249 research outputs found

    Statistical anisotropy of CMB as a probe of conformal rolling scenario

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    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

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    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

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    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

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    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

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    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

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    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

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    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 χ\chi, which interacts with electromagnetism through the Rayleigh operator as χ2FμνFμν/Λ2\chi^2 F_{\mu \nu} F^{\mu \nu}/\Lambda^2. For primordial magnetic fields present in the early Universe this operator forces the Z2Z_2-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 χ\chi 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 χ\chi 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 χ\chi 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

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    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. &nbsp; &nbsp; Keywords: nuclear reactor, neutron flux, loss of measuring information, sensor readings restore

    Feigenbaum scenario without parameters

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    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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