251 research outputs found
Statistical anisotropy of CMB as a probe of conformal rolling scenario
Search for the statistical anisotropy in the CMB data is a powerful tool for
constraining models of the early Universe. In this paper we focus on the
recently proposed cosmological scenario with conformal rolling. We consider two
sub-scenarios, one of which involves a long intermediate stage between
conformal rolling and conventional hot epoch. Primordial scalar perturbations
generated within these sub-scenarios have different direction-dependent power
spectra, both characterized by a single parameter h^2. We search for the
signatures of this anisotropy in the seven-year WMAP data using quadratic
maximum likelihood method, first applied for similar purposes by Hanson and
Lewis. We confirm the large quadrupole anisotropy detected in V and W bands,
which has been argued to originate from systematic effects rather than from
cosmology. We construct an estimator for the parameter h^2. In the case of the
sub-scenario with the intermediate stage we set an upper limit h^2 < 0.045 at
the 95% confidence level. The constraint on h^2 is much weaker in the case of
another sub-scenario, where the intermediate stage is absent.Comment: 27 pages, 4 figures. Stronger constraint in case of sub-scenario A
obtained. Version accepted for publication in JCA
Revisiting constraints on (pseudo)conformal Universe with Planck data
We revisit constraints on the (pseudo)conformal Universe from the
non-observation of statistical anisotropy in the Planck data. The quadratic
maximal likelihood estimator is applied to the Planck temperature maps at
frequencies 143 GHz and 217 GHz as well as their cross-correlation. The
strongest constraint is obtained in the scenario of the (pseudo)conformal
Universe with a long intermediate evolution after conformal symmetry breaking.
In terms of the relevant parameter (coupling constant), the limit is h^2
<0.0013 at 95% C.L. (using the cross-estimator). The analogous limit is much
weaker in the scenario without the intermediate stage (h^2 \ln
\frac{H_0}{\Lambda}<0.52) allowing the coupling constant to be of order one. In
the latter case, the non-Gaussianity in the 4-point function appears to be a
more promising signature.Comment: 13 pages, 2 figures. Appendix with detailed computation of the Fisher
matrix adde
Development of electronic communications in the financial market-based system
Purpose: The article aims at revealing opportunities for forming long-term effective partnership communication with the consumer in the financial market. It elicits prospects for the development of communications in the financial market, considers reactions as responsive behavioral switching nodes evolving in the course of interaction and defines opportunities for forming long-term effective partnerships with consumers. Design / Methodology / Approach: To provide information for marketing communications in the financial market and ensure security, it is necessary: first, to study possible risks of communication and problems which are likely to happen in the course and as a result of interaction and counteraction to hostile manipulations in the information network; second, to provide protection of consumers and target groups' rights and cooperation with public authorities in the field of information and communication security; third, to monitor staff activities; fourth, to entail market research and analysis of new segments, market stakeholders of traditional and innovative services. Findings: To enhance effectiveness of electronic communications in the financial market-based system, a set of measures for information support of marketing communications in the financial market has been elaborated to further ensure security. The technique of modern PR-communications in business is a universal tool of marketing technologies designed to create favorable public opinion and a positive perception of a certain economic entity. At the same time, maximum coverage implies forecasting the future development of the market situation in the financial market and establishing contact with the interested audience. Practical implications: The results of the study can be introduced into management practice to adapt the existing system of banking products distribution to innovative market demands and indicators of hidden and unmet demand and to develop and ideally implement innovative banking services. Originality/Value: The major contribution of this research is to identify prospects for communications development in the financial market and form reactions as response behavioral switching nodes arising in the course of interaction.peer-reviewe
Effect of intermediate Minkowskian evolution on CMB bispectrum
We consider a non-inflationary early Universe scenario in which relevant
scalar perturbations get frozen out at some point, but then are defrosted and
follow a long nearly Minkowskian evolution before the hot era. This
intermediate stage leaves specific imprint on the CMB 3-point function, largely
independent of details of microscopic physics. In particular, the CMB
bispectrum undergoes oscillations in the multipole l space with roughly
constant amplitude. The latter is in contrast to the oscillatory bispectrum
enhanced in the flattened triangle limit, as predicted by inflation with
non-Bunch--Davies vacuum. Given this and other peculiar features of the
bispectrum, stringent constraints imposed by the Planck data may not apply. The
CMB 3-point function is suppressed by the inverse duration squared of the
Minkowskian evolution, but can be of observable size for relatively short
intermediate Minkowskian stage.Comment: 27 pages, 5 figures; references added, representation of the material
improved; matches journal versio
Effect of magnetic field on the velocity autocorrelation and the caging of particles in two-dimensional Yukawa liquids
We investigate the effect of an external magnetic field on the velocity
autocorrelation function and the "caging" of the particles in a two-dimensional
strongly coupled Yukawa liquid, via numerical simulations. The influence of the
coupling strength on the position of the dominant peak in the frequency
spectrum of the velocity autocorrelation function confirms the onset of a joint
effect of the magnetic field and strong correlations at high coupling. Our
molecular dynamics simulations quantify the decorrelation of the particles'
surroundings - the magnetic field is found to increase significantly the caging
time, which reaches values well beyond the timescale of plasma oscillations.
The observation of the increased caging time is in accordance with findings
that the magnetic field decreases diffusion in similar systems
Synthesis and application of zeolite and glass fiber supported zero valent iron nanoparticles as membrane component for removal nitrate and Cr (+6) ions
In the present paper the synthesis and characterization of zeolite and glass fiber supported zero valent iron
nanoparticles (Ze-ZVI, GF-ZVI NPs) are reported.ZVI, Ze-ZVI and GF-ZVI NPs size, composition and
morphology were characterized by Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM),
Energy Dispersive Spectroscopy (EDS). Synthesized nanostructures were tested as reducing agents of nitrate
and hexavalent Chromium. Batch experiments were carried for revealing of efficacy of prepared nanomaterials
(ZE-ZVI NPs and GF-ZVI NPs). Nitrate removal efficiency (at initial concentration 50 mg/mL) was rapidly
increased from 26% to 76% for GF-ZVI NPs at 60-240 min time interval for and from 34% to 90% for ZE-ZVI
NPs at the same time interval.Also was studied the efficacy of prepared nanostructures ZE-ZVI and ZE-ZVI
NPs as membrane component with 5% of ZVI NPS weight contentfor the removal of nitrate from water
solution that made 85% for ZE-ZVI NPs and 76% for GF-ZVI NPs, respectively. The results of this study
indicate that the application of GF-ZVI and ZE-ZVI NPs as membrane component is advantageous because it
allows to prevent the additional pollution of treated solution caused by unreacted ZVI NPs
Observing primordial magnetic fields through Dark Matter
Primordial magnetic fields are often thought to be the early Universe seeds
that have bloomed into what we observe today as galactic and extra-galactic
magnetic fields. Owing to their minuscule strength, primordial magnetic fields
are very hard to detect in cosmological and astrophysical observations. We show
how this changes if a part of neutral Dark Matter has a magnetic
susceptibility. In this way, by studying Dark Matter one can obtain information
about the properties of primordial magnetic fields, even if the latter have a
comoving amplitude B_0 \lesssim0.01~\mbox{nG}. In our model Dark Matter is a
stable singlet scalar , which interacts with electromagnetism through the
Rayleigh operator as . For primordial
magnetic fields present in the early Universe this operator forces the
-symmetry of the model to be spontaneously broken. Later, when the
primordial magnetic field redshifts below a critical value, the symmetry is
restored through an "inverse phase transition". At that point the field
begins to oscillate and acts as a "magnetomorphic" Dark Matter component,
inheriting the properties of the primordial magnetic field space distribution.
In particular, for a nearly flat spectrum of magnetic field fluctuations, the
scalar carries a statistically anisotropic isocurvature mode. We discuss
the parameter space of the model and consider the possibility that the bulk of
the Dark Matter is composed of the same particles produced via the
freeze-in mechanism.Comment: 29 pages and 4 figures, v2 with updated reference
On the Refinement of the Algorithm for the Reconstruction of Missing ICMS-sensor Readings
Constant monitoring of the state of the core ensures safe operation of a nuclear reactor. This article examines the recovering of the energy release in the core of a nuclear reactor on the basis of the indications of height sensors. There are many cases of sensors failure. Any reduction in the number of sensor indications increases the error. The missing measurement information can be recovered by mathematical methods, and replacement of the failed sensors can be avoided. It is suggested that a set of axial and radial ‘natural’ functions determined by means of statistical estimates obtained from archival data be constructed. The procedure proposed makes it possible to recovery the field even with a significant loss of measurement information.
Keywords: nuclear reactor, neutron flux, loss of measuring information, sensor readings restore
Feigenbaum scenario without parameters
Typically, the period-doubling bifurcations exhibited by nonlinear
dissipative systems are observed when varying systems' parameters. In contrast,
the period-doubling bifurcations considered in the current research are induced
by changing the initial conditions whereas parameter values are fixed. Thus,
the studied bifurcations can be classified as the period-doubling bifurcations
without parameters. Moreover, we show a cascade of the period-doubling
bifurcations without parameters resulting in transition to deterministic chaos.
The explored effects are demonstrated by means of numerical modelling on an
example of a modified Anishchenko-Astakhov self-oscillator where the ability to
exhibit bifurcations without parameters is associated with the properties of a
memristor. Finally, we compare the dynamics of the ideal-memristor-based
oscillator with the behaviour of a model taking into account the memristor
forgetting effect.Comment: 9 pages, 5 figure
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