Fluctuations of CMBR in accelerating universe

The influence of the observed relict vacuum energy on the fluctuations of CMBR going through cosmological matter condensations is studied in the framework of the Einstein-Strauss-de Sitter vakuola model. It is shown that refraction of light at the matching surface of the vakuola and the expanding Friedman universe can be very important during accelerated expansion of the universe, when the velocity of the matching surface relative to static Schwarzchildian observers becomes relativistic. Relevance of the refraction effect for the temperature fluctuations of CMBR is given in terms of the redshift and the angular extension of the fluctuating region

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Wat weten we over het aardrijkskundeonderwijs? Hoe sluit het aan bij de beelden die leerlingen in hun hoofd hebben? Welk venster op de wereld bieden de schoolboeken? Wat werkt goed en wat niet als je leerlingen iets wil leren? Kun je geografisch besef toetsen en hoe doe je dat dan? Hoe leid je goede aardrijkskundeleraren op

Новый взгляд на творчество М. Горького: обзор научных публикаций последнего пятнадцатилетия

Проблема переосмысления творческого наследия русского писателя М. Горького является одной из самых актуальных в современном литературоведении. Кризис методологии, затронувший гуманитарные науки в конце XX века, привел к пересмотру многих казавшихся неоспоримыми истин в горьковедении. В статье предложен краткий аналитический обзор тех исследований последних пятнадцати лет, в которых представлены наиболее перспективные результаты, значимые с точки зрения нового подхода к изучению творчества М. Горького.The problem of a new view on the creative heritage of a Russian writer Maxim Gorky is one of the more urgent in modern literary criticism. Late XX century methodological crisis of humanities has led to a revision of most principles in Gorky studies that had earlier seemed irrefutable. A shot analytical review of the last 15 years' most valuable researches is offered in the article

Small-group work and relational thinking in geographical mysteries: A study in Dutch secondary education

Teaching and Teacher Learning (ICLON

Quasiperiodic oscillations in a strong gravitational field around neutron stars testing braneworld models

The strong gravitational field of neutron stars in the brany universe could be described by spherically symmetric solutions with a metric in the exterior to the brany stars being of the Reissner-Nordstrom type containing a brany tidal charge representing the tidal effect of the bulk spacetime onto the star structure. We investigate the role of the tidal charge in orbital models of high-frequency quasiperiodic oscillations (QPOs) observed in neutron star binary systems. We focus on the relativistic precession model. We give the radial profiles of frequencies of the Keplerian (vertical) and radial epicyclic oscillations. We show how the standard relativistic precession model modified by the tidal charge fits the observational data, giving estimates of the allowed values of the tidal charge and the brane tension based on the processes going in the vicinity of neutron stars. We compare the strong field regime restrictions with those given in the weak-field limit of solar system experiments.Comment: 26 pages, 6 figure

Profiles of emission lines generated by rings orbiting braneworld Kerr black holes

In the framework of the braneworld models, rotating black holes can be described by the Kerr metric with a tidal charge representing the influence of the non-local gravitational (tidal) effects of the bulk space Weyl tensor onto the black hole spacetime. We study the influence of the tidal charge onto profiled spectral lines generated by radiating tori orbiting in vicinity of a rotating black hole. We show that with lowering the negative tidal charge of the black hole, the profiled line becomes to be flatter and wider keeping their standard character with flux stronger at the blue edge of the profiled line. The extension of the line grows with radius falling and inclination angle growing. With growing inclination angle a small hump appears in the profiled lines due to the strong lensing effect of photons coming from regions behind the black hole. For positive tidal charge ($b>0$) and high inclination angles two small humps appear in the profiled lines close to the red and blue edge of the lines due to the strong lensing effect. We can conclude that for all values of $b$, the strongest effect on the profiled lines shape (extension) is caused by the changes of the inclination angle.Comment: Accepted by General Relativity and Gravitatio

Magnetized Particle Capture Cross Section for Braneworld Black Hole

Capture cross section of magnetized particle (with nonzero magnetic moment) by braneworld black hole in uniform magnetic field is considered. The magnetic moment of particle was chosen as it was done by \citet{rs99} and for the simplicity particle with zero electric charge is chosen. It is shown that the spin of particle as well as the brane parameter are to sustain the stability of particles circularly orbiting around the black hole in braneworld i.e. spin of particles and brane parameter try to prevent the capture by black hole.Comment: 7 pages, 4 figures, Accepted for publication in Astrophysics & Space Scienc