are recruited in a phasic manner specifically during burst firing of nRT cells and provide sufficient GABA-AR activation to control major thalamocortical oscillations
Analytic self-similar solutions of the Kardar-Parisi-Zhang interface growing equation with various noise terms
The one-dimensional Kardar-Parisi-Zhang dynamic interface growth equation with the self-similar ansatz is analyzed. As a new feature additional analytic terms are added. From the mathematical point of view, these can be considered as various noise distribution functions. Six different cases were investigated among others Gaussian, Lorentzian, white or even pink noise. Analytic solutions are evaluated and analyzed for all cases. All results are expressible with various special functions like Kummer, Heun, Whittaker or error functions showing a very rich mathematical structure with some common general characteristics
Spin effects in gravitational radiation backreaction III. Compact binaries with two spinning components
The secular evolution of a spinning, massive binary system in eccentric orbit
is analyzed, expanding and generalizing our previous treatments of the
Lense-Thirring motion and the one-spin limit. The spin-orbit and spin-spin
effects up to the 3/2 post-Newtonian order are considered, both in the
equations of motion and in the radiative losses. The description of the orbit
in terms of the true anomaly parametrization provides a simple averaging
technique, based on the residue theorem, over eccentric orbits. The evolution
equations of the angle variables characterizing the relative orientation of the
spin and orbital angular momenta reveal a speed-up effect due to the
eccentricity. The dissipative evolutions of the relevant dynamical and angular
variables is presented in the form of a closed system of differential
equations.Comment: 10 pages, 1 figur
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